platform/kernel/linux-amlogic.git
6 years agocrypto: blkcipher - fix crash flushing dcache in error path
Eric Biggers [Mon, 23 Jul 2018 17:54:57 +0000 (10:54 -0700)]
crypto: blkcipher - fix crash flushing dcache in error path

commit 0868def3e4100591e7a1fdbf3eed1439cc8f7ca3 upstream.

Like the skcipher_walk case:

scatterwalk_done() is only meant to be called after a nonzero number of
bytes have been processed, since scatterwalk_pagedone() will flush the
dcache of the *previous* page.  But in the error case of
blkcipher_walk_done(), e.g. if the input wasn't an integer number of
blocks, scatterwalk_done() was actually called after advancing 0 bytes.
This caused a crash ("BUG: unable to handle kernel paging request")
during '!PageSlab(page)' on architectures like arm and arm64 that define
ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE, provided that the input was
page-aligned as in that case walk->offset == 0.

Fix it by reorganizing blkcipher_walk_done() to skip the
scatterwalk_advance() and scatterwalk_done() if an error has occurred.

This bug was found by syzkaller fuzzing.

Reproducer, assuming ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE:

#include <linux/if_alg.h>
#include <sys/socket.h>
#include <unistd.h>

int main()
{
struct sockaddr_alg addr = {
.salg_type = "skcipher",
.salg_name = "ecb(aes-generic)",
};
char buffer[4096] __attribute__((aligned(4096))) = { 0 };
int fd;

fd = socket(AF_ALG, SOCK_SEQPACKET, 0);
bind(fd, (void *)&addr, sizeof(addr));
setsockopt(fd, SOL_ALG, ALG_SET_KEY, buffer, 16);
fd = accept(fd, NULL, NULL);
write(fd, buffer, 15);
read(fd, buffer, 15);
}

Reported-by: Liu Chao <liuchao741@huawei.com>
Fixes: 5cde0af2a982 ("[CRYPTO] cipher: Added block cipher type")
Cc: <stable@vger.kernel.org> # v2.6.19+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agocrypto: vmac - separate tfm and request context
Eric Biggers [Mon, 18 Jun 2018 17:22:38 +0000 (10:22 -0700)]
crypto: vmac - separate tfm and request context

commit bb29648102335586e9a66289a1d98a0cb392b6e5 upstream.

syzbot reported a crash in vmac_final() when multiple threads
concurrently use the same "vmac(aes)" transform through AF_ALG.  The bug
is pretty fundamental: the VMAC template doesn't separate per-request
state from per-tfm (per-key) state like the other hash algorithms do,
but rather stores it all in the tfm context.  That's wrong.

Also, vmac_final() incorrectly zeroes most of the state including the
derived keys and cached pseudorandom pad.  Therefore, only the first
VMAC invocation with a given key calculates the correct digest.

Fix these bugs by splitting the per-tfm state from the per-request state
and using the proper init/update/final sequencing for requests.

Reproducer for the crash:

    #include <linux/if_alg.h>
    #include <sys/socket.h>
    #include <unistd.h>

    int main()
    {
            int fd;
            struct sockaddr_alg addr = {
                    .salg_type = "hash",
                    .salg_name = "vmac(aes)",
            };
            char buf[256] = { 0 };

            fd = socket(AF_ALG, SOCK_SEQPACKET, 0);
            bind(fd, (void *)&addr, sizeof(addr));
            setsockopt(fd, SOL_ALG, ALG_SET_KEY, buf, 16);
            fork();
            fd = accept(fd, NULL, NULL);
            for (;;)
                    write(fd, buf, 256);
    }

The immediate cause of the crash is that vmac_ctx_t.partial_size exceeds
VMAC_NHBYTES, causing vmac_final() to memset() a negative length.

Reported-by: syzbot+264bca3a6e8d645550d3@syzkaller.appspotmail.com
Fixes: f1939f7c5645 ("crypto: vmac - New hash algorithm for intel_txt support")
Cc: <stable@vger.kernel.org> # v2.6.32+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agocrypto: vmac - require a block cipher with 128-bit block size
Eric Biggers [Mon, 18 Jun 2018 17:22:37 +0000 (10:22 -0700)]
crypto: vmac - require a block cipher with 128-bit block size

commit 73bf20ef3df262026c3470241ae4ac8196943ffa upstream.

The VMAC template assumes the block cipher has a 128-bit block size, but
it failed to check for that.  Thus it was possible to instantiate it
using a 64-bit block size cipher, e.g. "vmac(cast5)", causing
uninitialized memory to be used.

Add the needed check when instantiating the template.

Fixes: f1939f7c5645 ("crypto: vmac - New hash algorithm for intel_txt support")
Cc: <stable@vger.kernel.org> # v2.6.32+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agocrypto: x86/sha256-mb - fix digest copy in sha256_mb_mgr_get_comp_job_avx2()
Eric Biggers [Fri, 29 Jun 2018 21:14:35 +0000 (14:14 -0700)]
crypto: x86/sha256-mb - fix digest copy in sha256_mb_mgr_get_comp_job_avx2()

commit af839b4e546613aed1fbd64def73956aa98631e7 upstream.

There is a copy-paste error where sha256_mb_mgr_get_comp_job_avx2()
copies the SHA-256 digest state from sha256_mb_mgr::args::digest to
job_sha256::result_digest.  Consequently, the sha256_mb algorithm
sometimes calculates the wrong digest.  Fix it.

Reproducer using AF_ALG:

    #include <assert.h>
    #include <linux/if_alg.h>
    #include <stdio.h>
    #include <string.h>
    #include <sys/socket.h>
    #include <unistd.h>

    static const __u8 expected[32] =
        "\xad\x7f\xac\xb2\x58\x6f\xc6\xe9\x66\xc0\x04\xd7\xd1\xd1\x6b\x02"
        "\x4f\x58\x05\xff\x7c\xb4\x7c\x7a\x85\xda\xbd\x8b\x48\x89\x2c\xa7";

    int main()
    {
        int fd;
        struct sockaddr_alg addr = {
            .salg_type = "hash",
            .salg_name = "sha256_mb",
        };
        __u8 data[4096] = { 0 };
        __u8 digest[32];
        int ret;
        int i;

        fd = socket(AF_ALG, SOCK_SEQPACKET, 0);
        bind(fd, (void *)&addr, sizeof(addr));
        fork();
        fd = accept(fd, 0, 0);
        do {
            ret = write(fd, data, 4096);
            assert(ret == 4096);
            ret = read(fd, digest, 32);
            assert(ret == 32);
        } while (memcmp(digest, expected, 32) == 0);

        printf("wrong digest: ");
        for (i = 0; i < 32; i++)
            printf("%02x", digest[i]);
        printf("\n");
    }

Output was:

    wrong digest: ad7facb2000000000000000000000000ffffffef7cb47c7a85dabd8b48892ca7

Fixes: 172b1d6b5a93 ("crypto: sha256-mb - fix ctx pointer and digest copy")
Cc: <stable@vger.kernel.org> # v4.8+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agokbuild: verify that $DEPMOD is installed
Randy Dunlap [Mon, 2 Jul 2018 02:46:06 +0000 (19:46 -0700)]
kbuild: verify that $DEPMOD is installed

commit 934193a654c1f4d0643ddbf4b2529b508cae926e upstream.

Verify that 'depmod' ($DEPMOD) is installed.
This is a partial revert of commit 620c231c7a7f
("kbuild: do not check for ancient modutils tools").

Also update Documentation/process/changes.rst to refer to
kmod instead of module-init-tools.

Fixes kernel bugzilla #198965:
https://bugzilla.kernel.org/show_bug.cgi?id=198965

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Lucas De Marchi <lucas.demarchi@profusion.mobi>
Cc: Lucas De Marchi <lucas.de.marchi@gmail.com>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Chih-Wei Huang <cwhuang@linux.org.tw>
Cc: stable@vger.kernel.org # any kernel since 2012
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agoi2c: ismt: fix wrong device address when unmap the data buffer
Liwei Song [Tue, 13 Jun 2017 04:59:53 +0000 (00:59 -0400)]
i2c: ismt: fix wrong device address when unmap the data buffer

commit 17e83549e199d89aace7788a9f11c108671eecf5 upstream.

Fix the following kernel bug:

kernel BUG at drivers/iommu/intel-iommu.c:3260!
invalid opcode: 0000 [#5] PREEMPT SMP
Hardware name: Intel Corp. Harcuvar/Server, BIOS HAVLCRB0.X64.0013.D39.1608311820 08/31/2016
task: ffff880175389950 ti: ffff880176bec000 task.ti: ffff880176bec000
RIP: 0010:[<ffffffff8150a83b>]  [<ffffffff8150a83b>] intel_unmap+0x25b/0x260
RSP: 0018:ffff880176bef5e8  EFLAGS: 00010296
RAX: 0000000000000024 RBX: ffff8800773c7c88 RCX: 000000000000ce04
RDX: 0000000080000000 RSI: 0000000000000000 RDI: 0000000000000009
RBP: ffff880176bef638 R08: 0000000000000010 R09: 0000000000000004
R10: ffff880175389c78 R11: 0000000000000a4f R12: ffff8800773c7868
R13: 00000000ffffac88 R14: ffff8800773c7818 R15: 0000000000000001
FS:  00007fef21258700(0000) GS:ffff88017b5c0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000066d6d8 CR3: 000000007118c000 CR4: 00000000003406e0
Stack:
 00000000ffffac88 ffffffff8199867f ffff880176bef5f8 ffff880100000030
 ffff880176bef668 ffff8800773c7c88 ffff880178288098 ffff8800772c0010
 ffff8800773c7818 0000000000000001 ffff880176bef648 ffffffff8150a86e
Call Trace:
 [<ffffffff8199867f>] ? printk+0x46/0x48
 [<ffffffff8150a86e>] intel_unmap_page+0xe/0x10
 [<ffffffffa039d99b>] ismt_access+0x27b/0x8fa [i2c_ismt]
 [<ffffffff81554420>] ? __pm_runtime_suspend+0xa0/0xa0
 [<ffffffff815544a0>] ? pm_suspend_timer_fn+0x80/0x80
 [<ffffffff81554420>] ? __pm_runtime_suspend+0xa0/0xa0
 [<ffffffff815544a0>] ? pm_suspend_timer_fn+0x80/0x80
 [<ffffffff8143dfd0>] ? pci_bus_read_dev_vendor_id+0xf0/0xf0
 [<ffffffff8172b36c>] i2c_smbus_xfer+0xec/0x4b0
 [<ffffffff810aa4d5>] ? vprintk_emit+0x345/0x530
 [<ffffffffa038936b>] i2cdev_ioctl_smbus+0x12b/0x240 [i2c_dev]
 [<ffffffff810aa829>] ? vprintk_default+0x29/0x40
 [<ffffffffa0389b33>] i2cdev_ioctl+0x63/0x1ec [i2c_dev]
 [<ffffffff811b04c8>] do_vfs_ioctl+0x328/0x5d0
 [<ffffffff8119d8ec>] ? vfs_write+0x11c/0x190
 [<ffffffff8109d449>] ? rt_up_read+0x19/0x20
 [<ffffffff811b07f1>] SyS_ioctl+0x81/0xa0
 [<ffffffff819a351b>] system_call_fastpath+0x16/0x6e

This happen When run "i2cdetect -y 0" detect SMBus iSMT adapter.

After finished I2C block read/write, when unmap the data buffer,
a wrong device address was pass to dma_unmap_single().

To fix this, give dma_unmap_single() the "dev" parameter, just like
what dma_map_single() does, then unmap can find the right devices.

Fixes: 13f35ac14cd0 ("i2c: Adding support for Intel iSMT SMBus 2.0 host controller")
Signed-off-by: Liwei Song <liwei.song@windriver.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agokasan: don't emit builtin calls when sanitization is off
Andrey Konovalov [Tue, 6 Feb 2018 23:36:00 +0000 (15:36 -0800)]
kasan: don't emit builtin calls when sanitization is off

commit 0e410e158e5baa1300bdf678cea4f4e0cf9d8b94 upstream.

With KASAN enabled the kernel has two different memset() functions, one
with KASAN checks (memset) and one without (__memset).  KASAN uses some
macro tricks to use the proper version where required.  For example
memset() calls in mm/slub.c are without KASAN checks, since they operate
on poisoned slab object metadata.

The issue is that clang emits memset() calls even when there is no
memset() in the source code.  They get linked with improper memset()
implementation and the kernel fails to boot due to a huge amount of KASAN
reports during early boot stages.

The solution is to add -fno-builtin flag for files with KASAN_SANITIZE :=
n marker.

Link: http://lkml.kernel.org/r/8ffecfffe04088c52c42b92739c2bd8a0bcb3f5e.1516384594.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[ Sami: Backported to 4.9 avoiding c5caf21ab0cf8 and e7c52b84fb ]
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/mm: Disable ioremap free page handling on x86-PAE
Toshi Kani [Wed, 27 Jun 2018 14:13:46 +0000 (08:13 -0600)]
x86/mm: Disable ioremap free page handling on x86-PAE

commit f967db0b9ed44ec3057a28f3b28efc51df51b835 upstream.

ioremap() supports pmd mappings on x86-PAE.  However, kernel's pmd
tables are not shared among processes on x86-PAE.  Therefore, any
update to sync'd pmd entries need re-syncing.  Freeing a pte page
also leads to a vmalloc fault and hits the BUG_ON in vmalloc_sync_one().

Disable free page handling on x86-PAE.  pud_free_pmd_page() and
pmd_free_pte_page() simply return 0 if a given pud/pmd entry is present.
This assures that ioremap() does not update sync'd pmd entries at the
cost of falling back to pte mappings.

Fixes: 28ee90fe6048 ("x86/mm: implement free pmd/pte page interfaces")
Reported-by: Joerg Roedel <joro@8bytes.org>
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: mhocko@suse.com
Cc: akpm@linux-foundation.org
Cc: hpa@zytor.com
Cc: cpandya@codeaurora.org
Cc: linux-mm@kvack.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: stable@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20180627141348.21777-2-toshi.kani@hpe.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86: i8259: Add missing include file
Guenter Roeck [Wed, 15 Aug 2018 20:22:27 +0000 (13:22 -0700)]
x86: i8259: Add missing include file

commit 0a957467c5fd46142bc9c52758ffc552d4c5e2f7 upstream.

i8259.h uses inb/outb and thus needs to include asm/io.h to avoid the
following build error, as seen with x86_64:defconfig and CONFIG_SMP=n.

  In file included from drivers/rtc/rtc-cmos.c:45:0:
  arch/x86/include/asm/i8259.h: In function 'inb_pic':
  arch/x86/include/asm/i8259.h:32:24: error:
implicit declaration of function 'inb'

  arch/x86/include/asm/i8259.h: In function 'outb_pic':
  arch/x86/include/asm/i8259.h:45:2: error:
implicit declaration of function 'outb'

Reported-by: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Suggested-by: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Fixes: 447ae3166702 ("x86: Don't include linux/irq.h from asm/hardirq.h")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/l1tf: Fix build error seen if CONFIG_KVM_INTEL is disabled
Guenter Roeck [Wed, 15 Aug 2018 15:38:33 +0000 (08:38 -0700)]
x86/l1tf: Fix build error seen if CONFIG_KVM_INTEL is disabled

commit 1eb46908b35dfbac0ec1848d4b1e39667e0187e9 upstream.

allmodconfig+CONFIG_INTEL_KVM=n results in the following build error.

  ERROR: "l1tf_vmx_mitigation" [arch/x86/kvm/kvm.ko] undefined!

Fixes: 5b76a3cff011 ("KVM: VMX: Tell the nested hypervisor to skip L1D flush on vmentry")
Reported-by: Meelis Roos <mroos@linux.ee>
Cc: Meelis Roos <mroos@linux.ee>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agoLinux 4.9.120 v4.9.120
Greg Kroah-Hartman [Wed, 15 Aug 2018 16:14:55 +0000 (18:14 +0200)]
Linux 4.9.120

6 years agox86/CPU/AMD: Have smp_num_siblings and cpu_llc_id always be present
Borislav Petkov [Fri, 27 Apr 2018 21:34:34 +0000 (16:34 -0500)]
x86/CPU/AMD: Have smp_num_siblings and cpu_llc_id always be present

commit f8b64d08dde2714c62751d18ba77f4aeceb161d3 upstream.

Move smp_num_siblings and cpu_llc_id to cpu/common.c so that they're
always present as symbols and not only in the CONFIG_SMP case. Then,
other code using them doesn't need ugly ifdeffery anymore. Get rid of
some ifdeffery.

Signed-off-by: Borislav Petkov <bpetkov@suse.de>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1524864877-111962-2-git-send-email-suravee.suthikulpanit@amd.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/cpu/amd: Limit cpu_core_id fixup to families older than F17h
Suravee Suthikulpanit [Mon, 31 Jul 2017 08:51:58 +0000 (10:51 +0200)]
x86/cpu/amd: Limit cpu_core_id fixup to families older than F17h

commit b89b41d0b8414690ec0030c134b8bde209e6d06c upstream.

Current cpu_core_id fixup causes downcored F17h configurations to be
incorrect:

  NODE: 0
  processor  0 core id : 0
  processor  1 core id : 1
  processor  2 core id : 2
  processor  3 core id : 4
  processor  4 core id : 5
  processor  5 core id : 0

  NODE: 1
  processor  6 core id : 2
  processor  7 core id : 3
  processor  8 core id : 4
  processor  9 core id : 0
  processor 10 core id : 1
  processor 11 core id : 2

Code that relies on the cpu_core_id, like match_smt(), for example,
which builds the thread siblings masks used by the scheduler, is
mislead.

So, limit the fixup to pre-F17h machines. The new value for cpu_core_id
for F17h and later will represent the CPUID_Fn8000001E_EBX[CoreId],
which is guaranteed to be unique for each core within a socket.

This way we have:

  NODE: 0
  processor  0 core id : 0
  processor  1 core id : 1
  processor  2 core id : 2
  processor  3 core id : 4
  processor  4 core id : 5
  processor  5 core id : 6

  NODE: 1
  processor  6 core id : 8
  processor  7 core id : 9
  processor  8 core id : 10
  processor  9 core id : 12
  processor 10 core id : 13
  processor 11 core id : 14

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
[ Heavily massaged. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yazen Ghannam <Yazen.Ghannam@amd.com>
Link: http://lkml.kernel.org/r/20170731085159.9455-2-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/speculation/l1tf: Unbreak !__HAVE_ARCH_PFN_MODIFY_ALLOWED architectures
Jiri Kosina [Sat, 14 Jul 2018 19:56:13 +0000 (21:56 +0200)]
x86/speculation/l1tf: Unbreak !__HAVE_ARCH_PFN_MODIFY_ALLOWED architectures

commit 6c26fcd2abfe0a56bbd95271fce02df2896cfd24 upstream.

pfn_modify_allowed() and arch_has_pfn_modify_check() are outside of the
!__ASSEMBLY__ section in include/asm-generic/pgtable.h, which confuses
assembler on archs that don't have __HAVE_ARCH_PFN_MODIFY_ALLOWED (e.g.
ia64) and breaks build:

    include/asm-generic/pgtable.h: Assembler messages:
    include/asm-generic/pgtable.h:538: Error: Unknown opcode `static inline bool pfn_modify_allowed(unsigned long pfn,pgprot_t prot)'
    include/asm-generic/pgtable.h:540: Error: Unknown opcode `return true'
    include/asm-generic/pgtable.h:543: Error: Unknown opcode `static inline bool arch_has_pfn_modify_check(void)'
    include/asm-generic/pgtable.h:545: Error: Unknown opcode `return false'
    arch/ia64/kernel/entry.S:69: Error: `mov' does not fit into bundle

Move those two static inlines into the !__ASSEMBLY__ section so that they
don't confuse the asm build pass.

Fixes: 42e4089c7890 ("x86/speculation/l1tf: Disallow non privileged high MMIO PROT_NONE mappings")
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[groeck: Context changes]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/init: fix build with CONFIG_SWAP=n
Vlastimil Babka [Tue, 14 Aug 2018 18:50:47 +0000 (20:50 +0200)]
x86/init: fix build with CONFIG_SWAP=n

commit 792adb90fa724ce07c0171cbc96b9215af4b1045 upstream.

The introduction of generic_max_swapfile_size and arch-specific versions has
broken linking on x86 with CONFIG_SWAP=n due to undefined reference to
'generic_max_swapfile_size'. Fix it by compiling the x86-specific
max_swapfile_size() only with CONFIG_SWAP=y.

Reported-by: Tomas Pruzina <pruzinat@gmail.com>
Fixes: 377eeaa8e11f ("x86/speculation/l1tf: Limit swap file size to MAX_PA/2")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agocpu/hotplug: Non-SMP machines do not make use of booted_once
Abel Vesa [Tue, 14 Aug 2018 21:26:00 +0000 (00:26 +0300)]
cpu/hotplug: Non-SMP machines do not make use of booted_once

commit 269777aa530f3438ec1781586cdac0b5fe47b061 upstream.

Commit 0cc3cd21657b ("cpu/hotplug: Boot HT siblings at least once")
breaks non-SMP builds.

[ I suspect the 'bool' fields should just be made to be bitfields and be
  exposed regardless of configuration, but that's a separate cleanup
  that I'll leave to the owners of this file for later.   - Linus ]

Fixes: 0cc3cd21657b ("cpu/hotplug: Boot HT siblings at least once")
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Abel Vesa <abelvesa@linux.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/smp: fix non-SMP broken build due to redefinition of apic_id_is_primary_thread
Vlastimil Babka [Tue, 14 Aug 2018 21:38:57 +0000 (23:38 +0200)]
x86/smp: fix non-SMP broken build due to redefinition of apic_id_is_primary_thread

commit d0055f351e647f33f3b0329bff022213bf8aa085 upstream.

The function has an inline "return false;" definition with CONFIG_SMP=n
but the "real" definition is also visible leading to "redefinition of
‘apic_id_is_primary_thread’" compiler error.

Guard it with #ifdef CONFIG_SMP

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Fixes: 6a4d2657e048 ("x86/smp: Provide topology_is_primary_thread()")
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/microcode: Allow late microcode loading with SMT disabled
Josh Poimboeuf [Fri, 10 Aug 2018 07:31:10 +0000 (08:31 +0100)]
x86/microcode: Allow late microcode loading with SMT disabled

commit 07d981ad4cf1e78361c6db1c28ee5ba105f96cc1 upstream

The kernel unnecessarily prevents late microcode loading when SMT is
disabled.  It should be safe to allow it if all the primary threads are
online.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/microcode: Do not upload microcode if CPUs are offline
Ashok Raj [Wed, 28 Feb 2018 10:28:43 +0000 (11:28 +0100)]
x86/microcode: Do not upload microcode if CPUs are offline

commit 30ec26da9967d0d785abc24073129a34c3211777 upstream.

Avoid loading microcode if any of the CPUs are offline, and issue a
warning. Having different microcode revisions on the system at any time
is outright dangerous.

[ Borislav: Massage changelog. ]

Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Tested-by: Ashok Raj <ashok.raj@intel.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Arjan Van De Ven <arjan.van.de.ven@intel.com>
Link: http://lkml.kernel.org/r/1519352533-15992-4-git-send-email-ashok.raj@intel.com
Link: https://lkml.kernel.org/r/20180228102846.13447-5-bp@alien8.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agotools headers: Synchronise x86 cpufeatures.h for L1TF additions
David Woodhouse [Wed, 8 Aug 2018 10:00:16 +0000 (11:00 +0100)]
tools headers: Synchronise x86 cpufeatures.h for L1TF additions

commit e24f14b0ff985f3e09e573ba1134bfdf42987e05 upstream

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/mm/kmmio: Make the tracer robust against L1TF
Andi Kleen [Tue, 7 Aug 2018 22:09:38 +0000 (15:09 -0700)]
x86/mm/kmmio: Make the tracer robust against L1TF

commit 1063711b57393c1999248cccb57bebfaf16739e7 upstream

The mmio tracer sets io mapping PTEs and PMDs to non present when enabled
without inverting the address bits, which makes the PTE entry vulnerable
for L1TF.

Make it use the right low level macros to actually invert the address bits
to protect against L1TF.

In principle this could be avoided because MMIO tracing is not likely to be
enabled on production machines, but the fix is straigt forward and for
consistency sake it's better to get rid of the open coded PTE manipulation.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/mm/pat: Make set_memory_np() L1TF safe
Andi Kleen [Tue, 7 Aug 2018 22:09:39 +0000 (15:09 -0700)]
x86/mm/pat: Make set_memory_np() L1TF safe

commit 958f79b9ee55dfaf00c8106ed1c22a2919e0028b upstream

set_memory_np() is used to mark kernel mappings not present, but it has
it's own open coded mechanism which does not have the L1TF protection of
inverting the address bits.

Replace the open coded PTE manipulation with the L1TF protecting low level
PTE routines.

Passes the CPA self test.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[ dwmw2: Pull in pud_mkhuge() from commit a00cc7d9dd, and pfn_pud() ]
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/speculation/l1tf: Make pmd/pud_mknotpresent() invert
Andi Kleen [Tue, 7 Aug 2018 22:09:37 +0000 (15:09 -0700)]
x86/speculation/l1tf: Make pmd/pud_mknotpresent() invert

commit 0768f91530ff46683e0b372df14fd79fe8d156e5 upstream

Some cases in THP like:
  - MADV_FREE
  - mprotect
  - split

mark the PMD non present for temporarily to prevent races. The window for
an L1TF attack in these contexts is very small, but it wants to be fixed
for correctness sake.

Use the proper low level functions for pmd/pud_mknotpresent() to address
this.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/speculation/l1tf: Invert all not present mappings
Andi Kleen [Tue, 7 Aug 2018 22:09:36 +0000 (15:09 -0700)]
x86/speculation/l1tf: Invert all not present mappings

commit f22cc87f6c1f771b57c407555cfefd811cdd9507 upstream

For kernel mappings PAGE_PROTNONE is not necessarily set for a non present
mapping, but the inversion logic explicitely checks for !PRESENT and
PROT_NONE.

Remove the PROT_NONE check and make the inversion unconditional for all not
present mappings.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agocpu/hotplug: Fix SMT supported evaluation
Thomas Gleixner [Tue, 7 Aug 2018 06:19:57 +0000 (08:19 +0200)]
cpu/hotplug: Fix SMT supported evaluation

commit bc2d8d262cba5736332cbc866acb11b1c5748aa9 upstream

Josh reported that the late SMT evaluation in cpu_smt_state_init() sets
cpu_smt_control to CPU_SMT_NOT_SUPPORTED in case that 'nosmt' was supplied
on the kernel command line as it cannot differentiate between SMT disabled
by BIOS and SMT soft disable via 'nosmt'. That wreckages the state and
makes the sysfs interface unusable.

Rework this so that during bringup of the non boot CPUs the availability of
SMT is determined in cpu_smt_allowed(). If a newly booted CPU is not a
'primary' thread then set the local cpu_smt_available marker and evaluate
this explicitely right after the initial SMP bringup has finished.

SMT evaulation on x86 is a trainwreck as the firmware has all the
information _before_ booting the kernel, but there is no interface to query
it.

Fixes: 73d5e2b47264 ("cpu/hotplug: detect SMT disabled by BIOS")
Reported-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agoKVM: VMX: Tell the nested hypervisor to skip L1D flush on vmentry
Paolo Bonzini [Sun, 5 Aug 2018 14:07:47 +0000 (16:07 +0200)]
KVM: VMX: Tell the nested hypervisor to skip L1D flush on vmentry

commit 5b76a3cff011df2dcb6186c965a2e4d809a05ad4 upstream

When nested virtualization is in use, VMENTER operations from the nested
hypervisor into the nested guest will always be processed by the bare metal
hypervisor, and KVM's "conditional cache flushes" mode in particular does a
flush on nested vmentry.  Therefore, include the "skip L1D flush on
vmentry" bit in KVM's suggested ARCH_CAPABILITIES setting.

Add the relevant Documentation.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/speculation: Use ARCH_CAPABILITIES to skip L1D flush on vmentry
Paolo Bonzini [Sun, 5 Aug 2018 14:07:46 +0000 (16:07 +0200)]
x86/speculation: Use ARCH_CAPABILITIES to skip L1D flush on vmentry

commit 8e0b2b916662e09dd4d09e5271cdf214c6b80e62 upstream

Bit 3 of ARCH_CAPABILITIES tells a hypervisor that L1D flush on vmentry is
not needed.  Add a new value to enum vmx_l1d_flush_state, which is used
either if there is no L1TF bug at all, or if bit 3 is set in ARCH_CAPABILITIES.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/speculation: Simplify sysfs report of VMX L1TF vulnerability
Paolo Bonzini [Sun, 5 Aug 2018 14:07:45 +0000 (16:07 +0200)]
x86/speculation: Simplify sysfs report of VMX L1TF vulnerability

commit ea156d192f5257a5bf393d33910d3b481bf8a401 upstream

Three changes to the content of the sysfs file:

 - If EPT is disabled, L1TF cannot be exploited even across threads on the
   same core, and SMT is irrelevant.

 - If mitigation is completely disabled, and SMT is enabled, print "vulnerable"
   instead of "vulnerable, SMT vulnerable"

 - Reorder the two parts so that the main vulnerability state comes first
   and the detail on SMT is second.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agoKVM: VMX: support MSR_IA32_ARCH_CAPABILITIES as a feature MSR
Paolo Bonzini [Mon, 25 Jun 2018 12:04:37 +0000 (14:04 +0200)]
KVM: VMX: support MSR_IA32_ARCH_CAPABILITIES as a feature MSR

commit cd28325249a1ca0d771557ce823e0308ad629f98 upstream

This lets userspace read the MSR_IA32_ARCH_CAPABILITIES and check that all
requested features are available on the host.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agoKVM: X86: Allow userspace to define the microcode version
Wanpeng Li [Wed, 28 Feb 2018 06:03:31 +0000 (14:03 +0800)]
KVM: X86: Allow userspace to define the microcode version

commit 518e7b94817abed94becfe6a44f1ece0d4745afe upstream

Linux (among the others) has checks to make sure that certain features
aren't enabled on a certain family/model/stepping if the microcode version
isn't greater than or equal to a known good version.

By exposing the real microcode version, we're preventing buggy guests that
don't check that they are running virtualized (i.e., they should trust the
hypervisor) from disabling features that are effectively not buggy.

Suggested-by: Filippo Sironi <sironi@amazon.de>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Liran Alon <liran.alon@oracle.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agoKVM: X86: Introduce kvm_get_msr_feature()
Wanpeng Li [Wed, 28 Feb 2018 06:03:30 +0000 (14:03 +0800)]
KVM: X86: Introduce kvm_get_msr_feature()

commit 66421c1ec340096b291af763ed5721314cdd9c5c upstream

Introduce kvm_get_msr_feature() to handle the msrs which are supported
by different vendors and sharing the same emulation logic.

Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Liran Alon <liran.alon@oracle.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agoKVM: SVM: Add MSR-based feature support for serializing LFENCE
Tom Lendacky [Fri, 23 Feb 2018 23:18:20 +0000 (00:18 +0100)]
KVM: SVM: Add MSR-based feature support for serializing LFENCE

commit d1d93fa90f1afa926cb060b7f78ab01a65705b4d upstream

In order to determine if LFENCE is a serializing instruction on AMD
processors, MSR 0xc0011029 (MSR_F10H_DECFG) must be read and the state
of bit 1 checked.  This patch will add support to allow a guest to
properly make this determination.

Add the MSR feature callback operation to svm.c and add MSR 0xc0011029
to the list of MSR-based features.  If LFENCE is serializing, then the
feature is supported, allowing the hypervisor to set the value of the
MSR that guest will see.  Support is also added to write (hypervisor only)
and read the MSR value for the guest.  A write by the guest will result in
a #GP.  A read by the guest will return the value as set by the host.  In
this way, the support to expose the feature to the guest is controlled by
the hypervisor.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agoKVM: x86: Add a framework for supporting MSR-based features
Tom Lendacky [Wed, 21 Feb 2018 19:39:51 +0000 (13:39 -0600)]
KVM: x86: Add a framework for supporting MSR-based features

commit 801e459a6f3a63af9d447e6249088c76ae16efc4 upstream

Provide a new KVM capability that allows bits within MSRs to be recognized
as features.  Two new ioctls are added to the /dev/kvm ioctl routine to
retrieve the list of these MSRs and then retrieve their values. A kvm_x86_ops
callback is used to determine support for the listed MSR-based features.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[Tweaked documentation. - Radim]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agoDocumentation/l1tf: Remove Yonah processors from not vulnerable list
Thomas Gleixner [Sun, 5 Aug 2018 15:06:12 +0000 (17:06 +0200)]
Documentation/l1tf: Remove Yonah processors from not vulnerable list

commit 58331136136935c631c2b5f06daf4c3006416e91 upstream

Dave reported, that it's not confirmed that Yonah processors are
unaffected. Remove them from the list.

Reported-by: ave Hansen <dave.hansen@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/KVM/VMX: Don't set l1tf_flush_l1d from vmx_handle_external_intr()
Nicolai Stange [Sun, 22 Jul 2018 11:38:18 +0000 (13:38 +0200)]
x86/KVM/VMX: Don't set l1tf_flush_l1d from vmx_handle_external_intr()

commit 18b57ce2eb8c8b9a24174a89250cf5f57c76ecdc upstream

For VMEXITs caused by external interrupts, vmx_handle_external_intr()
indirectly calls into the interrupt handlers through the host's IDT.

It follows that these interrupts get accounted for in the
kvm_cpu_l1tf_flush_l1d per-cpu flag.

The subsequently executed vmx_l1d_flush() will thus be aware that some
interrupts have happened and conduct a L1d flush anyway.

Setting l1tf_flush_l1d from vmx_handle_external_intr() isn't needed
anymore. Drop it.

Signed-off-by: Nicolai Stange <nstange@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/irq: Let interrupt handlers set kvm_cpu_l1tf_flush_l1d
Nicolai Stange [Sun, 29 Jul 2018 11:06:04 +0000 (13:06 +0200)]
x86/irq: Let interrupt handlers set kvm_cpu_l1tf_flush_l1d

commit ffcba43ff66c7dab34ec700debd491d2a4d319b4 upstream

The last missing piece to having vmx_l1d_flush() take interrupts after
VMEXIT into account is to set the kvm_cpu_l1tf_flush_l1d per-cpu flag on
irq entry.

Issue calls to kvm_set_cpu_l1tf_flush_l1d() from entering_irq(),
ipi_entering_ack_irq(), smp_reschedule_interrupt() and
uv_bau_message_interrupt().

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Nicolai Stange <nstange@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86: Don't include linux/irq.h from asm/hardirq.h
Nicolai Stange [Sun, 29 Jul 2018 10:15:33 +0000 (12:15 +0200)]
x86: Don't include linux/irq.h from asm/hardirq.h

commit 447ae316670230d7d29430e2cbf1f5db4f49d14c upstream

The next patch in this series will have to make the definition of
irq_cpustat_t available to entering_irq().

Inclusion of asm/hardirq.h into asm/apic.h would cause circular header
dependencies like

  asm/smp.h
    asm/apic.h
      asm/hardirq.h
        linux/irq.h
          linux/topology.h
            linux/smp.h
              asm/smp.h

or

  linux/gfp.h
    linux/mmzone.h
      asm/mmzone.h
        asm/mmzone_64.h
          asm/smp.h
            asm/apic.h
              asm/hardirq.h
                linux/irq.h
                  linux/irqdesc.h
                    linux/kobject.h
                      linux/sysfs.h
                        linux/kernfs.h
                          linux/idr.h
                            linux/gfp.h

and others.

This causes compilation errors because of the header guards becoming
effective in the second inclusion: symbols/macros that had been defined
before wouldn't be available to intermediate headers in the #include chain
anymore.

A possible workaround would be to move the definition of irq_cpustat_t
into its own header and include that from both, asm/hardirq.h and
asm/apic.h.

However, this wouldn't solve the real problem, namely asm/harirq.h
unnecessarily pulling in all the linux/irq.h cruft: nothing in
asm/hardirq.h itself requires it. Also, note that there are some other
archs, like e.g. arm64, which don't have that #include in their
asm/hardirq.h.

Remove the linux/irq.h #include from x86' asm/hardirq.h.

Fix resulting compilation errors by adding appropriate #includes to *.c
files as needed.

Note that some of these *.c files could be cleaned up a bit wrt. to their
set of #includes, but that should better be done from separate patches, if
at all.

Signed-off-by: Nicolai Stange <nstange@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[dwmw2: More fixes for EFI and Xen in 4.9]
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/KVM/VMX: Introduce per-host-cpu analogue of l1tf_flush_l1d
Nicolai Stange [Fri, 27 Jul 2018 11:22:16 +0000 (13:22 +0200)]
x86/KVM/VMX: Introduce per-host-cpu analogue of l1tf_flush_l1d

commit 45b575c00d8e72d69d75dd8c112f044b7b01b069 upstream

Part of the L1TF mitigation for vmx includes flushing the L1D cache upon
VMENTRY.

L1D flushes are costly and two modes of operations are provided to users:
"always" and the more selective "conditional" mode.

If operating in the latter, the cache would get flushed only if a host side
code path considered unconfined had been traversed. "Unconfined" in this
context means that it might have pulled in sensitive data like user data
or kernel crypto keys.

The need for L1D flushes is tracked by means of the per-vcpu flag
l1tf_flush_l1d. KVM exit handlers considered unconfined set it. A
vmx_l1d_flush() subsequently invoked before the next VMENTER will conduct a
L1d flush based on its value and reset that flag again.

Currently, interrupts delivered "normally" while in root operation between
VMEXIT and VMENTER are not taken into account. Part of the reason is that
these don't leave any traces and thus, the vmx code is unable to tell if
any such has happened.

As proposed by Paolo Bonzini, prepare for tracking all interrupts by
introducing a new per-cpu flag, "kvm_cpu_l1tf_flush_l1d". It will be in
strong analogy to the per-vcpu ->l1tf_flush_l1d.

A later patch will make interrupt handlers set it.

For the sake of cache locality, group kvm_cpu_l1tf_flush_l1d into x86'
per-cpu irq_cpustat_t as suggested by Peter Zijlstra.

Provide the helpers kvm_set_cpu_l1tf_flush_l1d(),
kvm_clear_cpu_l1tf_flush_l1d() and kvm_get_cpu_l1tf_flush_l1d(). Make them
trivial resp. non-existent for !CONFIG_KVM_INTEL as appropriate.

Let vmx_l1d_flush() handle kvm_cpu_l1tf_flush_l1d in the same way as
l1tf_flush_l1d.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Nicolai Stange <nstange@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/irq: Demote irq_cpustat_t::__softirq_pending to u16
Nicolai Stange [Fri, 27 Jul 2018 10:46:29 +0000 (12:46 +0200)]
x86/irq: Demote irq_cpustat_t::__softirq_pending to u16

commit 9aee5f8a7e30330d0a8f4c626dc924ca5590aba5 upstream

An upcoming patch will extend KVM's L1TF mitigation in conditional mode
to also cover interrupts after VMEXITs. For tracking those, stores to a
new per-cpu flag from interrupt handlers will become necessary.

In order to improve cache locality, this new flag will be added to x86's
irq_cpustat_t.

Make some space available there by shrinking the ->softirq_pending bitfield
from 32 to 16 bits: the number of bits actually used is only NR_SOFTIRQS,
i.e. 10.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Nicolai Stange <nstange@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/KVM/VMX: Move the l1tf_flush_l1d test to vmx_l1d_flush()
Nicolai Stange [Sat, 21 Jul 2018 20:35:28 +0000 (22:35 +0200)]
x86/KVM/VMX: Move the l1tf_flush_l1d test to vmx_l1d_flush()

commit 5b6ccc6c3b1a477fbac9ec97a0b4c1c48e765209 upstream

Currently, vmx_vcpu_run() checks if l1tf_flush_l1d is set and invokes
vmx_l1d_flush() if so.

This test is unncessary for the "always flush L1D" mode.

Move the check to vmx_l1d_flush()'s conditional mode code path.

Notes:
- vmx_l1d_flush() is likely to get inlined anyway and thus, there's no
  extra function call.

- This inverts the (static) branch prediction, but there hadn't been any
  explicit likely()/unlikely() annotations before and so it stays as is.

Signed-off-by: Nicolai Stange <nstange@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/KVM/VMX: Replace 'vmx_l1d_flush_always' with 'vmx_l1d_flush_cond'
Nicolai Stange [Sat, 21 Jul 2018 20:25:00 +0000 (22:25 +0200)]
x86/KVM/VMX: Replace 'vmx_l1d_flush_always' with 'vmx_l1d_flush_cond'

commit 427362a142441f08051369db6fbe7f61c73b3dca upstream

The vmx_l1d_flush_always static key is only ever evaluated if
vmx_l1d_should_flush is enabled. In that case however, there are only two
L1d flushing modes possible: "always" and "conditional".

The "conditional" mode's implementation tends to require more sophisticated
logic than the "always" mode.

Avoid inverted logic by replacing the 'vmx_l1d_flush_always' static key
with a 'vmx_l1d_flush_cond' one.

There is no change in functionality.

Signed-off-by: Nicolai Stange <nstange@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/KVM/VMX: Don't set l1tf_flush_l1d to true from vmx_l1d_flush()
Nicolai Stange [Sat, 21 Jul 2018 20:16:56 +0000 (22:16 +0200)]
x86/KVM/VMX: Don't set l1tf_flush_l1d to true from vmx_l1d_flush()

commit 379fd0c7e6a391e5565336a646f19f218fb98c6c upstream

vmx_l1d_flush() gets invoked only if l1tf_flush_l1d is true. There's no
point in setting l1tf_flush_l1d to true from there again.

Signed-off-by: Nicolai Stange <nstange@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agocpu/hotplug: detect SMT disabled by BIOS
Josh Poimboeuf [Wed, 25 Jul 2018 10:00:27 +0000 (12:00 +0200)]
cpu/hotplug: detect SMT disabled by BIOS

commit 73d5e2b472640b1fcdb61ae8be389912ef211bda upstream

If SMT is disabled in BIOS, the CPU code doesn't properly detect it.
The /sys/devices/system/cpu/smt/control file shows 'on', and the 'l1tf'
vulnerabilities file shows SMT as vulnerable.

Fix it by forcing 'cpu_smt_control' to CPU_SMT_NOT_SUPPORTED in such a
case.  Unfortunately the detection can only be done after bringing all
the CPUs online, so we have to overwrite any previous writes to the
variable.

Reported-by: Joe Mario <jmario@redhat.com>
Tested-by: Jiri Kosina <jkosina@suse.cz>
Fixes: f048c399e0f7 ("x86/topology: Provide topology_smt_supported()")
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agoDocumentation/l1tf: Fix typos
Tony Luck [Thu, 19 Jul 2018 20:49:58 +0000 (13:49 -0700)]
Documentation/l1tf: Fix typos

commit 1949f9f49792d65dba2090edddbe36a5f02e3ba3 upstream

Fix spelling and other typos

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/KVM/VMX: Initialize the vmx_l1d_flush_pages' content
Nicolai Stange [Wed, 18 Jul 2018 17:07:38 +0000 (19:07 +0200)]
x86/KVM/VMX: Initialize the vmx_l1d_flush_pages' content

commit 288d152c23dcf3c09da46c5c481903ca10ebfef7 upstream

The slow path in vmx_l1d_flush() reads from vmx_l1d_flush_pages in order
to evict the L1d cache.

However, these pages are never cleared and, in theory, their data could be
leaked.

More importantly, KSM could merge a nested hypervisor's vmx_l1d_flush_pages
to fewer than 1 << L1D_CACHE_ORDER host physical pages and this would break
the L1d flushing algorithm: L1D on x86_64 is tagged by physical addresses.

Fix this by initializing the individual vmx_l1d_flush_pages with a
different pattern each.

Rename the "empty_zp" asm constraint identifier in vmx_l1d_flush() to
"flush_pages" to reflect this change.

Fixes: a47dd5f06714 ("x86/KVM/VMX: Add L1D flush algorithm")
Signed-off-by: Nicolai Stange <nstange@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agoDocumentation: Add section about CPU vulnerabilities
Thomas Gleixner [Fri, 13 Jul 2018 14:23:26 +0000 (16:23 +0200)]
Documentation: Add section about CPU vulnerabilities

commit 3ec8ce5d866ec6a08a9cfab82b62acf4a830b35f upstream

Add documentation for the L1TF vulnerability and the mitigation mechanisms:

  - Explain the problem and risks
  - Document the mitigation mechanisms
  - Document the command line controls
  - Document the sysfs files

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lkml.kernel.org/r/20180713142323.287429944@linutronix.de
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/bugs, kvm: Introduce boot-time control of L1TF mitigations
Jiri Kosina [Fri, 13 Jul 2018 14:23:25 +0000 (16:23 +0200)]
x86/bugs, kvm: Introduce boot-time control of L1TF mitigations

commit d90a7a0ec83fb86622cd7dae23255d3c50a99ec8 upstream

Introduce the 'l1tf=' kernel command line option to allow for boot-time
switching of mitigation that is used on processors affected by L1TF.

The possible values are:

  full
Provides all available mitigations for the L1TF vulnerability. Disables
SMT and enables all mitigations in the hypervisors. SMT control via
/sys/devices/system/cpu/smt/control is still possible after boot.
Hypervisors will issue a warning when the first VM is started in
a potentially insecure configuration, i.e. SMT enabled or L1D flush
disabled.

  full,force
Same as 'full', but disables SMT control. Implies the 'nosmt=force'
command line option. sysfs control of SMT and the hypervisor flush
control is disabled.

  flush
Leaves SMT enabled and enables the conditional hypervisor mitigation.
Hypervisors will issue a warning when the first VM is started in a
potentially insecure configuration, i.e. SMT enabled or L1D flush
disabled.

  flush,nosmt
Disables SMT and enables the conditional hypervisor mitigation. SMT
control via /sys/devices/system/cpu/smt/control is still possible
after boot. If SMT is reenabled or flushing disabled at runtime
hypervisors will issue a warning.

  flush,nowarn
Same as 'flush', but hypervisors will not warn when
a VM is started in a potentially insecure configuration.

  off
Disables hypervisor mitigations and doesn't emit any warnings.

Default is 'flush'.

Let KVM adhere to these semantics, which means:

  - 'lt1f=full,force' : Performe L1D flushes. No runtime control
       possible.

  - 'l1tf=full'
  - 'l1tf-flush'
  - 'l1tf=flush,nosmt' : Perform L1D flushes and warn on VM start if
  SMT has been runtime enabled or L1D flushing
  has been run-time enabled

  - 'l1tf=flush,nowarn' : Perform L1D flushes and no warnings are emitted.

  - 'l1tf=off' : L1D flushes are not performed and no warnings
  are emitted.

KVM can always override the L1D flushing behavior using its 'vmentry_l1d_flush'
module parameter except when lt1f=full,force is set.

This makes KVM's private 'nosmt' option redundant, and as it is a bit
non-systematic anyway (this is something to control globally, not on
hypervisor level), remove that option.

Add the missing Documentation entry for the l1tf vulnerability sysfs file
while at it.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20180713142323.202758176@linutronix.de
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agocpu/hotplug: Set CPU_SMT_NOT_SUPPORTED early
Thomas Gleixner [Fri, 13 Jul 2018 14:23:24 +0000 (16:23 +0200)]
cpu/hotplug: Set CPU_SMT_NOT_SUPPORTED early

commit fee0aede6f4739c87179eca76136f83210953b86 upstream

The CPU_SMT_NOT_SUPPORTED state is set (if the processor does not support
SMT) when the sysfs SMT control file is initialized.

That was fine so far as this was only required to make the output of the
control file correct and to prevent writes in that case.

With the upcoming l1tf command line parameter, this needs to be set up
before the L1TF mitigation selection and command line parsing happens.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20180713142323.121795971@linutronix.de
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agocpu/hotplug: Expose SMT control init function
Jiri Kosina [Fri, 13 Jul 2018 14:23:23 +0000 (16:23 +0200)]
cpu/hotplug: Expose SMT control init function

commit 8e1b706b6e819bed215c0db16345568864660393 upstream

The L1TF mitigation will gain a commend line parameter which allows to set
a combination of hypervisor mitigation and SMT control.

Expose cpu_smt_disable() so the command line parser can tweak SMT settings.

[ tglx: Split out of larger patch and made it preserve an already existing
   force off state ]

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20180713142323.039715135@linutronix.de
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/kvm: Allow runtime control of L1D flush
Thomas Gleixner [Fri, 13 Jul 2018 14:23:22 +0000 (16:23 +0200)]
x86/kvm: Allow runtime control of L1D flush

commit 895ae47f9918833c3a880fbccd41e0692b37e7d9 upstream

All mitigation modes can be switched at run time with a static key now:

 - Use sysfs_streq() instead of strcmp() to handle the trailing new line
   from sysfs writes correctly.
 - Make the static key management handle multiple invocations properly.
 - Set the module parameter file to RW

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20180713142322.954525119@linutronix.de
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/kvm: Serialize L1D flush parameter setter
Thomas Gleixner [Fri, 13 Jul 2018 14:23:21 +0000 (16:23 +0200)]
x86/kvm: Serialize L1D flush parameter setter

commit dd4bfa739a72508b75760b393d129ed7b431daab upstream

Writes to the parameter files are not serialized at the sysfs core
level, so local serialization is required.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20180713142322.873642605@linutronix.de
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/kvm: Add static key for flush always
Thomas Gleixner [Fri, 13 Jul 2018 14:23:20 +0000 (16:23 +0200)]
x86/kvm: Add static key for flush always

commit 4c6523ec59fe895ea352a650218a6be0653910b1 upstream

Avoid the conditional in the L1D flush control path.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20180713142322.790914912@linutronix.de
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/kvm: Move l1tf setup function
Thomas Gleixner [Fri, 13 Jul 2018 14:23:19 +0000 (16:23 +0200)]
x86/kvm: Move l1tf setup function

commit 7db92e165ac814487264632ab2624e832f20ae38 upstream

In preparation of allowing run time control for L1D flushing, move the
setup code to the module parameter handler.

In case of pre module init parsing, just store the value and let vmx_init()
do the actual setup after running kvm_init() so that enable_ept is having
the correct state.

During run-time invoke it directly from the parameter setter to prepare for
run-time control.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20180713142322.694063239@linutronix.de
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/l1tf: Handle EPT disabled state proper
Thomas Gleixner [Fri, 13 Jul 2018 14:23:18 +0000 (16:23 +0200)]
x86/l1tf: Handle EPT disabled state proper

commit a7b9020b06ec6d7c3f3b0d4ef1a9eba12654f4f7 upstream

If Extended Page Tables (EPT) are disabled or not supported, no L1D
flushing is required. The setup function can just avoid setting up the L1D
flush for the EPT=n case.

Invoke it after the hardware setup has be done and enable_ept has the
correct state and expose the EPT disabled state in the mitigation status as
well.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20180713142322.612160168@linutronix.de
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/kvm: Drop L1TF MSR list approach
Thomas Gleixner [Fri, 13 Jul 2018 14:23:17 +0000 (16:23 +0200)]
x86/kvm: Drop L1TF MSR list approach

commit 2f055947ae5e2741fb2dc5bba1033c417ccf4faa upstream

The VMX module parameter to control the L1D flush should become
writeable.

The MSR list is set up at VM init per guest VCPU, but the run time
switching is based on a static key which is global. Toggling the MSR list
at run time might be feasible, but for now drop this optimization and use
the regular MSR write to make run-time switching possible.

The default mitigation is the conditional flush anyway, so for extra
paranoid setups this will add some small overhead, but the extra code
executed is in the noise compared to the flush itself.

Aside of that the EPT disabled case is not handled correctly at the moment
and the MSR list magic is in the way for fixing that as well.

If it's really providing a significant advantage, then this needs to be
revisited after the code is correct and the control is writable.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20180713142322.516940445@linutronix.de
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/litf: Introduce vmx status variable
Thomas Gleixner [Fri, 13 Jul 2018 14:23:16 +0000 (16:23 +0200)]
x86/litf: Introduce vmx status variable

commit 72c6d2db64fa18c996ece8f06e499509e6c9a37e upstream

Store the effective mitigation of VMX in a status variable and use it to
report the VMX state in the l1tf sysfs file.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lkml.kernel.org/r/20180713142322.433098358@linutronix.de
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agocpu/hotplug: Online siblings when SMT control is turned on
Thomas Gleixner [Sat, 7 Jul 2018 09:40:18 +0000 (11:40 +0200)]
cpu/hotplug: Online siblings when SMT control is turned on

commit 215af5499d9e2b55f111d2431ea20218115f29b3 upstream

Writing 'off' to /sys/devices/system/cpu/smt/control offlines all SMT
siblings. Writing 'on' merily enables the abilify to online them, but does
not online them automatically.

Make 'on' more useful by onlining all offline siblings.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/KVM/VMX: Use MSR save list for IA32_FLUSH_CMD if required
Konrad Rzeszutek Wilk [Thu, 28 Jun 2018 21:10:36 +0000 (17:10 -0400)]
x86/KVM/VMX: Use MSR save list for IA32_FLUSH_CMD if required

commit 390d975e0c4e60ce70d4157e0dd91ede37824603 upstream

If the L1D flush module parameter is set to 'always' and the IA32_FLUSH_CMD
MSR is available, optimize the VMENTER code with the MSR save list.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/KVM/VMX: Extend add_atomic_switch_msr() to allow VMENTER only MSRs
Konrad Rzeszutek Wilk [Thu, 21 Jun 2018 02:01:22 +0000 (22:01 -0400)]
x86/KVM/VMX: Extend add_atomic_switch_msr() to allow VMENTER only MSRs

commit 989e3992d2eca32c3f1404f2bc91acda3aa122d8 upstream

The IA32_FLUSH_CMD MSR needs only to be written on VMENTER. Extend
add_atomic_switch_msr() with an entry_only parameter to allow storing the
MSR only in the guest (ENTRY) MSR array.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/KVM/VMX: Separate the VMX AUTOLOAD guest/host number accounting
Konrad Rzeszutek Wilk [Thu, 21 Jun 2018 02:00:47 +0000 (22:00 -0400)]
x86/KVM/VMX: Separate the VMX AUTOLOAD guest/host number accounting

commit 3190709335dd31fe1aeeebfe4ffb6c7624ef971f upstream

This allows to load a different number of MSRs depending on the context:
VMEXIT or VMENTER.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/KVM/VMX: Add find_msr() helper function
Konrad Rzeszutek Wilk [Thu, 21 Jun 2018 00:11:39 +0000 (20:11 -0400)]
x86/KVM/VMX: Add find_msr() helper function

commit ca83b4a7f2d068da79a029d323024aa45decb250 upstream

.. to help find the MSR on either the guest or host MSR list.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/KVM/VMX: Split the VMX MSR LOAD structures to have an host/guest numbers
Konrad Rzeszutek Wilk [Wed, 20 Jun 2018 17:58:37 +0000 (13:58 -0400)]
x86/KVM/VMX: Split the VMX MSR LOAD structures to have an host/guest numbers

commit 33966dd6b2d2c352fae55412db2ea8cfff5df13a upstream

There is no semantic change but this change allows an unbalanced amount of
MSRs to be loaded on VMEXIT and VMENTER, i.e. the number of MSRs to save or
restore on VMEXIT or VMENTER may be different.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agokvm: nVMX: Update MSR load counts on a VMCS switch
Jim Mattson [Tue, 4 Oct 2016 17:48:38 +0000 (10:48 -0700)]
kvm: nVMX: Update MSR load counts on a VMCS switch

Commit 83bafef1a131d1b8743d63658a180948bc880a74 upstream

When L0 establishes (or removes) an MSR entry in the VM-entry or VM-exit
MSR load lists, the change should affect the dormant VMCS as well as the
current VMCS. Moreover, the vmcs02 MSR-load addresses should be
initialized.

[ dwmw2: Pulled in to 4.9 backports for L1TF ]

Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/KVM/VMX: Add L1D flush logic
Paolo Bonzini [Mon, 2 Jul 2018 11:07:14 +0000 (13:07 +0200)]
x86/KVM/VMX: Add L1D flush logic

commit c595ceee45707f00f64f61c54fb64ef0cc0b4e85 upstream

Add the logic for flushing L1D on VMENTER. The flush depends on the static
key being enabled and the new l1tf_flush_l1d flag being set.

The flags is set:
 - Always, if the flush module parameter is 'always'

 - Conditionally at:
   - Entry to vcpu_run(), i.e. after executing user space

   - From the sched_in notifier, i.e. when switching to a vCPU thread.

   - From vmexit handlers which are considered unsafe, i.e. where
     sensitive data can be brought into L1D:

     - The emulator, which could be a good target for other speculative
       execution-based threats,

     - The MMU, which can bring host page tables in the L1 cache.

     - External interrupts

     - Nested operations that require the MMU (see above). That is
       vmptrld, vmptrst, vmclear,vmwrite,vmread.

     - When handling invept,invvpid

[ tglx: Split out from combo patch and reduced to a single flag ]
[ dwmw2: Backported to 4.9, set l1tf_flush_l1d in svm/vmx code ]

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/KVM/VMX: Add L1D MSR based flush
Paolo Bonzini [Mon, 2 Jul 2018 11:03:48 +0000 (13:03 +0200)]
x86/KVM/VMX: Add L1D MSR based flush

commit 3fa045be4c720146b18a19cea7a767dc6ad5df94 upstream

336996-Speculative-Execution-Side-Channel-Mitigations.pdf defines a new MSR
(IA32_FLUSH_CMD aka 0x10B) which has similar write-only semantics to other
MSRs defined in the document.

The semantics of this MSR is to allow "finer granularity invalidation of
caching structures than existing mechanisms like WBINVD. It will writeback
and invalidate the L1 data cache, including all cachelines brought in by
preceding instructions, without invalidating all caches (eg. L2 or
LLC). Some processors may also invalidate the first level level instruction
cache on a L1D_FLUSH command. The L1 data and instruction caches may be
shared across the logical processors of a core."

Use it instead of the loop based L1 flush algorithm.

A copy of this document is available at
   https://bugzilla.kernel.org/show_bug.cgi?id=199511

[ tglx: Avoid allocating pages when the MSR is available ]

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/KVM/VMX: Add L1D flush algorithm
Paolo Bonzini [Mon, 2 Jul 2018 10:47:38 +0000 (12:47 +0200)]
x86/KVM/VMX: Add L1D flush algorithm

commit a47dd5f06714c844b33f3b5f517b6f3e81ce57b5 upstream

To mitigate the L1 Terminal Fault vulnerability it's required to flush L1D
on VMENTER to prevent rogue guests from snooping host memory.

CPUs will have a new control MSR via a microcode update to flush L1D with a
single MSR write, but in the absence of microcode a fallback to a software
based flush algorithm is required.

Add a software flush loop which is based on code from Intel.

[ tglx: Split out from combo patch ]
[ bpetkov: Polish the asm code ]

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/KVM/VMX: Add module argument for L1TF mitigation
Konrad Rzeszutek Wilk [Mon, 2 Jul 2018 10:29:30 +0000 (12:29 +0200)]
x86/KVM/VMX: Add module argument for L1TF mitigation

commit a399477e52c17e148746d3ce9a483f681c2aa9a0 upstream

Add a mitigation mode parameter "vmentry_l1d_flush" for CVE-2018-3620, aka
L1 terminal fault. The valid arguments are:

 - "always"  L1D cache flush on every VMENTER.
 - "cond" Conditional L1D cache flush, explained below
 - "never" Disable the L1D cache flush mitigation

"cond" is trying to avoid L1D cache flushes on VMENTER if the code executed
between VMEXIT and VMENTER is considered safe, i.e. is not bringing any
interesting information into L1D which might exploited.

[ tglx: Split out from a larger patch ]

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/KVM: Warn user if KVM is loaded SMT and L1TF CPU bug being present
Konrad Rzeszutek Wilk [Wed, 20 Jun 2018 15:29:53 +0000 (11:29 -0400)]
x86/KVM: Warn user if KVM is loaded SMT and L1TF CPU bug being present

commit 26acfb666a473d960f0fd971fe68f3e3ad16c70b upstream

If the L1TF CPU bug is present we allow the KVM module to be loaded as the
major of users that use Linux and KVM have trusted guests and do not want a
broken setup.

Cloud vendors are the ones that are uncomfortable with CVE 2018-3620 and as
such they are the ones that should set nosmt to one.

Setting 'nosmt' means that the system administrator also needs to disable
SMT (Hyper-threading) in the BIOS, or via the 'nosmt' command line
parameter, or via the /sys/devices/system/cpu/smt/control. See commit
05736e4ac13c ("cpu/hotplug: Provide knobs to control SMT").

Other mitigations are to use task affinity, cpu sets, interrupt binding,
etc - anything to make sure that _only_ the same guests vCPUs are running
on sibling threads.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agocpu/hotplug: Boot HT siblings at least once
Thomas Gleixner [Fri, 29 Jun 2018 14:05:48 +0000 (16:05 +0200)]
cpu/hotplug: Boot HT siblings at least once

commit 0cc3cd21657be04cb0559fe8063f2130493f92cf upstream

Due to the way Machine Check Exceptions work on X86 hyperthreads it's
required to boot up _all_ logical cores at least once in order to set the
CR4.MCE bit.

So instead of ignoring the sibling threads right away, let them boot up
once so they can configure themselves. After they came out of the initial
boot stage check whether its a "secondary" sibling and cancel the operation
which puts the CPU back into offline state.

[dwmw2: Backport to 4.9]

Reported-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agoRevert "x86/apic: Ignore secondary threads if nosmt=force"
Thomas Gleixner [Fri, 29 Jun 2018 14:05:47 +0000 (16:05 +0200)]
Revert "x86/apic: Ignore secondary threads if nosmt=force"

commit 506a66f374891ff08e064a058c446b336c5ac760 upstream

Dave Hansen reported, that it's outright dangerous to keep SMT siblings
disabled completely so they are stuck in the BIOS and wait for SIPI.

The reason is that Machine Check Exceptions are broadcasted to siblings and
the soft disabled sibling has CR4.MCE = 0. If a MCE is delivered to a
logical core with CR4.MCE = 0, it asserts IERR#, which shuts down or
reboots the machine. The MCE chapter in the SDM contains the following
blurb:

    Because the logical processors within a physical package are tightly
    coupled with respect to shared hardware resources, both logical
    processors are notified of machine check errors that occur within a
    given physical processor. If machine-check exceptions are enabled when
    a fatal error is reported, all the logical processors within a physical
    package are dispatched to the machine-check exception handler. If
    machine-check exceptions are disabled, the logical processors enter the
    shutdown state and assert the IERR# signal. When enabling machine-check
    exceptions, the MCE flag in control register CR4 should be set for each
    logical processor.

Reverting the commit which ignores siblings at enumeration time solves only
half of the problem. The core cpuhotplug logic needs to be adjusted as
well.

This thoughtful engineered mechanism also turns the boot process on all
Intel HT enabled systems into a MCE lottery. MCE is enabled on the boot CPU
before the secondary CPUs are brought up. Depending on the number of
physical cores the window in which this situation can happen is smaller or
larger. On a HSW-EX it's about 750ms:

MCE is enabled on the boot CPU:

[    0.244017] mce: CPU supports 22 MCE banks

The corresponding sibling #72 boots:

[    1.008005] .... node  #0, CPUs:    #72

That means if an MCE hits on physical core 0 (logical CPUs 0 and 72)
between these two points the machine is going to shutdown. At least it's a
known safe state.

It's obvious that the early boot can be hit by an MCE as well and then runs
into the same situation because MCEs are not yet enabled on the boot CPU.
But after enabling them on the boot CPU, it does not make any sense to
prevent the kernel from recovering.

Adjust the nosmt kernel parameter documentation as well.

Reverts: 2207def700f9 ("x86/apic: Ignore secondary threads if nosmt=force")
Reported-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/speculation/l1tf: Fix up pte->pfn conversion for PAE
Michal Hocko [Wed, 27 Jun 2018 15:46:50 +0000 (17:46 +0200)]
x86/speculation/l1tf: Fix up pte->pfn conversion for PAE

commit e14d7dfb41f5807a0c1c26a13f2b8ef16af24935 upstream

Jan has noticed that pte_pfn and co. resp. pfn_pte are incorrect for
CONFIG_PAE because phys_addr_t is wider than unsigned long and so the
pte_val reps. shift left would get truncated. Fix this up by using proper
types.

[dwmw2: Backport to 4.9]

Fixes: 6b28baca9b1f ("x86/speculation/l1tf: Protect PROT_NONE PTEs against speculation")
Reported-by: Jan Beulich <JBeulich@suse.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/speculation/l1tf: Protect PAE swap entries against L1TF
Vlastimil Babka [Fri, 22 Jun 2018 15:39:33 +0000 (17:39 +0200)]
x86/speculation/l1tf: Protect PAE swap entries against L1TF

commit 0d0f6249058834ffe1ceaad0bb31464af66f6e7a upstream

The PAE 3-level paging code currently doesn't mitigate L1TF by flipping the
offset bits, and uses the high PTE word, thus bits 32-36 for type, 37-63 for
offset. The lower word is zeroed, thus systems with less than 4GB memory are
safe. With 4GB to 128GB the swap type selects the memory locations vulnerable
to L1TF; with even more memory, also the swap offfset influences the address.
This might be a problem with 32bit PAE guests running on large 64bit hosts.

By continuing to keep the whole swap entry in either high or low 32bit word of
PTE we would limit the swap size too much. Thus this patch uses the whole PAE
PTE with the same layout as the 64bit version does. The macros just become a
bit tricky since they assume the arch-dependent swp_entry_t to be 32bit.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/CPU/AMD: Move TOPOEXT reenablement before reading smp_num_siblings
Borislav Petkov [Fri, 22 Jun 2018 09:34:11 +0000 (11:34 +0200)]
x86/CPU/AMD: Move TOPOEXT reenablement before reading smp_num_siblings

commit 7ce2f0393ea2396142b7faf6ee9b1f3676d08a5f upstream

The TOPOEXT reenablement is a workaround for broken BIOSen which didn't
enable the CPUID bit. amd_get_topology_early(), however, relies on
that bit being set so that it can read out the CPUID leaf and set
smp_num_siblings properly.

Move the reenablement up to early_init_amd(). While at it, simplify
amd_get_topology_early().

[dwmw2: Backport to 4.9]

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/cpufeatures: Add detection of L1D cache flush support.
Konrad Rzeszutek Wilk [Wed, 20 Jun 2018 20:42:58 +0000 (16:42 -0400)]
x86/cpufeatures: Add detection of L1D cache flush support.

commit 11e34e64e4103955fc4568750914c75d65ea87ee upstream

336996-Speculative-Execution-Side-Channel-Mitigations.pdf defines a new MSR
(IA32_FLUSH_CMD) which is detected by CPUID.7.EDX[28]=1 bit being set.

This new MSR "gives software a way to invalidate structures with finer
granularity than other architectual methods like WBINVD."

A copy of this document is available at
  https://bugzilla.kernel.org/show_bug.cgi?id=199511

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/speculation/l1tf: Extend 64bit swap file size limit
Vlastimil Babka [Thu, 21 Jun 2018 10:36:29 +0000 (12:36 +0200)]
x86/speculation/l1tf: Extend 64bit swap file size limit

commit 1a7ed1ba4bba6c075d5ad61bb75e3fbc870840d6 upstream

The previous patch has limited swap file size so that large offsets cannot
clear bits above MAX_PA/2 in the pte and interfere with L1TF mitigation.

It assumed that offsets are encoded starting with bit 12, same as pfn. But
on x86_64, offsets are encoded starting with bit 9.

Thus the limit can be raised by 3 bits. That means 16TB with 42bit MAX_PA
and 256TB with 46bit MAX_PA.

Fixes: 377eeaa8e11f ("x86/speculation/l1tf: Limit swap file size to MAX_PA/2")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/apic: Ignore secondary threads if nosmt=force
Thomas Gleixner [Tue, 5 Jun 2018 12:00:11 +0000 (14:00 +0200)]
x86/apic: Ignore secondary threads if nosmt=force

commit 2207def700f902f169fc237b717252c326f9e464 upstream

nosmt on the kernel command line merely prevents the onlining of the
secondary SMT siblings.

nosmt=force makes the APIC detection code ignore the secondary SMT siblings
completely, so they even do not show up as possible CPUs. That reduces the
amount of memory allocations for per cpu variables and saves other
resources from being allocated too large.

This is not fully equivalent to disabling SMT in the BIOS because the low
level SMT enabling in the BIOS can result in partitioning of resources
between the siblings, which is not undone by just ignoring them. Some CPUs
can use the full resources when their sibling is not onlined, but this is
depending on the CPU family and model and it's not well documented whether
this applies to all partitioned resources. That means depending on the
workload disabling SMT in the BIOS might result in better performance.

Linus analysis of the Intel manual:

  The intel optimization manual is not very clear on what the partitioning
  rules are.

  I find:

    "In general, the buffers for staging instructions between major pipe
     stages  are partitioned. These buffers include µop queues after the
     execution trace cache, the queues after the register rename stage, the
     reorder buffer which stages instructions for retirement, and the load
     and store buffers.

     In the case of load and store buffers, partitioning also provided an
     easier implementation to maintain memory ordering for each logical
     processor and detect memory ordering violations"

  but some of that partitioning may be relaxed if the HT thread is "not
  active":

    "In Intel microarchitecture code name Sandy Bridge, the micro-op queue
     is statically partitioned to provide 28 entries for each logical
     processor,  irrespective of software executing in single thread or
     multiple threads. If one logical processor is not active in Intel
     microarchitecture code name Ivy Bridge, then a single thread executing
     on that processor  core can use the 56 entries in the micro-op queue"

  but I do not know what "not active" means, and how dynamic it is. Some of
  that partitioning may be entirely static and depend on the early BIOS
  disabling of HT, and even if we park the cores, the resources will just be
  wasted.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/cpu/AMD: Evaluate smp_num_siblings early
Thomas Gleixner [Tue, 5 Jun 2018 22:57:38 +0000 (00:57 +0200)]
x86/cpu/AMD: Evaluate smp_num_siblings early

commit 1e1d7e25fd759eddf96d8ab39d0a90a1979b2d8c upstream

To support force disabling of SMT it's required to know the number of
thread siblings early. amd_get_topology() cannot be called before the APIC
driver is selected, so split out the part which initializes
smp_num_siblings and invoke it from amd_early_init().

[dwmw2: Backport to 4.9]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/CPU/AMD: Do not check CPUID max ext level before parsing SMP info
Borislav Petkov [Fri, 15 Jun 2018 18:48:39 +0000 (20:48 +0200)]
x86/CPU/AMD: Do not check CPUID max ext level before parsing SMP info

commit 119bff8a9c9bb00116a844ec68be7bc4b1c768f5 upstream

Old code used to check whether CPUID ext max level is >= 0x80000008 because
that last leaf contains the number of cores of the physical CPU.  The three
functions called there now do not depend on that leaf anymore so the check
can go.

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/cpu/intel: Evaluate smp_num_siblings early
Thomas Gleixner [Tue, 5 Jun 2018 23:00:55 +0000 (01:00 +0200)]
x86/cpu/intel: Evaluate smp_num_siblings early

commit 1910ad5624968f93be48e8e265513c54d66b897c upstream

Make use of the new early detection function to initialize smp_num_siblings
on the boot cpu before the MP-Table or ACPI/MADT scan happens. That's
required for force disabling SMT.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/cpu/topology: Provide detect_extended_topology_early()
Thomas Gleixner [Tue, 5 Jun 2018 22:55:39 +0000 (00:55 +0200)]
x86/cpu/topology: Provide detect_extended_topology_early()

commit 95f3d39ccf7aaea79d1ffdac1c887c2e100ec1b6 upstream

To support force disabling of SMT it's required to know the number of
thread siblings early. detect_extended_topology() cannot be called before
the APIC driver is selected, so split out the part which initializes
smp_num_siblings.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/cpu/common: Provide detect_ht_early()
Thomas Gleixner [Tue, 5 Jun 2018 22:53:57 +0000 (00:53 +0200)]
x86/cpu/common: Provide detect_ht_early()

commit 545401f4448a807b963ff17b575e0a393e68b523 upstream

To support force disabling of SMT it's required to know the number of
thread siblings early. detect_ht() cannot be called before the APIC driver
is selected, so split out the part which initializes smp_num_siblings.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/cpu/AMD: Remove the pointless detect_ht() call
Thomas Gleixner [Tue, 5 Jun 2018 22:47:10 +0000 (00:47 +0200)]
x86/cpu/AMD: Remove the pointless detect_ht() call

commit 44ca36de56d1bf196dca2eb67cd753a46961ffe6 upstream

Real 32bit AMD CPUs do not have SMT and the only value of the call was to
reach the magic printout which got removed.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/cpu: Remove the pointless CPU printout
Thomas Gleixner [Tue, 5 Jun 2018 22:36:15 +0000 (00:36 +0200)]
x86/cpu: Remove the pointless CPU printout

commit 55e6d279abd92cfd7576bba031e7589be8475edb upstream

The value of this printout is dubious at best and there is no point in
having it in two different places along with convoluted ways to reach it.

Remove it completely.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agocpu/hotplug: Provide knobs to control SMT
Thomas Gleixner [Tue, 29 May 2018 15:48:27 +0000 (17:48 +0200)]
cpu/hotplug: Provide knobs to control SMT

commit 05736e4ac13c08a4a9b1ef2de26dd31a32cbee57 upstream

Provide a command line and a sysfs knob to control SMT.

The command line options are:

 'nosmt': Enumerate secondary threads, but do not online them

 'nosmt=force': Ignore secondary threads completely during enumeration
  via MP table and ACPI/MADT.

The sysfs control file has the following states (read/write):

 'on':  SMT is enabled. Secondary threads can be freely onlined
 'off':  SMT is disabled. Secondary threads, even if enumerated
   cannot be onlined
 'forceoff':  SMT is permanentely disabled. Writes to the control
   file are rejected.
 'notsupported': SMT is not supported by the CPU

The command line option 'nosmt' sets the sysfs control to 'off'. This
can be changed to 'on' to reenable SMT during runtime.

The command line option 'nosmt=force' sets the sysfs control to
'forceoff'. This cannot be changed during runtime.

When SMT is 'on' and the control file is changed to 'off' then all online
secondary threads are offlined and attempts to online a secondary thread
later on are rejected.

When SMT is 'off' and the control file is changed to 'on' then secondary
threads can be onlined again. The 'off' -> 'on' transition does not
automatically online the secondary threads.

When the control file is set to 'forceoff', the behaviour is the same as
setting it to 'off', but the operation is irreversible and later writes to
the control file are rejected.

When the control status is 'notsupported' then writes to the control file
are rejected.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agocpu/hotplug: Split do_cpu_down()
Thomas Gleixner [Tue, 29 May 2018 15:49:05 +0000 (17:49 +0200)]
cpu/hotplug: Split do_cpu_down()

commit cc1fe215e1efa406b03aa4389e6269b61342dec5 upstream

Split out the inner workings of do_cpu_down() to allow reuse of that
function for the upcoming SMT disabling mechanism.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agocpu/hotplug: Make bringup/teardown of smp threads symmetric
Thomas Gleixner [Tue, 29 May 2018 17:05:25 +0000 (19:05 +0200)]
cpu/hotplug: Make bringup/teardown of smp threads symmetric

commit c4de65696d865c225fda3b9913b31284ea65ea96 upstream

The asymmetry caused a warning to trigger if the bootup was stopped in state
CPUHP_AP_ONLINE_IDLE. The warning no longer triggers as kthread_park() can
now be invoked on already or still parked threads. But there is still no
reason to have this be asymmetric.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/topology: Provide topology_smt_supported()
Thomas Gleixner [Thu, 21 Jun 2018 08:37:20 +0000 (10:37 +0200)]
x86/topology: Provide topology_smt_supported()

commit f048c399e0f7490ab7296bc2c255d37eb14a9675 upstream

Provide information whether SMT is supoorted by the CPUs. Preparatory patch
for SMT control mechanism.

Suggested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/smp: Provide topology_is_primary_thread()
Thomas Gleixner [Tue, 29 May 2018 15:50:22 +0000 (17:50 +0200)]
x86/smp: Provide topology_is_primary_thread()

commit 6a4d2657e048f096c7ffcad254010bd94891c8c0 upstream

If the CPU is supporting SMT then the primary thread can be found by
checking the lower APIC ID bits for zero. smp_num_siblings is used to build
the mask for the APIC ID bits which need to be taken into account.

This uses the MPTABLE or ACPI/MADT supplied APIC ID, which can be different
than the initial APIC ID in CPUID. But according to AMD the lower bits have
to be consistent. Intel gave a tentative confirmation as well.

Preparatory patch to support disabling SMT at boot/runtime.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/bugs: Move the l1tf function and define pr_fmt properly
Konrad Rzeszutek Wilk [Wed, 20 Jun 2018 20:42:57 +0000 (16:42 -0400)]
x86/bugs: Move the l1tf function and define pr_fmt properly

commit 56563f53d3066afa9e63d6c997bf67e76a8b05c0 upstream

The pr_warn in l1tf_select_mitigation would have used the prior pr_fmt
which was defined as "Spectre V2 : ".

Move the function to be past SSBD and also define the pr_fmt.

Fixes: 17dbca119312 ("x86/speculation/l1tf: Add sysfs reporting for l1tf")
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/speculation/l1tf: Limit swap file size to MAX_PA/2
Andi Kleen [Wed, 13 Jun 2018 22:48:28 +0000 (15:48 -0700)]
x86/speculation/l1tf: Limit swap file size to MAX_PA/2

commit 377eeaa8e11fe815b1d07c81c4a0e2843a8c15eb upstream

For the L1TF workaround its necessary to limit the swap file size to below
MAX_PA/2, so that the higher bits of the swap offset inverted never point
to valid memory.

Add a mechanism for the architecture to override the swap file size check
in swapfile.c and add a x86 specific max swapfile check function that
enforces that limit.

The check is only enabled if the CPU is vulnerable to L1TF.

In VMs with 42bit MAX_PA the typical limit is 2TB now, on a native system
with 46bit PA it is 32TB. The limit is only per individual swap file, so
it's always possible to exceed these limits with multiple swap files or
partitions.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/speculation/l1tf: Disallow non privileged high MMIO PROT_NONE mappings
Andi Kleen [Wed, 13 Jun 2018 22:48:27 +0000 (15:48 -0700)]
x86/speculation/l1tf: Disallow non privileged high MMIO PROT_NONE mappings

commit 42e4089c7890725fcd329999252dc489b72f2921 upstream

For L1TF PROT_NONE mappings are protected by inverting the PFN in the page
table entry. This sets the high bits in the CPU's address space, thus
making sure to point to not point an unmapped entry to valid cached memory.

Some server system BIOSes put the MMIO mappings high up in the physical
address space. If such an high mapping was mapped to unprivileged users
they could attack low memory by setting such a mapping to PROT_NONE. This
could happen through a special device driver which is not access
protected. Normal /dev/mem is of course access protected.

To avoid this forbid PROT_NONE mappings or mprotect for high MMIO mappings.

Valid page mappings are allowed because the system is then unsafe anyways.

It's not expected that users commonly use PROT_NONE on MMIO. But to
minimize any impact this is only enforced if the mapping actually refers to
a high MMIO address (defined as the MAX_PA-1 bit being set), and also skip
the check for root.

For mmaps this is straight forward and can be handled in vm_insert_pfn and
in remap_pfn_range().

For mprotect it's a bit trickier. At the point where the actual PTEs are
accessed a lot of state has been changed and it would be difficult to undo
on an error. Since this is a uncommon case use a separate early page talk
walk pass for MMIO PROT_NONE mappings that checks for this condition
early. For non MMIO and non PROT_NONE there are no changes.

[dwmw2: Backport to 4.9]

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/speculation/l1tf: Add sysfs reporting for l1tf
Andi Kleen [Wed, 13 Jun 2018 22:48:26 +0000 (15:48 -0700)]
x86/speculation/l1tf: Add sysfs reporting for l1tf

commit 17dbca119312b4e8173d4e25ff64262119fcef38 upstream

L1TF core kernel workarounds are cheap and normally always enabled, However
they still should be reported in sysfs if the system is vulnerable or
mitigated. Add the necessary CPU feature/bug bits.

- Extend the existing checks for Meltdowns to determine if the system is
  vulnerable. All CPUs which are not vulnerable to Meltdown are also not
  vulnerable to L1TF

- Check for 32bit non PAE and emit a warning as there is no practical way
  for mitigation due to the limited physical address bits

- If the system has more than MAX_PA/2 physical memory the invert page
  workarounds don't protect the system against the L1TF attack anymore,
  because an inverted physical address will also point to valid
  memory. Print a warning in this case and report that the system is
  vulnerable.

Add a function which returns the PFN limit for the L1TF mitigation, which
will be used in follow up patches for sanity and range checks.

[ tglx: Renamed the CPU feature bit to L1TF_PTEINV ]
[ dwmw2: Backport to 4.9 (cpufeatures.h, E820) ]

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/speculation/l1tf: Make sure the first page is always reserved
Andi Kleen [Wed, 13 Jun 2018 22:48:25 +0000 (15:48 -0700)]
x86/speculation/l1tf: Make sure the first page is always reserved

commit 10a70416e1f067f6c4efda6ffd8ea96002ac4223 upstream

The L1TF workaround doesn't make any attempt to mitigate speculate accesses
to the first physical page for zeroed PTEs. Normally it only contains some
data from the early real mode BIOS.

It's not entirely clear that the first page is reserved in all
configurations, so add an extra reservation call to make sure it is really
reserved. In most configurations (e.g.  with the standard reservations)
it's likely a nop.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/speculation/l1tf: Protect PROT_NONE PTEs against speculation
Andi Kleen [Wed, 13 Jun 2018 22:48:24 +0000 (15:48 -0700)]
x86/speculation/l1tf: Protect PROT_NONE PTEs against speculation

commit 6b28baca9b1f0d4a42b865da7a05b1c81424bd5c upstream

When PTEs are set to PROT_NONE the kernel just clears the Present bit and
preserves the PFN, which creates attack surface for L1TF speculation
speculation attacks.

This is important inside guests, because L1TF speculation bypasses physical
page remapping. While the host has its own migitations preventing leaking
data from other VMs into the guest, this would still risk leaking the wrong
page inside the current guest.

This uses the same technique as Linus' swap entry patch: while an entry is
is in PROTNONE state invert the complete PFN part part of it. This ensures
that the the highest bit will point to non existing memory.

The invert is done by pte/pmd_modify and pfn/pmd/pud_pte for PROTNONE and
pte/pmd/pud_pfn undo it.

This assume that no code path touches the PFN part of a PTE directly
without using these primitives.

This doesn't handle the case that MMIO is on the top of the CPU physical
memory. If such an MMIO region was exposed by an unpriviledged driver for
mmap it would be possible to attack some real memory.  However this
situation is all rather unlikely.

For 32bit non PAE the inversion is not done because there are really not
enough bits to protect anything.

Q: Why does the guest need to be protected when the HyperVisor already has
   L1TF mitigations?

A: Here's an example:

   Physical pages 1 2 get mapped into a guest as
   GPA 1 -> PA 2
   GPA 2 -> PA 1
   through EPT.

   The L1TF speculation ignores the EPT remapping.

   Now the guest kernel maps GPA 1 to process A and GPA 2 to process B, and
   they belong to different users and should be isolated.

   A sets the GPA 1 PA 2 PTE to PROT_NONE to bypass the EPT remapping and
   gets read access to the underlying physical page. Which in this case
   points to PA 2, so it can read process B's data, if it happened to be in
   L1, so isolation inside the guest is broken.

   There's nothing the hypervisor can do about this. This mitigation has to
   be done in the guest itself.

[ tglx: Massaged changelog ]
[ dwmw2: backported to 4.9 ]

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/speculation/l1tf: Protect swap entries against L1TF
Linus Torvalds [Wed, 13 Jun 2018 22:48:23 +0000 (15:48 -0700)]
x86/speculation/l1tf: Protect swap entries against L1TF

commit 2f22b4cd45b67b3496f4aa4c7180a1271c6452f6 upstream

With L1 terminal fault the CPU speculates into unmapped PTEs, and resulting
side effects allow to read the memory the PTE is pointing too, if its
values are still in the L1 cache.

For swapped out pages Linux uses unmapped PTEs and stores a swap entry into
them.

To protect against L1TF it must be ensured that the swap entry is not
pointing to valid memory, which requires setting higher bits (between bit
36 and bit 45) that are inside the CPUs physical address space, but outside
any real memory.

To do this invert the offset to make sure the higher bits are always set,
as long as the swap file is not too big.

Note there is no workaround for 32bit !PAE, or on systems which have more
than MAX_PA/2 worth of memory. The later case is very unlikely to happen on
real systems.

[AK: updated description and minor tweaks by. Split out from the original
     patch ]

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/speculation/l1tf: Change order of offset/type in swap entry
Linus Torvalds [Wed, 13 Jun 2018 22:48:22 +0000 (15:48 -0700)]
x86/speculation/l1tf: Change order of offset/type in swap entry

commit bcd11afa7adad8d720e7ba5ef58bdcd9775cf45f upstream

If pages are swapped out, the swap entry is stored in the corresponding
PTE, which has the Present bit cleared. CPUs vulnerable to L1TF speculate
on PTE entries which have the present bit set and would treat the swap
entry as phsyical address (PFN). To mitigate that the upper bits of the PTE
must be set so the PTE points to non existent memory.

The swap entry stores the type and the offset of a swapped out page in the
PTE. type is stored in bit 9-13 and offset in bit 14-63. The hardware
ignores the bits beyond the phsyical address space limit, so to make the
mitigation effective its required to start 'offset' at the lowest possible
bit so that even large swap offsets do not reach into the physical address
space limit bits.

Move offset to bit 9-58 and type to bit 59-63 which are the bits that
hardware generally doesn't care about.

That, in turn, means that if you on desktop chip with only 40 bits of
physical addressing, now that the offset starts at bit 9, there needs to be
30 bits of offset actually *in use* until bit 39 ends up being set, which
means when inverted it will again point into existing memory.

So that's 4 terabyte of swap space (because the offset is counted in pages,
so 30 bits of offset is 42 bits of actual coverage). With bigger physical
addressing, that obviously grows further, until the limit of the offset is
hit (at 50 bits of offset - 62 bits of actual swap file coverage).

This is a preparatory change for the actual swap entry inversion to protect
against L1TF.

[ AK: Updated description and minor tweaks. Split into two parts ]
[ tglx: Massaged changelog ]

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agomm: x86: move _PAGE_SWP_SOFT_DIRTY from bit 7 to bit 1
Naoya Horiguchi [Fri, 8 Sep 2017 23:10:46 +0000 (16:10 -0700)]
mm: x86: move _PAGE_SWP_SOFT_DIRTY from bit 7 to bit 1

commit eee4818baac0f2b37848fdf90e4b16430dc536ac upstream

_PAGE_PSE is used to distinguish between a truly non-present
(_PAGE_PRESENT=0) PMD, and a PMD which is undergoing a THP split and
should be treated as present.

But _PAGE_SWP_SOFT_DIRTY currently uses the _PAGE_PSE bit, which would
cause confusion between one of those PMDs undergoing a THP split, and a
soft-dirty PMD.  Dropping _PAGE_PSE check in pmd_present() does not work
well, because it can hurt optimization of tlb handling in thp split.

Thus, we need to move the bit.

In the current kernel, bits 1-4 are not used in non-present format since
commit 00839ee3b299 ("x86/mm: Move swap offset/type up in PTE to work
around erratum").  So let's move _PAGE_SWP_SOFT_DIRTY to bit 1.  Bit 7
is used as reserved (always clear), so please don't use it for other
purpose.

[dwmw2: Pulled in to 4.9 backport to support L1TF changes]

Link: http://lkml.kernel.org/r/20170717193955.20207-3-zi.yan@sent.com
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/speculation/l1tf: Increase 32bit PAE __PHYSICAL_PAGE_SHIFT
Andi Kleen [Wed, 13 Jun 2018 22:48:21 +0000 (15:48 -0700)]
x86/speculation/l1tf: Increase 32bit PAE __PHYSICAL_PAGE_SHIFT

commit 50896e180c6aa3a9c61a26ced99e15d602666a4c upstream

L1 Terminal Fault (L1TF) is a speculation related vulnerability. The CPU
speculates on PTE entries which do not have the PRESENT bit set, if the
content of the resulting physical address is available in the L1D cache.

The OS side mitigation makes sure that a !PRESENT PTE entry points to a
physical address outside the actually existing and cachable memory
space. This is achieved by inverting the upper bits of the PTE. Due to the
address space limitations this only works for 64bit and 32bit PAE kernels,
but not for 32bit non PAE.

This mitigation applies to both host and guest kernels, but in case of a
64bit host (hypervisor) and a 32bit PAE guest, inverting the upper bits of
the PAE address space (44bit) is not enough if the host has more than 43
bits of populated memory address space, because the speculation treats the
PTE content as a physical host address bypassing EPT.

The host (hypervisor) protects itself against the guest by flushing L1D as
needed, but pages inside the guest are not protected against attacks from
other processes inside the same guest.

For the guest the inverted PTE mask has to match the host to provide the
full protection for all pages the host could possibly map into the
guest. The hosts populated address space is not known to the guest, so the
mask must cover the possible maximal host address space, i.e. 52 bit.

On 32bit PAE the maximum PTE mask is currently set to 44 bit because that
is the limit imposed by 32bit unsigned long PFNs in the VMs. This limits
the mask to be below what the host could possible use for physical pages.

The L1TF PROT_NONE protection code uses the PTE masks to determine which
bits to invert to make sure the higher bits are set for unmapped entries to
prevent L1TF speculation attacks against EPT inside guests.

In order to invert all bits that could be used by the host, increase
__PHYSICAL_PAGE_SHIFT to 52 to match 64bit.

The real limit for a 32bit PAE kernel is still 44 bits because all Linux
PTEs are created from unsigned long PFNs, so they cannot be higher than 44
bits on a 32bit kernel. So these extra PFN bits should be never set. The
only users of this macro are using it to look at PTEs, so it's safe.

[ tglx: Massaged changelog ]

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agox86/irqflags: Provide a declaration for native_save_fl
Nick Desaulniers [Fri, 3 Aug 2018 17:05:50 +0000 (10:05 -0700)]
x86/irqflags: Provide a declaration for native_save_fl

commit 208cbb32558907f68b3b2a081ca2337ac3744794 upstream.

It was reported that the commit d0a8d9378d16 is causing users of gcc < 4.9
to observe -Werror=missing-prototypes errors.

Indeed, it seems that:
extern inline unsigned long native_save_fl(void) { return 0; }

compiled with -Werror=missing-prototypes produces this warning in gcc <
4.9, but not gcc >= 4.9.

Fixes: d0a8d9378d16 ("x86/paravirt: Make native_save_fl() extern inline").
Reported-by: David Laight <david.laight@aculab.com>
Reported-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: hpa@zytor.com
Cc: jgross@suse.com
Cc: kstewart@linuxfoundation.org
Cc: gregkh@linuxfoundation.org
Cc: boris.ostrovsky@oracle.com
Cc: astrachan@google.com
Cc: mka@chromium.org
Cc: arnd@arndb.de
Cc: tstellar@redhat.com
Cc: sedat.dilek@gmail.com
Cc: David.Laight@aculab.com
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180803170550.164688-1-ndesaulniers@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
6 years agokprobes/x86: Fix %p uses in error messages
Masami Hiramatsu [Sat, 28 Apr 2018 12:37:03 +0000 (21:37 +0900)]
kprobes/x86: Fix %p uses in error messages

commit 0ea063306eecf300fcf06d2f5917474b580f666f upstream.

Remove all %p uses in error messages in kprobes/x86.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: David Howells <dhowells@redhat.com>
Cc: David S . Miller <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jon Medhurst <tixy@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Tobin C . Harding <me@tobin.cc>
Cc: Will Deacon <will.deacon@arm.com>
Cc: acme@kernel.org
Cc: akpm@linux-foundation.org
Cc: brueckner@linux.vnet.ibm.com
Cc: linux-arch@vger.kernel.org
Cc: rostedt@goodmis.org
Cc: schwidefsky@de.ibm.com
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/lkml/152491902310.9916.13355297638917767319.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>