Sean Christopherson [Mon, 2 Mar 2020 23:56:25 +0000 (15:56 -0800)]
KVM: x86: Make kvm_mpx_supported() an inline function
Expose kvm_mpx_supported() as a static inline so that it can be inlined
in kvm_intel.ko.
No functional change intended.
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 2 Mar 2020 23:56:24 +0000 (15:56 -0800)]
KVM: x86: Use supported_xcr0 to detect MPX support
Query supported_xcr0 when checking for MPX support instead of invoking
->mpx_supported() and drop ->mpx_supported() as kvm_mpx_supported() was
its last user. Rename vmx_mpx_supported() to cpu_has_vmx_mpx() to
better align with VMX/VMCS nomenclature.
Modify VMX's adjustment of xcr0 to call cpus_has_vmx_mpx() (renamed from
vmx_mpx_supported()) directly to avoid reading supported_xcr0 before
it's fully configured.
No functional change intended.
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
[Test that *all* bits are set. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 2 Mar 2020 23:56:23 +0000 (15:56 -0800)]
KVM: x86: Calculate the supported xcr0 mask at load time
Add a new global variable, supported_xcr0, to track which xcr0 bits can
be exposed to the guest instead of calculating the mask on every call.
The supported bits are constant for a given instance of KVM.
This paves the way toward eliminating the ->mpx_supported() call in
kvm_mpx_supported(), e.g. eliminates multiple retpolines in VMX's nested
VM-Enter path, and eventually toward eliminating ->mpx_supported()
altogether.
No functional change intended.
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 2 Mar 2020 23:56:22 +0000 (15:56 -0800)]
KVM: VMX: Add helpers to query Intel PT mode
Add helpers to query which of the (two) supported PT modes is active.
The primary motivation is to help document that there is a third PT mode
(host-only) that's currently not supported by KVM. As is, it's not
obvious that PT_MODE_SYSTEM != !PT_MODE_HOST_GUEST and vice versa, e.g.
that "pt_mode == PT_MODE_SYSTEM" and "pt_mode != PT_MODE_HOST_GUEST" are
two distinct checks.
No functional change intended.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 2 Mar 2020 23:56:21 +0000 (15:56 -0800)]
KVM: x86: Use common loop iterator when handling CPUID 0xD.N
Use __do_cpuid_func()'s common loop iterator, "i", when enumerating the
sub-leafs for CPUID 0xD now that the CPUID 0xD loop doesn't need to
manual maintain separate counts for the entries index and CPUID index.
No functional changed intended.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 2 Mar 2020 23:56:20 +0000 (15:56 -0800)]
KVM: x86: Drop redundant array size check
Drop a "nent >= maxnent" check in kvm_get_cpuid() that's fully redundant
now that kvm_get_cpuid() isn't indexing the array to pass an entry to
do_cpuid_func().
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 2 Mar 2020 23:56:19 +0000 (15:56 -0800)]
KVM: x86: Encapsulate CPUID entries and metadata in struct
Add a struct to hold the array of CPUID entries and its associated
metadata when handling KVM_GET_SUPPORTED_CPUID. Lookup and provide
the correct entry in do_host_cpuid(), which eliminates the majority of
array indexing shenanigans, e.g. entries[i -1], and generally makes the
code more readable. The last array indexing holdout is kvm_get_cpuid(),
which can't really be avoided without throwing the baby out with the
bathwater.
No functional change intended.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 2 Mar 2020 23:56:18 +0000 (15:56 -0800)]
KVM: x86: Refactor CPUID 0x4 and 0x8000001d handling
Refactoring the sub-leaf handling for CPUID 0x4/0x8000001d to eliminate
a one-off variable and its associated brackets.
No functional change intended.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 2 Mar 2020 23:56:17 +0000 (15:56 -0800)]
KVM: x86: Hoist loop counter and terminator to top of __do_cpuid_func()
Declare "i" and "max_idx" at the top of __do_cpuid_func() to consolidate
a handful of declarations in various case statements.
More importantly, establish the pattern of using max_idx instead of e.g.
entry->eax as the loop terminator in preparation for refactoring how
entry is handled in __do_cpuid_func().
No functional change intended.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 2 Mar 2020 23:56:16 +0000 (15:56 -0800)]
KVM: x86: Consolidate CPUID array max num entries checking
Move the nent vs. maxnent check and nent increment into do_host_cpuid()
to consolidate what is now identical code. To signal success vs.
failure, return the entry and NULL respectively. A future patch will
build on this to also move the entry retrieval into do_host_cpuid().
No functional change intended.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 2 Mar 2020 23:56:15 +0000 (15:56 -0800)]
KVM: x86: Drop redundant boot cpu checks on SSBD feature bits
Drop redundant checks when "emulating" SSBD feature across vendors,
i.e. advertising the AMD variant when running on an Intel CPU and vice
versa. Both SPEC_CTRL_SSBD and AMD_SSBD are already defined in the
leaf-specific feature masks and are *not* forcefully set by the kernel,
i.e. will already be set in the entry when supported by the host.
Functionally, this changes nothing, but the redundant check is
confusing, especially when considering future patches that will further
differentiate between "real" and "emulated" feature bits.
No functional change intended.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 2 Mar 2020 23:56:14 +0000 (15:56 -0800)]
KVM: x86: Drop the explicit @index from do_cpuid_7_mask()
Drop the index param from do_cpuid_7_mask() and instead switch on the
entry's index, which is guaranteed to be set by do_host_cpuid().
No functional change intended.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 2 Mar 2020 23:56:13 +0000 (15:56 -0800)]
KVM: x86: Clean up CPUID 0x7 sub-leaf loop
Refactor the sub-leaf loop for CPUID 0x7 to move the main leaf out of
said loop. The emitted code savings is basically a mirage, as the
handling of the main leaf can easily be split to its own helper to avoid
code bloat.
No functional change intended.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 2 Mar 2020 23:56:12 +0000 (15:56 -0800)]
KVM: x86: Refactor CPUID 0xD.N sub-leaf entry creation
Increment the number of CPUID entries immediately after do_host_cpuid()
in preparation for moving the logic into do_host_cpuid(). Handle the
rare/impossible case of encountering a bogus sub-leaf by decrementing
the number entries on failure.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 2 Mar 2020 23:56:11 +0000 (15:56 -0800)]
KVM: x86: Warn on zero-size save state for valid CPUID 0xD.N sub-leaf
WARN if the save state size for a valid XCR0-managed sub-leaf is zero,
which would indicate a KVM or CPU bug. Add a comment to explain why KVM
WARNs so the reader doesn't have to tease out the relevant bits from
Intel's SDM and KVM's XCR0/XSS code.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 2 Mar 2020 23:56:10 +0000 (15:56 -0800)]
KVM: x86: Check for CPUID 0xD.N support before validating array size
Now that sub-leaf 1 is handled separately, verify the next sub-leaf is
needed before rejecting KVM_GET_SUPPORTED_CPUID due to an insufficiently
sized userspace array.
Note, although this is technically a bug, it's not visible to userspace
as KVM_GET_SUPPORTED_CPUID is guaranteed to fail on KVM_CPUID_SIGNATURE,
which is hardcoded to be added after leaf 0xD. The real motivation for
the change is to tightly couple the nent/maxnent and do_host_cpuid()
sequences in preparation for future cleanup.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 2 Mar 2020 23:56:09 +0000 (15:56 -0800)]
KVM: x86: Move CPUID 0xD.1 handling out of the index>0 loop
Mov the sub-leaf 1 handling for CPUID 0xD out of the index>0 loop so
that the loop only handles index>2. Sub-leafs 2+ have identical
semantics, whereas sub-leaf 1 is effectively a feature sub-leaf.
Moving sub-leaf 1 out of the loop does duplicate a bit of code, but
the nent/maxnent code will be consolidated in a future patch, and
duplicating the clear of ECX/EDX is arguably a good thing as the reasons
for clearing said registers are completely different.
No functional change intended.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 2 Mar 2020 23:56:08 +0000 (15:56 -0800)]
KVM: x86: Check userspace CPUID array size after validating sub-leaf
Verify that the next sub-leaf of CPUID 0x4 (or 0x8000001d) is valid
before rejecting the entire KVM_GET_SUPPORTED_CPUID due to insufficent
space in the userspace array.
Note, although this is technically a bug, it's not visible to userspace
as KVM_GET_SUPPORTED_CPUID is guaranteed to fail on KVM_CPUID_SIGNATURE,
which is hardcoded to be added after the affected leafs. The real
motivation for the change is to tightly couple the nent/maxnent and
do_host_cpuid() sequences in preparation for future cleanup.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 2 Mar 2020 23:56:07 +0000 (15:56 -0800)]
KVM: x86: Clean up error handling in kvm_dev_ioctl_get_cpuid()
Clean up the error handling in kvm_dev_ioctl_get_cpuid(), which has
gotten a bit crusty as the function has evolved over the years.
Opportunistically hoist the static @funcs declaration to the top of the
function to make it more obvious that it's a "static const".
No functional change intended.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 2 Mar 2020 23:56:06 +0000 (15:56 -0800)]
KVM: x86: Simplify handling of Centaur CPUID leafs
Refactor the handling of the Centaur-only CPUID leaf to detect the leaf
via a runtime query instead of adding a one-off callback in the static
array. When the callback was introduced, there were additional fields
in the array's structs, and more importantly, retpoline wasn't a thing.
No functional change intended.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 2 Mar 2020 23:56:05 +0000 (15:56 -0800)]
KVM: x86: Refactor loop around do_cpuid_func() to separate helper
Move the guts of kvm_dev_ioctl_get_cpuid()'s CPUID func loop to a
separate helper to improve code readability and pave the way for future
cleanup.
No functional change intended.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 2 Mar 2020 23:56:04 +0000 (15:56 -0800)]
KVM: x86: Return -E2BIG when KVM_GET_SUPPORTED_CPUID hits max entries
Fix a long-standing bug that causes KVM to return 0 instead of -E2BIG
when userspace's array is insufficiently sized.
This technically breaks backwards compatibility, e.g. a userspace with a
hardcoded cpuid->nent could theoretically be broken as it would see an
error instead of success if cpuid->nent is less than the number of
entries required to fully enumerate the host CPU. But, the lowest known
cpuid->nent hardcoded by a VMM is 100 (lkvm and selftests), and the
limit for current processors on Intel and AMD is well under a 100. E.g.
Intel's Icelake server with all the bells and whistles tops out at ~60
entries (variable due to SGX sub-leafs), and AMD's CPUID documentation
allows for less than 50. CPUID 0xD sub-leaves on current kernels are
capped by the value of KVM_SUPPORTED_XCR0, and therefore so many subleaves
cannot have appeared on current kernels.
Note, while the Fixes: tag is accurate with respect to the immediate
bug, it's likely that similar bugs in KVM_GET_SUPPORTED_CPUID existed
prior to the refactoring, e.g. Qemu contains a workaround for the broken
KVM_GET_SUPPORTED_CPUID behavior that predates the buggy commit by over
two years. The Qemu workaround is also likely the main reason the bug
has gone unreported for so long.
Qemu hack:
commit
76ae317f7c16aec6b469604b1764094870a75470
Author: Mark McLoughlin <markmc@redhat.com>
Date: Tue May 19 18:55:21 2009 +0100
kvm: work around supported cpuid ioctl() brokenness
KVM_GET_SUPPORTED_CPUID has been known to fail to return -E2BIG
when it runs out of entries. Detect this by always trying again
with a bigger table if the ioctl() fills the table.
Fixes:
831bf664e9c1f ("KVM: Refactor and simplify kvm_dev_ioctl_get_supported_cpuid")
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 23:29:50 +0000 (15:29 -0800)]
KVM: x86: Shrink the usercopy region of the emulation context
Shuffle a few operand structs to the end of struct x86_emulate_ctxt and
update the cache creation to whitelist only the region of the emulation
context that is expected to be copied to/from user memory, e.g. the
instruction operands, registers, and fetch/io/mem caches.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 23:29:49 +0000 (15:29 -0800)]
KVM: x86: Move kvm_emulate.h into KVM's private directory
Now that the emulation context is dynamically allocated and not embedded
in struct kvm_vcpu, move its header, kvm_emulate.h, out of the public
asm directory and into KVM's private x86 directory.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 23:29:48 +0000 (15:29 -0800)]
KVM: x86: Dynamically allocate per-vCPU emulation context
Allocate the emulation context instead of embedding it in struct
kvm_vcpu_arch.
Dynamic allocation provides several benefits:
- Shrinks the size x86 vcpus by ~2.5k bytes, dropping them back below
the PAGE_ALLOC_COSTLY_ORDER threshold.
- Allows for dropping the include of kvm_emulate.h from asm/kvm_host.h
and moving kvm_emulate.h into KVM's private directory.
- Allows a reducing KVM's attack surface by shrinking the amount of
vCPU data that is exposed to usercopy.
- Allows a future patch to disable the emulator entirely, which may or
may not be a realistic endeavor.
Mark the entire struct as valid for usercopy to maintain existing
behavior with respect to hardened usercopy. Future patches can shrink
the usercopy range to cover only what is necessary.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 23:29:43 +0000 (15:29 -0800)]
KVM: x86: Move emulation-only helpers to emulate.c
Move ctxt_virt_addr_bits() and emul_is_noncanonical_address() from x86.h
to emulate.c. This eliminates all references to struct x86_emulate_ctxt
from x86.h, and sets the stage for a future patch to stop including
kvm_emulate.h in asm/kvm_host.h.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 23:29:42 +0000 (15:29 -0800)]
KVM: x86: Explicitly pass an exception struct to check_intercept
Explicitly pass an exception struct when checking for intercept from
the emulator, which eliminates the last reference to arch.emulate_ctxt
in vendor specific code.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 23:29:41 +0000 (15:29 -0800)]
KVM: x86: Refactor I/O emulation helpers to provide vcpu-only variant
Add variants of the I/O helpers that take a vCPU instead of an emulation
context. This will eventually allow KVM to limit use of the emulation
context to the full emulation path.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Peter Xu [Wed, 4 Mar 2020 17:51:52 +0000 (12:51 -0500)]
KVM: Drop gfn_to_pfn_atomic()
It's never used anywhere now.
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Thu, 5 Mar 2020 00:24:22 +0000 (16:24 -0800)]
KVM: x86: Fix warning due to implicit truncation on 32-bit KVM
Explicitly cast the integer literal to an unsigned long when stuffing a
non-canonical value into the host virtual address during private memslot
deletion. The explicit cast fixes a warning that gets promoted to an
error when running with KVM's newfangled -Werror setting.
arch/x86/kvm/x86.c:9739:9: error: large integer implicitly truncated
to unsigned type [-Werror=overflow]
Fixes:
a3e967c0b87d3 ("KVM: Terminate memslot walks via used_slots"
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 3 Mar 2020 02:02:40 +0000 (18:02 -0800)]
KVM: nVMX: Drop unnecessary check on ept caps for execute-only
Drop the call to cpu_has_vmx_ept_execute_only() when calculating which
EPT capabilities will be exposed to L1 for nested EPT. The resulting
configuration is immediately sanitized by the passed in @ept_caps, and
except for the call from vmx_check_processor_compat(), @ept_caps is the
capabilities that are queried by cpu_has_vmx_ept_execute_only(). For
vmx_check_processor_compat(), KVM *wants* to ignore vmx_capability.ept
so that a divergence in EPT capabilities between CPUs is detected.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 3 Mar 2020 02:02:39 +0000 (18:02 -0800)]
KVM: x86/mmu: Rename kvm_mmu->get_cr3() to ->get_guest_pgd()
Rename kvm_mmu->get_cr3() to call out that it is retrieving a guest
value, as opposed to kvm_mmu->set_cr3(), which sets a host value, and to
note that it will return something other than CR3 when nested EPT is in
use. Hopefully the new name will also make it more obvious that L1's
nested_cr3 is returned in SVM's nested NPT case.
No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 3 Mar 2020 02:02:38 +0000 (18:02 -0800)]
KVM: nVMX: Rename EPTP validity helper and associated variables
Rename valid_ept_address() to nested_vmx_check_eptp() to follow the nVMX
nomenclature and to reflect that the function now checks a lot more than
just the address contained in the EPTP. Rename address to new_eptp in
associated code.
No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 3 Mar 2020 02:02:37 +0000 (18:02 -0800)]
KVM: nVMX: Rename nested_ept_get_cr3() to nested_ept_get_eptp()
Rename the accessor for vmcs12.EPTP to use "eptp" instead of "cr3". The
accessor has no relation to cr3 whatsoever, other than it being assigned
to the also poorly named kvm_mmu->get_cr3() hook.
No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 3 Mar 2020 02:02:36 +0000 (18:02 -0800)]
KVM: nVMX: Allow L1 to use 5-level page walks for nested EPT
Add support for 5-level nested EPT, and advertise said support in the
EPT capabilities MSR. KVM's MMU can already handle 5-level legacy page
tables, there's no reason to force an L1 VMM to use shadow paging if it
wants to employ 5-level page tables.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 3 Mar 2020 02:02:35 +0000 (18:02 -0800)]
KVM: x86/mmu: Drop kvm_mmu_extended_role.cr4_la57 hack
Drop kvm_mmu_extended_role.cr4_la57 now that mmu_role doesn't mask off
level, which already incorporates the guest's CR4.LA57 for a shadow MMU
by querying is_la57_mode().
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 3 Mar 2020 02:02:34 +0000 (18:02 -0800)]
KVM: x86/mmu: Don't drop level/direct from MMU role calculation
Use the calculated role as-is when propagating it to kvm_mmu.mmu_role,
i.e. stop masking off meaningful fields. The concept of masking off
fields came from kvm_mmu_pte_write(), which (correctly) ignores certain
fields when comparing kvm_mmu_page.role against kvm_mmu.mmu_role, e.g.
the current mmu's access and level have no relation to a shadow page's
access and level.
Masking off the level causes problems for 5-level paging, e.g. CR4.LA57
has its own redundant flag in the extended role, and nested EPT would
need a similar hack to support 5-level paging for L2.
Opportunistically rework the mask for kvm_mmu_pte_write() to define the
fields that should be ignored as opposed to the fields that should be
checked, i.e. make it opt-out instead of opt-in so that new fields are
automatically picked up. While doing so, stop ignoring "direct". The
field is effectively ignored anyways because kvm_mmu_pte_write() is only
reached with an indirect mmu and the loop only walks indirect shadow
pages, but double checking "direct" literally costs nothing.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Jay Zhou [Tue, 3 Mar 2020 08:07:10 +0000 (16:07 +0800)]
kvm: selftests: Support dirty log initial-all-set test
Since the new capability KVM_DIRTY_LOG_INITIALLY_SET of
KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2 has been introduced, tweak the
clear_dirty_log_test to use it.
Signed-off-by: Jay Zhou <jianjay.zhou@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 3 Mar 2020 06:27:35 +0000 (22:27 -0800)]
KVM: nVMX: Properly handle userspace interrupt window request
Return true for vmx_interrupt_allowed() if the vCPU is in L2 and L1 has
external interrupt exiting enabled. IRQs are never blocked in hardware
if the CPU is in the guest (L2 from L1's perspective) when IRQs trigger
VM-Exit.
The new check percolates up to kvm_vcpu_ready_for_interrupt_injection()
and thus vcpu_run(), and so KVM will exit to userspace if userspace has
requested an interrupt window (to inject an IRQ into L1).
Remove the @external_intr param from vmx_check_nested_events(), which is
actually an indicator that userspace wants an interrupt window, e.g.
it's named @req_int_win further up the stack. Injecting a VM-Exit into
L1 to try and bounce out to L0 userspace is all kinds of broken and is
no longer necessary.
Remove the hack in nested_vmx_vmexit() that attempted to workaround the
breakage in vmx_check_nested_events() by only filling interrupt info if
there's an actual interrupt pending. The hack actually made things
worse because it caused KVM to _never_ fill interrupt info when the
LAPIC resides in userspace (kvm_cpu_has_interrupt() queries
interrupt.injected, which is always cleared by prepare_vmcs12() before
reaching the hack in nested_vmx_vmexit()).
Fixes:
6550c4df7e50 ("KVM: nVMX: Fix interrupt window request with "Acknowledge interrupt on exit"")
Cc: stable@vger.kernel.org
Cc: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Wanpeng Li [Fri, 28 Feb 2020 03:18:41 +0000 (11:18 +0800)]
KVM: X86: trigger kvmclock sync request just once on VM creation
In the progress of vCPUs creation, it queues a kvmclock sync worker to the global
workqueue before each vCPU creation completes. The workqueue subsystem guarantees
not to queue the already queued work; however, we can make the logic more clear by
making just one leader to trigger this kvmclock sync request, and also save on
cacheline bouncing caused by test_and_set_bit.
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Wanpeng Li [Wed, 26 Feb 2020 02:41:02 +0000 (10:41 +0800)]
KVM: LAPIC: Recalculate apic map in batch
In the vCPU reset and set APIC_BASE MSR path, the apic map will be recalculated
several times, each time it will consume 10+ us observed by ftrace in my
non-overcommit environment since the expensive memory allocate/mutex/rcu etc
operations. This patch optimizes it by recaluating apic map in batch, I hope
this can benefit the serverless scenario which can frequently create/destroy
VMs.
Before patch:
kvm_lapic_reset ~27us
After patch:
kvm_lapic_reset ~14us
Observed by ftrace, improve ~48%.
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Miaohe Lin [Thu, 27 Feb 2020 03:20:54 +0000 (11:20 +0800)]
KVM: Fix some obsolete comments
Remove some obsolete comments, fix wrong function name and description.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Jay Zhou [Thu, 27 Feb 2020 01:32:27 +0000 (09:32 +0800)]
KVM: x86: enable dirty log gradually in small chunks
It could take kvm->mmu_lock for an extended period of time when
enabling dirty log for the first time. The main cost is to clear
all the D-bits of last level SPTEs. This situation can benefit from
manual dirty log protect as well, which can reduce the mmu_lock
time taken. The sequence is like this:
1. Initialize all the bits of the dirty bitmap to 1 when enabling
dirty log for the first time
2. Only write protect the huge pages
3. KVM_GET_DIRTY_LOG returns the dirty bitmap info
4. KVM_CLEAR_DIRTY_LOG will clear D-bit for each of the leaf level
SPTEs gradually in small chunks
Under the Intel(R) Xeon(R) Gold 6152 CPU @ 2.10GHz environment,
I did some tests with a 128G windows VM and counted the time taken
of memory_global_dirty_log_start, here is the numbers:
VM Size Before After optimization
128G 460ms 10ms
Signed-off-by: Jay Zhou <jianjay.zhou@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 28 Feb 2020 22:52:40 +0000 (14:52 -0800)]
KVM: x86/mmu: Reuse the current root if possible for fast switch
Reuse the current root when possible instead of grabbing a different
root from the array of cached roots. Doing so avoids unnecessary MMU
switches and also fixes a quirk where KVM can't reuse roots without
creating multiple roots since the cache is a victim cache, i.e. roots
are added to the cache when they're "evicted", not when they are
created. The quirk could be fixed by adding roots to the cache on
creation, but that would reduce the effective size of the cache as one
of its entries would be burned to track the current root.
Reusing the current root is especially helpful for nested virt as the
current root is almost always usable for the "new" MMU on nested
VM-entry/VM-exit.
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 28 Feb 2020 22:52:39 +0000 (14:52 -0800)]
KVM: x86/mmu: Ignore guest CR3 on fast root switch for direct MMU
Ignore the guest's CR3 when looking for a cached root for a direct MMU,
the guest's CR3 has no impact on the direct MMU's shadow pages (the
role check ensures compatibility with CR0.WP, etc...).
Zero out root_cr3 when allocating the direct roots to make it clear that
it's ignored.
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Oliver Upton [Fri, 28 Feb 2020 08:59:04 +0000 (00:59 -0800)]
KVM: SVM: Inhibit APIC virtualization for X2APIC guest
The AVIC does not support guest use of the x2APIC interface. Currently,
KVM simply chooses to squash the x2APIC feature in the guest's CPUID
If the AVIC is enabled. Doing so prevents KVM from running a guest
with greater than 255 vCPUs, as such a guest necessitates the use
of the x2APIC interface.
Instead, inhibit AVIC enablement on a per-VM basis whenever the x2APIC
feature is set in the guest's CPUID.
Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Peter Xu [Fri, 28 Feb 2020 18:30:20 +0000 (13:30 -0500)]
KVM: Remove unnecessary asm/kvm_host.h includes
Remove includes of asm/kvm_host.h from files that already include
linux/kvm_host.h to make it more obvious that there is no ordering issue
between the two headers. linux/kvm_host.h includes asm/kvm_host.h to
pick up architecture specific settings, and this will never change, i.e.
including asm/kvm_host.h after linux/kvm_host.h may seem problematic,
but in practice is simply redundant.
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Andrew Jones [Mon, 24 Feb 2020 16:10:49 +0000 (17:10 +0100)]
KVM: selftests: Fix unknown ucall command asserts
The TEST_ASSERT in x86_64/platform_info_test.c would have print 'ucall'
instead of 'uc.cmd'. Also fix all uc.cmd format types.
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 27 Jan 2020 00:41:13 +0000 (16:41 -0800)]
KVM: x86: Consolidate VM allocation and free for VMX and SVM
Move the VM allocation and free code to common x86 as the logic is
more or less identical across SVM and VMX.
Note, although hyperv.hv_pa_pg is part of the common kvm->arch, it's
(currently) only allocated by VMX VMs. But, since kfree() plays nice
when passed a NULL pointer, the superfluous call for SVM is harmless
and avoids future churn if SVM gains support for HyperV's direct TLB
flush.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
[Make vm_size a field instead of a function. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 27 Jan 2020 00:41:12 +0000 (16:41 -0800)]
KVM: x86: Directly return __vmalloc() result in ->vm_alloc()
Directly return the __vmalloc() result in {svm,vmx}_vm_alloc() to pave
the way for handling VM alloc/free in common x86 code, and to obviate
the need to check the result of __vmalloc() in vendor specific code.
Add a build-time assertion to ensure each structs' "kvm" field stays at
offset 0, which allows interpreting a "struct kvm_{svm,vmx}" as a
"struct kvm".
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Mon, 27 Jan 2020 00:41:11 +0000 (16:41 -0800)]
KVM: x86: Gracefully handle __vmalloc() failure during VM allocation
Check the result of __vmalloc() to avoid dereferencing a NULL pointer in
the event that allocation failres.
Fixes:
d1e5b0e98ea27 ("kvm: Make VM ioctl do valloc for some archs")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Eric Hankland [Sat, 22 Feb 2020 02:34:13 +0000 (18:34 -0800)]
KVM: x86: Adjust counter sample period after a wrmsr
The sample_period of a counter tracks when that counter will
overflow and set global status/trigger a PMI. However this currently
only gets set when the initial counter is created or when a counter is
resumed; this updates the sample period after a wrmsr so running
counters will accurately reflect their new value.
Signed-off-by: Eric Hankland <ehankland@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 21:07:36 +0000 (13:07 -0800)]
KVM: x86/mmu: Consolidate open coded variants of memslot TLB flushes
Replace open coded instances of kvm_arch_flush_remote_tlbs_memslot()'s
functionality with calls to the aforementioned function. Update the
comment in kvm_arch_flush_remote_tlbs_memslot() to elaborate on how it
is used and why it asserts that slots_lock is held.
No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 21:07:35 +0000 (13:07 -0800)]
KVM: x86/mmu: Use range-based TLB flush for dirty log memslot flush
Use the with_address() variant when performing a TLB flush for a
specific memslot via kvm_arch_flush_remote_tlbs_memslot(), i.e. when
flushing after clearing dirty bits during KVM_{GET,CLEAR}_DIRTY_LOG.
This aligns all dirty log memslot-specific TLB flushes to use the
with_address() variant and paves the way for consolidating the relevant
code.
Note, moving to the with_address() variant only affects functionality
when running as a HyperV guest.
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 21:07:34 +0000 (13:07 -0800)]
KVM: x86/mmu: Move kvm_arch_flush_remote_tlbs_memslot() to mmu.c
Move kvm_arch_flush_remote_tlbs_memslot() from x86.c to mmu.c in
preparation for calling kvm_flush_remote_tlbs_with_address() instead of
kvm_flush_remote_tlbs(). The with_address() variant is statically
defined in mmu.c, arguably kvm_arch_flush_remote_tlbs_memslot() belongs
in mmu.c anyways, and defining kvm_arch_flush_remote_tlbs_memslot() in
mmu.c will allow the compiler to inline said function when a future
patch consolidates open coded variants of the function.
No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 21:07:33 +0000 (13:07 -0800)]
KVM: selftests: Add test for KVM_SET_USER_MEMORY_REGION
Add a KVM selftest to test moving the base gfn of a userspace memory
region. Although the basic concept of moving memory regions is not x86
specific, the assumptions regarding large pages and MMIO shenanigans
used to verify the correctness make this x86_64 only for the time being.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 21:07:32 +0000 (13:07 -0800)]
KVM: Dynamically size memslot array based on number of used slots
Now that the memslot logic doesn't assume memslots are always non-NULL,
dynamically size the array of memslots instead of unconditionally
allocating memory for the maximum number of memslots.
Note, because a to-be-deleted memslot must first be invalidated, the
array size cannot be immediately reduced when deleting a memslot.
However, consecutive deletions will realize the memory savings, i.e.
a second deletion will trim the entry.
Tested-by: Christoffer Dall <christoffer.dall@arm.com>
Tested-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 21:07:31 +0000 (13:07 -0800)]
KVM: Terminate memslot walks via used_slots
Refactor memslot handling to treat the number of used slots as the de
facto size of the memslot array, e.g. return NULL from id_to_memslot()
when an invalid index is provided instead of relying on npages==0 to
detect an invalid memslot. Rework the sorting and walking of memslots
in advance of dynamically sizing memslots to aid bisection and debug,
e.g. with luck, a bug in the refactoring will bisect here and/or hit a
WARN instead of randomly corrupting memory.
Alternatively, a global null/invalid memslot could be returned, i.e. so
callers of id_to_memslot() don't have to explicitly check for a NULL
memslot, but that approach runs the risk of introducing difficult-to-
debug issues, e.g. if the global null slot is modified. Constifying
the return from id_to_memslot() to combat such issues is possible, but
would require a massive refactoring of arch specific code and would
still be susceptible to casting shenanigans.
Add function comments to update_memslots() and search_memslots() to
explicitly (and loudly) state how memslots are sorted.
Opportunistically stuff @hva with a non-canonical value when deleting a
private memslot on x86 to detect bogus usage of the freed slot.
No functional change intended.
Tested-by: Christoffer Dall <christoffer.dall@arm.com>
Tested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 21:07:30 +0000 (13:07 -0800)]
KVM: Ensure validity of memslot with respect to kvm_get_dirty_log()
Rework kvm_get_dirty_log() so that it "returns" the associated memslot
on success. A future patch will rework memslot handling such that
id_to_memslot() can return NULL, returning the memslot makes it more
obvious that the validity of the memslot has been verified, i.e.
precludes the need to add validity checks in the arch code that are
technically unnecessary.
To maintain ordering in s390, move the call to kvm_arch_sync_dirty_log()
from s390's kvm_vm_ioctl_get_dirty_log() to the new kvm_get_dirty_log().
This is a nop for PPC, the only other arch that doesn't select
KVM_GENERIC_DIRTYLOG_READ_PROTECT, as its sync_dirty_log() is empty.
Ideally, moving the sync_dirty_log() call would be done in a separate
patch, but it can't be done in a follow-on patch because that would
temporarily break s390's ordering. Making the move in a preparatory
patch would be functionally correct, but would create an odd scenario
where the moved sync_dirty_log() would operate on a "different" memslot
due to consuming the result of a different id_to_memslot(). The
memslot couldn't actually be different as slots_lock is held, but the
code is confusing enough as it is, i.e. moving sync_dirty_log() in this
patch is the lesser of all evils.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 21:07:29 +0000 (13:07 -0800)]
KVM: Provide common implementation for generic dirty log functions
Move the implementations of KVM_GET_DIRTY_LOG and KVM_CLEAR_DIRTY_LOG
for CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT into common KVM code.
The arch specific implemenations are extremely similar, differing
only in whether the dirty log needs to be sync'd from hardware (x86)
and how the TLBs are flushed. Add new arch hooks to handle sync
and TLB flush; the sync will also be used for non-generic dirty log
support in a future patch (s390).
The ulterior motive for providing a common implementation is to
eliminate the dependency between arch and common code with respect to
the memslot referenced by the dirty log, i.e. to make it obvious in the
code that the validity of the memslot is guaranteed, as a future patch
will rework memslot handling such that id_to_memslot() can return NULL.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 21:07:28 +0000 (13:07 -0800)]
KVM: Clean up local variable usage in __kvm_set_memory_region()
Clean up __kvm_set_memory_region() to achieve several goals:
- Remove local variables that serve no real purpose
- Improve the readability of the code
- Better show the relationship between the 'old' and 'new' memslot
- Prepare for dynamically sizing memslots
- Document subtle gotchas (via comments)
Note, using 'tmp' to hold the initial memslot is not strictly necessary
at this juncture, e.g. 'old' could be directly copied from
id_to_memslot(), but keep the pointer usage as id_to_memslot() will be
able to return a NULL pointer once memslots are dynamically sized.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 21:07:27 +0000 (13:07 -0800)]
KVM: Simplify kvm_free_memslot() and all its descendents
Now that all callers of kvm_free_memslot() pass NULL for @dont, remove
the param from the top-level routine and all arch's implementations.
No functional change intended.
Tested-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 21:07:26 +0000 (13:07 -0800)]
KVM: Move memslot deletion to helper function
Move memslot deletion into its own routine so that the success path for
other memslot updates does not need to use kvm_free_memslot(), i.e. can
explicitly destroy the dirty bitmap when necessary. This paves the way
for dropping @dont from kvm_free_memslot(), i.e. all callers now pass
NULL for @dont.
Add a comment above the code to make a copy of the existing memslot
prior to deletion, it is not at all obvious that the pointer will become
stale during sorting and/or installation of new memslots.
Note, kvm_arch_commit_memory_region() allows an architecture to free
resources when moving a memslot or changing its flags, e.g. x86 frees
its arch specific memslot metadata during commit_memory_region().
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Tested-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 21:07:25 +0000 (13:07 -0800)]
KVM: x86: Free arrays for old memslot when moving memslot's base gfn
Explicitly free the metadata arrays (stored in slot->arch) in the old
memslot structure when moving the memslot's base gfn is committed. This
eliminates x86's dependency on kvm_free_memslot() being called when a
memslot move is committed, and paves the way for removing the funky code
in kvm_free_memslot() that conditionally frees structures based on its
@dont param.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 21:07:24 +0000 (13:07 -0800)]
KVM: Drop "const" attribute from old memslot in commit_memory_region()
Drop the "const" attribute from @old in kvm_arch_commit_memory_region()
to allow arch specific code to free arch specific resources in the old
memslot without having to cast away the attribute. Freeing resources in
kvm_arch_commit_memory_region() paves the way for simplifying
kvm_free_memslot() by eliminating the last usage of its @dont param.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 21:07:23 +0000 (13:07 -0800)]
KVM: Move setting of memslot into helper routine
Split out the core functionality of setting a memslot into a separate
helper in preparation for moving memslot deletion into its own routine.
Tested-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 21:07:22 +0000 (13:07 -0800)]
KVM: Refactor error handling for setting memory region
Replace a big pile o' gotos with returns to make it more obvious what
error code is being returned, and to prepare for refactoring the
functional, i.e. post-checks, portion of __kvm_set_memory_region().
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 21:07:21 +0000 (13:07 -0800)]
KVM: Explicitly free allocated-but-unused dirty bitmap
Explicitly free an allocated-but-unused dirty bitmap instead of relying
on kvm_free_memslot() if an error occurs in __kvm_set_memory_region().
There is no longer a need to abuse kvm_free_memslot() to free arch
specific resources as arch specific code is now called only after the
common flow is guaranteed to succeed. Arch code can still fail, but
it's responsible for its own cleanup in that case.
Eliminating the error path's abuse of kvm_free_memslot() paves the way
for simplifying kvm_free_memslot(), i.e. dropping its @dont param.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 21:07:20 +0000 (13:07 -0800)]
KVM: Drop kvm_arch_create_memslot()
Remove kvm_arch_create_memslot() now that all arch implementations are
effectively nops. Removing kvm_arch_create_memslot() eliminates the
possibility for arch specific code to allocate memory prior to setting
a memslot, which sets the stage for simplifying kvm_free_memslot().
Cc: Janosch Frank <frankja@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 21:07:19 +0000 (13:07 -0800)]
KVM: x86: Allocate memslot resources during prepare_memory_region()
Allocate the various metadata structures associated with a new memslot
during kvm_arch_prepare_memory_region(), which paves the way for
removing kvm_arch_create_memslot() altogether. Moving x86's memory
allocation only changes the order of kernel memory allocations between
x86 and common KVM code.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 21:07:18 +0000 (13:07 -0800)]
KVM: PPC: Move memslot memory allocation into prepare_memory_region()
Allocate the rmap array during kvm_arch_prepare_memory_region() to pave
the way for removing kvm_arch_create_memslot() altogether. Moving PPC's
memory allocation only changes the order of kernel memory allocations
between PPC and common KVM code.
No functional change intended.
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 21:07:17 +0000 (13:07 -0800)]
KVM: Don't free new memslot if allocation of said memslot fails
The two implementations of kvm_arch_create_memslot() in x86 and PPC are
both good citizens and free up all local resources if creation fails.
Return immediately (via a superfluous goto) instead of calling
kvm_free_memslot().
Note, the call to kvm_free_memslot() is effectively an expensive nop in
this case as there are no resources to be freed.
No functional change intended.
Acked-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 21:07:16 +0000 (13:07 -0800)]
KVM: Reinstall old memslots if arch preparation fails
Reinstall the old memslots if preparing the new memory region fails
after invalidating a to-be-{re}moved memslot.
Remove the superfluous 'old_memslots' variable so that it's somewhat
clear that the error handling path needs to free the unused memslots,
not simply the 'old' memslots.
Fixes:
bc6678a33d9b9 ("KVM: introduce kvm->srcu and convert kvm_set_memory_region to SRCU update")
Reviewed-by: Christoffer Dall <christoffer.dall@arm.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 21:07:15 +0000 (13:07 -0800)]
KVM: x86: Allocate new rmap and large page tracking when moving memslot
Reallocate a rmap array and recalcuate large page compatibility when
moving an existing memslot to correctly handle the alignment properties
of the new memslot. The number of rmap entries required at each level
is dependent on the alignment of the memslot's base gfn with respect to
that level, e.g. moving a large-page aligned memslot so that it becomes
unaligned will increase the number of rmap entries needed at the now
unaligned level.
Not updating the rmap array is the most obvious bug, as KVM accesses
garbage data beyond the end of the rmap. KVM interprets the bad data as
pointers, leading to non-canonical #GPs, unexpected #PFs, etc...
general protection fault: 0000 [#1] SMP
CPU: 0 PID: 1909 Comm: move_memory_reg Not tainted 5.4.0-rc7+ #139
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
RIP: 0010:rmap_get_first+0x37/0x50 [kvm]
Code: <48> 8b 3b 48 85 ff 74 ec e8 6c f4 ff ff 85 c0 74 e3 48 89 d8 5b c3
RSP: 0018:
ffffc9000021bbc8 EFLAGS:
00010246
RAX:
ffff00617461642e RBX:
ffff00617461642e RCX:
0000000000000012
RDX:
ffff88827400f568 RSI:
ffffc9000021bbe0 RDI:
ffff88827400f570
RBP:
0010000000000000 R08:
ffffc9000021bd00 R09:
ffffc9000021bda8
R10:
ffffc9000021bc48 R11:
0000000000000000 R12:
0030000000000000
R13:
0000000000000000 R14:
ffff88827427d700 R15:
ffffc9000021bce8
FS:
00007f7eda014700(0000) GS:
ffff888277a00000(0000) knlGS:
0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0:
0000000080050033
CR2:
00007f7ed9216ff8 CR3:
0000000274391003 CR4:
0000000000162eb0
Call Trace:
kvm_mmu_slot_set_dirty+0xa1/0x150 [kvm]
__kvm_set_memory_region.part.64+0x559/0x960 [kvm]
kvm_set_memory_region+0x45/0x60 [kvm]
kvm_vm_ioctl+0x30f/0x920 [kvm]
do_vfs_ioctl+0xa1/0x620
ksys_ioctl+0x66/0x70
__x64_sys_ioctl+0x16/0x20
do_syscall_64+0x4c/0x170
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f7ed9911f47
Code: <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 21 6f 2c 00 f7 d8 64 89 01 48
RSP: 002b:
00007ffc00937498 EFLAGS:
00000246 ORIG_RAX:
0000000000000010
RAX:
ffffffffffffffda RBX:
0000000001ab0010 RCX:
00007f7ed9911f47
RDX:
0000000001ab1350 RSI:
000000004020ae46 RDI:
0000000000000004
RBP:
000000000000000a R08:
0000000000000000 R09:
00007f7ed9214700
R10:
00007f7ed92149d0 R11:
0000000000000246 R12:
00000000bffff000
R13:
0000000000000003 R14:
00007f7ed9215000 R15:
0000000000000000
Modules linked in: kvm_intel kvm irqbypass
---[ end trace
0c5f570b3358ca89 ]---
The disallow_lpage tracking is more subtle. Failure to update results
in KVM creating large pages when it shouldn't, either due to stale data
or again due to indexing beyond the end of the metadata arrays, which
can lead to memory corruption and/or leaking data to guest/userspace.
Note, the arrays for the old memslot are freed by the unconditional call
to kvm_free_memslot() in __kvm_set_memory_region().
Fixes:
05da45583de9b ("KVM: MMU: large page support")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 23:03:09 +0000 (15:03 -0800)]
KVM: x86: Move gpa_val and gpa_available into the emulator context
Move the GPA tracking into the emulator context now that the context is
guaranteed to be initialized via __init_emulate_ctxt() prior to
dereferencing gpa_{available,val}, i.e. now that seeing a stale
gpa_available will also trigger a WARN due to an invalid context.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Tue, 18 Feb 2020 23:03:08 +0000 (15:03 -0800)]
KVM: x86: Add EMULTYPE_PF when emulation is triggered by a page fault
Add a new emulation type flag to explicitly mark emulation related to a
page fault. Move the propation of the GPA into the emulator from the
page fault handler into x86_emulate_instruction, using EMULTYPE_PF as an
indicator that cr2 is valid. Similarly, don't propagate cr2 into the
exception.address when it's *not* valid.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Miaohe Lin [Thu, 13 Feb 2020 02:37:44 +0000 (10:37 +0800)]
KVM: apic: remove unused function apic_lvt_vector()
The function apic_lvt_vector() is unused now, remove it.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Miaohe Lin [Mon, 17 Feb 2020 15:02:30 +0000 (23:02 +0800)]
KVM: VMX: Add 'else' to split mutually exclusive case
Each if branch in handle_external_interrupt_irqoff() is mutually
exclusive. Add 'else' to make it clear and also avoid some unnecessary
check.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Miaohe Lin [Thu, 13 Feb 2020 02:53:25 +0000 (10:53 +0800)]
KVM: x86: eliminate some unreachable code
These code are unreachable, remove them.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Miaohe Lin [Sat, 15 Feb 2020 02:44:22 +0000 (10:44 +0800)]
KVM: x86: Fix print format and coding style
Use %u to print u32 var and correct some coding style.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Chia-I Wu [Thu, 13 Feb 2020 21:30:34 +0000 (13:30 -0800)]
KVM: vmx: rewrite the comment in vmx_get_mt_mask
Better reflect the structure of the code and metion why we could not
always honor the guest.
Signed-off-by: Chia-I Wu <olvaffe@gmail.com>
Cc: Gurchetan Singh <gurchetansingh@chromium.org>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Andrew Jones [Fri, 14 Feb 2020 14:59:17 +0000 (15:59 +0100)]
KVM: selftests: Convert some printf's to pr_info's
We leave some printf's because they inform the user the test is being
skipped. QUIET should not disable those. We also leave the printf's
used for help text.
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Andrew Jones [Fri, 14 Feb 2020 14:59:16 +0000 (15:59 +0100)]
KVM: selftests: Rework debug message printing
There were a few problems with the way we output "debug" messages.
The first is that we used DEBUG() which is defined when NDEBUG is
not defined, but NDEBUG will never be defined for kselftests
because it relies too much on assert(). The next is that most
of the DEBUG() messages were actually "info" messages, which
users may want to turn off if they just want a silent test that
either completes or asserts. Finally, a debug message output from
a library function, and thus for all tests, was annoying when its
information wasn't interesting for a test.
Rework these messages so debug messages only output when DEBUG
is defined and info messages output unless QUIET is defined.
Also name the functions pr_debug and pr_info and make sure that
when they're disabled we eat all the inputs. The later avoids
unused variable warnings when the variables were only defined
for the purpose of printing.
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Ben Gardon [Thu, 23 Jan 2020 18:04:34 +0000 (10:04 -0800)]
KVM: selftests: Time guest demand paging
In order to quantify demand paging performance, time guest execution
during demand paging.
Signed-off-by: Ben Gardon <bgardon@google.com>
[Move timespec-diff to test_util.h]
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Ben Gardon [Thu, 23 Jan 2020 18:04:33 +0000 (10:04 -0800)]
KVM: selftests: Support multiple vCPUs in demand paging test
Most VMs have multiple vCPUs, the concurrent execution of which has a
substantial impact on demand paging performance. Add an option to create
multiple vCPUs to each access disjoint regions of memory.
Signed-off-by: Ben Gardon <bgardon@google.com>
[guest_code() can't return, use GUEST_ASSERT(). Ensure the number
of guests pages is compatible with the host.]
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Ben Gardon [Thu, 23 Jan 2020 18:04:32 +0000 (10:04 -0800)]
KVM: selftests: Add support for vcpu_args_set to aarch64 and s390x
Currently vcpu_args_set is only implemented for x86. This makes writing
tests with multiple vCPUs difficult as each guest vCPU must either a.)
do the same thing or b.) derive some kind of unique token from it's
registers or the architecture. To simplify the process of writing tests
with multiple vCPUs for s390 and aarch64, add set args functions for
those architectures.
Signed-off-by: Ben Gardon <bgardon@google.com>
[Fixed array index (num => i) and made some style changes.]
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Ben Gardon [Thu, 23 Jan 2020 18:04:31 +0000 (10:04 -0800)]
KVM: selftests: Pass args to vCPU in global vCPU args struct
In preparation for supporting multiple vCPUs in the demand paging test,
pass arguments to the vCPU in a consolidated global struct instead of
syncing multiple globals.
Signed-off-by: Ben Gardon <bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Ben Gardon [Thu, 23 Jan 2020 18:04:30 +0000 (10:04 -0800)]
KVM: selftests: Add memory size parameter to the demand paging test
Add an argument to allow the demand paging test to work on larger and
smaller guest sizes.
Signed-off-by: Ben Gardon <bgardon@google.com>
[Rewrote parse_size() to simplify and provide user more flexibility as
to how sizes are input. Also fixed size overflow assert.]
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Ben Gardon [Thu, 20 Feb 2020 17:09:59 +0000 (18:09 +0100)]
KVM: selftests: Add configurable demand paging delay
When running the demand paging test with the -u option, the User Fault
FD handler essentially adds an arbitrary delay to page fault resolution.
To enable better simulation of a real demand paging scenario, add a
configurable delay to the UFFD handler.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Ben Gardon <bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Ben Gardon [Thu, 20 Feb 2020 17:09:12 +0000 (18:09 +0100)]
KVM: selftests: Add demand paging content to the demand paging test
The demand paging test is currently a simple page access test which, while
potentially useful, doesn't add much versus the existing dirty logging
test. To improve the demand paging test, add a basic userfaultfd demand
paging implementation.
Signed-off-by: Ben Gardon <bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Ben Gardon [Thu, 23 Jan 2020 18:04:27 +0000 (10:04 -0800)]
KVM: selftests: Create a demand paging test
While userfaultfd, KVM's demand paging implementation, is not specific
to KVM, having a benchmark for its performance will be useful for
guiding performance improvements to KVM. As a first step towards creating
a userfaultfd demand paging test, create a simple memory access test,
based on dirty_log_test.
Reviewed-by: Oliver Upton <oupton@google.com>
Signed-off-by: Ben Gardon <bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Andrew Jones [Fri, 14 Feb 2020 14:59:20 +0000 (15:59 +0100)]
KVM: selftests: Introduce num-pages conversion utilities
Guests and hosts don't have to have the same page size. This means
calculations are necessary when selecting the number of guest pages
to allocate in order to ensure the number is compatible with the
host. Provide utilities to help with those calculations and apply
them where appropriate.
We also revert commit
bffed38d4fb5 ("kvm: selftests: aarch64:
dirty_log_test: fix unaligned memslot size") and then use
vm_adjust_num_guest_pages() there instead.
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Andrew Jones [Fri, 14 Feb 2020 14:59:19 +0000 (15:59 +0100)]
KVM: selftests: Introduce vm_guest_mode_params
This array will allow us to easily translate modes to their parameter
values.
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Andrew Jones [Fri, 14 Feb 2020 14:59:18 +0000 (15:59 +0100)]
KVM: selftests: Rename vm_guest_mode_params
We're going to want this name in the library code, so use a shorter
name in the tests.
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Andrew Jones [Fri, 14 Feb 2020 14:59:14 +0000 (15:59 +0100)]
KVM: selftests: aarch64: Remove unnecessary ifdefs
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Andrew Jones [Fri, 14 Feb 2020 14:59:13 +0000 (15:59 +0100)]
KVM: selftests: Remove unnecessary defines
BITS_PER_LONG and friends are provided by linux/bitops.h
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Andrew Jones [Fri, 14 Feb 2020 14:59:15 +0000 (15:59 +0100)]
KVM: selftests: aarch64: Use stream when given
I'm not sure how we ended up using printf instead of fprintf in
virt_dump(). Fix it.
Signed-off-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Christian Borntraeger [Mon, 24 Feb 2020 10:15:59 +0000 (11:15 +0100)]
KVM: s390: rstify new ioctls in api.rst
We also need to rstify the new ioctls that we added in parallel to the
rstification of the kvm docs.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Oliver Upton [Tue, 4 Feb 2020 23:26:31 +0000 (15:26 -0800)]
KVM: nVMX: Check IO instruction VM-exit conditions
Consult the 'unconditional IO exiting' and 'use IO bitmaps' VM-execution
controls when checking instruction interception. If the 'use IO bitmaps'
VM-execution control is 1, check the instruction access against the IO
bitmaps to determine if the instruction causes a VM-exit.
Signed-off-by: Oliver Upton <oupton@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Oliver Upton [Tue, 4 Feb 2020 23:26:30 +0000 (15:26 -0800)]
KVM: nVMX: Refactor IO bitmap checks into helper function
Checks against the IO bitmap are useful for both instruction emulation
and VM-exit reflection. Refactor the IO bitmap checks into a helper
function.
Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>