Sean Christopherson [Fri, 20 Mar 2020 21:28:30 +0000 (14:28 -0700)]
KVM: nVMX: Don't flush TLB on nested VMX transition
Unconditionally skip the TLB flush triggered when reusing a root for a
nested transition as nested_vmx_transition_tlb_flush() ensures the TLB
is flushed when needed, regardless of whether the MMU can reuse a cached
root (or the last root).
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-35-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:29 +0000 (14:28 -0700)]
KVM: nVMX: Skip MMU sync on nested VMX transition when possible
Skip the MMU sync when reusing a cached root if EPT is enabled or L1
enabled VPID for L2.
If EPT is enabled, guest-physical mappings aren't flushed even if VPID
is disabled, i.e. L1 can't expect stale TLB entries to be flushed if it
has enabled EPT and L0 isn't shadowing PTEs (for L1 or L2) if L1 has
EPT disabled.
If VPID is enabled (and EPT is disabled), then L1 can't expect stale TLB
entries to be flushed (for itself or L2).
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-34-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:28 +0000 (14:28 -0700)]
KVM: x86/mmu: Add module param to force TLB flush on root reuse
Add a module param, flush_on_reuse, to override skip_tlb_flush and
skip_mmu_sync when performing a so called "fast cr3 switch", i.e. when
reusing a cached root. The primary motiviation for the control is to
provide a fallback mechanism in the event that TLB flushing and/or MMU
sync bugs are exposed/introduced by upcoming changes to stop
unconditionally flushing on nested VMX transitions.
Suggested-by: Jim Mattson <jmattson@google.com>
Suggested-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-33-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:27 +0000 (14:28 -0700)]
KVM: x86/mmu: Add separate override for MMU sync during fast CR3 switch
Add a separate "skip" override for MMU sync, a future change to avoid
TLB flushes on nested VMX transitions may need to sync the MMU even if
the TLB flush is unnecessary.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-32-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:26 +0000 (14:28 -0700)]
KVM: x86/mmu: Move fast_cr3_switch() side effects to __kvm_mmu_new_cr3()
Handle the side effects of a fast CR3 (PGD) switch up a level in
__kvm_mmu_new_cr3(), which is the only caller of fast_cr3_switch().
This consolidates handling all side effects in __kvm_mmu_new_cr3()
(where freeing the current root when KVM can't do a fast switch is
already handled), and ameliorates the pain of adding a second boolean in
a future patch to provide a separate "skip" override for the MMU sync.
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-31-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:25 +0000 (14:28 -0700)]
KVM: VMX: Don't reload APIC access page if its control is disabled
Don't reload the APIC access page if its control is disabled, e.g. if
the guest is running with x2APIC (likely) or with the local APIC
disabled (unlikely), to avoid unnecessary TLB flushes and VMWRITEs.
Unconditionally reload the APIC access page and flush the TLB when
the guest's virtual APIC transitions to "xAPIC enabled", as any
changes to the APIC access page's mapping will not be recorded while
the guest's virtual APIC is disabled.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-30-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:24 +0000 (14:28 -0700)]
KVM: VMX: Retrieve APIC access page HPA only when necessary
Move the retrieval of the HPA associated with L1's APIC access page into
VMX code to avoid unnecessarily calling gfn_to_page(), e.g. when the
vCPU is in guest mode (L2). Alternatively, the optimization logic in
VMX could be mirrored into the common x86 code, but that will get ugly
fast when further optimizations are introduced.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-29-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:23 +0000 (14:28 -0700)]
KVM: nVMX: Reload APIC access page on nested VM-Exit only if necessary
Defer reloading L1's APIC page by logging the need for a reload and
processing it during nested VM-Exit instead of unconditionally reloading
the APIC page on nested VM-Exit. This eliminates a TLB flush on the
majority of VM-Exits as the APIC page rarely needs to be reloaded.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-28-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:22 +0000 (14:28 -0700)]
KVM: nVMX: Selectively use TLB_FLUSH_CURRENT for nested VM-Enter/VM-Exit
Flush only the current context, as opposed to all contexts, when
requesting a TLB flush to handle the scenario where a L1 does not expect
a TLB flush, but one is required because L1 and L2 shared an ASID. This
occurs if EPT is disabled (no per-EPTP tag), VPID is enabled (hardware
doesn't flush unconditionally) and vmcs02 does not have its own VPID due
to exhaustion of available VPIDs.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-27-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:21 +0000 (14:28 -0700)]
KVM: x86/mmu: Use KVM_REQ_TLB_FLUSH_CURRENT for MMU specific flushes
Flush only the current ASID/context when requesting a TLB flush due to a
change in the current vCPU's MMU to avoid blasting away TLB entries
associated with other ASIDs/contexts, e.g. entries cached for L1 when
a change in L2's MMU requires a flush.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-26-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:20 +0000 (14:28 -0700)]
KVM: x86: Introduce KVM_REQ_TLB_FLUSH_CURRENT to flush current ASID
Add KVM_REQ_TLB_FLUSH_CURRENT to allow optimized TLB flushing of VMX's
EPTP/VPID contexts[*] from the KVM MMU and/or in a deferred manner, e.g.
to flush L2's context during nested VM-Enter.
Convert KVM_REQ_TLB_FLUSH to KVM_REQ_TLB_FLUSH_CURRENT in flows where
the flush is directly associated with vCPU-scoped instruction emulation,
i.e. MOV CR3 and INVPCID.
Add a comment in vmx_vcpu_load_vmcs() above its KVM_REQ_TLB_FLUSH to
make it clear that it deliberately requests a flush of all contexts.
Service any pending flush request on nested VM-Exit as it's possible a
nested VM-Exit could occur after requesting a flush for L2. Add the
same logic for nested VM-Enter even though it's _extremely_ unlikely
for flush to be pending on nested VM-Enter, but theoretically possible
(in the future) due to RSM (SMM) emulation.
[*] Intel also has an Address Space Identifier (ASID) concept, e.g.
EPTP+VPID+PCID == ASID, it's just not documented in the SDM because
the rules of invalidation are different based on which piece of the
ASID is being changed, i.e. whether the EPTP, VPID, or PCID context
must be invalidated.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-25-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:19 +0000 (14:28 -0700)]
KVM: nVMX: Add helper to handle TLB flushes on nested VM-Enter/VM-Exit
Add a helper to determine whether or not a full TLB flush needs to be
performed on nested VM-Enter/VM-Exit, as the logic is identical for both
flows and needs a fairly beefy comment to boot. This also provides a
common point to make future adjustments to the logic.
Handle vpid12 changes the new helper as well even though it is specific
to VM-Enter. The vpid12 logic is an extension of the flushing logic,
and it's worth the extra bool parameter to provide a single location for
the flushing logic.
Cc: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-24-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:18 +0000 (14:28 -0700)]
KVM: x86: Rename ->tlb_flush() to ->tlb_flush_all()
Rename ->tlb_flush() to ->tlb_flush_all() in preparation for adding a
new hook to flush only the current ASID/context.
Opportunstically replace the comment in vmx_flush_tlb() that explains
why it flushes all EPTP/VPID contexts with a comment explaining why it
unconditionally uses INVEPT when EPT is enabled. I.e. rely on the "all"
part of the name to clarify why it does global INVEPT/INVVPID.
No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-23-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:17 +0000 (14:28 -0700)]
KVM: SVM: Document the ASID logic in svm_flush_tlb()
Add a comment in svm_flush_tlb() to document why it flushes only the
current ASID, even when it is invoked when flushing remote TLBs.
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-22-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:16 +0000 (14:28 -0700)]
KVM: VMX: Introduce vmx_flush_tlb_current()
Add a helper to flush TLB entries only for the current EPTP/VPID context
and use it for the existing direct invocations of vmx_flush_tlb(). TLB
flushes that are specific to the current vCPU state do not need to flush
other contexts.
Note, both converted call sites happen to be related to the APIC access
page, this is purely coincidental.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-21-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:15 +0000 (14:28 -0700)]
KVM: nVMX: Move nested_get_vpid02() to vmx/nested.h
Move nested_get_vpid02() to vmx/nested.h so that a future patch can
reference it from vmx.c to implement context-specific TLB flushing.
No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-20-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:14 +0000 (14:28 -0700)]
KVM: VMX: Move vmx_flush_tlb() to vmx.c
Move vmx_flush_tlb() to vmx.c and make it non-inline static now that all
its callers live in vmx.c.
No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-19-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:13 +0000 (14:28 -0700)]
KVM: SVM: Wire up ->tlb_flush_guest() directly to svm_flush_tlb()
Use svm_flush_tlb() directly for kvm_x86_ops->tlb_flush_guest() now that
the @invalidate_gpa param to ->tlb_flush() is gone, i.e. the wrapper for
->tlb_flush_guest() is no longer necessary.
No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-18-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:12 +0000 (14:28 -0700)]
KVM: x86: Drop @invalidate_gpa param from kvm_x86_ops' tlb_flush()
Drop @invalidate_gpa from ->tlb_flush() and kvm_vcpu_flush_tlb() now
that all callers pass %true for said param, or ignore the param (SVM has
an internal call to svm_flush_tlb() in svm_flush_tlb_guest that somewhat
arbitrarily passes %false).
Remove __vmx_flush_tlb() as it is no longer used.
No functional change intended.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-17-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:11 +0000 (14:28 -0700)]
KVM: VMX: Clean up vmx_flush_tlb_gva()
Refactor vmx_flush_tlb_gva() to remove a superfluous local variable and
clean up its comment, which is oddly located below the code it is
commenting.
No functional change intended.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-16-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Vitaly Kuznetsov [Wed, 25 Mar 2020 16:28:24 +0000 (12:28 -0400)]
KVM: x86: make Hyper-V PV TLB flush use tlb_flush_guest()
Hyper-V PV TLB flush mechanism does TLB flush on behalf of the guest
so doing tlb_flush_all() is an overkill, switch to using tlb_flush_guest()
(just like KVM PV TLB flush mechanism) instead. Introduce
KVM_REQ_HV_TLB_FLUSH to support the change.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:10 +0000 (14:28 -0700)]
KVM: x86: Move "flush guest's TLB" logic to separate kvm_x86_ops hook
Add a dedicated hook to handle flushing TLB entries on behalf of the
guest, i.e. for a paravirtualized TLB flush, and use it directly instead
of bouncing through kvm_vcpu_flush_tlb().
For VMX, change the effective implementation implementation to never do
INVEPT and flush only the current context, i.e. to always flush via
INVVPID(SINGLE_CONTEXT). The INVEPT performed by __vmx_flush_tlb() when
@invalidate_gpa=false and enable_vpid=0 is unnecessary, as it will only
flush guest-physical mappings; linear and combined mappings are flushed
by VM-Enter when VPID is disabled, and changes in the guest pages tables
do not affect guest-physical mappings.
When EPT and VPID are enabled, doing INVVPID is not required (by Intel's
architecture) to invalidate guest-physical mappings, i.e. TLB entries
that cache guest-physical mappings can live across INVVPID as the
mappings are associated with an EPTP, not a VPID. The intent of
@invalidate_gpa is to inform vmx_flush_tlb() that it must "invalidate
gpa mappings", i.e. do INVEPT and not simply INVVPID. Other than nested
VPID handling, which now calls vpid_sync_context() directly, the only
scenario where KVM can safely do INVVPID instead of INVEPT (when EPT is
enabled) is if KVM is flushing TLB entries from the guest's perspective,
i.e. is only required to invalidate linear mappings.
For SVM, flushing TLB entries from the guest's perspective can be done
by flushing the current ASID, as changes to the guest's page tables are
associated only with the current ASID.
Adding a dedicated ->tlb_flush_guest() paves the way toward removing
@invalidate_gpa, which is a potentially dangerous control flag as its
meaning is not exactly crystal clear, even for those who are familiar
with the subtleties of what mappings Intel CPUs are/aren't allowed to
keep across various invalidation scenarios.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-15-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:09 +0000 (14:28 -0700)]
KVM: nVMX: Use vpid_sync_vcpu_addr() to emulate INVVPID with address
Use vpid_sync_vcpu_addr() to emulate the "individual address" variant of
INVVPID now that said function handles the fallback case of the (host)
CPU not supporting "individual address".
Note, the "vpid == 0" checks in the vpid_sync_*() helpers aren't
actually redundant with the "!operand.vpid" check in handle_invvpid(),
as the vpid passed to vpid_sync_vcpu_addr() is a KVM (host) controlled
value, i.e. vpid02 can be zero even if operand.vpid is non-zero.
No functional change intended.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-14-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:08 +0000 (14:28 -0700)]
KVM: VMX: Drop redundant capability checks in low level INVVPID helpers
Remove the INVVPID capabilities checks from vpid_sync_vcpu_single() and
vpid_sync_vcpu_global() now that all callers ensure the INVVPID variant
is supported. Note, in some cases the guarantee is provided in concert
with hardware_setup(), which enables VPID if and only if at least of
invvpid_single() or invvpid_global() is supported.
Drop the WARN_ON_ONCE() from vmx_flush_tlb() as vpid_sync_vcpu_single()
will trigger a WARN() on INVVPID failure, i.e. if SINGLE_CONTEXT isn't
supported.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-13-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:07 +0000 (14:28 -0700)]
KVM: VMX: Handle INVVPID fallback logic in vpid_sync_vcpu_addr()
Directly invoke vpid_sync_context() to do a global INVVPID when the
individual address variant is not supported instead of deferring such
behavior to the caller. This allows for additional consolidation of
code as the logic is basically identical to the emulation of the
individual address variant in handle_invvpid().
No functional change intended.
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-12-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:06 +0000 (14:28 -0700)]
KVM: VMX: Move vpid_sync_vcpu_addr() down a few lines
Move vpid_sync_vcpu_addr() below vpid_sync_context() so that it can be
refactored in a future patch to call vpid_sync_context() directly when
the "individual address" INVVPID variant isn't supported.
No functional change intended.
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-11-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:05 +0000 (14:28 -0700)]
KVM: VMX: Use vpid_sync_context() directly when possible
Use vpid_sync_context() directly for flows that run if and only if
enable_vpid=1, or more specifically, nested VMX flows that are gated by
vmx->nested.msrs.secondary_ctls_high.SECONDARY_EXEC_ENABLE_VPID being
set, which is allowed if and only if enable_vpid=1. Because these flows
call __vmx_flush_tlb() with @invalidate_gpa=false, the if-statement that
decides between INVEPT and INVVPID will always go down the INVVPID path,
i.e. call vpid_sync_context() because
"enable_ept && (invalidate_gpa || !enable_vpid)" always evaluates false.
This helps pave the way toward removing @invalidate_gpa and @vpid from
__vmx_flush_tlb() and its callers.
Opportunstically drop unnecessary brackets in handle_invvpid() around an
affected __vmx_flush_tlb()->vpid_sync_context() conversion.
No functional change intended.
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-10-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:04 +0000 (14:28 -0700)]
KVM: VMX: Skip global INVVPID fallback if vpid==0 in vpid_sync_context()
Skip the global INVVPID in the unlikely scenario that vpid==0 and the
SINGLE_CONTEXT variant of INVVPID is unsupported. If vpid==0, there's
no need to INVVPID as it's impossible to do VM-Enter with VPID enabled
and vmcs.VPID==0, i.e. there can't be any TLB entries for the vCPU with
vpid==0. The fact that the SINGLE_CONTEXT variant isn't supported is
irrelevant.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-9-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Junaid Shahid [Fri, 20 Mar 2020 21:28:03 +0000 (14:28 -0700)]
KVM: x86: Sync SPTEs when injecting page/EPT fault into L1
When injecting a page fault or EPT violation/misconfiguration, KVM is
not syncing any shadow PTEs associated with the faulting address,
including those in previous MMUs that are associated with L1's current
EPTP (in a nested EPT scenario), nor is it flushing any hardware TLB
entries. All this is done by kvm_mmu_invalidate_gva.
Page faults that are either !PRESENT or RSVD are exempt from the flushing,
as the CPU is not allowed to cache such translations.
Signed-off-by: Junaid Shahid <junaids@google.com>
Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-8-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Wed, 25 Mar 2020 16:50:03 +0000 (12:50 -0400)]
KVM: x86: cleanup kvm_inject_emulated_page_fault
To reconstruct the kvm_mmu to be used for page fault injection, we
can simply use fault->nested_page_fault. This matches how
fault->nested_page_fault is assigned in the first place by
FNAME(walk_addr_generic).
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Tue, 24 Mar 2020 00:42:57 +0000 (20:42 -0400)]
KVM: x86: introduce kvm_mmu_invalidate_gva
Wrap the combination of mmu->invlpg and kvm_x86_ops->tlb_flush_gva
into a new function. This function also lets us specify the host PGD to
invalidate and also the MMU, both of which will be useful in fixing and
simplifying kvm_inject_emulated_page_fault.
A nested guest's MMU however has g_context->invlpg == NULL. Instead of
setting it to nonpaging_invlpg, make kvm_mmu_invalidate_gva the only
entry point to mmu->invlpg and make a NULL invlpg pointer equivalent
to nonpaging_invlpg, saving a retpoline.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:28:01 +0000 (14:28 -0700)]
KVM: x86: Export kvm_propagate_fault() (as kvm_inject_emulated_page_fault)
Export the page fault propagation helper so that VMX can use it to
correctly emulate TLB invalidation on page faults in an upcoming patch.
In the (hopefully) not-too-distant future, SGX virtualization will also
want access to the helper for injecting page faults to the correct level
(L1 vs. L2) when emulating ENCLS instructions.
Rename the function to kvm_inject_emulated_page_fault() to clarify that
it is (a) injecting a fault and (b) only for page faults. WARN if it's
invoked with an exception other than PF_VECTOR.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-6-sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Junaid Shahid [Fri, 20 Mar 2020 21:28:00 +0000 (14:28 -0700)]
KVM: nVMX: Invalidate all roots when emulating INVVPID without EPT
Free all roots when emulating INVVPID for L1 and EPT is disabled, as
outstanding changes to the page tables managed by L1 need to be
recognized. Because L1 and L2 share an MMU when EPT is disabled, and
because VPID is not tracked by the MMU role, all roots in the current
MMU (root_mmu) need to be freed, otherwise a future nested VM-Enter or
VM-Exit could do a fast CR3 switch (without a flush/sync) and consume
stale SPTEs.
Fixes:
5c614b3583e7b ("KVM: nVMX: nested VPID emulation")
Signed-off-by: Junaid Shahid <junaids@google.com>
[sean: ported to upstream KVM, reworded the comment and changelog]
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-5-sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:27:59 +0000 (14:27 -0700)]
KVM: nVMX: Invalidate all EPTP contexts when emulating INVEPT for L1
Free all L2 (guest_mmu) roots when emulating INVEPT for L1. Outstanding
changes to the EPT tables managed by L1 need to be recognized, and
relying on KVM to always flush L2's EPTP context on nested VM-Enter is
dangerous.
Similar to handle_invpcid(), rely on kvm_mmu_free_roots() to do a remote
TLB flush if necessary, e.g. if L1 has never entered L2 then there is
nothing to be done.
Nuking all L2 roots is overkill for the single-context variant, but it's
the safe and easy bet. A more precise zap mechanism will be added in
the future. Add a TODO to call out that KVM only needs to invalidate
affected contexts.
Fixes:
14c07ad89f4d ("x86/kvm/mmu: introduce guest_mmu")
Reported-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-4-sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:27:58 +0000 (14:27 -0700)]
KVM: nVMX: Validate the EPTP when emulating INVEPT(EXTENT_CONTEXT)
Signal VM-Fail for the single-context variant of INVEPT if the specified
EPTP is invalid. Per the INEVPT pseudocode in Intel's SDM, it's subject
to the standard EPT checks:
If VM entry with the "enable EPT" VM execution control set to 1 would
fail due to the EPTP value then VMfail(Invalid operand to INVEPT/INVVPID);
Fixes:
bfd0a56b90005 ("nEPT: Nested INVEPT")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-3-sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 20 Mar 2020 21:27:57 +0000 (14:27 -0700)]
KVM: VMX: Flush all EPTP/VPID contexts on remote TLB flush
Flush all EPTP/VPID contexts if a TLB flush _may_ have been triggered by
a remote or deferred TLB flush, i.e. by KVM_REQ_TLB_FLUSH. Remote TLB
flushes require all contexts to be invalidated, not just the active
contexts, e.g. all mappings in all contexts for a given HVA need to be
invalidated on a mmu_notifier invalidation. Similarly, the instigator
of the deferred TLB flush may be expecting all contexts to be flushed,
e.g. vmx_vcpu_load_vmcs().
Without nested VMX, flushing only the current EPTP/VPID context isn't
problematic because KVM uses a constant VPID for each vCPU, and
mmu_alloc_direct_roots() all but guarantees KVM will use a single EPTP
for L1. In the rare case where a different EPTP is created or reused,
KVM (currently) unconditionally flushes the new EPTP context prior to
entering the guest.
With nested VMX, KVM conditionally uses a different VPID for L2, and
unconditionally uses a different EPTP for L2. Because KVM doesn't
_intentionally_ guarantee L2's EPTP/VPID context is flushed on nested
VM-Enter, it'd be possible for a malicious L1 to attack the host and/or
different VMs by exploiting the lack of flushing for L2.
1) Launch nested guest from malicious L1.
2) Nested VM-Enter to L2.
3) Access target GPA 'g'. CPU inserts TLB entry tagged with L2's ASID
mapping 'g' to host PFN 'x'.
2) Nested VM-Exit to L1.
3) L1 triggers kernel same-page merging (ksm) by duplicating/zeroing
the page for PFN 'x'.
4) Host kernel merges PFN 'x' with PFN 'y', i.e. unmaps PFN 'x' and
remaps the page to PFN 'y'. mmu_notifier sends invalidate command,
KVM flushes TLB only for L1's ASID.
4) Host kernel reallocates PFN 'x' to some other task/guest.
5) Nested VM-Enter to L2. KVM does not invalidate L2's EPTP or VPID.
6) L2 accesses GPA 'g' and gains read/write access to PFN 'x' via its
stale TLB entry.
However, current KVM unconditionally flushes L1's EPTP/VPID context on
nested VM-Exit. But, that behavior is mostly unintentional, KVM doesn't
go out of its way to flush EPTP/VPID on nested VM-Enter/VM-Exit, rather
a TLB flush is guaranteed to occur prior to re-entering L1 due to
__kvm_mmu_new_cr3() always being called with skip_tlb_flush=false. On
nested VM-Enter, this happens via kvm_init_shadow_ept_mmu() (nested EPT
enabled) or in nested_vmx_load_cr3() (nested EPT disabled). On nested
VM-Exit it occurs via nested_vmx_load_cr3().
This also fixes a bug where a deferred TLB flush in the context of L2,
with EPT disabled, would flush L1's VPID instead of L2's VPID, as
vmx_flush_tlb() flushes L1's VPID regardless of is_guest_mode().
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Ben Gardon <bgardon@google.com>
Cc: Jim Mattson <jmattson@google.com>
Cc: Junaid Shahid <junaids@google.com>
Cc: Liran Alon <liran.alon@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: John Haxby <john.haxby@oracle.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Fixes:
efebf0aaec3d ("KVM: nVMX: Do not flush TLB on L1<->L2 transitions if L1 uses VPID and EPT")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200320212833.3507-2-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Wainer dos Santos Moschetta [Fri, 10 Apr 2020 23:17:07 +0000 (16:17 -0700)]
selftests: kvm: Add testcase for creating max number of memslots
This patch introduces test_add_max_memory_regions(), which checks
that a VM can have added memory slots up to the limit defined in
KVM_CAP_NR_MEMSLOTS. Then attempt to add one more slot to
verify it fails as expected.
Signed-off-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200410231707.7128-11-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 10 Apr 2020 23:17:06 +0000 (16:17 -0700)]
KVM: selftests: Make set_memory_region_test common to all architectures
Make set_memory_region_test available on all architectures by wrapping
the bits that are x86-specific in ifdefs. A future testcase
to create the maximum number of memslots will be architecture
agnostic.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200410231707.7128-10-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 10 Apr 2020 23:17:05 +0000 (16:17 -0700)]
KVM: selftests: Add "zero" testcase to set_memory_region_test
Add a testcase for running a guest with no memslots to the memory region
test. The expected result on x86_64 is that the guest will trigger an
internal KVM error due to the initial code fetch encountering a
non-existent memslot and resulting in an emulation failure.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200410231707.7128-9-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Wainer dos Santos Moschetta [Fri, 10 Apr 2020 23:17:04 +0000 (16:17 -0700)]
selftests: kvm: Add vm_get_fd() in kvm_util
Introduces the vm_get_fd() function in kvm_util which returns
the VM file descriptor.
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200410231707.7128-8-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 10 Apr 2020 23:17:03 +0000 (16:17 -0700)]
KVM: selftests: Add "delete" testcase to set_memory_region_test
Add a testcase for deleting memslots while the guest is running.
Like the "move" testcase, this is x86_64-only as it relies on MMIO
happening when a non-existent memslot is encountered.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200410231707.7128-7-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 10 Apr 2020 23:17:02 +0000 (16:17 -0700)]
KVM: sefltests: Add explicit synchronization to move mem region test
Use sem_post() and sem_timedwait() to synchronize test stages between
the vCPU thread and the main thread instead of using usleep() to wait
for the vCPU thread and hoping for the best.
Opportunistically refactor the code to make it suck less in general,
and to prepare for adding more testcases.
Suggested-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200410231707.7128-6-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 10 Apr 2020 23:17:01 +0000 (16:17 -0700)]
KVM: selftests: Add GUEST_ASSERT variants to pass values to host
Add variants of GUEST_ASSERT to pass values back to the host, e.g. to
help debug/understand a failure when the the cause of the assert isn't
necessarily binary.
It'd probably be possible to auto-calculate the number of arguments and
just have a single GUEST_ASSERT, but there are a limited number of
variants and silently eating arguments could lead to subtle code bugs.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200410231707.7128-5-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 10 Apr 2020 23:17:00 +0000 (16:17 -0700)]
KVM: selftests: Add util to delete memory region
Add a utility to delete a memory region, it will be used by x86's
set_memory_region_test.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Message-Id: <
20200410231707.7128-4-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 10 Apr 2020 23:16:59 +0000 (16:16 -0700)]
KVM: selftests: Use kernel's list instead of homebrewed replacement
Replace the KVM selftests' homebrewed linked lists for vCPUs and memory
regions with the kernel's 'struct list_head'.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Message-Id: <
20200410231707.7128-3-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Fri, 10 Apr 2020 23:16:58 +0000 (16:16 -0700)]
KVM: selftests: Take vcpu pointer instead of id in vm_vcpu_rm()
The sole caller of vm_vcpu_rm() already has the vcpu pointer, take it
directly instead of doing an extra lookup.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Message-Id: <
20200410231707.7128-2-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Eric Northup [Wed, 15 Apr 2020 01:23:20 +0000 (18:23 -0700)]
KVM: pass through CPUID(0x80000006)
Return the host's L2 cache and TLB information for CPUID.0x80000006
instead of zeroing out the entry as part of KVM_GET_SUPPORTED_CPUID.
This allows a userspace VMM to feed KVM_GET_SUPPORTED_CPUID's output
directly into KVM_SET_CPUID2 (without breaking the guest).
Signed-off-by: Eric Northup (Google) <digitaleric@gmail.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Jon Cargille <jcargill@google.com>
Message-Id: <
20200415012320.236065-1-jcargill@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Peter Shier [Wed, 10 Oct 2018 22:56:53 +0000 (15:56 -0700)]
KVM: x86: Return updated timer current count register from KVM_GET_LAPIC
kvm_vcpu_ioctl_get_lapic (implements KVM_GET_LAPIC ioctl) does a bulk copy
of the LAPIC registers but must take into account that the one-shot and
periodic timer current count register is computed upon reads and is not
present in register state. When restoring LAPIC state (e.g. after
migration), restart timers from their their current count values at time of
save.
Note: When a one-shot timer expires, the code in arch/x86/kvm/lapic.c does
not zero the value of the LAPIC initial count register (emulating HW
behavior). If no other timer is run and pending prior to a subsequent
KVM_GET_LAPIC call, the returned register set will include the expired
one-shot initial count. On a subsequent KVM_SET_LAPIC call the code will
see a non-zero initial count and start a new one-shot timer using the
expired timer's count. This is a prior existing bug and will be addressed
in a separate patch. Thanks to jmattson@google.com for this find.
Signed-off-by: Peter Shier <pshier@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <
20181010225653.238911-1-pshier@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Colin Ian King [Fri, 10 Apr 2020 11:35:26 +0000 (12:35 +0100)]
KVM: remove redundant assignment to variable r
The variable r is being assigned with a value that is never read
and it is being updated later with a new value. The initialization is
redundant and can be removed.
Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Message-Id: <
20200410113526.13822-1-colin.king@canonical.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Uros Bizjak [Thu, 9 Apr 2020 11:49:26 +0000 (13:49 +0200)]
KVM: SVM: Fix __svm_vcpu_run declaration.
The function returns no value.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Fixes:
199cd1d7b534 ("KVM: SVM: Split svm_vcpu_run inline assembly to separate file")
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Message-Id: <
20200409114926.1407442-1-ubizjak@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Uros Bizjak [Thu, 9 Apr 2020 12:04:40 +0000 (14:04 +0200)]
KVM: SVM: Do not setup frame pointer in __svm_vcpu_run
__svm_vcpu_run is a leaf function and does not need
a frame pointer. %rbp is also destroyed a few instructions
later when guest registers are loaded.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Message-Id: <
20200409120440.1427215-1-ubizjak@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Borislav Petkov [Sat, 11 Apr 2020 16:09:27 +0000 (18:09 +0200)]
KVM: SVM: Fix build error due to missing release_pages() include
Fix:
arch/x86/kvm/svm/sev.c: In function ‘sev_pin_memory’:
arch/x86/kvm/svm/sev.c:360:3: error: implicit declaration of function ‘release_pages’;\
did you mean ‘reclaim_pages’? [-Werror=implicit-function-declaration]
360 | release_pages(pages, npinned);
| ^~~~~~~~~~~~~
| reclaim_pages
because svm.c includes pagemap.h but the carved out sev.c needs it too.
Triggered by a randconfig build.
Fixes:
eaf78265a4ab ("KVM: SVM: Move SEV code to separate file")
Signed-off-by: Borislav Petkov <bp@suse.de>
Message-Id: <
20200411160927.27954-1-bp@alien8.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Uros Bizjak [Tue, 14 Apr 2020 11:36:12 +0000 (13:36 +0200)]
KVM: SVM: Do not mark svm_vcpu_run with STACK_FRAME_NON_STANDARD
svm_vcpu_run does not change stack or frame pointer anymore.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Message-Id: <
20200414113612.104501-1-ubizjak@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Oliver Upton [Tue, 14 Apr 2020 22:12:41 +0000 (22:12 +0000)]
kvm: nVMX: match comment with return type for nested_vmx_exit_reflected
nested_vmx_exit_reflected() returns a bool, not int. As such, refer to
the return values as true/false in the comment instead of 1/0.
Signed-off-by: Oliver Upton <oupton@google.com>
Message-Id: <
20200414221241.134103-1-oupton@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Oliver Upton [Tue, 14 Apr 2020 22:47:45 +0000 (22:47 +0000)]
kvm: nVMX: reflect MTF VM-exits if injected by L1
According to SDM 26.6.2, it is possible to inject an MTF VM-exit via the
VM-entry interruption-information field regardless of the 'monitor trap
flag' VM-execution control. KVM appropriately copies the VM-entry
interruption-information field from vmcs12 to vmcs02. However, if L1
has not set the 'monitor trap flag' VM-execution control, KVM fails to
reflect the subsequent MTF VM-exit into L1.
Fix this by consulting the VM-entry interruption-information field of
vmcs12 to determine if L1 has injected the MTF VM-exit. If so, reflect
the exit, regardless of the 'monitor trap flag' VM-execution control.
Fixes:
5f3d45e7f282 ("kvm/x86: add support for MONITOR_TRAP_FLAG")
Signed-off-by: Oliver Upton <oupton@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Message-Id: <
20200414224746.240324-1-oupton@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Wed, 8 Apr 2020 06:40:59 +0000 (23:40 -0700)]
KVM: s390: Return last valid slot if approx index is out-of-bounds
Return the index of the last valid slot from gfn_to_memslot_approx() if
its binary search loop yielded an out-of-bounds index. The index can
be out-of-bounds if the specified gfn is less than the base of the
lowest memslot (which is also the last valid memslot).
Note, the sole caller, kvm_s390_get_cmma(), ensures used_slots is
non-zero.
Fixes:
afdad61615cc3 ("KVM: s390: Fix storage attributes migration with memory slots")
Cc: stable@vger.kernel.org # 4.19.x: 0774a964ef56: KVM: Fix out of range accesses to memslots
Cc: stable@vger.kernel.org # 4.19.x
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200408064059.8957-3-sean.j.christopherson@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Sean Christopherson [Wed, 8 Apr 2020 06:40:58 +0000 (23:40 -0700)]
KVM: Check validity of resolved slot when searching memslots
Check that the resolved slot (somewhat confusingly named 'start') is a
valid/allocated slot before doing the final comparison to see if the
specified gfn resides in the associated slot. The resolved slot can be
invalid if the binary search loop terminated because the search index
was incremented beyond the number of used slots.
This bug has existed since the binary search algorithm was introduced,
but went unnoticed because KVM statically allocated memory for the max
number of slots, i.e. the access would only be truly out-of-bounds if
all possible slots were allocated and the specified gfn was less than
the base of the lowest memslot. Commit
36947254e5f98 ("KVM: Dynamically
size memslot array based on number of used slots") eliminated the "all
possible slots allocated" condition and made the bug embarrasingly easy
to hit.
Fixes:
9c1a5d38780e6 ("kvm: optimize GFN to memslot lookup with large slots amount")
Reported-by: syzbot+d889b59b2bb87d4047a2@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <
20200408064059.8957-2-sean.j.christopherson@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Uros Bizjak [Tue, 14 Apr 2020 07:14:14 +0000 (09:14 +0200)]
KVM: VMX: Enable machine check support for 32bit targets
There is no reason to limit the use of do_machine_check
to 64bit targets. MCE handling works for both target familes.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: stable@vger.kernel.org
Fixes:
a0861c02a981 ("KVM: Add VT-x machine check support")
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Message-Id: <
20200414071414.45636-1-ubizjak@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Mon, 13 Apr 2020 07:17:58 +0000 (03:17 -0400)]
KVM: SVM: move more vmentry code to assembly
Manipulate IF around vmload/vmsave to remove the confusing usage of
local_irq_enable where interrupts are actually disabled via GIF.
And stuff the RSB immediately without waiting for a RET to avoid
Spectre-v2 attacks.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Mon, 13 Apr 2020 07:20:06 +0000 (03:20 -0400)]
KVM: SVM: fix compilation with modular PSP and non-modular KVM
Use svm_sev_enabled() in order to cull all calls to PSP code. Otherwise,
compilation fails with undefined symbols if the PSP device driver is compiled
as a module and KVM is not.
Reported-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Vitaly Kuznetsov [Wed, 1 Apr 2020 08:13:48 +0000 (10:13 +0200)]
KVM: VMX: fix crash cleanup when KVM wasn't used
If KVM wasn't used at all before we crash the cleanup procedure fails with
BUG: unable to handle page fault for address:
ffffffffffffffc8
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD
23215067 P4D
23215067 PUD
23217067 PMD 0
Oops: 0000 [#8] SMP PTI
CPU: 0 PID: 3542 Comm: bash Kdump: loaded Tainted: G D 5.6.0-rc2+ #823
RIP: 0010:crash_vmclear_local_loaded_vmcss.cold+0x19/0x51 [kvm_intel]
The root cause is that loaded_vmcss_on_cpu list is not yet initialized,
we initialize it in hardware_enable() but this only happens when we start
a VM.
Previously, we used to have a bitmap with enabled CPUs and that was
preventing [masking] the issue.
Initialized loaded_vmcss_on_cpu list earlier, right before we assign
crash_vmclear_loaded_vmcss pointer. blocked_vcpu_on_cpu list and
blocked_vcpu_on_cpu_lock are moved altogether for consistency.
Fixes:
31603d4fc2bb ("KVM: VMX: Always VMCLEAR in-use VMCSes during crash with kexec support")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <
20200401081348.1345307-1-vkuznets@redhat.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Wanpeng Li [Thu, 2 Apr 2020 08:20:26 +0000 (16:20 +0800)]
KVM: X86: Filter out the broadcast dest for IPI fastpath
Except destination shorthand, a destination value 0xffffffff is used to
broadcast interrupts, let's also filter out this for single target IPI
fastpath.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <
1585815626-28370-1-git-send-email-wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Paolo Bonzini [Tue, 7 Apr 2020 12:31:44 +0000 (08:31 -0400)]
Merge tag 'kvm-s390-master-5.7-1' of git://git./linux/kernel/git/kvms390/linux into HEAD
KVM: s390: Fixes for vsie (nested hypervisors)
- Several fixes for corner cases of nesting. Still relevant as it might
crash host or first level guest or temporarily leak memory.
David Hildenbrand [Fri, 3 Apr 2020 15:30:48 +0000 (17:30 +0200)]
KVM: s390: vsie: Fix possible race when shadowing region 3 tables
We have to properly retry again by returning -EINVAL immediately in case
somebody else instantiated the table concurrently. We missed to add the
goto in this function only. The code now matches the other, similar
shadowing functions.
We are overwriting an existing region 2 table entry. All allocated pages
are added to the crst_list to be freed later, so they are not lost
forever. However, when unshadowing the region 2 table, we wouldn't trigger
unshadowing of the original shadowed region 3 table that we replaced. It
would get unshadowed when the original region 3 table is modified. As it's
not connected to the page table hierarchy anymore, it's not going to get
used anymore. However, for a limited time, this page table will stick
around, so it's in some sense a temporary memory leak.
Identified by manual code inspection. I don't think this classifies as
stable material.
Fixes:
998f637cc4b9 ("s390/mm: avoid races on region/segment/page table shadowing")
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20200403153050.20569-4-david@redhat.com
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
David Hildenbrand [Fri, 3 Apr 2020 15:30:47 +0000 (17:30 +0200)]
KVM: s390: vsie: Fix delivery of addressing exceptions
Whenever we get an -EFAULT, we failed to read in guest 2 physical
address space. Such addressing exceptions are reported via a program
intercept to the nested hypervisor.
We faked the intercept, we have to return to guest 2. Instead, right
now we would be returning -EFAULT from the intercept handler, eventually
crashing the VM.
the correct thing to do is to return 1 as rc == 1 is the internal
representation of "we have to go back into g2".
Addressing exceptions can only happen if the g2->g3 page tables
reference invalid g2 addresses (say, either a table or the final page is
not accessible - so something that basically never happens in sane
environments.
Identified by manual code inspection.
Fixes:
a3508fbe9dc6 ("KVM: s390: vsie: initial support for nested virtualization")
Cc: <stable@vger.kernel.org> # v4.8+
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20200403153050.20569-3-david@redhat.com
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
[borntraeger@de.ibm.com: fix patch description]
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
David Hildenbrand [Fri, 3 Apr 2020 15:30:46 +0000 (17:30 +0200)]
KVM: s390: vsie: Fix region 1 ASCE sanity shadow address checks
In case we have a region 1 the following calculation
(31 + ((gmap->asce & _ASCE_TYPE_MASK) >> 2)*11)
results in 64. As shifts beyond the size are undefined the compiler is
free to use instructions like sllg. sllg will only use 6 bits of the
shift value (here 64) resulting in no shift at all. That means that ALL
addresses will be rejected.
The can result in endless loops, e.g. when prefix cannot get mapped.
Fixes:
4be130a08420 ("s390/mm: add shadow gmap support")
Tested-by: Janosch Frank <frankja@linux.ibm.com>
Reported-by: Janosch Frank <frankja@linux.ibm.com>
Cc: <stable@vger.kernel.org> # v4.8+
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20200403153050.20569-2-david@redhat.com
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
[borntraeger@de.ibm.com: fix patch description, remove WARN_ON_ONCE]
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Oliver Upton [Mon, 6 Apr 2020 20:12:37 +0000 (20:12 +0000)]
KVM: nVMX: don't clear mtf_pending when nested events are blocked
If nested events are blocked, don't clear the mtf_pending flag to avoid
missing later delivery of the MTF VM-exit.
Fixes:
5ef8acbdd687c ("KVM: nVMX: Emulate MTF when performing instruction emulation")
Signed-off-by: Oliver Upton <oupton@google.com>
Message-Id: <
20200406201237.178725-1-oupton@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Uros Bizjak [Mon, 6 Apr 2020 20:21:08 +0000 (22:21 +0200)]
KVM: VMX: Remove unnecessary exception trampoline in vmx_vmenter
The exception trampoline in .fixup section is not needed, the exception
handling code can jump directly to the label in the .text section.
Changes since v1:
- Fix commit message.
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Message-Id: <
20200406202108.74300-1-ubizjak@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Uros Bizjak [Mon, 30 Mar 2020 13:02:13 +0000 (15:02 +0200)]
KVM: SVM: Split svm_vcpu_run inline assembly to separate file
The compiler (GCC) does not like the situation, where there is inline
assembly block that clobbers all available machine registers in the
middle of the function. This situation can be found in function
svm_vcpu_run in file kvm/svm.c and results in many register spills and
fills to/from stack frame.
This patch fixes the issue with the same approach as was done for
VMX some time ago. The big inline assembly is moved to a separate
assembly .S file, taking into account all ABI requirements.
There are two main benefits of the above approach:
* elimination of several register spills and fills to/from stack
frame, and consequently smaller function .text size. The binary size
of svm_vcpu_run is lowered from 2019 to 1626 bytes.
* more efficient access to a register save array. Currently, register
save array is accessed as:
7b00: 48 8b 98 28 02 00 00 mov 0x228(%rax),%rbx
7b07: 48 8b 88 18 02 00 00 mov 0x218(%rax),%rcx
7b0e: 48 8b 90 20 02 00 00 mov 0x220(%rax),%rdx
and passing ia pointer to a register array as an argument to a function one gets:
12: 48 8b 48 08 mov 0x8(%rax),%rcx
16: 48 8b 50 10 mov 0x10(%rax),%rdx
1a: 48 8b 58 18 mov 0x18(%rax),%rbx
As a result, the total size, considering that the new function size is 229
bytes, gets lowered by 164 bytes.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Joerg Roedel [Tue, 24 Mar 2020 09:41:54 +0000 (10:41 +0100)]
KVM: SVM: Move SEV code to separate file
Move the SEV specific parts of svm.c into the new sev.c file.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Message-Id: <
20200324094154.32352-5-joro@8bytes.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Joerg Roedel [Tue, 31 Mar 2020 16:17:38 +0000 (12:17 -0400)]
KVM: SVM: Move AVIC code to separate file
Move the AVIC related functions from svm.c to the new avic.c file.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Message-Id: <
20200324094154.32352-4-joro@8bytes.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Joerg Roedel [Tue, 24 Mar 2020 09:41:52 +0000 (10:41 +0100)]
KVM: SVM: Move Nested SVM Implementation to nested.c
Split out the code for the nested SVM implementation and move it to a
separate file.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Message-Id: <
20200324094154.32352-3-joro@8bytes.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Joerg Roedel [Tue, 24 Mar 2020 09:41:51 +0000 (10:41 +0100)]
kVM SVM: Move SVM related files to own sub-directory
Move svm.c and pmu_amd.c into their own arch/x86/kvm/svm/
subdirectory.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Message-Id: <
20200324094154.32352-2-joro@8bytes.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Linus Torvalds [Thu, 2 Apr 2020 22:13:15 +0000 (15:13 -0700)]
Merge tag 'for-linus' of git://git./virt/kvm/kvm
Pull kvm updates from Paolo Bonzini:
"ARM:
- GICv4.1 support
- 32bit host removal
PPC:
- secure (encrypted) using under the Protected Execution Framework
ultravisor
s390:
- allow disabling GISA (hardware interrupt injection) and protected
VMs/ultravisor support.
x86:
- New dirty bitmap flag that sets all bits in the bitmap when dirty
page logging is enabled; this is faster because it doesn't require
bulk modification of the page tables.
- Initial work on making nested SVM event injection more similar to
VMX, and less buggy.
- Various cleanups to MMU code (though the big ones and related
optimizations were delayed to 5.8). Instead of using cr3 in
function names which occasionally means eptp, KVM too has
standardized on "pgd".
- A large refactoring of CPUID features, which now use an array that
parallels the core x86_features.
- Some removal of pointer chasing from kvm_x86_ops, which will also
be switched to static calls as soon as they are available.
- New Tigerlake CPUID features.
- More bugfixes, optimizations and cleanups.
Generic:
- selftests: cleanups, new MMU notifier stress test, steal-time test
- CSV output for kvm_stat"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (277 commits)
x86/kvm: fix a missing-prototypes "vmread_error"
KVM: x86: Fix BUILD_BUG() in __cpuid_entry_get_reg() w/ CONFIG_UBSAN=y
KVM: VMX: Add a trampoline to fix VMREAD error handling
KVM: SVM: Annotate svm_x86_ops as __initdata
KVM: VMX: Annotate vmx_x86_ops as __initdata
KVM: x86: Drop __exit from kvm_x86_ops' hardware_unsetup()
KVM: x86: Copy kvm_x86_ops by value to eliminate layer of indirection
KVM: x86: Set kvm_x86_ops only after ->hardware_setup() completes
KVM: VMX: Configure runtime hooks using vmx_x86_ops
KVM: VMX: Move hardware_setup() definition below vmx_x86_ops
KVM: x86: Move init-only kvm_x86_ops to separate struct
KVM: Pass kvm_init()'s opaque param to additional arch funcs
s390/gmap: return proper error code on ksm unsharing
KVM: selftests: Fix cosmetic copy-paste error in vm_mem_region_move()
KVM: Fix out of range accesses to memslots
KVM: X86: Micro-optimize IPI fastpath delay
KVM: X86: Delay read msr data iff writes ICR MSR
KVM: PPC: Book3S HV: Add a capability for enabling secure guests
KVM: arm64: GICv4.1: Expose HW-based SGIs in debugfs
KVM: arm64: GICv4.1: Allow non-trapping WFI when using HW SGIs
...
Linus Torvalds [Thu, 2 Apr 2020 21:52:12 +0000 (14:52 -0700)]
Merge tag 'x86-urgent-2020-04-02' of git://git./linux/kernel/git/tip/tip
Pull x86 fix from Ingo Molnar:
"A single fix addressing Sparse warnings. <asm/bitops.h> is changed
non-trivially to avoid the warnings, but generated code is not
supposed to be affected"
* tag 'x86-urgent-2020-04-02' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86: Fix bitops.h warning with a moved cast
Linus Torvalds [Thu, 2 Apr 2020 21:49:46 +0000 (14:49 -0700)]
Merge branch 'next-integrity' of git://git./linux/kernel/git/zohar/linux-integrity
Pull integrity updates from Mimi Zohar:
"Just a couple of updates for linux-5.7:
- A new Kconfig option to enable IMA architecture specific runtime
policy rules needed for secure and/or trusted boot, as requested.
- Some message cleanup (eg. pr_fmt, additional error messages)"
* 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
ima: add a new CONFIG for loading arch-specific policies
integrity: Remove duplicate pr_fmt definitions
IMA: Add log statements for failure conditions
IMA: Update KBUILD_MODNAME for IMA files to ima
Linus Torvalds [Thu, 2 Apr 2020 20:55:34 +0000 (13:55 -0700)]
Merge branch 'akpm' (patches from Andrew)
Merge updates from Andrew Morton:
"A large amount of MM, plenty more to come.
Subsystems affected by this patch series:
- tools
- kthread
- kbuild
- scripts
- ocfs2
- vfs
- mm: slub, kmemleak, pagecache, gup, swap, memcg, pagemap, mremap,
sparsemem, kasan, pagealloc, vmscan, compaction, mempolicy,
hugetlbfs, hugetlb"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (155 commits)
include/linux/huge_mm.h: check PageTail in hpage_nr_pages even when !THP
mm/hugetlb: fix build failure with HUGETLB_PAGE but not HUGEBTLBFS
selftests/vm: fix map_hugetlb length used for testing read and write
mm/hugetlb: remove unnecessary memory fetch in PageHeadHuge()
mm/hugetlb.c: clean code by removing unnecessary initialization
hugetlb_cgroup: add hugetlb_cgroup reservation docs
hugetlb_cgroup: add hugetlb_cgroup reservation tests
hugetlb: support file_region coalescing again
hugetlb_cgroup: support noreserve mappings
hugetlb_cgroup: add accounting for shared mappings
hugetlb: disable region_add file_region coalescing
hugetlb_cgroup: add reservation accounting for private mappings
mm/hugetlb_cgroup: fix hugetlb_cgroup migration
hugetlb_cgroup: add interface for charge/uncharge hugetlb reservations
hugetlb_cgroup: add hugetlb_cgroup reservation counter
hugetlbfs: Use i_mmap_rwsem to address page fault/truncate race
hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization
mm/memblock.c: remove redundant assignment to variable max_addr
mm: mempolicy: require at least one nodeid for MPOL_PREFERRED
mm: mempolicy: use VM_BUG_ON_VMA in queue_pages_test_walk()
...
Linus Torvalds [Thu, 2 Apr 2020 20:02:07 +0000 (13:02 -0700)]
Merge tag 'xfs-5.7-merge-8' of git://git./fs/xfs/xfs-linux
Pull xfs updates from Darrick Wong:
"There's a lot going on this cycle with cleanups in the log code, the
btree code, and the xattr code.
We're tightening of metadata validation and online fsck checking, and
introducing a common btree rebuilding library so that we can refactor
xfs_repair and introduce online repair in a future cycle.
We also fixed a few visible bugs -- most notably there's one in
getdents that we introduced in 5.6; and a fix for hangs when disabling
quotas.
This series has been running fstests & other QA in the background for
over a week and looks good so far.
I anticipate sending a second pull request next week. That batch will
change how xfs interacts with memory reclaim; how the log batches and
throttles log items; how hard writes near ENOSPC will try to squeeze
more space out of the filesystem; and hopefully fix the last of the
umount hangs after a catastrophic failure. That should ease a lot of
problems when running at the limits, but for now I'm leaving that in
for-next for another week to make sure we got all the subtleties
right.
Summary:
- Fix a hard to trigger race between iclog error checking and log
shutdown.
- Strengthen the AGF verifier.
- Ratelimit some of the more spammy error messages.
- Remove the icdinode uid/gid members and just use the ones in the
vfs inode.
- Hold ILOCK across insert/collapse range.
- Clean up the extended attribute interfaces.
- Clean up the attr flags mess.
- Restore PF_MEMALLOC after exiting xfsaild thread to avoid
triggering warnings in the process accounting code.
- Remove the flexibly-sized array from struct xfs_agfl to eliminate
compiler warnings about unaligned pointers and packed structures.
- Various macro and typedef removals.
- Stale metadata buffers if we decide they're corrupt outside of a
verifier.
- Check directory data/block/free block owners.
- Fix a UAF when aborting inactivation of a corrupt xattr fork.
- Teach online scrub to report failed directory and attr name lookups
as a metadata corruption instead of a runtime error.
- Avoid potential buffer overflows in sysfs files by using scnprintf.
- Fix a regression in getdents lookups due to a mistake in pointer
arithmetic.
- Refactor btree cursor private data structures to use anonymous
unions.
- Cleanups in the log unmounting code.
- Fix a potential mishandling of ENOMEM errors on multi-block
directory buffer lookups.
- Fix an incorrect test in the block allocation code.
- Cleanups and name prefix shortening in the scrub code.
- Introduce btree bulk loading code for online repair and scrub.
- Fix a quotaoff log item leak (and hang) when the fs goes down
midway through a quotaoff operation.
- Remove di_version from the incore inode.
- Refactor some of the log shutdown checking code.
- Record the forcing of the log unmount records in the log force
counters.
- Fix a longstanding bug where quotacheck would purge the
administrator's default quota grace interval and warning limits.
- Reduce memory usage when scrubbing directory and xattr trees.
- Don't let fsfreeze race with GETFSMAP or online scrub.
- Handle bio_add_page failures more gracefully in xlog_write_iclog"
* tag 'xfs-5.7-merge-8' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (108 commits)
xfs: prohibit fs freezing when using empty transactions
xfs: shutdown on failure to add page to log bio
xfs: directory bestfree check should release buffers
xfs: drop all altpath buffers at the end of the sibling check
xfs: preserve default grace interval during quotacheck
xfs: remove xlog_state_want_sync
xfs: move the ioerror check out of xlog_state_clean_iclog
xfs: refactor xlog_state_clean_iclog
xfs: remove the aborted parameter to xlog_state_done_syncing
xfs: simplify log shutdown checking in xfs_log_release_iclog
xfs: simplify the xfs_log_release_iclog calling convention
xfs: factor out a xlog_wait_on_iclog helper
xfs: merge xlog_cil_push into xlog_cil_push_work
xfs: remove the di_version field from struct icdinode
xfs: simplify a check in xfs_ioctl_setattr_check_cowextsize
xfs: simplify di_flags2 inheritance in xfs_ialloc
xfs: only check the superblock version for dinode size calculation
xfs: add a new xfs_sb_version_has_v3inode helper
xfs: fix unmount hang and memory leak on shutdown during quotaoff
xfs: factor out quotaoff intent AIL removal and memory free
...
Linus Torvalds [Thu, 2 Apr 2020 19:59:36 +0000 (12:59 -0700)]
Merge tag 'vfs-5.7-merge-1' of git://git./fs/xfs/xfs-linux
Pull hibernation fix from Darrick Wong:
"Fix a regression where we broke the userspace hibernation driver by
disallowing writes to the swap device"
* tag 'vfs-5.7-merge-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
hibernate: Allow uswsusp to write to swap
Linus Torvalds [Thu, 2 Apr 2020 19:57:18 +0000 (12:57 -0700)]
Merge tag 'iomap-5.7-merge-2' of git://git./fs/xfs/xfs-linux
Pull iomap updates from Darrick Wong:
"We're fixing tracepoints and comments in this cycle, so there
shouldn't be any surprises here.
I anticipate sending a second pull request next week with a single bug
fix for readahead, but it's still undergoing QA.
Summary:
- Fix a broken tracepoint
- Fix a broken comment"
* tag 'iomap-5.7-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
iomap: fix comments in iomap_dio_rw
iomap: Remove pgoff from tracepoints
Linus Torvalds [Thu, 2 Apr 2020 19:30:08 +0000 (12:30 -0700)]
Merge branch 'work.dotdot1' of git://git./linux/kernel/git/viro/vfs
Pull vfs pathwalk sanitizing from Al Viro:
"Massive pathwalk rewrite and cleanups.
Several iterations have been posted; hopefully this thing is getting
readable and understandable now. Pretty much all parts of pathname
resolutions are affected...
The branch is identical to what has sat in -next, except for commit
message in "lift all calls of step_into() out of follow_dotdot/
follow_dotdot_rcu", crediting Qian Cai for reporting the bug; only
commit message changed there."
* 'work.dotdot1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (69 commits)
lookup_open(): don't bother with fallbacks to lookup+create
atomic_open(): no need to pass struct open_flags anymore
open_last_lookups(): move complete_walk() into do_open()
open_last_lookups(): lift O_EXCL|O_CREAT handling into do_open()
open_last_lookups(): don't abuse complete_walk() when all we want is unlazy
open_last_lookups(): consolidate fsnotify_create() calls
take post-lookup part of do_last() out of loop
link_path_walk(): sample parent's i_uid and i_mode for the last component
__nd_alloc_stack(): make it return bool
reserve_stack(): switch to __nd_alloc_stack()
pick_link(): take reserving space on stack into a new helper
pick_link(): more straightforward handling of allocation failures
fold path_to_nameidata() into its only remaining caller
pick_link(): pass it struct path already with normal refcounting rules
fs/namei.c: kill follow_mount()
non-RCU analogue of the previous commit
helper for mount rootwards traversal
follow_dotdot(): be lazy about changing nd->path
follow_dotdot_rcu(): be lazy about changing nd->path
follow_dotdot{,_rcu}(): massage loops
...
Qian Cai [Thu, 2 Apr 2020 15:39:55 +0000 (11:39 -0400)]
x86/kvm: fix a missing-prototypes "vmread_error"
The commit
842f4be95899 ("KVM: VMX: Add a trampoline to fix VMREAD error
handling") removed the declaration of vmread_error() causes a W=1 build
failure with KVM_WERROR=y. Fix it by adding it back.
arch/x86/kvm/vmx/vmx.c:359:17: error: no previous prototype for 'vmread_error' [-Werror=missing-prototypes]
asmlinkage void vmread_error(unsigned long field, bool fault)
^~~~~~~~~~~~
Signed-off-by: Qian Cai <cai@lca.pw>
Message-Id: <
20200402153955.1695-1-cai@lca.pw>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Linus Torvalds [Thu, 2 Apr 2020 18:22:17 +0000 (11:22 -0700)]
Merge branch 'for-linus' of git://git./linux/kernel/git/ebiederm/user-namespace
Pull exec/proc updates from Eric Biederman:
"This contains two significant pieces of work: the work to sort out
proc_flush_task, and the work to solve a deadlock between strace and
exec.
Fixing proc_flush_task so that it no longer requires a persistent
mount makes improvements to proc possible. The removal of the
persistent mount solves an old regression that that caused the hidepid
mount option to only work on remount not on mount. The regression was
found and reported by the Android folks. This further allows Alexey
Gladkov's work making proc mount options specific to an individual
mount of proc to move forward.
The work on exec starts solving a long standing issue with exec that
it takes mutexes of blocking userspace applications, which makes exec
extremely deadlock prone. For the moment this adds a second mutex with
a narrower scope that handles all of the easy cases. Which makes the
tricky cases easy to spot. With a little luck the code to solve those
deadlocks will be ready by next merge window"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (25 commits)
signal: Extend exec_id to 64bits
pidfd: Use new infrastructure to fix deadlocks in execve
perf: Use new infrastructure to fix deadlocks in execve
proc: io_accounting: Use new infrastructure to fix deadlocks in execve
proc: Use new infrastructure to fix deadlocks in execve
kernel/kcmp.c: Use new infrastructure to fix deadlocks in execve
kernel: doc: remove outdated comment cred.c
mm: docs: Fix a comment in process_vm_rw_core
selftests/ptrace: add test cases for dead-locks
exec: Fix a deadlock in strace
exec: Add exec_update_mutex to replace cred_guard_mutex
exec: Move exec_mmap right after de_thread in flush_old_exec
exec: Move cleanup of posix timers on exec out of de_thread
exec: Factor unshare_sighand out of de_thread and call it separately
exec: Only compute current once in flush_old_exec
pid: Improve the comment about waiting in zap_pid_ns_processes
proc: Remove the now unnecessary internal mount of proc
uml: Create a private mount of proc for mconsole
uml: Don't consult current to find the proc_mnt in mconsole_proc
proc: Use a list of inodes to flush from proc
...
Matthew Wilcox (Oracle) [Thu, 2 Apr 2020 04:11:58 +0000 (21:11 -0700)]
include/linux/huge_mm.h: check PageTail in hpage_nr_pages even when !THP
It's even more important to check that we don't have a tail page when
calling hpage_nr_pages() when THP are disabled.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Link: http://lkml.kernel.org/r/20200318140253.6141-4-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Christophe Leroy [Thu, 2 Apr 2020 04:11:54 +0000 (21:11 -0700)]
mm/hugetlb: fix build failure with HUGETLB_PAGE but not HUGEBTLBFS
When CONFIG_HUGETLB_PAGE is set but not CONFIG_HUGETLBFS, the following
build failure is encoutered:
In file included from arch/powerpc/mm/fault.c:33:0:
include/linux/hugetlb.h: In function 'hstate_inode':
include/linux/hugetlb.h:477:9: error: implicit declaration of function 'HUGETLBFS_SB' [-Werror=implicit-function-declaration]
return HUGETLBFS_SB(i->i_sb)->hstate;
^
include/linux/hugetlb.h:477:30: error: invalid type argument of '->' (have 'int')
return HUGETLBFS_SB(i->i_sb)->hstate;
^
Gate hstate_inode() with CONFIG_HUGETLBFS instead of CONFIG_HUGETLB_PAGE.
Fixes:
a137e1cc6d6e ("hugetlbfs: per mount huge page sizes")
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Nishanth Aravamudan <nacc@us.ibm.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Adam Litke <agl@us.ibm.com>
Cc: Andi Kleen <ak@suse.de>
Link: http://lkml.kernel.org/r/7e8c3a3c9a587b9cd8a2f146df32a421b961f3a2.1584432148.git.christophe.leroy@c-s.fr
Link: https://patchwork.ozlabs.org/patch/1255548/#2386036
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Christophe Leroy [Thu, 2 Apr 2020 04:11:51 +0000 (21:11 -0700)]
selftests/vm: fix map_hugetlb length used for testing read and write
Commit
fa7b9a805c79 ("tools/selftest/vm: allow choosing mem size and page
size in map_hugetlb") added the possibility to change the size of memory
mapped for the test, but left the read and write test using the default
value. This is unnoticed when mapping a length greater than the default
one, but segfaults otherwise.
Fix read_bytes() and write_bytes() by giving them the real length.
Also fix the call to munmap().
Fixes:
fa7b9a805c79 ("tools/selftest/vm: allow choosing mem size and page size in map_hugetlb")
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Leonardo Bras <leonardo@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/9a404a13c871c4bd0ba9ede68f69a1225180dd7e.1580978385.git.christophe.leroy@c-s.fr
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Vlastimil Babka [Thu, 2 Apr 2020 04:11:48 +0000 (21:11 -0700)]
mm/hugetlb: remove unnecessary memory fetch in PageHeadHuge()
Commit
f1e61557f023 ("mm: pack compound_dtor and compound_order into one
word in struct page") changed compound_dtor from a pointer to an array
index in order to pack it. To check if page has the hugeltbfs
compound_dtor, we can just compare the index directly without fetching the
function pointer. Said commit did that with PageHuge() and we can do the
same with PageHeadHuge() to make the code a bit smaller and faster.
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Neha Agarwal <nehaagarwal@google.com>
Link: http://lkml.kernel.org/r/20200311172440.6988-1-vbabka@suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mateusz Nosek [Thu, 2 Apr 2020 04:11:45 +0000 (21:11 -0700)]
mm/hugetlb.c: clean code by removing unnecessary initialization
Previously variable 'check_addr' was initialized, but was not read later
before reassigning. So the initialization can be removed.
Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Link: http://lkml.kernel.org/r/20200303212354.25226-1-mateusznosek0@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mina Almasry [Thu, 2 Apr 2020 04:11:41 +0000 (21:11 -0700)]
hugetlb_cgroup: add hugetlb_cgroup reservation docs
Add docs for how to use hugetlb_cgroup reservations, and their behavior.
Signed-off-by: Mina Almasry <almasrymina@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Sandipan Das <sandipan@linux.ibm.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Link: http://lkml.kernel.org/r/20200211213128.73302-9-almasrymina@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mina Almasry [Thu, 2 Apr 2020 04:11:38 +0000 (21:11 -0700)]
hugetlb_cgroup: add hugetlb_cgroup reservation tests
The tests use both shared and private mapped hugetlb memory, and monitors
the hugetlb usage counter as well as the hugetlb reservation counter.
They test different configurations such as hugetlb memory usage via
hugetlbfs, or MAP_HUGETLB, or shmget/shmat, and with and without
MAP_POPULATE.
Also add test for hugetlb reservation reparenting, since this is a subtle
issue.
Signed-off-by: Mina Almasry <almasrymina@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Sandipan Das <sandipan@linux.ibm.com> [powerpc64]
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Sandipan Das <sandipan@linux.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Link: http://lkml.kernel.org/r/20200211213128.73302-8-almasrymina@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mina Almasry [Thu, 2 Apr 2020 04:11:35 +0000 (21:11 -0700)]
hugetlb: support file_region coalescing again
An earlier patch in this series disabled file_region coalescing in order
to hang the hugetlb_cgroup uncharge info on the file_region entries.
This patch re-adds support for coalescing of file_region entries.
Essentially everytime we add an entry, we call a recursive function that
tries to coalesce the added region with the regions next to it. The worst
case call depth for this function is 3: one to coalesce with the region
next to it, one to coalesce to the region prev, and one to reach the base
case.
This is an important performance optimization as private mappings add
their entries page by page, and we could incur big performance costs for
large mappings with lots of file_region entries in their resv_map.
[almasrymina@google.com: fix CONFIG_CGROUP_HUGETLB ifdefs]
Link: http://lkml.kernel.org/r/20200214204544.231482-1-almasrymina@google.com
[almasrymina@google.com: remove check_coalesce_bug debug code]
Link: http://lkml.kernel.org/r/20200219233610.13808-1-almasrymina@google.com
Signed-off-by: Mina Almasry <almasrymina@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Sandipan Das <sandipan@linux.ibm.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Link: http://lkml.kernel.org/r/20200211213128.73302-7-almasrymina@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mina Almasry [Thu, 2 Apr 2020 04:11:31 +0000 (21:11 -0700)]
hugetlb_cgroup: support noreserve mappings
Support MAP_NORESERVE accounting as part of the new counter.
For each hugepage allocation, at allocation time we check if there is a
reservation for this allocation or not. If there is a reservation for
this allocation, then this allocation was charged at reservation time, and
we don't re-account it. If there is no reserevation for this allocation,
we charge the appropriate hugetlb_cgroup.
The hugetlb_cgroup to uncharge for this allocation is stored in
page[3].private. We use new APIs added in an earlier patch to set this
pointer.
Signed-off-by: Mina Almasry <almasrymina@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Sandipan Das <sandipan@linux.ibm.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Link: http://lkml.kernel.org/r/20200211213128.73302-6-almasrymina@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mina Almasry [Thu, 2 Apr 2020 04:11:28 +0000 (21:11 -0700)]
hugetlb_cgroup: add accounting for shared mappings
For shared mappings, the pointer to the hugetlb_cgroup to uncharge lives
in the resv_map entries, in file_region->reservation_counter.
After a call to region_chg, we charge the approprate hugetlb_cgroup, and
if successful, we pass on the hugetlb_cgroup info to a follow up
region_add call. When a file_region entry is added to the resv_map via
region_add, we put the pointer to that cgroup in
file_region->reservation_counter. If charging doesn't succeed, we report
the error to the caller, so that the kernel fails the reservation.
On region_del, which is when the hugetlb memory is unreserved, we also
uncharge the file_region->reservation_counter.
[akpm@linux-foundation.org: forward declare struct file_region]
Signed-off-by: Mina Almasry <almasrymina@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Sandipan Das <sandipan@linux.ibm.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Link: http://lkml.kernel.org/r/20200211213128.73302-5-almasrymina@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mina Almasry [Thu, 2 Apr 2020 04:11:25 +0000 (21:11 -0700)]
hugetlb: disable region_add file_region coalescing
A follow up patch in this series adds hugetlb cgroup uncharge info the
file_region entries in resv->regions. The cgroup uncharge info may differ
for different regions, so they can no longer be coalesced at region_add
time. So, disable region coalescing in region_add in this patch.
Behavior change:
Say a resv_map exists like this [0->1], [2->3], and [5->6].
Then a region_chg/add call comes in region_chg/add(f=0, t=5).
Old code would generate resv->regions: [0->5], [5->6].
New code would generate resv->regions: [0->1], [1->2], [2->3], [3->5],
[5->6].
Special care needs to be taken to handle the resv->adds_in_progress
variable correctly. In the past, only 1 region would be added for every
region_chg and region_add call. But now, each call may add multiple
regions, so we can no longer increment adds_in_progress by 1 in
region_chg, or decrement adds_in_progress by 1 after region_add or
region_abort. Instead, region_chg calls add_reservation_in_range() to
count the number of regions needed and allocates those, and that info is
passed to region_add and region_abort to decrement adds_in_progress
correctly.
We've also modified the assumption that region_add after region_chg never
fails. region_chg now pre-allocates at least 1 region for region_add. If
region_add needs more regions than region_chg has allocated for it, then
it may fail.
[almasrymina@google.com: fix file_region entry allocations]
Link: http://lkml.kernel.org/r/20200219012736.20363-1-almasrymina@google.com
Signed-off-by: Mina Almasry <almasrymina@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Sandipan Das <sandipan@linux.ibm.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Link: http://lkml.kernel.org/r/20200211213128.73302-4-almasrymina@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mina Almasry [Thu, 2 Apr 2020 04:11:21 +0000 (21:11 -0700)]
hugetlb_cgroup: add reservation accounting for private mappings
Normally the pointer to the cgroup to uncharge hangs off the struct page,
and gets queried when it's time to free the page. With hugetlb_cgroup
reservations, this is not possible. Because it's possible for a page to
be reserved by one task and actually faulted in by another task.
The best place to put the hugetlb_cgroup pointer to uncharge for
reservations is in the resv_map. But, because the resv_map has different
semantics for private and shared mappings, the code patch to
charge/uncharge shared and private mappings is different. This patch
implements charging and uncharging for private mappings.
For private mappings, the counter to uncharge is in
resv_map->reservation_counter. On initializing the resv_map this is set
to NULL. On reservation of a region in private mapping, the tasks
hugetlb_cgroup is charged and the hugetlb_cgroup is placed is
resv_map->reservation_counter.
On hugetlb_vm_op_close, we uncharge resv_map->reservation_counter.
[akpm@linux-foundation.org: forward declare struct resv_map]
Signed-off-by: Mina Almasry <almasrymina@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Sandipan Das <sandipan@linux.ibm.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Link: http://lkml.kernel.org/r/20200211213128.73302-3-almasrymina@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mina Almasry [Thu, 2 Apr 2020 04:11:18 +0000 (21:11 -0700)]
mm/hugetlb_cgroup: fix hugetlb_cgroup migration
Commit
c32300516047 ("hugetlb_cgroup: add interface for charge/uncharge
hugetlb reservations") mistakingly doesn't handle the migration of *both*
the reservation hugetlb_cgroup and the fault hugetlb_cgroup correctly.
What should happen is that both cgroups shuold be queried from the old
page, then both set to NULL on the old page, then both inserted into the
new page.
The mistake also creates the following warning:
mm/hugetlb_cgroup.c: In function 'hugetlb_cgroup_migrate':
mm/hugetlb_cgroup.c:777:25: warning: variable 'h_cg' set but not used
[-Wunused-but-set-variable]
struct hugetlb_cgroup *h_cg;
^~~~
Solution is to add the missing steps, namly setting the reservation
hugetlb_cgroup to NULL on the old page, and setting the fault
hugetlb_cgroup on the new page.
Fixes:
c32300516047 ("hugetlb_cgroup: add interface for charge/uncharge hugetlb reservations")
Reported-by: Qian Cai <cai@lca.pw>
Signed-off-by: Mina Almasry <almasrymina@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Sandipan Das <sandipan@linux.ibm.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Link: http://lkml.kernel.org/r/20200218194727.46995-1-almasrymina@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mina Almasry [Thu, 2 Apr 2020 04:11:15 +0000 (21:11 -0700)]
hugetlb_cgroup: add interface for charge/uncharge hugetlb reservations
Augments hugetlb_cgroup_charge_cgroup to be able to charge hugetlb usage
or hugetlb reservation counter.
Adds a new interface to uncharge a hugetlb_cgroup counter via
hugetlb_cgroup_uncharge_counter.
Integrates the counter with hugetlb_cgroup, via hugetlb_cgroup_init,
hugetlb_cgroup_have_usage, and hugetlb_cgroup_css_offline.
Signed-off-by: Mina Almasry <almasrymina@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Sandipan Das <sandipan@linux.ibm.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Link: http://lkml.kernel.org/r/20200211213128.73302-2-almasrymina@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mina Almasry [Thu, 2 Apr 2020 04:11:11 +0000 (21:11 -0700)]
hugetlb_cgroup: add hugetlb_cgroup reservation counter
These counters will track hugetlb reservations rather than hugetlb memory
faulted in. This patch only adds the counter, following patches add the
charging and uncharging of the counter.
This is patch 1 of an 9 patch series.
Problem:
Currently tasks attempting to reserve more hugetlb memory than is
available get a failure at mmap/shmget time. This is thanks to Hugetlbfs
Reservations [1]. However, if a task attempts to reserve more hugetlb
memory than its hugetlb_cgroup limit allows, the kernel will allow the
mmap/shmget call, but will SIGBUS the task when it attempts to fault in
the excess memory.
We have users hitting their hugetlb_cgroup limits and thus we've been
looking at this failure mode. We'd like to improve this behavior such
that users violating the hugetlb_cgroup limits get an error on mmap/shmget
time, rather than getting SIGBUS'd when they try to fault the excess
memory in. This gives the user an opportunity to fallback more gracefully
to non-hugetlbfs memory for example.
The underlying problem is that today's hugetlb_cgroup accounting happens
at hugetlb memory *fault* time, rather than at *reservation* time. Thus,
enforcing the hugetlb_cgroup limit only happens at fault time, and the
offending task gets SIGBUS'd.
Proposed Solution:
A new page counter named
'hugetlb.xMB.rsvd.[limit|usage|max_usage]_in_bytes'. This counter has
slightly different semantics than
'hugetlb.xMB.[limit|usage|max_usage]_in_bytes':
- While usage_in_bytes tracks all *faulted* hugetlb memory,
rsvd.usage_in_bytes tracks all *reserved* hugetlb memory and hugetlb
memory faulted in without a prior reservation.
- If a task attempts to reserve more memory than limit_in_bytes allows,
the kernel will allow it to do so. But if a task attempts to reserve
more memory than rsvd.limit_in_bytes, the kernel will fail this
reservation.
This proposal is implemented in this patch series, with tests to verify
functionality and show the usage.
Alternatives considered:
1. A new cgroup, instead of only a new page_counter attached to the
existing hugetlb_cgroup. Adding a new cgroup seemed like a lot of code
duplication with hugetlb_cgroup. Keeping hugetlb related page counters
under hugetlb_cgroup seemed cleaner as well.
2. Instead of adding a new counter, we considered adding a sysctl that
modifies the behavior of hugetlb.xMB.[limit|usage]_in_bytes, to do
accounting at reservation time rather than fault time. Adding a new
page_counter seems better as userspace could, if it wants, choose to
enforce different cgroups differently: one via limit_in_bytes, and
another via rsvd.limit_in_bytes. This could be very useful if you're
transitioning how hugetlb memory is partitioned on your system one
cgroup at a time, for example. Also, someone may find usage for both
limit_in_bytes and rsvd.limit_in_bytes concurrently, and this approach
gives them the option to do so.
Testing:
- Added tests passing.
- Used libhugetlbfs for regression testing.
[1]: https://www.kernel.org/doc/html/latest/vm/hugetlbfs_reserv.html
Signed-off-by: Mina Almasry <almasrymina@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Sandipan Das <sandipan@linux.ibm.com>
Link: http://lkml.kernel.org/r/20200211213128.73302-1-almasrymina@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mike Kravetz [Thu, 2 Apr 2020 04:11:08 +0000 (21:11 -0700)]
hugetlbfs: Use i_mmap_rwsem to address page fault/truncate race
hugetlbfs page faults can race with truncate and hole punch operations.
Current code in the page fault path attempts to handle this by 'backing
out' operations if we encounter the race. One obvious omission in the
current code is removing a page newly added to the page cache. This is
pretty straight forward to address, but there is a more subtle and
difficult issue of backing out hugetlb reservations. To handle this
correctly, the 'reservation state' before page allocation needs to be
noted so that it can be properly backed out. There are four distinct
possibilities for reservation state: shared/reserved, shared/no-resv,
private/reserved and private/no-resv. Backing out a reservation may
require memory allocation which could fail so that needs to be taken
into account as well.
Instead of writing the required complicated code for this rare
occurrence, just eliminate the race. i_mmap_rwsem is now held in read
mode for the duration of page fault processing. Hold i_mmap_rwsem in
write mode when modifying i_size. In this way, truncation can not
proceed when page faults are being processed. In addition, i_size
will not change during fault processing so a single check can be made
to ensure faults are not beyond (proposed) end of file. Faults can
still race with hole punch, but that race is handled by existing code
and the use of hugetlb_fault_mutex.
With this modification, checks for races with truncation in the page
fault path can be simplified and removed. remove_inode_hugepages no
longer needs to take hugetlb_fault_mutex in the case of truncation.
Comments are expanded to explain reasoning behind locking.
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Prakash Sangappa <prakash.sangappa@oracle.com>
Link: http://lkml.kernel.org/r/20200316205756.146666-3-mike.kravetz@oracle.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mike Kravetz [Thu, 2 Apr 2020 04:11:05 +0000 (21:11 -0700)]
hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization
Patch series "hugetlbfs: use i_mmap_rwsem for more synchronization", v2.
While discussing the issue with huge_pte_offset [1], I remembered that
there were more outstanding hugetlb races. These issues are:
1) For shared pmds, huge PTE pointers returned by huge_pte_alloc can become
invalid via a call to huge_pmd_unshare by another thread.
2) hugetlbfs page faults can race with truncation causing invalid global
reserve counts and state.
A previous attempt was made to use i_mmap_rwsem in this manner as
described at [2]. However, those patches were reverted starting with [3]
due to locking issues.
To effectively use i_mmap_rwsem to address the above issues it needs to be
held (in read mode) during page fault processing. However, during fault
processing we need to lock the page we will be adding. Lock ordering
requires we take page lock before i_mmap_rwsem. Waiting until after
taking the page lock is too late in the fault process for the
synchronization we want to do.
To address this lock ordering issue, the following patches change the lock
ordering for hugetlb pages. This is not too invasive as hugetlbfs
processing is done separate from core mm in many places. However, I don't
really like this idea. Much ugliness is contained in the new routine
hugetlb_page_mapping_lock_write() of patch 1.
The only other way I can think of to address these issues is by catching
all the races. After catching a race, cleanup, backout, retry ... etc,
as needed. This can get really ugly, especially for huge page
reservations. At one time, I started writing some of the reservation
backout code for page faults and it got so ugly and complicated I went
down the path of adding synchronization to avoid the races. Any other
suggestions would be welcome.
[1] https://lore.kernel.org/linux-mm/
1582342427-230392-1-git-send-email-longpeng2@huawei.com/
[2] https://lore.kernel.org/linux-mm/
20181222223013.22193-1-mike.kravetz@oracle.com/
[3] https://lore.kernel.org/linux-mm/
20190103235452.29335-1-mike.kravetz@oracle.com
[4] https://lore.kernel.org/linux-mm/
1584028670.7365.182.camel@lca.pw/
[5] https://lore.kernel.org/lkml/
20200312183142.
108df9ac@canb.auug.org.au/
This patch (of 2):
While looking at BUGs associated with invalid huge page map counts, it was
discovered and observed that a huge pte pointer could become 'invalid' and
point to another task's page table. Consider the following:
A task takes a page fault on a shared hugetlbfs file and calls
huge_pte_alloc to get a ptep. Suppose the returned ptep points to a
shared pmd.
Now, another task truncates the hugetlbfs file. As part of truncation, it
unmaps everyone who has the file mapped. If the range being truncated is
covered by a shared pmd, huge_pmd_unshare will be called. For all but the
last user of the shared pmd, huge_pmd_unshare will clear the pud pointing
to the pmd. If the task in the middle of the page fault is not the last
user, the ptep returned by huge_pte_alloc now points to another task's
page table or worse. This leads to bad things such as incorrect page
map/reference counts or invalid memory references.
To fix, expand the use of i_mmap_rwsem as follows:
- i_mmap_rwsem is held in read mode whenever huge_pmd_share is called.
huge_pmd_share is only called via huge_pte_alloc, so callers of
huge_pte_alloc take i_mmap_rwsem before calling. In addition, callers
of huge_pte_alloc continue to hold the semaphore until finished with
the ptep.
- i_mmap_rwsem is held in write mode whenever huge_pmd_unshare is called.
One problem with this scheme is that it requires taking i_mmap_rwsem
before taking the page lock during page faults. This is not the order
specified in the rest of mm code. Handling of hugetlbfs pages is mostly
isolated today. Therefore, we use this alternative locking order for
PageHuge() pages.
mapping->i_mmap_rwsem
hugetlb_fault_mutex (hugetlbfs specific page fault mutex)
page->flags PG_locked (lock_page)
To help with lock ordering issues, hugetlb_page_mapping_lock_write() is
introduced to write lock the i_mmap_rwsem associated with a page.
In most cases it is easy to get address_space via vma->vm_file->f_mapping.
However, in the case of migration or memory errors for anon pages we do
not have an associated vma. A new routine _get_hugetlb_page_mapping()
will use anon_vma to get address_space in these cases.
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Prakash Sangappa <prakash.sangappa@oracle.com>
Link: http://lkml.kernel.org/r/20200316205756.146666-2-mike.kravetz@oracle.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>