KVM: x86/pmu: Defer reprogram_counter() to kvm_pmu_handle_event()

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Batch reprogramming PMU counters by setting KVM_REQ_PMU and thus
deferring reprogramming kvm_pmu_handle_event() to avoid reprogramming
a counter multiple times during a single VM-Exit.

Deferring programming will also allow KVM to fix a bug where immediately
reprogramming a counter can result in sleeping (taking a mutex) while
interrupts are disabled in the VM-Exit fastpath.

Introduce kvm_pmu_request_counter_reprogam() to make it obvious that
KVM is _requesting_ a reprogram and not actually doing the reprogram.

Opportunistically refine related comments to avoid misunderstandings.

Signed-off-by: Like Xu <likexu@tencent.com>
Link: https://lore.kernel.org/r/20220831085328.45489-5-likexu@tencent.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220923001355.3741194-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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Like Xu 2022-09-23 00:13:54 +00:00 • committed by Paolo Bonzini

parent dcbb816a28

commit 68fb4757e8

5 changed files with 22 additions and 10 deletions

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1

arch/x86/include/asm/kvm_host.h

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17

arch/x86/kvm/pmu.c

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6

arch/x86/kvm/pmu.h

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2

arch/x86/kvm/svm/pmu.c

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6

arch/x86/kvm/vmx/pmu_intel.c

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