Messages in this thread Patch in this message | | | Date | Fri, 5 Mar 2021 14:33:31 -0800 | Subject | [PATCH] x86/perf: Fix guest_get_msrs static call if there is no PMU | From | Sean Christopherson <> |
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Handle a NULL x86_pmu.guest_get_msrs at invocation instead of patching in perf_guest_get_msrs_nop() during setup. If there is no PMU, setup bails before updating the static calls, leaving x86_pmu.guest_get_msrs NULL and thus a complete nop. Ultimately, this causes VMX abort on VM-Exit due to KVM putting random garbage from the stack into the MSR load list.
Fixes: abd562df94d1 ("x86/perf: Use static_call for x86_pmu.guest_get_msrs") Cc: Like Xu <like.xu@linux.intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Jim Mattson <jmattson@google.com> Cc: kvm@vger.kernel.org Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Sean Christopherson <seanjc@google.com> --- arch/x86/events/core.c | 16 +++++----------- 1 file changed, 5 insertions(+), 11 deletions(-)
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 6ddeed3cd2ac..ff874461f14c 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -671,7 +671,11 @@ void x86_pmu_disable_all(void) struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr) { - return static_call(x86_pmu_guest_get_msrs)(nr); + if (x86_pmu.guest_get_msrs) + return static_call(x86_pmu_guest_get_msrs)(nr); + + *nr = 0; + return NULL; } EXPORT_SYMBOL_GPL(perf_guest_get_msrs); @@ -1944,13 +1948,6 @@ static void _x86_pmu_read(struct perf_event *event) x86_perf_event_update(event); } -static inline struct perf_guest_switch_msr * -perf_guest_get_msrs_nop(int *nr) -{ - *nr = 0; - return NULL; -} - static int __init init_hw_perf_events(void) { struct x86_pmu_quirk *quirk; @@ -2024,9 +2021,6 @@ static int __init init_hw_perf_events(void) if (!x86_pmu.read) x86_pmu.read = _x86_pmu_read; - if (!x86_pmu.guest_get_msrs) - x86_pmu.guest_get_msrs = perf_guest_get_msrs_nop; - x86_pmu_static_call_update(); /* -- 2.30.1.766.gb4fecdf3b7-goog
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