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@xxxxxxxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Jim Mattson <jmattson@xxxxxxxxxx>
Cc: kvm@xxxxxxxxxxxxxxx
Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
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
