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[5.15,167/207] KVM: x86/pmu: Fix reserved bits for AMD PerfEvtSeln register

Message ID 20211206145616.057749160@linuxfoundation.org
State Superseded
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman Dec. 6, 2021, 2:57 p.m. UTC 
From: Like Xu <likexu@tencent.com>

[ Upstream commit cb1d220da0faa5ca0deb93449aff953f0c2cce6d ]

If we run the following perf command in an AMD Milan guest:

  perf stat \
  -e cpu/event=0x1d0/ \
  -e cpu/event=0x1c7/ \
  -e cpu/umask=0x1f,event=0x18e/ \
  -e cpu/umask=0x7,event=0x18e/ \
  -e cpu/umask=0x18,event=0x18e/ \
  ./workload

dmesg will report a #GP warning from an unchecked MSR access
error on MSR_F15H_PERF_CTLx.

This is because according to APM (Revision: 4.03) Figure 13-7,
the bits [35:32] of AMD PerfEvtSeln register is a part of the
event select encoding, which extends the EVENT_SELECT field
from 8 bits to 12 bits.

Opportunistically update pmu->reserved_bits for reserved bit 19.

Reported-by: Jim Mattson <jmattson@google.com>
Fixes: ca724305a2b0 ("KVM: x86/vPMU: Implement AMD vPMU code for KVM")
Signed-off-by: Like Xu <likexu@tencent.com>
Message-Id: <20211118130320.95997-1-likexu@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kvm/svm/pmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/arch/x86/kvm/svm/pmu.c b/arch/x86/kvm/svm/pmu.c
index fdf587f19c5fb..e152241d1d709 100644
--- a/arch/x86/kvm/svm/pmu.c
+++ b/arch/x86/kvm/svm/pmu.c
@@ -282,7 +282,7 @@  static void amd_pmu_refresh(struct kvm_vcpu *vcpu)
 		pmu->nr_arch_gp_counters = AMD64_NUM_COUNTERS;
 
 	pmu->counter_bitmask[KVM_PMC_GP] = ((u64)1 << 48) - 1;
-	pmu->reserved_bits = 0xffffffff00200000ull;
+	pmu->reserved_bits = 0xfffffff000280000ull;
 	pmu->version = 1;
 	/* not applicable to AMD; but clean them to prevent any fall out */
 	pmu->counter_bitmask[KVM_PMC_FIXED] = 0;