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| author | Venkatesh Srinivas <venkateshs@google.com> | 2020-04-16 11:42:54 -0700 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-04-17 11:06:33 -0400 |
| commit | 2ca1a06a5440ae8aa7bb0709336d759395b7bbb8 (patch) | |
| tree | e2523202629412d88c4f430eba74d30e86eb2b3a /arch/x86/kvm/x86.c | |
| parent | 7289fdb5dcdbc5155b5531529c44105868a762f2 (diff) | |
| download | lwn-2ca1a06a5440ae8aa7bb0709336d759395b7bbb8.tar.gz lwn-2ca1a06a5440ae8aa7bb0709336d759395b7bbb8.zip | |
kvm: Handle reads of SandyBridge RAPL PMU MSRs rather than injecting #GP
Linux 3.14 unconditionally reads the RAPL PMU MSRs on boot, without handling
General Protection Faults on reading those MSRs. Rather than injecting a #GP,
which prevents boot, handle the MSRs by returning 0 for their data. Zero was
checked to be safe by code review of the RAPL PMU driver and in discussion
with the original driver author (eranian@google.com).
Signed-off-by: Venkatesh Srinivas <venkateshs@google.com>
Signed-off-by: Jon Cargille <jcargill@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Message-Id: <20200416184254.248374-1-jcargill@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 3cc3f673785c..919d3c8f9b65 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3060,6 +3060,17 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) case MSR_IA32_PERF_CTL: case MSR_AMD64_DC_CFG: case MSR_F15H_EX_CFG: + /* + * Intel Sandy Bridge CPUs must support the RAPL (running average power + * limit) MSRs. Just return 0, as we do not want to expose the host + * data here. Do not conditionalize this on CPUID, as KVM does not do + * so for existing CPU-specific MSRs. + */ + case MSR_RAPL_POWER_UNIT: + case MSR_PP0_ENERGY_STATUS: /* Power plane 0 (core) */ + case MSR_PP1_ENERGY_STATUS: /* Power plane 1 (graphics uncore) */ + case MSR_PKG_ENERGY_STATUS: /* Total package */ + case MSR_DRAM_ENERGY_STATUS: /* DRAM controller */ msr_info->data = 0; break; case MSR_F15H_PERF_CTL0 ... MSR_F15H_PERF_CTR5: |