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| author | Dmitry Bilunov <kmeaw@yandex-team.ru> | 2016-05-31 17:38:24 +0300 |
|---|---|---|
| committer | Radim Krčmář <rkrcmar@redhat.com> | 2016-06-02 17:38:50 +0200 |
| commit | 0c2df2a1affd183ba9c114915f42a2d464b4f58f (patch) | |
| tree | 1dc70df96a3da4d1cbe420b5225c2fc2ed631118 /arch | |
| parent | b19ee2ff3b287fea48a2896a381e31319394fe58 (diff) | |
| download | linux-0c2df2a1affd183ba9c114915f42a2d464b4f58f.tar.bz2 | |
KVM: Handle MSR_IA32_PERF_CTL
Intel CPUs having Turbo Boost feature implement an MSR to provide a
control interface via rdmsr/wrmsr instructions. One could detect the
presence of this feature by issuing one of these instructions and
handling the #GP exception which is generated in case the referenced MSR
is not implemented by the CPU.
KVM's vCPU model behaves exactly as a real CPU in this case by injecting
a fault when MSR_IA32_PERF_CTL is called (which KVM does not support).
However, some operating systems use this register during an early boot
stage in which their kernel is not capable of handling #GP correctly,
causing #DP and finally a triple fault effectively resetting the vCPU.
This patch implements a dummy handler for MSR_IA32_PERF_CTL to avoid the
crashes.
Signed-off-by: Dmitry Bilunov <kmeaw@yandex-team.ru>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/x86.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c805cf494154..d0a5b4b4e64d 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2314,6 +2314,7 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) case MSR_AMD64_NB_CFG: case MSR_FAM10H_MMIO_CONF_BASE: case MSR_AMD64_BU_CFG2: + case MSR_IA32_PERF_CTL: msr_info->data = 0; break; case MSR_K7_EVNTSEL0 ... MSR_K7_EVNTSEL3: |