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| author | Arbel Moshe <arbel.moshe@oracle.com> | 2018-03-12 14:12:53 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2018-03-17 00:02:01 +0300 |
| commit | 2d7921c499afebac78b13ab9a3758261a97e07b7 (patch) | |
| tree | 9fbeb2ebc8c352acdbaab0c13857de719467a76b /arch/x86/kvm/pmu.c | |
| parent | 9718420e9fd462ac6b7ea840f9e63eb6af7e1bda (diff) | |
| download | linux-2d7921c499afebac78b13ab9a3758261a97e07b7.tar.xz | |
KVM: x86: Add support for VMware backdoor Pseudo-PMCs
VMware exposes the following Pseudo PMCs:
0x10000: Physical host TSC
0x10001: Elapsed real time in ns
0x10002: Elapsed apparent time in ns
For more info refer to:
https://www.vmware.com/files/pdf/techpaper/Timekeeping-In-VirtualMachines.pdf
VMware allows access to these Pseduo-PMCs even when read via RDPMC
in Ring3 and CR4.PCE=0. Therefore, commit modifies x86 emulator
to allow access to these PMCs in this situation. In addition,
emulation of these PMCs were added to kvm_pmu_rdpmc().
Signed-off-by: Arbel Moshe <arbel.moshe@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/pmu.c')
| -rw-r--r-- | arch/x86/kvm/pmu.c | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index 026db42a86c3..58ead7db71a3 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -244,12 +244,49 @@ int kvm_pmu_is_valid_msr_idx(struct kvm_vcpu *vcpu, unsigned idx) return kvm_x86_ops->pmu_ops->is_valid_msr_idx(vcpu, idx); } +bool is_vmware_backdoor_pmc(u32 pmc_idx) +{ + switch (pmc_idx) { + case VMWARE_BACKDOOR_PMC_HOST_TSC: + case VMWARE_BACKDOOR_PMC_REAL_TIME: + case VMWARE_BACKDOOR_PMC_APPARENT_TIME: + return true; + } + return false; +} + +static int kvm_pmu_rdpmc_vmware(struct kvm_vcpu *vcpu, unsigned idx, u64 *data) +{ + u64 ctr_val; + + switch (idx) { + case VMWARE_BACKDOOR_PMC_HOST_TSC: + ctr_val = rdtsc(); + break; + case VMWARE_BACKDOOR_PMC_REAL_TIME: + ctr_val = ktime_get_boot_ns(); + break; + case VMWARE_BACKDOOR_PMC_APPARENT_TIME: + ctr_val = ktime_get_boot_ns() + + vcpu->kvm->arch.kvmclock_offset; + break; + default: + return 1; + } + + *data = ctr_val; + return 0; +} + int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data) { bool fast_mode = idx & (1u << 31); struct kvm_pmc *pmc; u64 ctr_val; + if (is_vmware_backdoor_pmc(idx)) + return kvm_pmu_rdpmc_vmware(vcpu, idx, data); + pmc = kvm_x86_ops->pmu_ops->msr_idx_to_pmc(vcpu, idx); if (!pmc) return 1; |