diff options
| author | Ladi Prosek <lprosek@redhat.com> | 2017-07-26 14:32:59 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2017-08-07 16:26:06 +0300 |
| commit | 72c139bacfa386145d7bbb68c47c8824716153b6 (patch) | |
| tree | 2661bf0f4153e7e302c78f1a849049db1b15a6e5 /arch | |
| parent | aae4e7a8bc44722fe70d58920a36916b1043195e (diff) | |
| download | linux-72c139bacfa386145d7bbb68c47c8824716153b6.tar.xz | |
KVM: hyperv: support HV_X64_MSR_TSC_FREQUENCY and HV_X64_MSR_APIC_FREQUENCY
It has been experimentally confirmed that supporting these two MSRs is one
of the necessary conditions for nested Hyper-V to use the TSC page. Modern
Windows guests are noticeably slower when they fall back to reading
timestamps from the HV_X64_MSR_TIME_REF_COUNT MSR instead of using the TSC
page.
The newly supported MSRs are advertised with the AccessFrequencyRegs
partition privilege flag and CPUID.40000003H:EDX[8] "Support for
determining timer frequencies is available" (both outside of the scope of
this KVM patch).
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/hyperv.c | 6 | ||||
| -rw-r--r-- | arch/x86/kvm/lapic.c | 2 | ||||
| -rw-r--r-- | arch/x86/kvm/lapic.h | 3 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.c | 1 |
4 files changed, 10 insertions, 2 deletions
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index 337b6d2730fa..bf9992300efa 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -1160,6 +1160,12 @@ static int kvm_hv_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata) return stimer_get_count(vcpu_to_stimer(vcpu, timer_index), pdata); } + case HV_X64_MSR_TSC_FREQUENCY: + data = (u64)vcpu->arch.virtual_tsc_khz * 1000; + break; + case HV_X64_MSR_APIC_FREQUENCY: + data = APIC_BUS_FREQUENCY; + break; default: vcpu_unimpl(vcpu, "Hyper-V unhandled rdmsr: 0x%x\n", msr); return 1; diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 589dcc117086..aaf10b6f5380 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -54,8 +54,6 @@ #define PRIu64 "u" #define PRIo64 "o" -#define APIC_BUS_CYCLE_NS 1 - /* #define apic_debug(fmt,arg...) printk(KERN_WARNING fmt,##arg) */ #define apic_debug(fmt, arg...) diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h index 29caa2c3dff9..215721e1426a 100644 --- a/arch/x86/kvm/lapic.h +++ b/arch/x86/kvm/lapic.h @@ -12,6 +12,9 @@ #define KVM_APIC_SHORT_MASK 0xc0000 #define KVM_APIC_DEST_MASK 0x800 +#define APIC_BUS_CYCLE_NS 1 +#define APIC_BUS_FREQUENCY (1000000000ULL / APIC_BUS_CYCLE_NS) + struct kvm_timer { struct hrtimer timer; s64 period; /* unit: ns */ diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index d734aa8c5b4f..72d82ab1ee22 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -993,6 +993,7 @@ static u32 emulated_msrs[] = { MSR_KVM_SYSTEM_TIME_NEW, MSR_KVM_WALL_CLOCK_NEW, HV_X64_MSR_GUEST_OS_ID, HV_X64_MSR_HYPERCALL, HV_X64_MSR_TIME_REF_COUNT, HV_X64_MSR_REFERENCE_TSC, + HV_X64_MSR_TSC_FREQUENCY, HV_X64_MSR_APIC_FREQUENCY, HV_X64_MSR_CRASH_P0, HV_X64_MSR_CRASH_P1, HV_X64_MSR_CRASH_P2, HV_X64_MSR_CRASH_P3, HV_X64_MSR_CRASH_P4, HV_X64_MSR_CRASH_CTL, HV_X64_MSR_RESET, |