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| author | Joerg Roedel <joerg.roedel@amd.com> | 2011-03-25 09:44:47 +0100 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2011-05-11 07:57:04 -0400 |
| commit | 1e993611d0dc879fde25515dc9867d1cfd4c5137 (patch) | |
| tree | 39bb576e536d5d3a1194118935c87b5257b04369 /arch/x86/kvm/x86.c | |
| parent | fbc0db76b77125e0a5131fb886cbaafa1ec5c525 (diff) | |
| download | lwn-1e993611d0dc879fde25515dc9867d1cfd4c5137.tar.gz lwn-1e993611d0dc879fde25515dc9867d1cfd4c5137.zip | |
KVM: X86: Let kvm-clock report the right tsc frequency
This patch changes the kvm_guest_time_update function to use
TSC frequency the guest actually has for updating its clock.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 25 |
1 files changed, 15 insertions, 10 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 0d6524fa2aff..78d729174d99 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -969,6 +969,14 @@ static inline int kvm_tsc_changes_freq(void) return ret; } +static u64 vcpu_tsc_khz(struct kvm_vcpu *vcpu) +{ + if (vcpu->arch.virtual_tsc_khz) + return vcpu->arch.virtual_tsc_khz; + else + return __this_cpu_read(cpu_tsc_khz); +} + static inline u64 nsec_to_cycles(u64 nsec) { u64 ret; @@ -982,20 +990,19 @@ static inline u64 nsec_to_cycles(u64 nsec) return ret; } -static void kvm_arch_set_tsc_khz(struct kvm *kvm, u32 this_tsc_khz) +static void kvm_init_tsc_catchup(struct kvm_vcpu *vcpu, u32 this_tsc_khz) { /* Compute a scale to convert nanoseconds in TSC cycles */ kvm_get_time_scale(this_tsc_khz, NSEC_PER_SEC / 1000, - &kvm->arch.virtual_tsc_shift, - &kvm->arch.virtual_tsc_mult); - kvm->arch.virtual_tsc_khz = this_tsc_khz; + &vcpu->arch.tsc_catchup_shift, + &vcpu->arch.tsc_catchup_mult); } static u64 compute_guest_tsc(struct kvm_vcpu *vcpu, s64 kernel_ns) { u64 tsc = pvclock_scale_delta(kernel_ns-vcpu->arch.last_tsc_nsec, - vcpu->kvm->arch.virtual_tsc_mult, - vcpu->kvm->arch.virtual_tsc_shift); + vcpu->arch.tsc_catchup_mult, + vcpu->arch.tsc_catchup_shift); tsc += vcpu->arch.last_tsc_write; return tsc; } @@ -1062,8 +1069,7 @@ static int kvm_guest_time_update(struct kvm_vcpu *v) local_irq_save(flags); kvm_get_msr(v, MSR_IA32_TSC, &tsc_timestamp); kernel_ns = get_kernel_ns(); - this_tsc_khz = __this_cpu_read(cpu_tsc_khz); - + this_tsc_khz = vcpu_tsc_khz(v); if (unlikely(this_tsc_khz == 0)) { local_irq_restore(flags); kvm_make_request(KVM_REQ_CLOCK_UPDATE, v); @@ -6060,8 +6066,7 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu) } vcpu->arch.pio_data = page_address(page); - if (!kvm->arch.virtual_tsc_khz) - kvm_arch_set_tsc_khz(kvm, max_tsc_khz); + kvm_init_tsc_catchup(vcpu, max_tsc_khz); r = kvm_mmu_create(vcpu); if (r < 0) |