This patch enhances the kvm_amd module with functions to support the TSC_RATE_MSR which can be used to set a given tsc frequency for the guest vcpu.
Signed-off-by: Joerg Roedel <[email protected]> --- arch/x86/include/asm/msr-index.h | 1 + arch/x86/kvm/svm.c | 44 +++++++++++++++++++++++++++++++++++++- 2 files changed, 44 insertions(+), 1 deletions(-) diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h index 5bfafb6..fdac548 100644 --- a/arch/x86/include/asm/msr-index.h +++ b/arch/x86/include/asm/msr-index.h @@ -106,6 +106,7 @@ complete list. */ #define MSR_AMD64_PATCH_LEVEL 0x0000008b +#define MSR_AMD64_TSC_RATIO 0xc0000104 #define MSR_AMD64_NB_CFG 0xc001001f #define MSR_AMD64_PATCH_LOADER 0xc0010020 #define MSR_AMD64_OSVW_ID_LENGTH 0xc0010140 diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 6bb15d5..72373b6 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -63,6 +63,8 @@ MODULE_LICENSE("GPL"); #define DEBUGCTL_RESERVED_BITS (~(0x3fULL)) +#define TSC_RATIO_RSVD 0xffffff0000000000ULL + static bool erratum_383_found __read_mostly; static const u32 host_save_user_msrs[] = { @@ -144,6 +146,12 @@ struct vcpu_svm { unsigned int3_injected; unsigned long int3_rip; u32 apf_reason; + + struct { + bool enabled; + u64 ratio; + } tsc_scale; + }; #define MSR_INVALID 0xffffffffU @@ -854,6 +862,32 @@ static void init_sys_seg(struct vmcb_seg *seg, uint32_t type) seg->base = 0; } +static u64 __scale_tsc(u64 ratio, u64 tsc) +{ + u64 mult, frac, _tsc; + + mult = ratio >> 32; + frac = ratio & ((1ULL << 32) - 1); + + _tsc = tsc; + _tsc *= mult; + _tsc += (tsc >> 32) * frac; + _tsc += ((tsc & ((1ULL << 32) - 1)) * frac) >> 32; + + return _tsc; +} + +static u64 svm_scale_tsc(struct kvm_vcpu *vcpu, u64 tsc) +{ + struct vcpu_svm *svm = to_svm(vcpu); + u64 _tsc = tsc; + + if (svm->tsc_scale.enabled) + _tsc = __scale_tsc(svm->tsc_scale.ratio, tsc); + + return _tsc; +} + static void svm_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset) { struct vcpu_svm *svm = to_svm(vcpu); @@ -1141,6 +1175,9 @@ static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu) for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++) rdmsrl(host_save_user_msrs[i], svm->host_user_msrs[i]); + + if (static_cpu_has(X86_FEATURE_TSCRATEMSR) && svm->tsc_scale.enabled) + wrmsrl(MSR_AMD64_TSC_RATIO, svm->tsc_scale.ratio); } static void svm_vcpu_put(struct kvm_vcpu *vcpu) @@ -1161,6 +1198,9 @@ static void svm_vcpu_put(struct kvm_vcpu *vcpu) #endif for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++) wrmsrl(host_save_user_msrs[i], svm->host_user_msrs[i]); + + if (static_cpu_has(X86_FEATURE_TSCRATEMSR) && svm->tsc_scale.enabled) + wrmsr(MSR_AMD64_TSC_RATIO, 0, 1); } static unsigned long svm_get_rflags(struct kvm_vcpu *vcpu) @@ -2813,7 +2853,9 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 *data) case MSR_IA32_TSC: { struct vmcb *vmcb = get_host_vmcb(svm); - *data = vmcb->control.tsc_offset + native_read_tsc(); + *data = vmcb->control.tsc_offset + + svm_scale_tsc(vcpu, native_read_tsc()); + break; } case MSR_STAR: -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
