4.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Owen Hofmann <[email protected]> commit 2680d6da455b636dd006636780c0f235c6561d70 upstream. vmx.c writes the TSC_MULTIPLIER field in vmx_vcpu_load, but only when a vcpu has migrated physical cpus. Record the last value written and update in vmx_vcpu_load on any change, otherwise a cpu migration must occur for TSC frequency scaling to take effect. Fixes: ff2c3a1803775cc72dc6f624b59554956396b0ee Signed-off-by: Owen Hofmann <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/x86/kvm/vmx.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -595,6 +595,8 @@ struct vcpu_vmx { /* Support for PML */ #define PML_ENTITY_NUM 512 struct page *pml_pg; + + u64 current_tsc_ratio; }; enum segment_cache_field { @@ -2062,14 +2064,16 @@ static void vmx_vcpu_load(struct kvm_vcp rdmsrl(MSR_IA32_SYSENTER_ESP, sysenter_esp); vmcs_writel(HOST_IA32_SYSENTER_ESP, sysenter_esp); /* 22.2.3 */ - /* Setup TSC multiplier */ - if (cpu_has_vmx_tsc_scaling()) - vmcs_write64(TSC_MULTIPLIER, - vcpu->arch.tsc_scaling_ratio); - vmx->loaded_vmcs->cpu = cpu; } + /* Setup TSC multiplier */ + if (kvm_has_tsc_control && + vmx->current_tsc_ratio != vcpu->arch.tsc_scaling_ratio) { + vmx->current_tsc_ratio = vcpu->arch.tsc_scaling_ratio; + vmcs_write64(TSC_MULTIPLIER, vmx->current_tsc_ratio); + } + vmx_vcpu_pi_load(vcpu, cpu); }
