KVM: x86: Add a common TSC scaling ratio field in kvm_vcpu_arch

This patch moves the field of TSC scaling ratio from the architecture
struct vcpu_svm to the common struct kvm_vcpu_arch.

Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 5333767560c01bf1fd0a2c9f2cf22ac3656e5634..f3354bd92364145ad36349a281fcee8b87189907 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -505,6 +505,7 @@ struct kvm_vcpu_arch {
        u32 virtual_tsc_mult;
        u32 virtual_tsc_khz;
        s64 ia32_tsc_adjust_msr;
+       u64 tsc_scaling_ratio;
 
        atomic_t nmi_queued;  /* unprocessed asynchronous NMIs */
        unsigned nmi_pending; /* NMI queued after currently running handler */

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 74712ead97877c6114ba6f78eb438518fa8b28d5..9c92e6f429d0b321f4860ba1138d6dc9d56c6a0b 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -158,8 +158,6 @@ struct vcpu_svm {
        unsigned long int3_rip;
        u32 apf_reason;
 
-       u64  tsc_ratio;
-
        /* cached guest cpuid flags for faster access */
        bool nrips_enabled      : 1;
 };
@@ -991,24 +989,22 @@ static u64 __scale_tsc(u64 ratio, u64 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_ratio != TSC_RATIO_DEFAULT)
-               _tsc = __scale_tsc(svm->tsc_ratio, tsc);
+       if (vcpu->arch.tsc_scaling_ratio != TSC_RATIO_DEFAULT)
+               _tsc = __scale_tsc(vcpu->arch.tsc_scaling_ratio, tsc);
 
        return _tsc;
 }
 
 static void svm_set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz, bool scale)
 {
-       struct vcpu_svm *svm = to_svm(vcpu);
        u64 ratio;
        u64 khz;
 
        /* Guest TSC same frequency as host TSC? */
        if (!scale) {
-               svm->tsc_ratio = TSC_RATIO_DEFAULT;
+               vcpu->arch.tsc_scaling_ratio = TSC_RATIO_DEFAULT;
                return;
        }
 
@@ -1033,7 +1029,7 @@ static void svm_set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz, bool scale)
                                user_tsc_khz);
                return;
        }
-       svm->tsc_ratio             = ratio;
+       vcpu->arch.tsc_scaling_ratio = ratio;
 }
 
 static u64 svm_read_tsc_offset(struct kvm_vcpu *vcpu)
@@ -1067,7 +1063,7 @@ static void svm_adjust_tsc_offset(struct kvm_vcpu *vcpu, s64 adjustment, bool ho
        struct vcpu_svm *svm = to_svm(vcpu);
 
        if (host) {
-               if (svm->tsc_ratio != TSC_RATIO_DEFAULT)
+               if (vcpu->arch.tsc_scaling_ratio != TSC_RATIO_DEFAULT)
                        WARN_ON(adjustment < 0);
                adjustment = svm_scale_tsc(vcpu, (u64)adjustment);
        }
@@ -1238,8 +1234,6 @@ static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id)
                goto out;
        }
 
-       svm->tsc_ratio = TSC_RATIO_DEFAULT;
-
        err = kvm_vcpu_init(&svm->vcpu, kvm, id);
        if (err)
                goto free_svm;
@@ -1325,10 +1319,12 @@ 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_ratio != __this_cpu_read(current_tsc_ratio)) {
-               __this_cpu_write(current_tsc_ratio, svm->tsc_ratio);
-               wrmsrl(MSR_AMD64_TSC_RATIO, svm->tsc_ratio);
+       if (static_cpu_has(X86_FEATURE_TSCRATEMSR)) {
+               u64 tsc_ratio = vcpu->arch.tsc_scaling_ratio;
+               if (tsc_ratio != __this_cpu_read(current_tsc_ratio)) {
+                       __this_cpu_write(current_tsc_ratio, tsc_ratio);
+                       wrmsrl(MSR_AMD64_TSC_RATIO, tsc_ratio);
+               }
        }
 }
 

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e728c539ecfbf1b9bd7e76e5098cfc682acbc2b0..ef5b9d66cd71a1593f24299e6dcea1aea79167a9 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -113,6 +113,7 @@ u8   __read_mostly kvm_tsc_scaling_ratio_frac_bits;
 EXPORT_SYMBOL_GPL(kvm_tsc_scaling_ratio_frac_bits);
 u64  __read_mostly kvm_max_tsc_scaling_ratio;
 EXPORT_SYMBOL_GPL(kvm_max_tsc_scaling_ratio);
+static u64 __read_mostly kvm_default_tsc_scaling_ratio;
 
 /* tsc tolerance in parts per million - default to 1/2 of the NTP threshold */
 static u32 __read_mostly tsc_tolerance_ppm = 250;
@@ -1258,8 +1259,11 @@ static void kvm_set_tsc_khz(struct kvm_vcpu *vcpu, u32 this_tsc_khz)
        int use_scaling = 0;
 
        /* tsc_khz can be zero if TSC calibration fails */
-       if (this_tsc_khz == 0)
+       if (this_tsc_khz == 0) {
+               /* set tsc_scaling_ratio to a safe value */
+               vcpu->arch.tsc_scaling_ratio = kvm_default_tsc_scaling_ratio;
                return;
+       }
 
        /* Compute a scale to convert nanoseconds in TSC cycles */
        kvm_get_time_scale(this_tsc_khz, NSEC_PER_SEC / 1000,
@@ -7367,6 +7371,9 @@ int kvm_arch_hardware_setup(void)
        if (r != 0)
                return r;
 
+       if (kvm_has_tsc_control)
+               kvm_default_tsc_scaling_ratio = 1ULL << kvm_tsc_scaling_ratio_frac_bits;
+
        kvm_init_msr_list();
        return 0;
 }