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 <joerg.roedel@xxxxxxx>
---
arch/x86/include/asm/msr-index.h | 1 +
arch/x86/kvm/svm.c | 54 +++++++++++++++++++++++++++++++++++++-
2 files changed, 54 insertions(+), 1 deletions(-)
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index fd5a1f3..a7b3e40 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -114,6 +114,7 @@
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 2a19322..2ce734c 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[] = {
@@ -144,8 +146,13 @@ struct vcpu_svm {
unsigned int3_injected;
unsigned long int3_rip;
u32 apf_reason;
+
+ u64 tsc_ratio;
};
+static DEFINE_PER_CPU(u64, current_tsc_ratio);
+#define TSC_RATIO_DEFAULT 0x0100000000ULL
+
#define MSR_INVALID 0xffffffffU
static struct svm_direct_access_msrs {
@@ -569,6 +576,10 @@ static int has_svm(void)
static void svm_hardware_disable(void *garbage)
{
+ /* Make sure we clean up behind us */
+ if (static_cpu_has(X86_FEATURE_TSCRATEMSR))
+ wrmsrl(MSR_AMD64_TSC_RATIO, TSC_RATIO_DEFAULT);
+
cpu_svm_disable();
}
@@ -610,6 +621,11 @@ static int svm_hardware_enable(void *garbage)
wrmsrl(MSR_VM_HSAVE_PA, page_to_pfn(sd->save_area) << PAGE_SHIFT);
+ if (static_cpu_has(X86_FEATURE_TSCRATEMSR)) {
+ wrmsrl(MSR_AMD64_TSC_RATIO, TSC_RATIO_DEFAULT);
+ __get_cpu_var(current_tsc_ratio) = TSC_RATIO_DEFAULT;
+ }
+
svm_init_erratum_383();
return 0;
@@ -854,6 +870,32 @@ 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_ratio != TSC_RATIO_DEFAULT)
+ _tsc = __scale_tsc(svm->tsc_ratio, tsc);
+
+ return _tsc;
+}
+
static void svm_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
{
struct vcpu_svm *svm = to_svm(vcpu);
@@ -1048,6 +1090,8 @@ 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;
@@ -1141,6 +1185,12 @@ 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 != __get_cpu_var(current_tsc_ratio)) {
+ __get_cpu_var(current_tsc_ratio) = svm->tsc_ratio;
+ wrmsrl(MSR_AMD64_TSC_RATIO, svm->tsc_ratio);
+ }
}
static void svm_vcpu_put(struct kvm_vcpu *vcpu)
@@ -2813,7 +2863,9 @@ 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
--
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