This patch implements a call-back into the architecture code
to allow the propagation of changes to the virtual tsc_khz
of the vcpu.
On SVM it updates the tsc_ratio variable, on VMX it does
nothing.
Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/svm.c | 33 +++++++++++++++++++++++++++++++++
arch/x86/kvm/vmx.c | 11 +++++++++++
3 files changed, 45 insertions(+), 0 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 0344b94..9958dd8 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -588,6 +588,7 @@ struct kvm_x86_ops {
bool (*has_wbinvd_exit)(void);
+ void (*set_tsc_khz)(struct kvm_vcpu *vcpu, u32 user_tsc_khz);
void (*write_tsc_offset)(struct kvm_vcpu *vcpu, u64 offset);
void (*get_exit_info)(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2);
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 2ce734c..f6d66c2 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -896,6 +896,38 @@ static u64 svm_scale_tsc(struct kvm_vcpu *vcpu, u64 tsc)
return _tsc;
}
+static void svm_set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz)
+{
+ struct vcpu_svm *svm = to_svm(vcpu);
+ u64 ratio;
+ u64 khz;
+
+ /* TSC scaling supported? */
+ if (!boot_cpu_has(X86_FEATURE_TSCRATEMSR))
+ return;
+
+ /* TSC-Scaling disabled or guest TSC same frequency as host TSC? */
+ if (user_tsc_khz == 0) {
+ vcpu->arch.virtual_tsc_khz = 0;
+ svm->tsc_ratio = TSC_RATIO_DEFAULT;
+ return;
+ }
+
+ khz = user_tsc_khz;
+
+ /* TSC scaling required - calculate ratio */
+ ratio = khz << 32;
+ do_div(ratio, tsc_khz);
+
+ if (ratio == 0 || ratio & TSC_RATIO_RSVD) {
+ WARN_ONCE(1, "Invalid TSC ratio - virtual-tsc-khz=%u\n",
+ user_tsc_khz);
+ return;
+ }
+ vcpu->arch.virtual_tsc_khz = user_tsc_khz;
+ svm->tsc_ratio = ratio;
+}
+
static void svm_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
{
struct vcpu_svm *svm = to_svm(vcpu);
@@ -4004,6 +4036,7 @@ static struct kvm_x86_ops svm_x86_ops = {
.has_wbinvd_exit = svm_has_wbinvd_exit,
+ .set_tsc_khz = svm_set_tsc_khz,
.write_tsc_offset = svm_write_tsc_offset,
.adjust_tsc_offset = svm_adjust_tsc_offset,
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 1bdb49d..0e5dfc6 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1161,6 +1161,16 @@ static u64 guest_read_tsc(void)
}
/*
+ * Empty call-back. Needs to be implemented when VMX enables the SET_TSC_KHZ
+ * ioctl. In this case the call-back should update internal vmx state to make
+ * the changes effective.
+ */
+static void vmx_set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz)
+{
+ /* Nothing to do here */
+}
+
+/*
* writes 'offset' into guest's timestamp counter offset register
*/
static void vmx_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
@@ -4496,6 +4506,7 @@ static struct kvm_x86_ops vmx_x86_ops = {
.has_wbinvd_exit = cpu_has_vmx_wbinvd_exit,
+ .set_tsc_khz = vmx_set_tsc_khz,
.write_tsc_offset = vmx_write_tsc_offset,
.adjust_tsc_offset = vmx_adjust_tsc_offset,
--
1.7.1
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