KVM: x86: nSVM: implement nested TSC scaling
This was tested by booting a nested guest with TSC=1Ghz,
observing the clocks, and doing about 100 cycles of migration.
Note that qemu patch is needed to support migration because
of a new MSR that needs to be placed in the migration state.
The patch will be sent to the qemu mailing list soon.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210914154825.104886-14-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index c19859e..0d7bbe5 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -140,6 +140,8 @@ struct vcpu_svm {
u64 next_rip;
u64 spec_ctrl;
+
+ u64 tsc_ratio_msr;
/*
* Contains guest-controlled bits of VIRT_SPEC_CTRL, which will be
* translated into the appropriate L2_CFG bits on the host to
@@ -160,7 +162,8 @@ struct vcpu_svm {
unsigned long int3_rip;
/* cached guest cpuid flags for faster access */
- bool nrips_enabled : 1;
+ bool nrips_enabled : 1;
+ bool tsc_scaling_enabled : 1;
u32 ldr_reg;
u32 dfr_reg;
@@ -483,6 +486,8 @@ int nested_svm_check_permissions(struct kvm_vcpu *vcpu);
int nested_svm_check_exception(struct vcpu_svm *svm, unsigned nr,
bool has_error_code, u32 error_code);
int nested_svm_exit_special(struct vcpu_svm *svm);
+void nested_svm_update_tsc_ratio_msr(struct kvm_vcpu *vcpu);
+void svm_write_tsc_multiplier(struct kvm_vcpu *vcpu, u64 multiplier);
void nested_load_control_from_vmcb12(struct vcpu_svm *svm,
struct vmcb_control_area *control);
void nested_sync_control_from_vmcb02(struct vcpu_svm *svm);