timing.patch

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 974d64bf0..ae0e8e4e9 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -2201,6 +2201,7 @@ int kvm_emulate_halt(struct kvm_vcpu *vcpu);
 int kvm_emulate_halt_noskip(struct kvm_vcpu *vcpu);
 int kvm_emulate_ap_reset_hold(struct kvm_vcpu *vcpu);
 int kvm_emulate_wbinvd(struct kvm_vcpu *vcpu);
+int kvm_emulate_rdtsc(struct kvm_vcpu *vcpu);
 
 void kvm_get_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg);
 void kvm_set_segment(struct kvm_vcpu *vcpu, struct kvm_segment *var, int seg);
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 52524e0ca..4f1fa7c89 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -2089,6 +2089,7 @@ EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_cpuid);
 
 int kvm_emulate_cpuid(struct kvm_vcpu *vcpu)
 {
+	vcpu->run->exit_reason = 123;
 	u32 eax, ebx, ecx, edx;
 
 	if (cpuid_fault_enabled(vcpu) && !kvm_require_cpl(vcpu, 0))
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index f2fa69dd5..b78c9bd3a 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1078,6 +1078,7 @@ static void init_vmcb(struct kvm_vcpu *vcpu, bool init_event)
 	svm_set_intercept(svm, INTERCEPT_XSETBV);
 	svm_set_intercept(svm, INTERCEPT_RDPRU);
 	svm_set_intercept(svm, INTERCEPT_RSM);
+	svm_set_intercept(svm, INTERCEPT_RDTSC);
 
 	if (!kvm_mwait_in_guest(vcpu->kvm)) {
 		svm_set_intercept(svm, INTERCEPT_MONITOR);
@@ -3223,6 +3224,7 @@ static int (*const svm_exit_handlers[])(struct kvm_vcpu *vcpu) = {
 	[SVM_EXIT_RSM]                          = rsm_interception,
 	[SVM_EXIT_AVIC_INCOMPLETE_IPI]		= avic_incomplete_ipi_interception,
 	[SVM_EXIT_AVIC_UNACCELERATED_ACCESS]	= avic_unaccelerated_access_interception,
+	[SVM_EXIT_RDTSC]                	= kvm_emulate_rdtsc,
 #ifdef CONFIG_KVM_AMD_SEV
 	[SVM_EXIT_VMGEXIT]			= sev_handle_vmgexit,
 #endif
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e6f2e34ec..1b4b3f6c7 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1308,6 +1308,7 @@ EXPORT_SYMBOL_FOR_KVM_INTERNAL(__kvm_set_xcr);
 int kvm_emulate_xsetbv(struct kvm_vcpu *vcpu)
 {
 	/* Note, #UD due to CR4.OSXSAVE=0 has priority over the intercept. */
+	vcpu->run->exit_reason = 123;
 	if (kvm_x86_call(get_cpl)(vcpu) != 0 ||
 	    __kvm_set_xcr(vcpu, kvm_rcx_read(vcpu), kvm_read_edx_eax(vcpu))) {
 		kvm_inject_gp(vcpu, 0);
@@ -2208,6 +2209,7 @@ int kvm_emulate_as_nop(struct kvm_vcpu *vcpu)
 
 int kvm_emulate_invd(struct kvm_vcpu *vcpu)
 {
+	vcpu->run->exit_reason = 123;
 	/* Treat an INVD instruction as a NOP and just skip it. */
 	return kvm_emulate_as_nop(vcpu);
 }
@@ -4379,6 +4381,9 @@ static int get_msr_mce(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, bool host)
 
 int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 {
+	u64 differece;
+	u64 final_time;
+
 	switch (msr_info->index) {
 	case MSR_IA32_PLATFORM_ID:
 	case MSR_IA32_EBL_CR_POWERON:
@@ -4445,17 +4450,10 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		 * return L1's TSC value to ensure backwards-compatible
 		 * behavior for migration.
 		 */
-		u64 offset, ratio;
-
-		if (msr_info->host_initiated) {
-			offset = vcpu->arch.l1_tsc_offset;
-			ratio = vcpu->arch.l1_tsc_scaling_ratio;
-		} else {
-			offset = vcpu->arch.tsc_offset;
-			ratio = vcpu->arch.tsc_scaling_ratio;
-		}
+		differece = rdtsc() - vcpu->last_exit_start;
+		final_time = vcpu->total_exit_time + differece;
 
-		msr_info->data = kvm_scale_tsc(rdtsc(), ratio) + offset;
+		msr_info->data = rdtsc() - final_time;
 		break;
 	}
 	case MSR_IA32_CR_PAT:
@@ -8496,6 +8494,7 @@ static void emulator_invlpg(struct x86_emulate_ctxt *ctxt, ulong address)
 
 static int kvm_emulate_wbinvd_noskip(struct kvm_vcpu *vcpu)
 {
+	vcpu->run->exit_reason = 123;
 	if (!need_emulate_wbinvd(vcpu))
 		return X86EMUL_CONTINUE;
 
@@ -8518,7 +8517,24 @@ int kvm_emulate_wbinvd(struct kvm_vcpu *vcpu)
 }
 EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_emulate_wbinvd);
 
+int kvm_emulate_rdtsc(struct kvm_vcpu *vcpu)
+{
+	u64 differece;
+	u64 final_time;
+	u64 data;
+
+	differece = rdtsc() - vcpu->last_exit_start;
+	final_time = vcpu->total_exit_time + differece;
+
+	data = rdtsc() - final_time;
 
+	vcpu->arch.regs[VCPU_REGS_RAX] = data & -1u;
+	vcpu->arch.regs[VCPU_REGS_RDX] = (data >> 32) & -1u;
+
+	vcpu->run->exit_reason = 123;
+	return kvm_skip_emulated_instruction(vcpu);
+}
+EXPORT_SYMBOL_GPL(kvm_emulate_rdtsc);
 
 static void emulator_wbinvd(struct x86_emulate_ctxt *ctxt)
 {
@@ -11046,7 +11062,7 @@ static void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu)
  * exiting to the userspace.  Otherwise, the value will be returned to the
  * userspace.
  */
-static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
+static int vcpu_enter_guest_real(struct kvm_vcpu *vcpu)
 {
 	int r;
 	bool req_int_win =
@@ -11484,6 +11500,24 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 	return r;
 }
 
+static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
+{
+	int result;
+	u64 difference;
+
+	vcpu->last_exit_start = rdtsc();
+
+	result = vcpu_enter_guest_real(vcpu);
+
+	if (vcpu->run->exit_reason == 123)
+	{
+		difference = rdtsc() - vcpu->last_exit_start;
+		vcpu->total_exit_time += difference;
+	}
+
+	return result;
+}
+
 static bool kvm_vcpu_running(struct kvm_vcpu *vcpu)
 {
 	return (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE &&
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 5bd76cf39..7d2715f82 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -352,6 +352,9 @@ struct kvm_vcpu {
 	unsigned int halt_poll_ns;
 	bool valid_wakeup;
 
+	u64 last_exit_start;
+	u64 total_exit_time;
+
 #ifdef CONFIG_HAS_IOMEM
 	int mmio_needed;
 	int mmio_read_completed;