[03/17] Unify vendor TSC logic

Commit Message

Zachary Amsden June 15, 2010, 7:34 a.m. UTC

None

Patch

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 91631b8..94f6ce8 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -253,7 +253,6 @@  struct kvm_mmu {
 };
 
 struct kvm_vcpu_arch {
-	u64 host_tsc;
 	/*
 	 * rip and regs accesses must go through
 	 * kvm_{register,rip}_{read,write} functions.
@@ -334,9 +333,10 @@  struct kvm_vcpu_arch {
 
 	gpa_t time;
 	struct pvclock_vcpu_time_info hv_clock;
-	unsigned int hv_clock_tsc_khz;
+	unsigned int hw_tsc_khz;
 	unsigned int time_offset;
 	struct page *time_page;
+	u64 last_host_tsc;
 
 	bool nmi_pending;
 	bool nmi_injected;
@@ -530,6 +530,7 @@  struct kvm_x86_ops {
 	u64 (*get_mt_mask)(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio);
 	int (*get_lpage_level)(void);
 	bool (*rdtscp_supported)(void);
+	void (*adjust_tsc_offset)(struct kvm_vcpu *vcpu, s64 adjustment);
 
 	void (*set_supported_cpuid)(u32 func, struct kvm_cpuid_entry2 *entry);
 
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 09b2145..ee2cf30 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -948,18 +948,6 @@  static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 	int i;
 
 	if (unlikely(cpu != vcpu->cpu)) {
-		u64 delta;
-
-		if (check_tsc_unstable()) {
-			/*
-			 * Make sure that the guest sees a monotonically
-			 * increasing TSC.
-			 */
-			delta = vcpu->arch.host_tsc - native_read_tsc();
-			svm->vmcb->control.tsc_offset += delta;
-			if (is_nested(svm))
-				svm->nested.hsave->control.tsc_offset += delta;
-		}
 		svm->asid_generation = 0;
 	}
 
@@ -975,8 +963,6 @@  static void svm_vcpu_put(struct kvm_vcpu *vcpu)
 	++vcpu->stat.host_state_reload;
 	for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++)
 		wrmsrl(host_save_user_msrs[i], svm->host_user_msrs[i]);
-
-	vcpu->arch.host_tsc = native_read_tsc();
 }
 
 static unsigned long svm_get_rflags(struct kvm_vcpu *vcpu)
@@ -3422,6 +3408,15 @@  static bool svm_rdtscp_supported(void)
 	return false;
 }
 
+static void svm_adjust_tsc_offset(struct kvm_vcpu *vcpu, s64 adjustment)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+
+	svm->vmcb->control.tsc_offset += adjustment;
+	if (is_nested(svm))
+		svm->nested.hsave->control.tsc_offset += adjustment;
+}
+
 static void svm_fpu_deactivate(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
@@ -3506,6 +3501,8 @@  static struct kvm_x86_ops svm_x86_ops = {
 	.rdtscp_supported = svm_rdtscp_supported,
 
 	.set_supported_cpuid = svm_set_supported_cpuid,
+
+	.adjust_tsc_offset = svm_adjust_tsc_offset,
 };
 
 static int __init svm_init(void)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index a657e08..a993e67 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -498,7 +498,6 @@  static void __vcpu_clear(void *arg)
 		vmcs_clear(vmx->vmcs);
 	if (per_cpu(current_vmcs, cpu) == vmx->vmcs)
 		per_cpu(current_vmcs, cpu) = NULL;
-	rdtscll(vmx->vcpu.arch.host_tsc);
 	list_del(&vmx->local_vcpus_link);
 	vmx->vcpu.cpu = -1;
 	vmx->launched = 0;
@@ -881,7 +880,6 @@  static void vmx_load_host_state(struct vcpu_vmx *vmx)
 static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
-	u64 tsc_this, delta, new_offset;
 	u64 phys_addr = __pa(per_cpu(vmxarea, cpu));
 
 	if (!vmm_exclusive)
@@ -914,16 +912,6 @@  static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 
 		rdmsrl(MSR_IA32_SYSENTER_ESP, sysenter_esp);
 		vmcs_writel(HOST_IA32_SYSENTER_ESP, sysenter_esp); /* 22.2.3 */
-
-		/*
-		 * Make sure the time stamp counter is monotonous.
-		 */
-		rdtscll(tsc_this);
-		if (tsc_this < vcpu->arch.host_tsc) {
-			delta = vcpu->arch.host_tsc - tsc_this;
-			new_offset = vmcs_read64(TSC_OFFSET) + delta;
-			vmcs_write64(TSC_OFFSET, new_offset);
-		}
 	}
 }
 
@@ -1153,6 +1141,12 @@  static void guest_write_tsc(u64 guest_tsc, u64 host_tsc)
 	vmcs_write64(TSC_OFFSET, guest_tsc - host_tsc);
 }
 
+static void vmx_adjust_tsc_offset(struct kvm_vcpu *vcpu, s64 adjustment)
+{
+	u64 offset = vmcs_read64(TSC_OFFSET);
+	vmcs_write64(TSC_OFFSET, offset + adjustment);
+}
+
 /*
  * Reads an msr value (of 'msr_index') into 'pdata'.
  * Returns 0 on success, non-0 otherwise.
@@ -4340,6 +4334,8 @@  static struct kvm_x86_ops vmx_x86_ops = {
 	.rdtscp_supported = vmx_rdtscp_supported,
 
 	.set_supported_cpuid = vmx_set_supported_cpuid,
+
+	.adjust_tsc_offset = vmx_adjust_tsc_offset,
 };
 
 static int __init vmx_init(void)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 0a102d3..c8289d0 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -929,9 +929,9 @@  static int kvm_write_guest_time(struct kvm_vcpu *v)
 		return 1;
 	}
 
-	if (unlikely(vcpu->hv_clock_tsc_khz != this_tsc_khz)) {
+	if (unlikely(vcpu->hw_tsc_khz != this_tsc_khz)) {
 		kvm_set_time_scale(this_tsc_khz, &vcpu->hv_clock);
-		vcpu->hv_clock_tsc_khz = this_tsc_khz;
+		vcpu->hw_tsc_khz = this_tsc_khz;
 	}
 
 	/* Keep irq disabled to prevent changes to the clock */
@@ -1805,18 +1805,24 @@  out:
 
 void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 {
+	kvm_x86_ops->vcpu_load(vcpu, cpu);
 	if (unlikely(vcpu->cpu != cpu)) {
+		/* Make sure TSC doesn't go backwards */
+		s64 tsc_delta = !vcpu->arch.last_host_tsc ? 0 : 
+				native_read_tsc() - vcpu->arch.last_host_tsc;
+		if (tsc_delta < 0 || check_tsc_unstable())
+			kvm_x86_ops->adjust_tsc_offset(vcpu, -tsc_delta);
 		kvm_migrate_timers(vcpu);
+		kvm_request_guest_time_update(vcpu);
+		vcpu->cpu = cpu;
 	}
-	kvm_x86_ops->vcpu_load(vcpu, cpu);
-	kvm_request_guest_time_update(vcpu);
-	vcpu->cpu = cpu;
 }
 
 void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 {
 	kvm_x86_ops->vcpu_put(vcpu);
 	kvm_put_guest_fpu(vcpu);
+	vcpu->arch.last_host_tsc = native_read_tsc();
 }
 
 static int is_efer_nx(void)