[4/5] KVM: Lazify fpu activation and deactivation

Commit Message

Avi Kivity Dec. 30, 2009, 4:25 p.m. UTC

None

Patch

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 627d50b..b3b3ce1 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -498,6 +498,7 @@  struct kvm_x86_ops {
 	void (*cache_reg)(struct kvm_vcpu *vcpu, enum kvm_reg reg);
 	unsigned long (*get_rflags)(struct kvm_vcpu *vcpu);
 	void (*set_rflags)(struct kvm_vcpu *vcpu, unsigned long rflags);
+	void (*fpu_deactivate)(struct kvm_vcpu *vcpu);
 
 	void (*tlb_flush)(struct kvm_vcpu *vcpu);
 
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index b2a7155..2a3890f 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -984,17 +984,8 @@  static void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
 	if (npt_enabled)
 		goto set;
 
-	if (kvm_read_cr0_bits(vcpu, X86_CR0_TS) && !(cr0 & X86_CR0_TS)) {
-		svm->vmcb->control.intercept_exceptions &= ~(1 << NM_VECTOR);
-		vcpu->fpu_active = 1;
-	}
-
 	vcpu->arch.cr0 = cr0;
 	cr0 |= X86_CR0_PG | X86_CR0_WP;
-	if (!vcpu->fpu_active) {
-		svm->vmcb->control.intercept_exceptions |= (1 << NM_VECTOR);
-		cr0 |= X86_CR0_TS;
-	}
 set:
 	/*
 	 * re-enable caching here because the QEMU bios
@@ -1250,6 +1241,8 @@  static int nm_interception(struct vcpu_svm *svm)
 	svm->vmcb->control.intercept_exceptions &= ~(1 << NM_VECTOR);
 	if (!kvm_read_cr0_bits(&svm->vcpu, X86_CR0_TS))
 		svm->vmcb->save.cr0 &= ~X86_CR0_TS;
+	else
+		svm->vmcb->save.cr0 |= X86_CR0_TS;
 	svm->vcpu.fpu_active = 1;
 
 	return 1;
@@ -2586,6 +2579,8 @@  static void svm_flush_tlb(struct kvm_vcpu *vcpu)
 
 static void svm_prepare_guest_switch(struct kvm_vcpu *vcpu)
 {
+	if (npt_enabled)
+		vcpu->fpu_active = 1;
 }
 
 static inline void sync_cr8_to_lapic(struct kvm_vcpu *vcpu)
@@ -2805,12 +2800,6 @@  static void svm_set_cr3(struct kvm_vcpu *vcpu, unsigned long root)
 
 	svm->vmcb->save.cr3 = root;
 	force_new_asid(vcpu);
-
-	if (vcpu->fpu_active) {
-		svm->vmcb->control.intercept_exceptions |= (1 << NM_VECTOR);
-		svm->vmcb->save.cr0 |= X86_CR0_TS;
-		vcpu->fpu_active = 0;
-	}
 }
 
 static int is_disabled(void)
@@ -2926,6 +2915,20 @@  static bool svm_rdtscp_supported(void)
 	return false;
 }
 
+static void svm_fpu_deactivate(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_svm *svm = to_svm(vcpu);
+
+	if (npt_enabled) {
+		/* hack: npt requires active fpu at this time */
+		vcpu->fpu_active = 1;
+		return;
+	}
+
+	svm->vmcb->control.intercept_exceptions |= 1 << NM_VECTOR;
+	svm->vmcb->save.cr0 |= X86_CR0_TS;
+}
+
 static struct kvm_x86_ops svm_x86_ops = {
 	.cpu_has_kvm_support = has_svm,
 	.disabled_by_bios = is_disabled,
@@ -2967,6 +2970,7 @@  static struct kvm_x86_ops svm_x86_ops = {
 	.cache_reg = svm_cache_reg,
 	.get_rflags = svm_get_rflags,
 	.set_rflags = svm_set_rflags,
+	.fpu_deactivate = svm_fpu_deactivate,
 
 	.tlb_flush = svm_flush_tlb,
 
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 0baf62f..7e0b45e 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -801,9 +801,6 @@  static void vmx_fpu_activate(struct kvm_vcpu *vcpu)
 
 static void vmx_fpu_deactivate(struct kvm_vcpu *vcpu)
 {
-	if (!vcpu->fpu_active)
-		return;
-	vcpu->fpu_active = 0;
 	vmcs_set_bits(GUEST_CR0, X86_CR0_TS);
 	update_exception_bitmap(vcpu);
 }
@@ -1727,8 +1724,6 @@  static void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
 	else
 		hw_cr0 = (cr0 & ~KVM_GUEST_CR0_MASK) | KVM_VM_CR0_ALWAYS_ON;
 
-	vmx_fpu_deactivate(vcpu);
-
 	if (vmx->rmode.vm86_active && (cr0 & X86_CR0_PE))
 		enter_pmode(vcpu);
 
@@ -1750,9 +1745,6 @@  static void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
 	vmcs_writel(CR0_READ_SHADOW, cr0);
 	vmcs_writel(GUEST_CR0, hw_cr0);
 	vcpu->arch.cr0 = cr0;
-
-	if (!(cr0 & X86_CR0_TS) || !(cr0 & X86_CR0_PE))
-		vmx_fpu_activate(vcpu);
 }
 
 static u64 construct_eptp(unsigned long root_hpa)
@@ -1783,8 +1775,6 @@  static void vmx_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
 
 	vmx_flush_tlb(vcpu);
 	vmcs_writel(GUEST_CR3, guest_cr3);
-	if (kvm_read_cr0_bits(vcpu, X86_CR0_PE))
-		vmx_fpu_deactivate(vcpu);
 }
 
 static void vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
@@ -2992,11 +2982,9 @@  static int handle_cr(struct kvm_vcpu *vcpu)
 		};
 		break;
 	case 2: /* clts */
-		vmx_fpu_deactivate(vcpu);
 		vcpu->arch.cr0 &= ~X86_CR0_TS;
 		vmcs_writel(CR0_READ_SHADOW, kvm_read_cr0(vcpu));
 		trace_kvm_cr_write(0, kvm_read_cr0(vcpu));
-		vmx_fpu_activate(vcpu);
 		skip_emulated_instruction(vcpu);
 		return 1;
 	case 1: /*mov from cr*/
@@ -4093,6 +4081,7 @@  static struct kvm_x86_ops vmx_x86_ops = {
 	.cache_reg = vmx_cache_reg,
 	.get_rflags = vmx_get_rflags,
 	.set_rflags = vmx_set_rflags,
+	.fpu_deactivate = vmx_fpu_deactivate,
 
 	.tlb_flush = vmx_flush_tlb,
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 78c4397..28c2020 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1509,8 +1509,8 @@  void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 
 void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 {
-	kvm_x86_ops->vcpu_put(vcpu);
 	kvm_put_guest_fpu(vcpu);
+	kvm_x86_ops->vcpu_put(vcpu);
 }
 
 static int is_efer_nx(void)
@@ -4988,6 +4988,10 @@  void kvm_put_guest_fpu(struct kvm_vcpu *vcpu)
 		return;
 
 	vcpu->guest_fpu_loaded = 0;
+	if (vcpu->fpu_active) {
+		vcpu->fpu_active = 0;
+		kvm_x86_ops->fpu_deactivate(vcpu);
+	}
 	kvm_fx_save(&vcpu->arch.guest_fx_image);
 	kvm_fx_restore(&vcpu->arch.host_fx_image);
 	++vcpu->stat.fpu_reload;