KVM: Lazify fpu activation and deactivation

[safe/jmp/linux-2.6] / arch / x86 / kvm / svm.c

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 3899c2d..5b336a8 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -984,17 +984,11 @@ 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);
+
+       if (!vcpu->fpu_active)
                cr0 |= X86_CR0_TS;
-       }
 set:
        /*
         * re-enable caching here because the QEMU bios
@@ -1250,6 +1244,8 @@ 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 +2582,8 @@ 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 +2803,6 @@ 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 +2918,20 @@ 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 +2973,7 @@ 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,