[PATCH 3/8] KVM: Activate fpu on clts

Avi Kivity
2010-01-21T13:31:54Z

Assume that if the guest executes clts, it knows what it's doing, and load the
guest fpu to prevent an #NM exception.

Signed-off-by: Avi Kivity <avi@redhat.com>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/svm.c | 8 +++++++-
arch/x86/kvm/vmx.c | 1 +
arch/x86/kvm/x86.c | 1 +
4 files changed, 10 insertions(+), 1 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index a1f0b5d..bf3ec76 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -512,6 +512,7 @@ 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_activate)(struct kvm_vcpu *vcpu);
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 8d7cb62..0f3738a 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1259,12 +1259,17 @@ static int ud_interception(struct vcpu_svm *svm)
return 1;
}

-static int nm_interception(struct vcpu_svm *svm)
+static void svm_fpu_activate(struct kvm_vcpu *vcpu)
{
+ struct vcpu_svm *svm = to_svm(vcpu);
svm->vmcb->control.intercept_exceptions &= ~(1 << NM_VECTOR);
svm->vcpu.fpu_active = 1;
update_cr0_intercept(svm);
+}

+static int nm_interception(struct vcpu_svm *svm)
+{
+ svm_fpu_activate(&svm->vcpu);
return 1;
}

@@ -2971,6 +2976,7 @@ static struct kvm_x86_ops svm_x86_ops = {
.cache_reg = svm_cache_reg,
.get_rflags = svm_get_rflags,
.set_rflags = svm_set_rflags,
+ .fpu_activate = svm_fpu_activate,
.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 7375ae1..372bc38 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3011,6 +3011,7 @@ static int handle_cr(struct kvm_vcpu *vcpu)
vmcs_writel(CR0_READ_SHADOW, kvm_read_cr0(vcpu));
trace_kvm_cr_write(0, kvm_read_cr0(vcpu));
skip_emulated_instruction(vcpu);
+ vmx_fpu_activate(vcpu);
return 1;
case 1: /*mov from cr*/
switch (cr) {
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index feca59f..09207ba 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3266,6 +3266,7 @@ int emulate_invlpg(struct kvm_vcpu *vcpu, gva_t address)
int emulate_clts(struct kvm_vcpu *vcpu)
{
kvm_x86_ops->set_cr0(vcpu, kvm_read_cr0_bits(vcpu, ~X86_CR0_TS));
+ kvm_x86_ops->fpu_activate(vcpu);
return X86EMUL_CONTINUE;
}

--
1.6.5.3