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authorAvi Kivity <avi@redhat.com>2009-12-30 18:07:40 +0200
committerMarcelo Tosatti <mtosatti@redhat.com>2010-03-01 12:35:50 -0300
commitedcafe3c5a06f46407c3f60145a36f269e56ff7f (patch)
tree3fc9e54eec11f0481e5d9e8517941f651866463b
parent02daab21d94dc4cf01b2fd09863d59a436900322 (diff)
KVM: VMX: Give the guest ownership of cr0.ts when the fpu is active
If the guest fpu is loaded, there is nothing interesing about cr0.ts; let the guest play with it as it will. This makes context switches between fpu intensive guest processes faster, as we won't trap the clts and cr0 write instructions. [marcelo: fix cr0 read shadow update on fpu deactivation; kills F8 install] Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
-rw-r--r--arch/x86/kvm/vmx.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index d11be3fb7c8..fc1964d5e97 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -803,12 +803,20 @@ static void vmx_fpu_activate(struct kvm_vcpu *vcpu)
if (kvm_read_cr0_bits(vcpu, X86_CR0_TS))
vmcs_set_bits(GUEST_CR0, X86_CR0_TS);
update_exception_bitmap(vcpu);
+ vcpu->arch.cr0_guest_owned_bits = X86_CR0_TS;
+ vmcs_writel(CR0_GUEST_HOST_MASK, ~vcpu->arch.cr0_guest_owned_bits);
}
+static void vmx_decache_cr0_guest_bits(struct kvm_vcpu *vcpu);
+
static void vmx_fpu_deactivate(struct kvm_vcpu *vcpu)
{
+ vmx_decache_cr0_guest_bits(vcpu);
vmcs_set_bits(GUEST_CR0, X86_CR0_TS);
update_exception_bitmap(vcpu);
+ vcpu->arch.cr0_guest_owned_bits = 0;
+ vmcs_writel(CR0_GUEST_HOST_MASK, ~vcpu->arch.cr0_guest_owned_bits);
+ vmcs_writel(CR0_READ_SHADOW, vcpu->arch.cr0);
}
static unsigned long vmx_get_rflags(struct kvm_vcpu *vcpu)
@@ -2996,8 +3004,7 @@ static int handle_cr(struct kvm_vcpu *vcpu)
};
break;
case 2: /* clts */
- vcpu->arch.cr0 &= ~X86_CR0_TS;
- vmcs_writel(CR0_READ_SHADOW, kvm_read_cr0(vcpu));
+ vmx_set_cr0(vcpu, kvm_read_cr0_bits(vcpu, ~X86_CR0_TS));
trace_kvm_cr_write(0, kvm_read_cr0(vcpu));
skip_emulated_instruction(vcpu);
return 1;