diff options
| author | Avi Kivity | 2009-12-30 18:07:40 +0200 |
|---|---|---|
| committer | Marcelo Tosatti | 2010-03-01 12:35:50 -0300 |
| commit | edcafe3c5a06f46407c3f60145a36f269e56ff7f (patch) | |
| tree | 3fc9e54eec11f0481e5d9e8517941f651866463b /arch/x86 | |
| parent | 02daab21d94dc4cf01b2fd09863d59a436900322 (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>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/vmx.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index d11be3fb7c80..fc1964d5e97c 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; |