[PATCH 05/47] KVM: VMX: Optimize vmx_get_cpl()

From: Avi Kivity
Date: Wed Aug 26 2009 - 06:41:07 EST


Instead of calling vmx_get_segment() (which reads a whole bunch of
vmcs fields), read only the cs selector which contains the cpl.

Signed-off-by: Avi Kivity <avi@xxxxxxxxxx>
---
arch/x86/kvm/vmx.c | 5 +----
1 files changed, 1 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 32e6d20..0ba706e 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1773,16 +1773,13 @@ static void vmx_get_segment(struct kvm_vcpu *vcpu,

static int vmx_get_cpl(struct kvm_vcpu *vcpu)
{
- struct kvm_segment kvm_seg;
-
if (!(vcpu->arch.cr0 & X86_CR0_PE)) /* if real mode */
return 0;

if (vmx_get_rflags(vcpu) & X86_EFLAGS_VM) /* if virtual 8086 */
return 3;

- vmx_get_segment(vcpu, &kvm_seg, VCPU_SREG_CS);
- return kvm_seg.selector & 3;
+ return vmcs_read16(GUEST_CS_SELECTOR) & 3;
}

static u32 vmx_segment_access_rights(struct kvm_segment *var)
--
1.6.4.1

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