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KVM: VMX: Optimize vmx_get_cpl()

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In long mode, vm86 mode is disallowed, so we need not check for
it.  Reading rflags.vm may require a VMREAD, so it is expensive.

Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Avi Kivity
2011-03-07 14:54:28 +02:00
parent 6de12732c4
commit f4c63e5d5a
1 changed files with 2 additions and 1 deletions
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arch/x86/kvm/vmx.c
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@@ -2120,7 +2120,8 @@ static int vmx_get_cpl(struct kvm_vcpu *vcpu)
if (!is_protmode(vcpu)) if (!is_protmode(vcpu))
return 0; return 0;
if (kvm_get_rflags(vcpu) & X86_EFLAGS_VM) /* if virtual 8086 */ if (!is_long_mode(vcpu)
&& (kvm_get_rflags(vcpu) & X86_EFLAGS_VM)) /* if virtual 8086 */
return 3; return 3;
return vmcs_read16(GUEST_CS_SELECTOR) & 3; return vmcs_read16(GUEST_CS_SELECTOR) & 3;