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KVM: Do not report TPR write to userspace if new value bigger or equal to a previous one.

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Saves many exits to userspace in a case of IRQ chip in userspace.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Gleb Natapov 2009-04-21 17:45:06 +03:00 committed by Avi Kivity
parent 615d519305
commit 0a5fff1923
2 changed files with 16 additions and 7 deletions
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4
arch/x86/kvm/svm.c
View File

@ -1862,9 +1862,13 @@ static int emulate_on_interception(struct vcpu_svm *svm,
static int cr8_write_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
{
u8 cr8_prev = kvm_get_cr8(&svm->vcpu);
/* instruction emulation calls kvm_set_cr8() */
emulate_instruction(&svm->vcpu, NULL, 0, 0, 0);
if (irqchip_in_kernel(svm->vcpu.kvm))
return 1;
if (cr8_prev <= kvm_get_cr8(&svm->vcpu))
return 1;
kvm_run->exit_reason = KVM_EXIT_SET_TPR;
return 0;
}

19
arch/x86/kvm/vmx.c
View File

@ -2724,13 +2724,18 @@ static int handle_cr(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
kvm_set_cr4(vcpu, kvm_register_read(vcpu, reg));
skip_emulated_instruction(vcpu);
return 1;
case 8:
kvm_set_cr8(vcpu, kvm_register_read(vcpu, reg));
skip_emulated_instruction(vcpu);
if (irqchip_in_kernel(vcpu->kvm))
return 1;
kvm_run->exit_reason = KVM_EXIT_SET_TPR;
return 0;
case 8: {
u8 cr8_prev = kvm_get_cr8(vcpu);
u8 cr8 = kvm_register_read(vcpu, reg);
kvm_set_cr8(vcpu, cr8);
skip_emulated_instruction(vcpu);
if (irqchip_in_kernel(vcpu->kvm))
return 1;
if (cr8_prev <= cr8)
return 1;
kvm_run->exit_reason = KVM_EXIT_SET_TPR;
return 0;
}
};
break;
case 2: /* clts */