[PATCH 37/54] KVM: VMX: Avoid exit when setting cr8 if the local apic is in the kernel

From: Avi Kivity
Date: Tue Jan 01 2008 - 10:48:09 EST


With apic in userspace, we must exit to userspace after a cr8 write in order
to update the tpr. But if the apic is in the kernel, the exit is unnecessary.

Noticed by Joerg Roedel.

Signed-off-by: Avi Kivity <avi@xxxxxxxxxxxx>
---
drivers/kvm/vmx.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index aa6bf2b..548e3a5 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -1973,6 +1973,8 @@ static int handle_cr(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
vcpu_load_rsp_rip(vcpu);
set_cr8(vcpu, vcpu->regs[reg]);
skip_emulated_instruction(vcpu);
+ if (irqchip_in_kernel(vcpu->kvm))
+ return 1;
kvm_run->exit_reason = KVM_EXIT_SET_TPR;
return 0;
};
--
1.5.3.7

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