[PATCH 16/37] KVM: VMX: When emulating on invalid vmx state, don't return to userspace unnecessarily

From: Avi Kivity
Date: Fri Feb 27 2009 - 05:38:27 EST


If we aren't doing mmio there's no need to exit to userspace (which will
just be confused).

Signed-off-by: Avi Kivity <avi@xxxxxxxxxx>
---
arch/x86/kvm/vmx.c | 8 ++++++--
1 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index a309be6..df454de 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -91,6 +91,7 @@ struct vcpu_vmx {
} rmode;
int vpid;
bool emulation_required;
+ enum emulation_result invalid_state_emulation_result;

/* Support for vnmi-less CPUs */
int soft_vnmi_blocked;
@@ -3130,7 +3131,8 @@ static int handle_nmi_window(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
static void handle_invalid_guest_state(struct kvm_vcpu *vcpu,
struct kvm_run *kvm_run)
{
- int err;
+ struct vcpu_vmx *vmx = to_vmx(vcpu);
+ enum emulation_result err = EMULATE_DONE;

preempt_enable();
local_irq_enable();
@@ -3154,6 +3156,8 @@ static void handle_invalid_guest_state(struct kvm_vcpu *vcpu,

local_irq_disable();
preempt_disable();
+
+ vmx->invalid_state_emulation_result = err;
}

/*
@@ -3205,7 +3209,7 @@ static int kvm_handle_exit(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
if (vmx->emulation_required && emulate_invalid_guest_state) {
if (guest_state_valid(vcpu))
vmx->emulation_required = 0;
- return 0;
+ return vmx->invalid_state_emulation_result != EMULATE_DO_MMIO;
}

/* Access CR3 don't cause VMExit in paging mode, so we need
--
1.6.0.6

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