[PATCH 20/58] KVM: VMX: Only reload guest msrs if they are already loaded

[Avi Kivity]

If we set an msr via an ioctl() instead of by handling a guest exit, we
have the host state loaded, so reloading the msrs would clobber host
state instead of guest state.

This fixes a host oops (and loss of a cpu) on a guest reboot.

Signed-off-by: Avi Kivity <avi@xxxxxxxxxxxx>
---
 drivers/kvm/vmx.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index 096cb6a..b353eaa 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -600,7 +600,8 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 data)
 		msr = find_msr_entry(vcpu, msr_index);
 		if (msr)
 			msr->data = data;
-		load_msrs(vcpu->guest_msrs, NR_BAD_MSRS);
+		if (vcpu->vmx_host_state.loaded)
+			load_msrs(vcpu->guest_msrs, NR_BAD_MSRS);
 		break;
 #endif
 	case MSR_IA32_SYSENTER_CS:
-- 
1.5.0.6

-
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