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

Avi Kivity
2007-06-17T09:44:01Z

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-atKUWr5tajBWk0Htik3J/w@public.gmane.org>
---
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: