Re: BUG with Win7 and user-return-notifier

Avi Kivity
2009-10-29T16:49:07Z

On 10/29/2009 06:07 PM, Jan Kiszka wrote:
>
> Question: When a VCPU migrates, what syncs the shared_msrs per-cpu vars
> before or after that, or why is this no problem?
>
>

The guest's msrs remain on the old cpu (until a new guest is switched in
or we return to userspace). The guest msrs are loaded into the new cpu
when vmx_save_host_state() is called as part or kvm_arch_vcpu_load().

> I'm currently following the theory that guest_msrs contains some
> non-EFER entry with 0 value, but shared_msrs has a different index in
> the slot passed to kvm_set_shared_msr.
>

That's a global...

--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.