[Qemu-devel] Re: kvm crashes with spice while loading qxl

[Paolo Bonzini]

On 03/08/2011 10:17 AM, Avi Kivity wrote:
> > Memory map can be protected by a read-write lock initially, so that vcpu
> > thread holds it for read. Later can be converted to URCU.
>
> rwlock is insufficient, need a way to force the vcpu off so a writer can
> actually do something.
>
> So we need some kind of priority rwlock where a reader lets the lock
> know how it can force it off in case a writer comes along.

If the reader is the VCPU thread, the VCPU thread can always be bounced 
via qemu_cpu_kick.

Paolo