Re: [Qemu-devel] [PATCH V3 2/3] virtio: destroy region cache during reset

[Jason Wang]

On 2017年03月14日 17:29, Cornelia Huck wrote:
> On Tue, 14 Mar 2017 11:01:41 +0800
> Jason Wang <address@hidden> wrote:
>
> > We don't destroy region cache during reset which can make the maps
> > of previous driver leaked to a buggy or malicious driver that don't
> > set vring address before starting to use the device. Fix this by
> > destroy the region cache during reset and validate it before trying to
> > see them.
> >
> > Cc: Cornelia Huck <address@hidden>
> > Cc: Paolo Bonzini <address@hidden>
> > Signed-off-by: Jason Wang <address@hidden>
> > ---
> > Changes from V2:
> > - introduce a helper and assert caches != NULL
> > Changes from v1:
> > - switch to use rcu in virtio_virtqueue_region_cache()
> > - use unlikely() when needed
> > ---
> >   hw/virtio/virtio.c | 46 ++++++++++++++++++++++++++++++----------------
> >   1 file changed, 30 insertions(+), 16 deletions(-)
> >
> > @@ -249,11 +255,10 @@ static inline void vring_used_idx_set(VirtQueue *vq, 
> > uint16_t val)
> >   /* Called within rcu_read_lock().  */
> >   static inline void vring_used_flags_set_bit(VirtQueue *vq, int mask)
> >   {
> > -    VRingMemoryRegionCaches *caches = atomic_rcu_read(&vq->vring.caches);
> > +    VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
> >       VirtIODevice *vdev = vq->vdev;
> >       hwaddr pa = offsetof(VRingUsed, flags);
> >       uint16_t flags = virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
> > -
> Unrelated whitespace change.

Right. If no more comments from any others. I think Michael can probably 
fix this during merge.

Thanks

> >       virtio_stw_phys_cached(vdev, &caches->used, pa, flags | mask);
> >       address_space_cache_invalidate(&caches->used, pa, sizeof(flags));
> >   }
> Other than that:
>
> Reviewed-by: Cornelia Huck <address@hidden>