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

[Jason Wang <jasowang@redhat.com>]

On 2017年03月14日 17:29, Cornelia Huck wrote:
> On Tue, 14 Mar 2017 11:01:41 +0800
> Jason Wang <jasowang@redhat.com> 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 <cornelia.huck@de.ibm.com>
>> Cc: Paolo Bonzini <pbonzini@redhat.com>
>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>> ---
>> 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 <cornelia.huck@de.ibm.com>
>
>