Re: [RFC PATCH-for-7.2 3/5] hw/display/qxl: Pass requested buffer size to qxl_phys2virt()

[Gerd Hoffmann]

On Mon, Nov 28, 2022 at 04:41:14PM +0100, Philippe Mathieu-Daudé wrote:
> On 28/11/22 16:08, Gerd Hoffmann wrote:
> > > @@ -228,7 +230,7 @@ static void qxl_unpack_chunks(void *dest, size_t 
> > > size, PCIQXLDevice *qxl,
> > >           if (offset == size) {
> > >               return;
> > >           }
> > > -        chunk = qxl_phys2virt(qxl, chunk->next_chunk, group_id);
> > > +        chunk = qxl_phys2virt(qxl, chunk->next_chunk, group_id, bytes);
> > >           if (!chunk) {
> > >               return;
> > >           }
> > 
> > Naa, its not that simple.  You get a QXLDataChunk passed in which
> > typically is verified *excluding* dynamically-sized chunk->data.
> 
> OK so IIUC 1/ this line should be:
> 
>   chunk = qxl_phys2virt(qxl, chunk->next_chunk, group_id,
>                         sizeof(QXLDataChunk));

Depends on whenever you do (2) inside or outside the loop ;)

> but 2/ we should check chunk->data[chunk->data_size] is valid (within
> the MR) before calling the memcpy(), right?

Yes.

take care,
  Gerd