On Tue, Jul 09, 2024 at 05:38:54PM -0300, Fabiano Rosas wrote:
> Philippe Mathieu-Daudé <philmd@xxxxxxxxxx> writes:
>
> > "General command" (GEN_CMD, CMD56) is described as:
> >
> > GEN_CMD is the same as the single block read or write
> > commands (CMD24 or CMD17). The difference is that [...]
> > the data block is not a memory payload data but has a
> > vendor specific format and meaning.
> >
> > Thus this block must not be stored overwriting data block
> > on underlying storage drive. Keep it in a dedicated
> > 'vendor_data[]' array.
> >
> > Signed-off-by: Philippe Mathieu-Daudé <philmd@xxxxxxxxxx>
> > Tested-by: Cédric Le Goater <clg@xxxxxxxxxx>
> > ---
> > RFC: Is it safe to reuse VMSTATE_UNUSED_V() (which happens
> > to be the same size)?
>
> Hi, sorry it took some time to get to this, I had just left for vacation
> when you first posted.
And I totally overlooked there's the email.. until you replied. Welcome
back.
>
> I think it's ok:
>
> {
> "field": "unused",
> "version_id": 1,
> "field_exists": false,
> "size": 512
> },
>
> vs.
>
> {
> "field": "vendor_data",
> "version_id": 0,
> "field_exists": false,
> "num": 512,
> "size": 1
> },
>
> The unused field was introduced in 2016 so there's no chance of
> migrating a QEMU that old to/from 9.1.
What happens if an old qemu 9.0 sends rubbish here to a new QEMU, while the
new QEMU would consider it meaningful data?
--
Peter Xu
