On Fri, Feb 1, 2019 at 4:17 PM Michael S. Tsirkin <m...@redhat.com> wrote:
>
> On Thu, Jan 31, 2019 at 04:19:11PM +0100, Stefano Garzarella wrote:
> > In order to avoid migration issues, we enable DISCARD and
> > WRITE ZEROES features only for machine type >= 4.0
> >
> > Suggested-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> > Signed-off-by: Stefano Garzarella <sgarz...@redhat.com>
> > ---
> > hw/block/virtio-blk.c | 2 ++
> > hw/core/machine.c | 1 +
> > include/hw/virtio/virtio-blk.h | 1 +
> > 3 files changed, 4 insertions(+)
> >
> > diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
> > index 8a6754d9a2..542ec52536 100644
> > --- a/hw/block/virtio-blk.c
> > +++ b/hw/block/virtio-blk.c
> > @@ -1026,6 +1026,8 @@ static Property virtio_blk_properties[] = {
> > DEFINE_PROP_UINT16("queue-size", VirtIOBlock, conf.queue_size, 128),
> > DEFINE_PROP_LINK("iothread", VirtIOBlock, conf.iothread, TYPE_IOTHREAD,
> > IOThread *),
> > + DEFINE_PROP_BIT("discard-wzeroes", VirtIOBlock, conf.discard_wzeroes,
> > 0,
> > + true),
> > DEFINE_PROP_END_OF_LIST(),
> > };
> >
>
> Thinking about it, are there security implications for discard?
> Should we make it default false?
Hi Michael,
I'm not completely sure but if the guest can write on a specific sector,
discard or write_zeroes operations should not have a security implication.
Do I miss something?
Thanks,
Stefano
