Re: [Qemu-devel] [PATCH v5 2/5] virtio-pmem: Add virtio pmem driver

Cornelia Huck
2019-04-10T14:32:22Z

On Wed, 10 Apr 2019 10:03:01 -0400 (EDT)
Pankaj Gupta <pagupta@redhat.com> wrote:

> >
> > On Wed, Apr 10, 2019 at 09:38:22AM +0530, Pankaj Gupta wrote:
> > > This patch adds virtio-pmem driver for KVM guest.
> > >
> > > Guest reads the persistent memory range information from
> > > Qemu over VIRTIO and registers it on nvdimm_bus. It also
> > > creates a nd_region object with the persistent memory
> > > range information so that existing 'nvdimm/pmem' driver
> > > can reserve this into system memory map. This way
> > > 'virtio-pmem' driver uses existing functionality of pmem
> > > driver to register persistent memory compatible for DAX
> > > capable filesystems.
> > >
> > > This also provides function to perform guest flush over
> > > VIRTIO from 'pmem' driver when userspace performs flush
> > > on DAX memory range.
> > >
> > > Signed-off-by: Pankaj Gupta <pagupta@redhat.com>

> > > diff --git a/include/uapi/linux/virtio_ids.h
> > > b/include/uapi/linux/virtio_ids.h
> > > index 6d5c3b2d4f4d..346389565ac1 100644
> > > --- a/include/uapi/linux/virtio_ids.h
> > > +++ b/include/uapi/linux/virtio_ids.h
> > > @@ -43,5 +43,6 @@
> > > #define VIRTIO_ID_INPUT 18 /* virtio input */
> > > #define VIRTIO_ID_VSOCK 19 /* virtio vsock transport */
> > > #define VIRTIO_ID_CRYPTO 20 /* virtio crypto */
> > > +#define VIRTIO_ID_PMEM 25 /* virtio pmem */
> > >
> > > #endif /* _LINUX_VIRTIO_IDS_H */
> >
> > Didn't Paolo point out someone is using 25 for audio?
>
>
> Sorry! I did not notice this.
>
> >
> > Please, reserve an ID with the Virtio TC before using it.
>
> I thought I requested[1] ID 25.
>
> [1] https://github.com/oasis-tcs/virtio-spec/issues/38
> [2] https://lists.oasis-open.org/archives/virtio-dev/201805/threads.html
>
> In that case I will send request for next available ID i.e 26?

Have the folks using this for audio sent a reservation request as well?
If not, I'd say the first requester should get the id...

(And yes, we need to be quicker with voting on/applying id
reservations :/)