On Wed, Mar 27, 2013 at 07:54:07PM -0700, Nicholas A. Bellinger wrote:
> Hi Asias,
>
> On Thu, 2013-03-28 at 10:17 +0800, Asias He wrote:
> > This patch fixes guest hang when booting seabios and guest.
> >
> > [ 0.576238] scsi0 : Virtio SCSI HBA
> > [ 0.616754] virtio_scsi virtio1: request:id 0 is not a head!
> >
> > vq->last_used_idx is initialized only when /dev/vhost-scsi is
> > opened or closed.
> >
> > vhost_scsi_open -> vhost_dev_init() -> vhost_vq_reset()
> > vhost_scsi_release() -> vhost_dev_cleanup -> vhost_vq_reset()
> >
> > So, when guest talks to tcm_vhost after seabios does, vq->last_used_idx
> > still contains the old valule for seabios. This confuses guest.
> >
> > Fix this by calling vhost_init_used() to init vq->last_used_idx when
> > we set endpoint.
> >
> > Signed-off-by: Asias He <asias@xxxxxxxxxx>
> > ---
> > drivers/vhost/tcm_vhost.c | 9 ++++++++-
> > 1 file changed, 8 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c
> > index 43fb11e..5e3d4487 100644
> > --- a/drivers/vhost/tcm_vhost.c
> > +++ b/drivers/vhost/tcm_vhost.c
> > @@ -781,8 +781,9 @@ static int vhost_scsi_set_endpoint(
> > {
> > struct tcm_vhost_tport *tv_tport;
> > struct tcm_vhost_tpg *tv_tpg;
> > + struct vhost_virtqueue *vq;
> > bool match = false;
> > - int index, ret;
> > + int index, ret, i;
> >
> > mutex_lock(&vs->dev.mutex);
> > /* Verify that ring has been setup correctly. */
> > @@ -826,6 +827,12 @@ static int vhost_scsi_set_endpoint(
> > if (match) {
> > memcpy(vs->vs_vhost_wwpn, t->vhost_wwpn,
> > sizeof(vs->vs_vhost_wwpn));
> > + for (i = 0; i < VHOST_SCSI_MAX_VQ; i++) {
> > + vq = &vs->vqs[i];
> > + mutex_lock(&vq->mutex);
> > + vhost_init_used(vq);
> > + mutex_unlock(&vq->mutex);
> > + }
>
> Already tried a similar patch earlier today, but as vhost_init_used()
> depends upon a vq->private_data being set it does not actually
> re-initialize ->last_used_idx..
>
Sigh... Ah, We have this in vhost_init_used
if (!vq->private_data)
return 0;
Michael, how bad if we let the original patch 1/2 and 2/2 go to 3.9.
--
Asias
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