| Message ID | 1426671309-13645-7-git-send-email-jasowang@redhat.com |
|---|---|
| State | New |
| Headers | show |
On Wed, Mar 18, 2015 at 05:34:56PM +0800, Jason Wang wrote: > There's no need to use vector 0 for invalid virtqueue. So this patch > changes to use VIRTIO_NO_VECTOR instead. > > Cc: Michael S. Tsirkin <mst@redhat.com> > Cc: Cornelia Huck <cornelia.huck@de.ibm.com> > CC: Christian Borntraeger <borntraeger@de.ibm.com> > Cc: Richard Henderson <rth@twiddle.net> > Cc: Alexander Graf <agraf@suse.de> > Signed-off-by: Jason Wang <jasowang@redhat.com> I don't know what does this actually do. Cornelia? > --- > hw/s390x/virtio-ccw.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c > index 130535c..c8b87aa 100644 > --- a/hw/s390x/virtio-ccw.c > +++ b/hw/s390x/virtio-ccw.c > @@ -281,7 +281,7 @@ static int virtio_ccw_set_vqs(SubchDev *sch, uint64_t addr, uint32_t align, > > virtio_queue_set_addr(vdev, index, addr); > if (!addr) { > - virtio_queue_set_vector(vdev, index, 0); > + virtio_queue_set_vector(vdev, index, VIRTIO_NO_VECTOR); > } else { > /* Fail if we don't have a big enough queue. */ > /* TODO: Add interface to handle vring.num changing */ Right below this, we have /* tell notify handler in case of config change */ vdev->config_vector = VIRTIO_PCI_QUEUE_MAX; which also does not seem to make sense. These changes need some testing though. > -- > 2.1.0
On Wed, 18 Mar 2015 14:08:56 +0100 "Michael S. Tsirkin" <mst@redhat.com> wrote: > On Wed, Mar 18, 2015 at 05:34:56PM +0800, Jason Wang wrote: > > There's no need to use vector 0 for invalid virtqueue. So this patch > > changes to use VIRTIO_NO_VECTOR instead. > > > > Cc: Michael S. Tsirkin <mst@redhat.com> > > Cc: Cornelia Huck <cornelia.huck@de.ibm.com> > > CC: Christian Borntraeger <borntraeger@de.ibm.com> > > Cc: Richard Henderson <rth@twiddle.net> > > Cc: Alexander Graf <agraf@suse.de> > > Signed-off-by: Jason Wang <jasowang@redhat.com> > > I don't know what does this actually do. > Cornelia? I actually have the same patch somewhere in my queue. The point here is that 0 is plain wrong (it's a valid queue), while VIRTIO_NO_VECTOR is most certainly no valid queue. > > > --- > > hw/s390x/virtio-ccw.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c > > index 130535c..c8b87aa 100644 > > --- a/hw/s390x/virtio-ccw.c > > +++ b/hw/s390x/virtio-ccw.c > > @@ -281,7 +281,7 @@ static int virtio_ccw_set_vqs(SubchDev *sch, uint64_t addr, uint32_t align, > > > > virtio_queue_set_addr(vdev, index, addr); > > if (!addr) { > > - virtio_queue_set_vector(vdev, index, 0); > > + virtio_queue_set_vector(vdev, index, VIRTIO_NO_VECTOR); > > } else { > > /* Fail if we don't have a big enough queue. */ > > /* TODO: Add interface to handle vring.num changing */ > > Right below this, we have > /* tell notify handler in case of config change */ > vdev->config_vector = VIRTIO_PCI_QUEUE_MAX; > > which also does not seem to make sense. Basically we have: - at most 64 virtqueues with their own indicators (always 64 indicator bits when using classic I/O interrupts, up to 64 indicator bits when using adapter interrupts) - another indicator bit for configuration changes (bit 0 of the secondary indicator bits) That way, the configuration change indicator is always one bit behind the last possible queue indicator. > > These changes need some testing though. My identical patch seemed to work for me.
On Fri, Mar 20, 2015 at 08:39:24AM +0100, Cornelia Huck wrote: > On Wed, 18 Mar 2015 14:08:56 +0100 > "Michael S. Tsirkin" <mst@redhat.com> wrote: > > > On Wed, Mar 18, 2015 at 05:34:56PM +0800, Jason Wang wrote: > > > There's no need to use vector 0 for invalid virtqueue. So this patch > > > changes to use VIRTIO_NO_VECTOR instead. > > > > > > Cc: Michael S. Tsirkin <mst@redhat.com> > > > Cc: Cornelia Huck <cornelia.huck@de.ibm.com> > > > CC: Christian Borntraeger <borntraeger@de.ibm.com> > > > Cc: Richard Henderson <rth@twiddle.net> > > > Cc: Alexander Graf <agraf@suse.de> > > > Signed-off-by: Jason Wang <jasowang@redhat.com> > > > > I don't know what does this actually do. > > Cornelia? > > I actually have the same patch somewhere in my queue. The point here is > that 0 is plain wrong (it's a valid queue), while VIRTIO_NO_VECTOR is > most certainly no valid queue. > > > > > > --- > > > hw/s390x/virtio-ccw.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c > > > index 130535c..c8b87aa 100644 > > > --- a/hw/s390x/virtio-ccw.c > > > +++ b/hw/s390x/virtio-ccw.c > > > @@ -281,7 +281,7 @@ static int virtio_ccw_set_vqs(SubchDev *sch, uint64_t addr, uint32_t align, > > > > > > virtio_queue_set_addr(vdev, index, addr); > > > if (!addr) { > > > - virtio_queue_set_vector(vdev, index, 0); > > > + virtio_queue_set_vector(vdev, index, VIRTIO_NO_VECTOR); > > > } else { > > > /* Fail if we don't have a big enough queue. */ > > > /* TODO: Add interface to handle vring.num changing */ > > > > Right below this, we have > > /* tell notify handler in case of config change */ > > vdev->config_vector = VIRTIO_PCI_QUEUE_MAX; > > > > which also does not seem to make sense. > > Basically we have: > > - at most 64 virtqueues with their own indicators (always 64 indicator > bits when using classic I/O interrupts, up to 64 indicator bits when > using adapter interrupts) > - another indicator bit for configuration changes (bit 0 of the > secondary indicator bits) > > That way, the configuration change indicator is always one bit behind > the last possible queue indicator. But VIRTIO_PCI_QUEUE_MAX only makes sense as a VQ number. Why does it make sense as a vector number? Jason's patches actually change VIRTIO_PCI_QUEUE_MAX so we need to figure our what to do for this code. > > > > These changes need some testing though. > > My identical patch seemed to work for me.
On Sat, 21 Mar 2015 19:27:49 +0100 "Michael S. Tsirkin" <mst@redhat.com> wrote: > On Fri, Mar 20, 2015 at 08:39:24AM +0100, Cornelia Huck wrote: > > On Wed, 18 Mar 2015 14:08:56 +0100 > > "Michael S. Tsirkin" <mst@redhat.com> wrote: > > > > > On Wed, Mar 18, 2015 at 05:34:56PM +0800, Jason Wang wrote: > > > > There's no need to use vector 0 for invalid virtqueue. So this patch > > > > changes to use VIRTIO_NO_VECTOR instead. > > > > > > > > Cc: Michael S. Tsirkin <mst@redhat.com> > > > > Cc: Cornelia Huck <cornelia.huck@de.ibm.com> > > > > CC: Christian Borntraeger <borntraeger@de.ibm.com> > > > > Cc: Richard Henderson <rth@twiddle.net> > > > > Cc: Alexander Graf <agraf@suse.de> > > > > Signed-off-by: Jason Wang <jasowang@redhat.com> > > > > > > I don't know what does this actually do. > > > Cornelia? > > > > I actually have the same patch somewhere in my queue. The point here is > > that 0 is plain wrong (it's a valid queue), while VIRTIO_NO_VECTOR is > > most certainly no valid queue. > > > > > > > > > --- > > > > hw/s390x/virtio-ccw.c | 2 +- > > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > > > diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c > > > > index 130535c..c8b87aa 100644 > > > > --- a/hw/s390x/virtio-ccw.c > > > > +++ b/hw/s390x/virtio-ccw.c > > > > @@ -281,7 +281,7 @@ static int virtio_ccw_set_vqs(SubchDev *sch, uint64_t addr, uint32_t align, > > > > > > > > virtio_queue_set_addr(vdev, index, addr); > > > > if (!addr) { > > > > - virtio_queue_set_vector(vdev, index, 0); > > > > + virtio_queue_set_vector(vdev, index, VIRTIO_NO_VECTOR); > > > > } else { > > > > /* Fail if we don't have a big enough queue. */ > > > > /* TODO: Add interface to handle vring.num changing */ > > > > > > Right below this, we have > > > /* tell notify handler in case of config change */ > > > vdev->config_vector = VIRTIO_PCI_QUEUE_MAX; > > > > > > which also does not seem to make sense. > > > > Basically we have: > > > > - at most 64 virtqueues with their own indicators (always 64 indicator > > bits when using classic I/O interrupts, up to 64 indicator bits when > > using adapter interrupts) > > - another indicator bit for configuration changes (bit 0 of the > > secondary indicator bits) > > > > That way, the configuration change indicator is always one bit behind > > the last possible queue indicator. > > But VIRTIO_PCI_QUEUE_MAX only makes sense as a VQ number. > Why does it make sense as a vector number? > Jason's patches actually change VIRTIO_PCI_QUEUE_MAX > so we need to figure our what to do for this code. We don't have "vectors" for virtio-ccw. It's just a concept mandated by common code, we just do an identity mapping. Using this value just pushes the notifier bits for config changes to behind the highest possible virtqueue.
diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c index 130535c..c8b87aa 100644 --- a/hw/s390x/virtio-ccw.c +++ b/hw/s390x/virtio-ccw.c @@ -281,7 +281,7 @@ static int virtio_ccw_set_vqs(SubchDev *sch, uint64_t addr, uint32_t align, virtio_queue_set_addr(vdev, index, addr); if (!addr) { - virtio_queue_set_vector(vdev, index, 0); + virtio_queue_set_vector(vdev, index, VIRTIO_NO_VECTOR); } else { /* Fail if we don't have a big enough queue. */ /* TODO: Add interface to handle vring.num changing */
There's no need to use vector 0 for invalid virtqueue. So this patch changes to use VIRTIO_NO_VECTOR instead. Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Cornelia Huck <cornelia.huck@de.ibm.com> CC: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Richard Henderson <rth@twiddle.net> Cc: Alexander Graf <agraf@suse.de> Signed-off-by: Jason Wang <jasowang@redhat.com> --- hw/s390x/virtio-ccw.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)