| Message ID | 1364531592-8368-4-git-send-email-nab@linux-iscsi.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Mar 29, 2013 at 04:33:12AM +0000, Nicholas A. Bellinger wrote: > From: Nicholas Bellinger <nab@linux-iscsi.org> > > With the virtio_queue_valid() checks in place to skip uninitialized VQs > within virtio-pci code, go ahead and skip the same uninitialized VQs > during vhost_verify_ring_mappings(). > > Note this patch does not prevent vhost_virtqueue_start() from executing > by checking virtio_queue_valid(), as other logic during seabios -> > virtio-scsi LLD guest hand-off appears to depend upon this execution. Weird. cpu_physical_memory_map only succeeds for PA==0 by chance, we really should not depend on this. So the right thing really should be to skip vhost_virtqueue_start IMHO, maybe add an explicit valid flag in vhost_virtqueue so vhost_verify_ring_mappings can check it. What exactly does it do that is needed? > > Cc: Michael S. Tsirkin <mst@redhat.com> > Cc: Asias He <asias@redhat.com> > Cc: Paolo Bonzini <pbonzini@redhat.com> > Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> > --- > hw/vhost.c | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > > diff --git a/hw/vhost.c b/hw/vhost.c > index 4d6aee3..3a71aee 100644 > --- a/hw/vhost.c > +++ b/hw/vhost.c > @@ -314,6 +314,9 @@ static int vhost_verify_ring_mappings(struct vhost_dev *dev, > hwaddr l; > void *p; > > + if (!vq->ring_phys || !vq->ring_size) { > + continue; > + } > if (!ranges_overlap(start_addr, size, vq->ring_phys, vq->ring_size)) { > continue; > } > -- > 1.7.2.5 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sun, 2013-03-31 at 10:45 +0300, Michael S. Tsirkin wrote: > On Fri, Mar 29, 2013 at 04:33:12AM +0000, Nicholas A. Bellinger wrote: > > From: Nicholas Bellinger <nab@linux-iscsi.org> > > > > With the virtio_queue_valid() checks in place to skip uninitialized VQs > > within virtio-pci code, go ahead and skip the same uninitialized VQs > > during vhost_verify_ring_mappings(). > > > > Note this patch does not prevent vhost_virtqueue_start() from executing > > by checking virtio_queue_valid(), as other logic during seabios -> > > virtio-scsi LLD guest hand-off appears to depend upon this execution. > > Weird. > cpu_physical_memory_map only succeeds for PA==0 by chance, > we really should not depend on this. > So the right thing really should be to skip vhost_virtqueue_start IMHO, > maybe add an explicit valid flag in vhost_virtqueue > so vhost_verify_ring_mappings can check it. > What exactly does it do that is needed? > So the issue with virtio_queue_valid() preventing vhost_virtqueue_start() execution in the original patch was that vhost_virtqueue_stop() was missing a matching virtio_queue_valid() call, which ended up triggering a bad ram pointer during subsequent cpu_physical_memory_unmap() calls to non-existent virtio queue memory.. With the matching virtio_queue_valid() call in place preventing vhost_virtqueue_stop() when vhost_virtqueue_start() is skipped for an uninitialized VQ, a explicit valid flag should not be necessary. --nab > > > > Cc: Michael S. Tsirkin <mst@redhat.com> > > Cc: Asias He <asias@redhat.com> > > Cc: Paolo Bonzini <pbonzini@redhat.com> > > Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> > > --- > > hw/vhost.c | 3 +++ > > 1 files changed, 3 insertions(+), 0 deletions(-) > > > > diff --git a/hw/vhost.c b/hw/vhost.c > > index 4d6aee3..3a71aee 100644 > > --- a/hw/vhost.c > > +++ b/hw/vhost.c > > @@ -314,6 +314,9 @@ static int vhost_verify_ring_mappings(struct vhost_dev *dev, > > hwaddr l; > > void *p; > > > > + if (!vq->ring_phys || !vq->ring_size) { > > + continue; > > + } > > if (!ranges_overlap(start_addr, size, vq->ring_phys, vq->ring_size)) { > > continue; > > } > > -- > > 1.7.2.5 > -- > To unsubscribe from this list: send the line "unsubscribe target-devel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/hw/vhost.c b/hw/vhost.c index 4d6aee3..3a71aee 100644 --- a/hw/vhost.c +++ b/hw/vhost.c @@ -314,6 +314,9 @@ static int vhost_verify_ring_mappings(struct vhost_dev *dev, hwaddr l; void *p; + if (!vq->ring_phys || !vq->ring_size) { + continue; + } if (!ranges_overlap(start_addr, size, vq->ring_phys, vq->ring_size)) { continue; }