Re: [Qemu-devel] [PATCH 2/3] virtio-pci: Add virtio_queue_valid checks ahead of virtio_queue_get_num

["Nicholas A. Bellinger" <nab@linux-iscsi.org>]

On Sun, 2013-03-31 at 10:37 +0300, Michael S. Tsirkin wrote:
> On Fri, Mar 29, 2013 at 04:33:11AM +0000, Nicholas A. Bellinger wrote:
> > From: Nicholas Bellinger <nab@linux-iscsi.org>
> > 
> > This patch adds a number of virtio_queue_valid() checks to virtio-pci
> > ahead of virtio_queue_get_num() usage in order to skip operation upon
> > the detection of an uninitialized VQ.
> > 
> > There is one exception in virtio_ioport_read():VIRTIO_PCI_QUEUE_NUM,
> > where virtio_queue_get_num() may still be called without a valid
> > vdev->vq[n].vring.desc physical address.
> > 
> > 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>
> 
> Makes sense. Minor nit: virtio_queue_valid calls virtio_queue_get_num
> internally, so we can drop it everywhere we know queue is valid.
> 

Yes, of course.  This includes every location in virtio-pci.c below..

Including for patch-v2.

> > ---
> >  hw/virtio-pci.c |   27 +++++++++++++++++++++++++++
> >  1 files changed, 27 insertions(+), 0 deletions(-)
> > 
> > diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
> > index 0d67b84..231ca0c 100644
> > --- a/hw/virtio-pci.c
> > +++ b/hw/virtio-pci.c
> > @@ -211,6 +211,9 @@ static void virtio_pci_start_ioeventfd(VirtIOPCIProxy *proxy)
> >      }
> >  
> >      for (n = 0; n < VIRTIO_PCI_QUEUE_MAX; n++) {
> > +        if (!virtio_queue_valid(proxy->vdev, n)) {
> > +            continue;
> > +        }
> >          if (!virtio_queue_get_num(proxy->vdev, n)) {
> >              continue;
> >          }
> > @@ -225,6 +228,9 @@ static void virtio_pci_start_ioeventfd(VirtIOPCIProxy *proxy)
> >  
> >  assign_error:
> >      while (--n >= 0) {
> > +        if (!virtio_queue_valid(proxy->vdev, n)) {
> > +            continue;
> > +        }
> >          if (!virtio_queue_get_num(proxy->vdev, n)) {
> >              continue;
> >          }
> > @@ -246,6 +252,9 @@ static void virtio_pci_stop_ioeventfd(VirtIOPCIProxy *proxy)
> >      }
> >  
> >      for (n = 0; n < VIRTIO_PCI_QUEUE_MAX; n++) {
> > +        if (!virtio_queue_valid(proxy->vdev, n)) {
> > +            continue;
> > +        }
> >          if (!virtio_queue_get_num(proxy->vdev, n)) {
> >              continue;
> >          }
> > @@ -546,6 +555,9 @@ static int kvm_virtio_pci_vector_use(VirtIOPCIProxy *proxy, int nvqs)
> >      MSIMessage msg;
> >  
> >      for (queue_no = 0; queue_no < nvqs; queue_no++) {
> > +        if (!virtio_queue_valid(vdev, queue_no)) {
> > +            continue;
> > +        }
> >          if (!virtio_queue_get_num(vdev, queue_no)) {
> >              break;
> >          }
> > @@ -593,6 +605,9 @@ static void kvm_virtio_pci_vector_release(VirtIOPCIProxy *proxy, int nvqs)
> >      int queue_no;
> >  
> >      for (queue_no = 0; queue_no < nvqs; queue_no++) {
> > +        if (!virtio_queue_valid(vdev, queue_no)) {
> > +            continue;
> > +        }
> >          if (!virtio_queue_get_num(vdev, queue_no)) {
> >              break;
> >          }
> > @@ -665,6 +680,9 @@ static int kvm_virtio_pci_vector_unmask(PCIDevice *dev, unsigned vector,
> >      int ret, queue_no;
> >  
> >      for (queue_no = 0; queue_no < proxy->nvqs_with_notifiers; queue_no++) {
> > +        if (!virtio_queue_valid(vdev, queue_no)) {
> > +            continue;
> > +        }
> >          if (!virtio_queue_get_num(vdev, queue_no)) {
> >              break;
> >          }
> > @@ -695,6 +713,9 @@ static void kvm_virtio_pci_vector_mask(PCIDevice *dev, unsigned vector)
> >      int queue_no;
> >  
> >      for (queue_no = 0; queue_no < proxy->nvqs_with_notifiers; queue_no++) {
> > +        if (!virtio_queue_valid(vdev, queue_no)) {
> > +            continue;
> > +        }
> >          if (!virtio_queue_get_num(vdev, queue_no)) {
> >              break;
> >          }
> > @@ -717,6 +738,9 @@ static void kvm_virtio_pci_vector_poll(PCIDevice *dev,
> >      VirtQueue *vq;
> >  
> >      for (queue_no = 0; queue_no < proxy->nvqs_with_notifiers; queue_no++) {
> > +        if (!virtio_queue_valid(vdev, queue_no)) {
> > +            continue;
> > +        }
> >          if (!virtio_queue_get_num(vdev, queue_no)) {
> >              break;
> >          }
> > @@ -790,6 +814,9 @@ static int virtio_pci_set_guest_notifiers(DeviceState *d, int nvqs, bool assign)
> >      }
> >  
> >      for (n = 0; n < nvqs; n++) {
> > +        if (!virtio_queue_valid(vdev, n)) {
> > +            continue;
> > +        }
> >          if (!virtio_queue_get_num(vdev, n)) {
> >              break;
> >          }
> > -- 
> > 1.7.2.5
> --
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