Linux Virtualization - Dec 2014 - [PATCH 1/2] virtio_ccw: future-proof finalize_features

Two enhancements for virtio_ccw, on top of latest 1.0 patchset

Cornelia Huck (1):
  virtio_ccw: finalize_features error handling

Michael S. Tsirkin (1):
  virtio_ccw: future-proof finalize_features

 drivers/s390/kvm/virtio_ccw.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

-- 
MST

We never negotiate revision > 1, but just to
make this code more likely to work when we do,
require VERSION_1 with any revision >= 1.

Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
---
 drivers/s390/kvm/virtio_ccw.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c
index f9f87ba..f92b9e6 100644
--- a/drivers/s390/kvm/virtio_ccw.c
+++ b/drivers/s390/kvm/virtio_ccw.c
@@ -758,7 +758,7 @@ static int virtio_ccw_finalize_features(struct virtio_device
*vdev)
 	struct virtio_feature_desc *features;
 	struct ccw1 *ccw;
 
-	if (vcdev->revision == 1 &&
+	if (vcdev->revision >= 1 &&
 	    !__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
 		dev_err(&vdev->dev, "virtio: device uses revision 1 "
 			"but does not have VIRTIO_F_VERSION_1\n");
-- 
MST

From: Cornelia Huck <cornelia.huck at de.ibm.com>

We previously tried to use device even if finalize_features failed, but
that's wrong since driver and device are now out of sync.

Fail probe if we detect failures during finalize_features.

Signed-off-by: Cornelia Huck <cornelia.huck at de.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
---
 drivers/s390/kvm/virtio_ccw.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c
index f92b9e6..71d7802 100644
--- a/drivers/s390/kvm/virtio_ccw.c
+++ b/drivers/s390/kvm/virtio_ccw.c
@@ -757,6 +757,7 @@ static int virtio_ccw_finalize_features(struct virtio_device
*vdev)
 	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
 	struct virtio_feature_desc *features;
 	struct ccw1 *ccw;
+	int ret;
 
 	if (vcdev->revision >= 1 &&
 	    !__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
@@ -767,12 +768,13 @@ static int virtio_ccw_finalize_features(struct
virtio_device *vdev)
 
 	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
 	if (!ccw)
-		return 0;
+		return -ENOMEM;
 
 	features = kzalloc(sizeof(*features), GFP_DMA | GFP_KERNEL);
-	if (!features)
+	if (!features) {
+		ret = -ENOMEM;
 		goto out_free;
-
+	}
 	/* Give virtio_ring a chance to accept features. */
 	vring_transport_features(vdev);
 
@@ -783,7 +785,9 @@ static int virtio_ccw_finalize_features(struct virtio_device
*vdev)
 	ccw->flags = 0;
 	ccw->count = sizeof(*features);
 	ccw->cda = (__u32)(unsigned long)features;
-	ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_FEAT);
+	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_FEAT);
+	if (ret)
+		goto out_free;
 
 	if (vcdev->revision == 0)
 		goto out_free;
@@ -795,13 +799,13 @@ static int virtio_ccw_finalize_features(struct
virtio_device *vdev)
 	ccw->flags = 0;
 	ccw->count = sizeof(*features);
 	ccw->cda = (__u32)(unsigned long)features;
-	ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_FEAT);
+	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_FEAT);
 
 out_free:
 	kfree(features);
 	kfree(ccw);
 
-	return 0;
+	return ret;
 }
 
 static void virtio_ccw_get_config(struct virtio_device *vdev,
-- 
MST

On Tue, 9 Dec 2014 15:53:34 +0200
"Michael S. Tsirkin" <mst at redhat.com> wrote:
> We never negotiate revision > 1, but just to
> make this code more likely to work when we do,
> require VERSION_1 with any revision >= 1.
> 
> Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
> ---
>  drivers/s390/kvm/virtio_ccw.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
Acked-by: Cornelia Huck <cornelia.huck at de.ibm.com>

On Tue, 9 Dec 2014 15:53:32 +0200
"Michael S. Tsirkin" <mst at redhat.com> wrote:
> Two enhancements for virtio_ccw, on top of latest 1.0 patchset
> 
> Cornelia Huck (1):
>   virtio_ccw: finalize_features error handling
> 
> Michael S. Tsirkin (1):
>   virtio_ccw: future-proof finalize_features
> 
>  drivers/s390/kvm/virtio_ccw.c | 18 +++++++++++-------
>  1 file changed, 11 insertions(+), 7 deletions(-)
> 
I tried to run this as a guest kernel with my virtio-1 qemu branch +
your revision patch on top and it at least boots :) More testing
tomorrow.

On Tue, Dec 09, 2014 at 06:27:53PM +0100, Cornelia Huck
wrote:
> On Tue, 9 Dec 2014 15:53:32 +0200
> "Michael S. Tsirkin" <mst at redhat.com> wrote:
> 
> > Two enhancements for virtio_ccw, on top of latest 1.0 patchset
> > 
> > Cornelia Huck (1):
> >   virtio_ccw: finalize_features error handling
> > 
> > Michael S. Tsirkin (1):
> >   virtio_ccw: future-proof finalize_features
> > 
> >  drivers/s390/kvm/virtio_ccw.c | 18 +++++++++++-------
> >  1 file changed, 11 insertions(+), 7 deletions(-)
> > 
> 
> I tried to run this as a guest kernel with my virtio-1 qemu branch +
> your revision patch on top and it at least boots :) More testing
> tomorrow.
It's best if you pick my tree from git.
vhost-next branch.

Hi Rusty, I guess you are busy.

I'd like to send all these patch series combined to Linus.  To see what
I have queued, you can check the vhost-next branch in my tree.

Will wait until tomorrow to give you a chance to respond.


On Tue, Dec 09, 2014 at 03:53:32PM +0200, Michael S. Tsirkin
wrote:
> Two enhancements for virtio_ccw, on top of latest 1.0 patchset
> 
> Cornelia Huck (1):
>   virtio_ccw: finalize_features error handling
> 
> Michael S. Tsirkin (1):
>   virtio_ccw: future-proof finalize_features
> 
>  drivers/s390/kvm/virtio_ccw.c | 18 +++++++++++-------
>  1 file changed, 11 insertions(+), 7 deletions(-)
> 
> -- 
> MST
>

"Michael S. Tsirkin" <mst at redhat.com>
writes:
> Hi Rusty, I guess you are busy.
>
> I'd like to send all these patch series combined to Linus.  To see what
> I have queued, you can check the vhost-next branch in my tree.
>
> Will wait until tomorrow to give you a chance to respond.
Hi Michael,

        Indeed, this is the last week of my sabbatical.  I am back
full time next week.  See my Ack on your patches.

Thanks.
Rusty.