[PATCH 1/1] s390/virtio_ccw: fix config change notifications

[PATCH 1/1] s390/virtio_ccw: fix config change notifications

[Halil Pasic]

Commit e3e9bda38e6d ("s390/virtio_ccw: use DMA handle from DMA API")
broke configuration change notifications for virtio-ccw by putting the
DMA address of *indicatorp directly into ccw->cda disregarding the fact
that if !!(vcdev->is_thinint) then the function
virtio_ccw_register_adapter_ind() will overwrite that ccw->cda value
with the address of the virtio_thinint_area so it can actually set up
the adapter interrupts via CCW_CMD_SET_IND_ADAPTER.  Thus we end up
pointing to the wrong object for both CCW_CMD_SET_IND if setting up the
adapter interrupts fails, and for CCW_CMD_SET_CONF_IND regardless
whether it succeeds or fails.

To fix this, let us save away the dma address of *indicatorp in a local
variable, and copy it to ccw->cda after the "vcdev->is_thinint" branch.

Reported-by: Boqiao Fu <bfu@redhat.com>
Reported-by: Sebastian Mitterle <smitterl@redhat.com>
Fixes: e3e9bda38e6d ("s390/virtio_ccw: use DMA handle from DMA API")
Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
---
I know that checkpatch.pl complains about a missing 'Closes' tag.
Unfortunately I don't have an appropriate URL at hand. @Sebastian,
@Boqiao: do you have any suggetions?
---
 drivers/s390/virtio/virtio_ccw.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index d7569f395559..d6491fc84e8c 100644
--- a/drivers/s390/virtio/virtio_ccw.c
+++ b/drivers/s390/virtio/virtio_ccw.c
@@ -698,6 +698,7 @@ static int virtio_ccw_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 	dma64_t *indicatorp = NULL;
 	int ret, i, queue_idx = 0;
 	struct ccw1 *ccw;
+	dma32_t indicatorp_dma = 0;
 
 	ccw = ccw_device_dma_zalloc(vcdev->cdev, sizeof(*ccw), NULL);
 	if (!ccw)
@@ -725,7 +726,7 @@ static int virtio_ccw_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 	*/
 	indicatorp = ccw_device_dma_zalloc(vcdev->cdev,
 					   sizeof(*indicatorp),
-					   &ccw->cda);
+					   &indicatorp_dma);
 	if (!indicatorp)
 		goto out;
 	*indicatorp = indicators_dma(vcdev);
@@ -735,6 +736,7 @@ static int virtio_ccw_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 			/* no error, just fall back to legacy interrupts */
 			vcdev->is_thinint = false;
 	}
+	ccw->cda = indicatorp_dma;
 	if (!vcdev->is_thinint) {
 		/* Register queue indicators with host. */
 		*indicators(vcdev) = 0;

base-commit: 83a7eefedc9b56fe7bfeff13b6c7356688ffa670
-- 
2.40.1

Re: [PATCH 1/1] s390/virtio_ccw: fix config change notifications

[Thomas Huth]

On 11/06/2024 23.47, Halil Pasic wrote:
> Commit e3e9bda38e6d ("s390/virtio_ccw: use DMA handle from DMA API")
> broke configuration change notifications for virtio-ccw by putting the
> DMA address of *indicatorp directly into ccw->cda disregarding the fact
> that if !!(vcdev->is_thinint) then the function
> virtio_ccw_register_adapter_ind() will overwrite that ccw->cda value
> with the address of the virtio_thinint_area so it can actually set up
> the adapter interrupts via CCW_CMD_SET_IND_ADAPTER.  Thus we end up
> pointing to the wrong object for both CCW_CMD_SET_IND if setting up the
> adapter interrupts fails, and for CCW_CMD_SET_CONF_IND regardless
> whether it succeeds or fails.
> 
> To fix this, let us save away the dma address of *indicatorp in a local
> variable, and copy it to ccw->cda after the "vcdev->is_thinint" branch.
> 
> Reported-by: Boqiao Fu <bfu@redhat.com>
> Reported-by: Sebastian Mitterle <smitterl@redhat.com>
> Fixes: e3e9bda38e6d ("s390/virtio_ccw: use DMA handle from DMA API")
> Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
> ---
> I know that checkpatch.pl complains about a missing 'Closes' tag.
> Unfortunately I don't have an appropriate URL at hand. @Sebastian,
> @Boqiao: do you have any suggetions?

Closes: https://issues.redhat.com/browse/RHEL-39983
?

Anyway, I've tested the patch and it indeed fixes the problem with 
virtio-balloon and the link state for me:

Tested-by: Thomas Huth <thuth@redhat.com>

Re: [PATCH 1/1] s390/virtio_ccw: fix config change notifications

[Halil Pasic]

On Wed, 12 Jun 2024 16:04:15 +0200
Thomas Huth <thuth@redhat.com> wrote:

> On 11/06/2024 23.47, Halil Pasic wrote:
> > Commit e3e9bda38e6d ("s390/virtio_ccw: use DMA handle from DMA API")
> > broke configuration change notifications for virtio-ccw by putting the
> > DMA address of *indicatorp directly into ccw->cda disregarding the fact
> > that if !!(vcdev->is_thinint) then the function
> > virtio_ccw_register_adapter_ind() will overwrite that ccw->cda value
> > with the address of the virtio_thinint_area so it can actually set up
> > the adapter interrupts via CCW_CMD_SET_IND_ADAPTER.  Thus we end up
> > pointing to the wrong object for both CCW_CMD_SET_IND if setting up the
> > adapter interrupts fails, and for CCW_CMD_SET_CONF_IND regardless
> > whether it succeeds or fails.
> > 
> > To fix this, let us save away the dma address of *indicatorp in a local
> > variable, and copy it to ccw->cda after the "vcdev->is_thinint" branch.
> > 
> > Reported-by: Boqiao Fu <bfu@redhat.com>
> > Reported-by: Sebastian Mitterle <smitterl@redhat.com>
> > Fixes: e3e9bda38e6d ("s390/virtio_ccw: use DMA handle from DMA API")
> > Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
> > ---
> > I know that checkpatch.pl complains about a missing 'Closes' tag.
> > Unfortunately I don't have an appropriate URL at hand. @Sebastian,
> > @Boqiao: do you have any suggetions?  
> 
> Closes: https://issues.redhat.com/browse/RHEL-39983
> ?

Yep! That is a public bug tracker bug. Qualifies!
@Vasily: Can you guys pick hat one up when picking the patch?

> 
> Anyway, I've tested the patch and it indeed fixes the problem with 
> virtio-balloon and the link state for me:
> 
> Tested-by: Thomas Huth <thuth@redhat.com>
> 

Thanks!

Re: [PATCH 1/1] s390/virtio_ccw: fix config change notifications

[Vasily Gorbik]

On Thu, Jun 13, 2024 at 03:21:15PM +0200, Halil Pasic wrote:
> On Wed, 12 Jun 2024 16:04:15 +0200
> Thomas Huth <thuth@redhat.com> wrote:
> 
> > On 11/06/2024 23.47, Halil Pasic wrote:
> > > Commit e3e9bda38e6d ("s390/virtio_ccw: use DMA handle from DMA API")
> > > broke configuration change notifications for virtio-ccw by putting the
> > > DMA address of *indicatorp directly into ccw->cda disregarding the fact
> > > that if !!(vcdev->is_thinint) then the function
> > > virtio_ccw_register_adapter_ind() will overwrite that ccw->cda value
> > > with the address of the virtio_thinint_area so it can actually set up
> > > the adapter interrupts via CCW_CMD_SET_IND_ADAPTER.  Thus we end up
> > > pointing to the wrong object for both CCW_CMD_SET_IND if setting up the
> > > adapter interrupts fails, and for CCW_CMD_SET_CONF_IND regardless
> > > whether it succeeds or fails.
> > > 
> > > To fix this, let us save away the dma address of *indicatorp in a local
> > > variable, and copy it to ccw->cda after the "vcdev->is_thinint" branch.
> > > 
> > > Reported-by: Boqiao Fu <bfu@redhat.com>
> > > Reported-by: Sebastian Mitterle <smitterl@redhat.com>
> > > Fixes: e3e9bda38e6d ("s390/virtio_ccw: use DMA handle from DMA API")
> > > Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
> > > ---
> > > I know that checkpatch.pl complains about a missing 'Closes' tag.
> > > Unfortunately I don't have an appropriate URL at hand. @Sebastian,
> > > @Boqiao: do you have any suggetions?  
> > 
> > Closes: https://issues.redhat.com/browse/RHEL-39983
> > ?
> 
> Yep! That is a public bug tracker bug. Qualifies!
> @Vasily: Can you guys pick hat one up when picking the patch?

Sure, applied. Thanks!

Re: [PATCH 1/1] s390/virtio_ccw: fix config change notifications

[Eric Farman]

On Tue, 2024-06-11 at 23:47 +0200, Halil Pasic wrote:
> Commit e3e9bda38e6d ("s390/virtio_ccw: use DMA handle from DMA API")
> broke configuration change notifications for virtio-ccw by putting
> the
> DMA address of *indicatorp directly into ccw->cda disregarding the
> fact
> that if !!(vcdev->is_thinint) then the function
> virtio_ccw_register_adapter_ind() will overwrite that ccw->cda value
> with the address of the virtio_thinint_area so it can actually set up
> the adapter interrupts via CCW_CMD_SET_IND_ADAPTER.  Thus we end up
> pointing to the wrong object for both CCW_CMD_SET_IND if setting up
> the
> adapter interrupts fails, and for CCW_CMD_SET_CONF_IND regardless
> whether it succeeds or fails.
> 
> To fix this, let us save away the dma address of *indicatorp in a
> local
> variable, and copy it to ccw->cda after the "vcdev->is_thinint"
> branch.
> 
> Reported-by: Boqiao Fu <bfu@redhat.com>
> Reported-by: Sebastian Mitterle <smitterl@redhat.com>
> Fixes: e3e9bda38e6d ("s390/virtio_ccw: use DMA handle from DMA API")
> Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
> ---
> I know that checkpatch.pl complains about a missing 'Closes' tag.
> Unfortunately I don't have an appropriate URL at hand. @Sebastian,
> @Boqiao: do you have any suggetions?
> ---
>  drivers/s390/virtio/virtio_ccw.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)

Reviewed-by: Eric Farman <farman@linux.ibm.com>