s390/virtio_ccw: Fix config change notifications

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.

Fixes: e3e9bda38e6d ("s390/virtio_ccw: use DMA handle from DMA API")
Reported-by: Boqiao Fu <bfu@redhat.com>
Reported-by: Sebastian Mitterle <smitterl@redhat.com>
Closes: https://issues.redhat.com/browse/RHEL-39983
Tested-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Link: https://lore.kernel.org/r/20240611214716.1002781-1-pasic@linux.ibm.com
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index d7569f3955591acc43dcb0e5df58c3104e3eea65..d6491fc84e8c54bf613ff80c30c762c0f0f714c2 100644 (file)
--- 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;