[PATCH RFC v4 12/16] virtio: allow to fail setting status

Cornelia Huck
2014-11-27T15:17:16Z

virtio-1 allow setting of the FEATURES_OK status bit to fail if
the negotiated feature bits are inconsistent: let's fail
virtio_set_status() in that case and update virtio-ccw to post an
error to the guest.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
---
hw/s390x/virtio-ccw.c | 20 ++++++++++++--------
hw/virtio/virtio.c | 24 +++++++++++++++++++++++-
include/hw/virtio/virtio.h | 3 ++-
3 files changed, 37 insertions(+), 10 deletions(-)

diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index 60d67a3..65bef4b 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -547,15 +547,19 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
virtio_ccw_stop_ioeventfd(dev);
}
- virtio_set_status(vdev, status);
- if (vdev->status == 0) {
- virtio_reset(vdev);
- }
- if (status & VIRTIO_CONFIG_S_DRIVER_OK) {
- virtio_ccw_start_ioeventfd(dev);
+ if (virtio_set_status(vdev, status) == 0) {
+ if (vdev->status == 0) {
+ virtio_reset(vdev);
+ }
+ if (status & VIRTIO_CONFIG_S_DRIVER_OK) {
+ virtio_ccw_start_ioeventfd(dev);
+ }
+ sch->curr_status.scsw.count = ccw.count - sizeof(status);
+ ret = 0;
+ } else {
+ /* Trigger a command reject. */
+ ret = -ENOSYS;
}
- sch->curr_status.scsw.count = ccw.count - sizeof(status);
- ret = 0;
}
break;
case CCW_CMD_SET_IND:
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 8cdc0cb..ab5c671 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -548,15 +548,37 @@ void virtio_update_irq(VirtIODevice *vdev)
virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
}

-void virtio_set_status(VirtIODevice *vdev, uint8_t val)
+static int virtio_validate_features(VirtIODevice *vdev)
+{
+ VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
+
+ if (k->validate_features) {
+ return k->validate_features(vdev);
+ } else {
+ return 0;
+ }
+}
+
+int virtio_set_status(VirtIODevice *vdev, uint8_t val)
{
VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
trace_virtio_set_status(vdev, val);

+ if (!virtio_device_is_legacy(vdev)) {
+ if (!(vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) &&
+ val & VIRTIO_CONFIG_S_FEATURES_OK) {
+ int ret = virtio_validate_features(vdev);
+
+ if (ret) {
+ return ret;
+ }
+ }
+ }
if (k->set_status) {
k->set_status(vdev, val);
}
vdev->status = val;
+ return 0;
}

bool target_words_bigendian(void);
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index ec1be3b..601578f 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -152,6 +152,7 @@ typedef struct VirtioDeviceClass {
uint32_t requested_features);
uint32_t (*bad_features)(VirtIODevice *vdev, unsigned int index);
void (*set_features)(VirtIODevice *vdev, unsigned int index, uint32_t val);
+ int (*validate_features)(VirtIODevice *vdev);
void (*get_config)(VirtIODevice *vdev, uint8_t *config);
void (*set_config)(VirtIODevice *vdev, const uint8_t *config);
void (*reset)(VirtIODevice *vdev);
@@ -235,7 +236,7 @@ void virtio_queue_set_align(VirtIODevice *vdev, int n, int align);
void virtio_queue_notify(VirtIODevice *vdev, int n);
uint16_t virtio_queue_vector(VirtIODevice *vdev, int n);
void virtio_queue_set_vector(VirtIODevice *vdev, int n, uint16_t vector);
-void virtio_set_status(VirtIODevice *vdev, uint8_t val);
+int virtio_set_status(VirtIODevice *vdev, uint8_t val);
void virtio_reset(void *opaque);
void virtio_update_irq(VirtIODevice *vdev);
int virtio_set_features(VirtIODevice *vdev, unsigned int index, uint32_t val);
--
1.7.9.5