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-rw-r--r--hw/block/m25p80.c5
-rw-r--r--hw/block/virtio-blk.c25
-rw-r--r--hw/block/xen_disk.c13
3 files changed, 39 insertions, 4 deletions
diff --git a/hw/block/m25p80.c b/hw/block/m25p80.c
index 8c3b7f0d3b..02a15441fa 100644
--- a/hw/block/m25p80.c
+++ b/hw/block/m25p80.c
@@ -624,6 +624,11 @@ static int m25p80_init(SSISlave *ss)
if (dinfo && dinfo->bdrv) {
DB_PRINT_L(0, "Binding to IF_MTD drive\n");
s->bdrv = dinfo->bdrv;
+ if (bdrv_is_read_only(s->bdrv)) {
+ fprintf(stderr, "Can't use a read-only drive");
+ return 1;
+ }
+
/* FIXME: Move to late init */
if (bdrv_read(s->bdrv, 0, s->storage, DIV_ROUND_UP(s->size,
BDRV_SECTOR_SIZE))) {
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index e2f55cc946..13f6d8276e 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -460,9 +460,9 @@ static void virtio_blk_dma_restart_cb(void *opaque, int running,
static void virtio_blk_reset(VirtIODevice *vdev)
{
-#ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
VirtIOBlock *s = VIRTIO_BLK(vdev);
+#ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
if (s->dataplane) {
virtio_blk_data_plane_stop(s->dataplane);
}
@@ -473,6 +473,7 @@ static void virtio_blk_reset(VirtIODevice *vdev)
* are per-device request lists.
*/
bdrv_drain_all();
+ bdrv_set_enable_write_cache(s->bs, s->original_wce);
}
/* coalesce internal state, copy to pci i/o region 0
@@ -564,7 +565,25 @@ static void virtio_blk_set_status(VirtIODevice *vdev, uint8_t status)
}
features = vdev->guest_features;
- bdrv_set_enable_write_cache(s->bs, !!(features & (1 << VIRTIO_BLK_F_WCE)));
+
+ /* A guest that supports VIRTIO_BLK_F_CONFIG_WCE must be able to send
+ * cache flushes. Thus, the "auto writethrough" behavior is never
+ * necessary for guests that support the VIRTIO_BLK_F_CONFIG_WCE feature.
+ * Leaving it enabled would break the following sequence:
+ *
+ * Guest started with "-drive cache=writethrough"
+ * Guest sets status to 0
+ * Guest sets DRIVER bit in status field
+ * Guest reads host features (WCE=0, CONFIG_WCE=1)
+ * Guest writes guest features (WCE=0, CONFIG_WCE=1)
+ * Guest writes 1 to the WCE configuration field (writeback mode)
+ * Guest sets DRIVER_OK bit in status field
+ *
+ * s->bs would erroneously be placed in writethrough mode.
+ */
+ if (!(features & (1 << VIRTIO_BLK_F_CONFIG_WCE))) {
+ bdrv_set_enable_write_cache(s->bs, !!(features & (1 << VIRTIO_BLK_F_WCE)));
+ }
}
static void virtio_blk_save(QEMUFile *f, void *opaque)
@@ -674,6 +693,7 @@ static int virtio_blk_device_init(VirtIODevice *vdev)
}
blkconf_serial(&blk->conf, &blk->serial);
+ s->original_wce = bdrv_enable_write_cache(blk->conf.bs);
if (blkconf_geometry(&blk->conf, NULL, 65535, 255, 255) < 0) {
return -1;
}
@@ -683,7 +703,6 @@ static int virtio_blk_device_init(VirtIODevice *vdev)
s->bs = blk->conf.bs;
s->conf = &blk->conf;
- memcpy(&(s->blk), blk, sizeof(struct VirtIOBlkConf));
s->rq = NULL;
s->sector_mask = (s->conf->logical_block_size / BDRV_SECTOR_SIZE) - 1;
diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c
index 668cc069ff..098f6c62c7 100644
--- a/hw/block/xen_disk.c
+++ b/hw/block/xen_disk.c
@@ -405,6 +405,7 @@ static int ioreq_map(struct ioreq *ioreq)
xen_be_printf(&ioreq->blkdev->xendev, 0,
"can't map grant ref %d (%s, %d maps)\n",
refs[i], strerror(errno), ioreq->blkdev->cnt_map);
+ ioreq->mapped = 1;
ioreq_unmap(ioreq);
return -1;
}
@@ -809,10 +810,15 @@ static int blk_connect(struct XenDevice *xendev)
xen_be_printf(&blkdev->xendev, 2, "create new bdrv (xenbus setup)\n");
blkdev->bs = bdrv_new(blkdev->dev);
if (blkdev->bs) {
+ Error *local_err = NULL;
BlockDriver *drv = bdrv_find_whitelisted_format(blkdev->fileproto,
readonly);
if (bdrv_open(blkdev->bs,
- blkdev->filename, NULL, qflags, drv) != 0) {
+ blkdev->filename, NULL, qflags, drv, &local_err) != 0)
+ {
+ xen_be_printf(&blkdev->xendev, 0, "error: %s\n",
+ error_get_pretty(local_err));
+ error_free(local_err);
bdrv_unref(blkdev->bs);
blkdev->bs = NULL;
}
@@ -824,6 +830,11 @@ static int blk_connect(struct XenDevice *xendev)
/* setup via qemu cmdline -> already setup for us */
xen_be_printf(&blkdev->xendev, 2, "get configured bdrv (cmdline setup)\n");
blkdev->bs = blkdev->dinfo->bdrv;
+ if (bdrv_is_read_only(blkdev->bs) && !readonly) {
+ xen_be_printf(&blkdev->xendev, 0, "Unexpected read-only drive");
+ blkdev->bs = NULL;
+ return -1;
+ }
/* blkdev->bs is not create by us, we get a reference
* so we can bdrv_unref() unconditionally */
bdrv_ref(blkdev->bs);