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authorMichael S. Tsirkin <mst@redhat.com>2016-04-03 15:23:37 +0300
committerMichael S. Tsirkin <mst@redhat.com>2016-04-07 15:16:39 +0300
commit05dbcb430795b2e1fb1d5c757f8619d3dbed0a1c (patch)
tree62a07c001c763f524d794ec83d25a5338f1a612c
parente8aabc64d7f5c8702e420c6fa478368f60718ae4 (diff)
downloadlinux-sh-05dbcb430795b2e1fb1d5c757f8619d3dbed0a1c.tar.gz
virtio: virtio 1.0 cs04 spec compliance for reset
The spec says: after writing 0 to device_status, the driver MUST wait for a read of device_status to return 0 before reinitializing the device. Cc: stable@vger.kernel.org Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Jason Wang <jasowang@redhat.com>
-rw-r--r--drivers/virtio/virtio_pci_modern.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
index f6f28cc7eb45..e76bd91a29da 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -17,6 +17,7 @@
*
*/
+#include <linux/delay.h>
#define VIRTIO_PCI_NO_LEGACY
#include "virtio_pci_common.h"
@@ -271,9 +272,13 @@ static void vp_reset(struct virtio_device *vdev)
struct virtio_pci_device *vp_dev = to_vp_device(vdev);
/* 0 status means a reset. */
vp_iowrite8(0, &vp_dev->common->device_status);
- /* Flush out the status write, and flush in device writes,
- * including MSI-X interrupts, if any. */
- vp_ioread8(&vp_dev->common->device_status);
+ /* After writing 0 to device_status, the driver MUST wait for a read of
+ * device_status to return 0 before reinitializing the device.
+ * This will flush out the status write, and flush in device writes,
+ * including MSI-X interrupts, if any.
+ */
+ while (vp_ioread8(&vp_dev->common->device_status))
+ msleep(1);
/* Flush pending VQ/configuration callbacks. */
vp_synchronize_vectors(vdev);
}