X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=kernel%2Fdrivers%2Fvirtio%2Fvirtio_pci_modern.c;fp=kernel%2Fdrivers%2Fvirtio%2Fvirtio_pci_modern.c;h=4469202eaa8e06ecd0b8e3c626e69856ab98bc3b;hb=52f993b8e89487ec9ee15a7fb4979e0f09a45b27;hp=8e5cf194cc0bd003888c1235b8d9bfc1cbc99e9c;hpb=c189ccac5702322ed843fe17057035b7222a59b6;p=kvmfornfv.git

diff --git a/kernel/drivers/virtio/virtio_pci_modern.c b/kernel/drivers/virtio/virtio_pci_modern.c
index 8e5cf194c..4469202ea 100644
--- a/kernel/drivers/virtio/virtio_pci_modern.c
+++ b/kernel/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);
 }