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| author | Michael S. Tsirkin <mst@redhat.com> | 2016-04-03 15:23:37 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-04-20 15:42:10 +0900 |
| commit | 5f6e35c2f9464c8b67b54ea5a919105c5f46f514 (patch) | |
| tree | 95af68aa972195d5b0ba16a69682bd8385308763 /drivers | |
| parent | 06e2d7dd90cbafd2d911f86785b69cec1bcd3b02 (diff) | |
| download | lwn-5f6e35c2f9464c8b67b54ea5a919105c5f46f514.tar.gz lwn-5f6e35c2f9464c8b67b54ea5a919105c5f46f514.zip | |
virtio: virtio 1.0 cs04 spec compliance for reset
commit 05dbcb430795b2e1fb1d5c757f8619d3dbed0a1c upstream.
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.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/virtio/virtio_pci_modern.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c index 8e5cf194cc0b..4469202eaa8e 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); } |