From: Michael S. Tsirkin Date: Sun, 3 Apr 2016 12:23:37 +0000 (+0300) Subject: virtio: virtio 1.0 cs04 spec compliance for reset X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=05dbcb430795b2e1fb1d5c757f8619d3dbed0a1c;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git 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 Acked-by: Jason Wang --- 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 #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); }