Virtio MMIO transport version 3 allows device reset to complete asynchronously. Unlike version 2, where writing zero to Status must complete the reset before the write returns, version 3 requires the driver to poll Status until it reads back zero before considering reset complete.
Update virtio-mmio accordingly: accept transport version 3 and, during reset, wait for Status to become zero. Keep the polling loop unbounded, consistent with virtio-pci, since the reset callback does not return an error code. Signed-off-by: Peter Hilber <[email protected]> Link: https://github.com/oasis-tcs/virtio-spec/commit/bb1dd2e1fe89b862f38f15873d835a698b196f89 --- drivers/virtio/virtio_mmio.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c index 510b7c4efdff..316f03b97356 100644 --- a/drivers/virtio/virtio_mmio.c +++ b/drivers/virtio/virtio_mmio.c @@ -55,6 +55,7 @@ #define pr_fmt(fmt) "virtio-mmio: " fmt #include <linux/acpi.h> +#include <linux/delay.h> #include <linux/dma-mapping.h> #include <linux/highmem.h> #include <linux/interrupt.h> @@ -114,9 +115,9 @@ static int vm_finalize_features(struct virtio_device *vdev) vring_transport_features(vdev); /* Make sure there are no mixed devices */ - if (vm_dev->version == 2 && + if (vm_dev->version >= 2 && !__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) { - dev_err(&vdev->dev, "New virtio-mmio devices (version 2) must provide VIRTIO_F_VERSION_1 feature!\n"); + dev_err(&vdev->dev, "New virtio-mmio devices (version >= 2) must provide VIRTIO_F_VERSION_1 feature!\n"); return -EINVAL; } @@ -254,6 +255,12 @@ static void vm_reset(struct virtio_device *vdev) /* 0 status means a reset. */ writel(0, vm_dev->base + VIRTIO_MMIO_STATUS); + + if (vm_dev->version >= 3) { + /* Wait for reset to complete. */ + while (vm_get_status(vdev)) + fsleep(1000); + } } @@ -600,7 +607,7 @@ static int virtio_mmio_probe(struct platform_device *pdev) /* Check device version */ vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION); - if (vm_dev->version < 1 || vm_dev->version > 2) { + if (vm_dev->version < 1 || vm_dev->version > 3) { dev_err(&pdev->dev, "Version %ld not supported!\n", vm_dev->version); rc = -ENXIO; -- 2.43.0
