3 files changed, 35 insertions, 5 deletions

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index bbbf588540ed..ce5e63d2c66a 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -373,6 +373,7 @@ static void vhost_vsock_handle_rx_kick(struct vhost_work *work)
 
 static int vhost_vsock_start(struct vhost_vsock *vsock)
 {
+        struct vhost_virtqueue *vq;
         size_t i;
         int ret;
 
@@ -383,19 +384,20 @@ static int vhost_vsock_start(struct vhost_vsock *vsock)
                 goto err;
 
         for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
-                struct vhost_virtqueue *vq = &vsock->vqs[i];
+                vq = &vsock->vqs[i];
 
                 mutex_lock(&vq->mutex);
 
                 if (!vhost_vq_access_ok(vq)) {
                         ret = -EFAULT;
-                        mutex_unlock(&vq->mutex);
                         goto err_vq;
                 }
 
                 if (!vq->private_data) {
                         vq->private_data = vsock;
-                        vhost_vq_init_access(vq);
+                        ret = vhost_vq_init_access(vq);
+                        if (ret)
+                                goto err_vq;
                 }
 
                 mutex_unlock(&vq->mutex);
@@ -405,8 +407,11 @@ static int vhost_vsock_start(struct vhost_vsock *vsock)
         return 0;
 
 err_vq:
+        vq->private_data = NULL;
+        mutex_unlock(&vq->mutex);
+
         for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
-                struct vhost_virtqueue *vq = &vsock->vqs[i];
+                vq = &vsock->vqs[i];
 
                 mutex_lock(&vq->mutex);
                 vq->private_data = NULL;
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index d47a2fcef818..c71fde5fe835 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -59,6 +59,7 @@
 #define pr_fmt(fmt) "virtio-mmio: " fmt
 
 #include <linux/acpi.h>
+#include <linux/dma-mapping.h>
 #include <linux/highmem.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
@@ -498,6 +499,7 @@ static int virtio_mmio_probe(struct platform_device *pdev)
         struct virtio_mmio_device *vm_dev;
         struct resource *mem;
         unsigned long magic;
+        int rc;
 
         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
         if (!mem)
@@ -547,9 +549,25 @@ static int virtio_mmio_probe(struct platform_device *pdev)
         }
         vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
 
-        if (vm_dev->version == 1)
+        if (vm_dev->version == 1) {
                 writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
 
+                rc = dma_set_mask(&pdev->dev, DMA_BIT_MASK(64));
+                /*
+                 * In the legacy case, ensure our coherently-allocated virtio
+                 * ring will be at an address expressable as a 32-bit PFN.
+                 */
+                if (!rc)
+                        dma_set_coherent_mask(&pdev->dev,
+                                              DMA_BIT_MASK(32 + PAGE_SHIFT));
+        } else {
+                rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
+        }
+        if (rc)
+                rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
+        if (rc)
+                dev_warn(&pdev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");
+
         platform_set_drvdata(pdev, vm_dev);
 
         return register_virtio_device(&vm_dev->vdev);
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 409aeaa49246..7e38ed79c3fc 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -159,6 +159,13 @@ static bool vring_use_dma_api(struct virtio_device *vdev)
         if (xen_domain())
                 return true;
 
+        /*
+         * On ARM-based machines, the DMA ops will do the right thing,
+         * so always use them with legacy devices.
+         */
+        if (IS_ENABLED(CONFIG_ARM) || IS_ENABLED(CONFIG_ARM64))
+                return !virtio_has_feature(vdev, VIRTIO_F_VERSION_1);
+
         return false;
 }