5 files changed, 39 insertions, 11 deletions

diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index 5809e5f5b157..5c92e4a50882 100644
--- a/drivers/virtio/Kconfig
+++ b/drivers/virtio/Kconfig
@@ -85,7 +85,7 @@ config VIRTIO_MEM
 	depends on VIRTIO
 	depends on MEMORY_HOTPLUG_SPARSE
 	depends on MEMORY_HOTREMOVE
-	select CONTIG_ALLOC
+	depends on CONTIG_ALLOC
 	help
 	 This driver provides access to virtio-mem paravirtualized memory
 	 devices, allowing to hotplug and hotunplug memory.
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 1f157d2f4952..8be02f333b7a 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -578,10 +578,14 @@ static int init_vqs(struct virtio_balloon *vb)
 static u32 virtio_balloon_cmd_id_received(struct virtio_balloon *vb)
 {
 	if (test_and_clear_bit(VIRTIO_BALLOON_CONFIG_READ_CMD_ID,
-			       &vb->config_read_bitmap))
+			       &vb->config_read_bitmap)) {
 		virtio_cread(vb->vdev, struct virtio_balloon_config,
 			     free_page_hint_cmd_id,
 			     &vb->cmd_id_received_cache);
+		/* Legacy balloon config space is LE, unlike all other devices. */
+		if (!virtio_has_feature(vb->vdev, VIRTIO_F_VERSION_1))
+			vb->cmd_id_received_cache = le32_to_cpu((__force __le32)vb->cmd_id_received_cache);
+	}
 
 	return vb->cmd_id_received_cache;
 }
@@ -974,6 +978,11 @@ static int virtballoon_probe(struct virtio_device *vdev)
 		/*
 		 * Let the hypervisor know that we are expecting a
 		 * specific value to be written back in balloon pages.
+		 *
+		 * If the PAGE_POISON value was larger than a byte we would
+		 * need to byte swap poison_val here to guarantee it is
+		 * little-endian. However for now it is a single byte so we
+		 * can pass it as-is.
 		 */
 		if (!want_init_on_free())
 			memset(&poison_val, PAGE_POISON, sizeof(poison_val));
diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
index 50c689f25045..f26f5f64ae82 100644
--- a/drivers/virtio/virtio_mem.c
+++ b/drivers/virtio/virtio_mem.c
@@ -101,6 +101,11 @@ struct virtio_mem {
 
 	/* The parent resource for all memory added via this device. */
 	struct resource *parent_resource;
+	/*
+	 * Copy of "System RAM (virtio_mem)" to be used for
+	 * add_memory_driver_managed().
+	 */
+	const char *resource_name;
 
 	/* Summary of all memory block states. */
 	unsigned long nb_mb_state[VIRTIO_MEM_MB_STATE_COUNT];
@@ -414,8 +419,20 @@ static int virtio_mem_mb_add(struct virtio_mem *vm, unsigned long mb_id)
 	if (nid == NUMA_NO_NODE)
 		nid = memory_add_physaddr_to_nid(addr);
 
+	/*
+	 * When force-unloading the driver and we still have memory added to
+	 * Linux, the resource name has to stay.
+	 */
+	if (!vm->resource_name) {
+		vm->resource_name = kstrdup_const("System RAM (virtio_mem)",
+						  GFP_KERNEL);
+		if (!vm->resource_name)
+			return -ENOMEM;
+	}
+
 	dev_dbg(&vm->vdev->dev, "adding memory block: %lu\n", mb_id);
-	return add_memory(nid, addr, memory_block_size_bytes());
+	return add_memory_driver_managed(nid, addr, memory_block_size_bytes(),
+					 vm->resource_name);
 }
 
 /*
@@ -1192,7 +1209,7 @@ static int virtio_mem_mb_plug_any_sb(struct virtio_mem *vm, unsigned long mb_id,
 						VIRTIO_MEM_MB_STATE_OFFLINE);
 	}
 
-	return rc;
+	return 0;
 }
 
 /*
@@ -1890,10 +1907,12 @@ static void virtio_mem_remove(struct virtio_device *vdev)
 	    vm->nb_mb_state[VIRTIO_MEM_MB_STATE_OFFLINE_PARTIAL] ||
 	    vm->nb_mb_state[VIRTIO_MEM_MB_STATE_ONLINE] ||
 	    vm->nb_mb_state[VIRTIO_MEM_MB_STATE_ONLINE_PARTIAL] ||
-	    vm->nb_mb_state[VIRTIO_MEM_MB_STATE_ONLINE_MOVABLE])
+	    vm->nb_mb_state[VIRTIO_MEM_MB_STATE_ONLINE_MOVABLE]) {
 		dev_warn(&vdev->dev, "device still has system memory added\n");
-	else
+	} else {
 		virtio_mem_delete_resource(vm);
+		kfree_const(vm->resource_name);
+	}
 
 	/* remove all tracking data - no locking needed */
 	vfree(vm->mb_state);
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index 9d16aaffca9d..627ac0487494 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -641,11 +641,11 @@ static int vm_cmdline_set(const char *device,
 			&vm_cmdline_id, &consumed);
 
 	/*
-	 * sscanf() must processes at least 2 chunks; also there
+	 * sscanf() must process at least 2 chunks; also there
 	 * must be no extra characters after the last chunk, so
 	 * str[consumed] must be '\0'
 	 */
-	if (processed < 2 || str[consumed])
+	if (processed < 2 || str[consumed] || irq == 0)
 		return -EINVAL;
 
 	resources[0].flags = IORESOURCE_MEM;
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 58b96baa8d48..a2de775801af 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -424,7 +424,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
 	struct vring_virtqueue *vq = to_vvq(_vq);
 	struct scatterlist *sg;
 	struct vring_desc *desc;
-	unsigned int i, n, avail, descs_used, uninitialized_var(prev), err_idx;
+	unsigned int i, n, avail, descs_used, prev, err_idx;
 	int head;
 	bool indirect;
 
@@ -1101,8 +1101,8 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq,
 	struct vring_packed_desc *desc;
 	struct scatterlist *sg;
 	unsigned int i, n, c, descs_used, err_idx;
-	__le16 uninitialized_var(head_flags), flags;
-	u16 head, id, uninitialized_var(prev), curr, avail_used_flags;
+	__le16 head_flags, flags;
+	u16 head, id, prev, curr, avail_used_flags;
 
 	START_USE(vq);