Commit ebf71552 authored by David Hildenbrand's avatar David Hildenbrand Committed by Michael S. Tsirkin
Browse files

virtio-mem: Add parent resource for all added "System RAM" 



Let's add a parent resource, named after the virtio device (inspired by
drivers/dax/kmem.c). This allows user space to identify which memory
belongs to which virtio-mem device.

With this change and two virtio-mem devices:
	:/# cat /proc/iomem
	00000000-00000fff : Reserved
	00001000-0009fbff : System RAM
	[...]
	140000000-333ffffff : virtio0
	  140000000-147ffffff : System RAM
	  148000000-14fffffff : System RAM
	  150000000-157ffffff : System RAM
	[...]
	334000000-3033ffffff : virtio1
	  338000000-33fffffff : System RAM
	  340000000-347ffffff : System RAM
	  348000000-34fffffff : System RAM
	[...]

Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20200507140139.17083-12-david@redhat.com


Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: default avatarPankaj Gupta <pankaj.gupta.linux@gmail.com>
parent 23e77b5d

drivers/virtio/virtio_mem.c

+51 −1
Original line number Diff line number Diff line
@@ -99,6 +99,9 @@ struct virtio_mem { 
	/* Id of the next memory bock to prepare when needed. */

	unsigned long next_mb_id;



	/* The parent resource for all memory added via this device. */

	struct resource *parent_resource;



	/* Summary of all memory block states. */

	unsigned long nb_mb_state[VIRTIO_MEM_MB_STATE_COUNT];

#define VIRTIO_MEM_NB_OFFLINE_THRESHOLD		10
@@ -1741,6 +1744,44 @@ static int virtio_mem_init(struct virtio_mem *vm) 
	return 0;

}



static int virtio_mem_create_resource(struct virtio_mem *vm)

{

	/*

	 * When force-unloading the driver and removing the device, we

	 * could have a garbage pointer. Duplicate the string.

	 */

	const char *name = kstrdup(dev_name(&vm->vdev->dev), GFP_KERNEL);



	if (!name)

		return -ENOMEM;



	vm->parent_resource = __request_mem_region(vm->addr, vm->region_size,

						   name, IORESOURCE_SYSTEM_RAM);

	if (!vm->parent_resource) {

		kfree(name);

		dev_warn(&vm->vdev->dev, "could not reserve device region\n");

		return -EBUSY;

	}



	/* The memory is not actually busy - make add_memory() work. */

	vm->parent_resource->flags &= ~IORESOURCE_BUSY;

	return 0;

}



static void virtio_mem_delete_resource(struct virtio_mem *vm)

{

	const char *name;



	if (!vm->parent_resource)

		return;



	name = vm->parent_resource->name;

	release_resource(vm->parent_resource);

	kfree(vm->parent_resource);

	kfree(name);

	vm->parent_resource = NULL;

}



static int virtio_mem_probe(struct virtio_device *vdev)

{

	struct virtio_mem *vm;
@@ -1770,11 +1811,16 @@ static int virtio_mem_probe(struct virtio_device *vdev) 
	if (rc)

		goto out_del_vq;



	/* create the parent resource for all memory */

	rc = virtio_mem_create_resource(vm);

	if (rc)

		goto out_del_vq;



	/* register callbacks */

	vm->memory_notifier.notifier_call = virtio_mem_memory_notifier_cb;

	rc = register_memory_notifier(&vm->memory_notifier);

	if (rc)

		goto out_del_vq;

		goto out_del_resource;

	rc = register_virtio_mem_device(vm);

	if (rc)

		goto out_unreg_mem;
@@ -1788,6 +1834,8 @@ static int virtio_mem_probe(struct virtio_device *vdev) 
	return 0;

out_unreg_mem:

	unregister_memory_notifier(&vm->memory_notifier);

out_del_resource:

	virtio_mem_delete_resource(vm);

out_del_vq:

	vdev->config->del_vqs(vdev);

out_free_vm:
@@ -1848,6 +1896,8 @@ static void virtio_mem_remove(struct virtio_device *vdev) 
	    vm->nb_mb_state[VIRTIO_MEM_MB_STATE_ONLINE_PARTIAL] ||

	    vm->nb_mb_state[VIRTIO_MEM_MB_STATE_ONLINE_MOVABLE])

		dev_warn(&vdev->dev, "device still has system memory added\n");

	else

		virtio_mem_delete_resource(vm);



	/* remove all tracking data - no locking needed */

	vfree(vm->mb_state);

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