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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: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20200507140139.17083-12-david@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
This commit is contained in:
David Hildenbrand 2020-05-07 16:01:35 +02:00 committed by Michael S. Tsirkin
parent 23e77b5dc9
commit ebf71552bb
1 changed files with 51 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

52
drivers/virtio/virtio_mem.c
View File

@ -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);