From ebf71552bb0e690cad523ad175e8c4c89a33c333 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Thu, 7 May 2020 16:01:35 +0200 Subject: [PATCH] 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" Cc: Pankaj Gupta Signed-off-by: David Hildenbrand Link: https://lore.kernel.org/r/20200507140139.17083-12-david@redhat.com Signed-off-by: Michael S. Tsirkin Reviewed-by: Pankaj Gupta --- drivers/virtio/virtio_mem.c | 52 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 51 insertions(+), 1 deletion(-) diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c index eb4c16d..80cdb9e 100644 --- a/drivers/virtio/virtio_mem.c +++ b/drivers/virtio/virtio_mem.c @@ -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); -- 2.7.4