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authorDavid Hildenbrand <david@redhat.com>2020-06-11 12:35:18 +0300
committerMichael S. Tsirkin <mst@redhat.com>2020-06-22 19:34:21 +0300
commitb3562c6087b585abba53d906f127d6fd5a92829c (patch)
tree11c8ae8bea9be152e900347feca15483cc6abe91 /drivers/virtio
parent1c3d69ab5348b661616992206357a3ebf19b1008 (diff)
downloadlinux-b3562c6087b585abba53d906f127d6fd5a92829c.tar.xz
virtio-mem: add memory via add_memory_driver_managed()
Virtio-mem managed memory is always detected and added by the virtio-mem driver, never using something like the firmware-provided memory map. This is the case after an ordinary system reboot, and has to be guaranteed after kexec. Especially, virtio-mem added memory resources can contain inaccessible parts ("unblocked memory blocks"), blindly forwarding them to a kexec kernel is dangerous, as unplugged memory will get accessed (esp. written). Let's use the new way of adding special driver-managed memory introduced in commit 7b7b27214bba ("mm/memory_hotplug: introduce add_memory_driver_managed()"). This will result in no entries in /sys/firmware/memmap ("raw firmware- provided memory map"), the memory resource will be flagged IORESOURCE_MEM_DRIVER_MANAGED (esp., kexec_file_load() will not place kexec images on this memory), and it is exposed as "System RAM (virtio_mem)" in /proc/iomem, so esp. kexec-tools can properly handle it. Example /proc/iomem before this change: [...] 140000000-333ffffff : virtio0 140000000-147ffffff : System RAM 334000000-533ffffff : virtio1 338000000-33fffffff : System RAM 340000000-347ffffff : System RAM 348000000-34fffffff : System RAM [...] Example /proc/iomem after this change: [...] 140000000-333ffffff : virtio0 140000000-147ffffff : System RAM (virtio_mem) 334000000-533ffffff : virtio1 338000000-33fffffff : System RAM (virtio_mem) 340000000-347ffffff : System RAM (virtio_mem) 348000000-34fffffff : System RAM (virtio_mem) [...] Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: teawater <teawaterz@linux.alibaba.com> Fixes: 5f1f79bbc9e26 ("virtio-mem: Paravirtualized memory hotplug") Signed-off-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/r/20200611093518.5737-1-david@redhat.com Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Diffstat (limited to 'drivers/virtio')
-rw-r--r--drivers/virtio/virtio_mem.c25
1 files changed, 22 insertions, 3 deletions
diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
index 5210ff0c5681..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);
}
/*
@@ -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);