Commit 500817bf authored by David Hildenbrand's avatar David Hildenbrand Committed by Michael S. Tsirkin
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virtio-mem: don't read big block size in Sub Block Mode 



We are reading a Big Block Mode value while in Sub Block Mode
when initializing. Fortunately, vm->bbm.bb_size maps to some counter
in the vm->sbm.mb_count array, which is 0 at that point in time.

No harm done; still, this was unintended and is not future-proof.

Fixes: 4ba50cd3 ("virtio-mem: Big Block Mode (BBM) memory hotplug")
Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20210602185720.31821-2-david@redhat.com


Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent efa08cb4

drivers/virtio/virtio_mem.c

+8 −7
Original line number Diff line number Diff line
@@ -2420,6 +2420,10 @@ static int virtio_mem_init(struct virtio_mem *vm) 
		dev_warn(&vm->vdev->dev,

			 "Some device memory is not addressable/pluggable. This can make some memory unusable.\n");



	/* Prepare the offline threshold - make sure we can add two blocks. */

	vm->offline_threshold = max_t(uint64_t, 2 * memory_block_size_bytes(),

				      VIRTIO_MEM_DEFAULT_OFFLINE_THRESHOLD);



	/*

	 * We want subblocks to span at least MAX_ORDER_NR_PAGES and

	 * pageblock_nr_pages pages. This:
@@ -2466,14 +2470,11 @@ static int virtio_mem_init(struct virtio_mem *vm) 
		       vm->bbm.bb_size - 1;

		vm->bbm.first_bb_id = virtio_mem_phys_to_bb_id(vm, addr);

		vm->bbm.next_bb_id = vm->bbm.first_bb_id;

	}



	/* Prepare the offline threshold - make sure we can add two blocks. */

	vm->offline_threshold = max_t(uint64_t, 2 * memory_block_size_bytes(),

				      VIRTIO_MEM_DEFAULT_OFFLINE_THRESHOLD);

	/* In BBM, we also want at least two big blocks. */

		/* Make sure we can add two big blocks. */

		vm->offline_threshold = max_t(uint64_t, 2 * vm->bbm.bb_size,

					      vm->offline_threshold);

	}



	dev_info(&vm->vdev->dev, "start address: 0x%llx", vm->addr);

	dev_info(&vm->vdev->dev, "region size: 0x%llx", vm->region_size);