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virtio-mem: don't read big block size in Sub Block Mode

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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: 4ba50cd335 ("virtio-mem: Big Block Mode (BBM) memory hotplug")
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20210602185720.31821-2-david@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
David Hildenbrand 2021-06-02 20:57:14 +02:00 committed by Michael S. Tsirkin
parent efa08cb468
commit 500817bf5e
1 changed files with 8 additions and 7 deletions
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15
drivers/virtio/virtio_mem.c
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@ -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. */
vm->offline_threshold = max_t(uint64_t, 2 * vm->bbm.bb_size,
vm->offline_threshold);
/* 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);