From c93d512dddb00e3eed2ce9484c55f5f1fbb54c8b Mon Sep 17 00:00:00 2001
From: dinglimin <[email protected]>
Date: Tue, 27 Feb 2024 19:02:52 +0800
Subject: [PATCH] blkio: Respect memory-alignment for bounce buffer allocations

cheery-pick from 10b2393e5e7f4c1d633f1ac8578465681c333efb

blkio_alloc_mem_region() requires that the requested buffer size is a
multiple of the memory-alignment property. If it isn't, the allocation
fails with a return value of -EINVAL.

Fix the call in blkio_resize_bounce_pool() to make sure the requested
size is properly aligned.

I observed this problem with vhost-vdpa, which requires page aligned
memory. As the virtio-blk device behind it still had 512 byte blocks, we
got bs->bl.request_alignment = 512, but actually any request that needed
a bounce buffer and was not aligned to 4k would fail without this fix.

Suggested-by: Stefano Garzarella <[email protected]>
Signed-off-by: Kevin Wolf <[email protected]>
Message-ID: <[email protected]>
Reviewed-by: Stefan Hajnoczi <[email protected]>
Reviewed-by: Stefano Garzarella <[email protected]>
Signed-off-by: Kevin Wolf <[email protected]>
Signed-off-by: dinglimin <[email protected]>
---
 block/blkio.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/block/blkio.c b/block/blkio.c
index 0a0a6c0f5f..b989617608 100644
--- a/block/blkio.c
+++ b/block/blkio.c
@@ -89,6 +89,9 @@ static int blkio_resize_bounce_pool(BDRVBlkioState *s, int64_t bytes)
     /* Pad size to reduce frequency of resize calls */
     bytes += 128 * 1024;
 
+    /* Align the pool size to avoid blkio_alloc_mem_region() failure */
+    bytes = QEMU_ALIGN_UP(bytes, s->mem_region_alignment);
+
     WITH_QEMU_LOCK_GUARD(&s->blkio_lock) {
         int ret;
 
-- 
2.27.0