| Message ID | 20240131173140.42398-1-kwolf@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | blkio: Respect memory-alignment for bounce buffer allocations | expand |
On Wed, Jan 31, 2024 at 06:31:40PM +0100, Kevin Wolf wrote: >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 <sgarzare@redhat.com> >Signed-off-by: Kevin Wolf <kwolf@redhat.com> >--- > block/blkio.c | 3 +++ > 1 file changed, 3 insertions(+) Thanks for fixinig this! Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> > >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; > >-- >2.43.0 >
On Wed, Jan 31, 2024 at 06:31:40PM +0100, Kevin Wolf wrote: > 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 <sgarzare@redhat.com> > Signed-off-by: Kevin Wolf <kwolf@redhat.com> > --- > block/blkio.c | 3 +++ > 1 file changed, 3 insertions(+) Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
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;
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 <sgarzare@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- block/blkio.c | 3 +++ 1 file changed, 3 insertions(+)