When the maximum IO size supported by the virtio-blk backend is large enough (>= 32MiB for 512B sectors), the computed blk_num_max will overflow. In particular, if it's a multiple of 32MiB, blk_num_max will end up as zero, causing IO requests to fail.
This is triggered by e.g. the SPDK virtio-blk vhost-user backend.
To fix it, just limit blk_num_max to 65535 before converting to u16.
Signed-off-by: Lukas Stockner lstockner@genesiscloud.com --- src/hw/virtio-blk.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/hw/virtio-blk.c b/src/hw/virtio-blk.c index e087fe4..137a2c3 100644 --- a/src/hw/virtio-blk.c +++ b/src/hw/virtio-blk.c @@ -92,7 +92,7 @@ virtio_blk_op(struct disk_op_s *op, int write) u16 blk_num_max;
if (vdrive->drive.blksize != 0 && max_io_size != 0) - blk_num_max = (u16)(max_io_size / vdrive->drive.blksize); + blk_num_max = (u16) min(max_io_size / vdrive->drive.blksize, 0xffff); else /* default blk_num_max if hardware doesnot advise a proper value */ blk_num_max = 64;
On Tue, Jun 06, 2023 at 03:29:52PM +0200, Lukas Stockner via SeaBIOS wrote:
When the maximum IO size supported by the virtio-blk backend is large enough (>= 32MiB for 512B sectors), the computed blk_num_max will overflow. In particular, if it's a multiple of 32MiB, blk_num_max will end up as zero, causing IO requests to fail.
This is triggered by e.g. the SPDK virtio-blk vhost-user backend.
To fix it, just limit blk_num_max to 65535 before converting to u16.
Thanks. I committed this change.
-Kevin
-
Kevin O'Connor -
Lukas Stockner