Mike Christie 0993d26ddd vhost-scsi: Fix alignment handling with windows ... [ Upstream commit 5ced58bfa1 ] The linux block layer requires bios/requests to have lengths with a 512 byte alignment. Some drivers/layers like dm-crypt and the directi IO code will test for it and just fail. Other drivers like SCSI just assume the requirement is met and will end up in infinte retry loops. The problem for drivers like SCSI is that it uses functions like blk_rq_cur_sectors and blk_rq_sectors which divide the request's length by 512. If there's lefovers then it just gets dropped. But other code in the block/scsi layer may use blk_rq_bytes/blk_rq_cur_bytes and end up thinking there is still data left and try to retry the cmd. We can then end up getting stuck in retry loops where part of the block/scsi thinks there is data left, but other parts think we want to do IOs of zero length. Linux will always check for alignment, but windows will not. When vhost-scsi then translates the iovec it gets from a windows guest to a scatterlist, we can end up with sg items where the sg->length is not divisible by 512 due to the misaligned offset: sg[0].offset = 255; sg[0].length = 3841; sg... sg[N].offset = 0; sg[N].length = 255; When the lio backends then convert the SG to bios or other iovecs, we end up sending them with the same misaligned values and can hit the issues above. This just has us drop down to allocating a temp page and copying the data when we detect a misaligned buffer and the IO is large enough that it will get split into multiple bad IOs. Signed-off-by: Mike Christie <michael.christie@oracle.com> Message-Id: <20230709202859.138387-2-michael.christie@oracle.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>		2023-09-13 09:47:54 +02:00
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Kconfig	vhost_task: Allow vhost layer to use copy_process	2023-03-23 12:45:36 +01:00
Makefile	…
iotlb.c	vhost_iotlb: split out IOTLB initialization	2022-05-31 12:44:28 -04:00
net.c	vhost_net: revert upend_idx only on retriable error	2023-06-08 15:43:08 -04:00
scsi.c	vhost-scsi: Fix alignment handling with windows	2023-09-13 09:47:54 +02:00
test.c	vhost-test: remove meaningless debug info	2023-02-20 19:26:58 -05:00
test.h	…
vdpa.c	vhost_vdpa: support PACKED when setting-getting vring_base	2023-06-09 12:08:04 -04:00
vhost.c	vhost: support PACKED when setting-getting vring_base	2023-06-09 12:07:52 -04:00
vhost.h	vhost: support PACKED when setting-getting vring_base	2023-06-09 12:07:52 -04:00
vringh.c	vringh: support VA with iotlb	2023-04-21 03:02:33 -04:00
vsock.c	vsock: support sockmap	2023-03-29 08:19:38 +01:00