diff options
| author | Paul Durrant <paul.durrant@citrix.com> | 2019-04-01 13:17:19 +0100 |
|---|---|---|
| committer | Anthony PERARD <anthony.perard@citrix.com> | 2019-04-04 18:00:07 +0100 |
| commit | 2bcd05cf24a7de34e7e265247c010977e43f40bc (patch) | |
| tree | 24f489fd871b4e6850844cbd5aca1711c20cc461 /hw/block/xen_blkif.h | |
| parent | 15f084505a8556b70134e9081176e90a1c178b7b (diff) | |
xen-block: scale sector based quantities correctly
The Xen blkif protocol requires that sector based quantities should be
interpreted strictly as multiples of 512 bytes. Specifically:
"first_sect and last_sect in blkif_request_segment, as well as
sector_number in blkif_request, are always expressed in 512-byte units."
Commit fcab2b464e06 "xen: add header and build dataplane/xen-block.c"
incorrectly modified behaviour to use the block device logical_block_size
property as the scale, instead of correctly shifting values by the
hardcoded BDRV_SECTOR_BITS (and hence scaling them to 512 byte units).
This patch undoes that change and restores compliance with the spec.
Furthermore, this patch also restores the original xen_disk behaviour
of advertizing a hardcoded 'sector-size' value of 512 in xenstore and
scaling 'sectors' accordingly. The realize() method is also modified to
fail if logical_block_size is set to anything other than 512.
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Message-Id: <20190401121719.27208-1-paul.durrant@citrix.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Diffstat (limited to 'hw/block/xen_blkif.h')
| -rw-r--r-- | hw/block/xen_blkif.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/hw/block/xen_blkif.h b/hw/block/xen_blkif.h index 3e6e1ea365..a353693ea0 100644 --- a/hw/block/xen_blkif.h +++ b/hw/block/xen_blkif.h @@ -143,4 +143,6 @@ static inline void blkif_get_x86_64_req(blkif_request_t *dst, } } +#define XEN_BLKIF_SECTOR_SIZE 512 + #endif /* XEN_BLKIF_H */ |