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authorChristian Borntraeger <borntraeger@de.ibm.com>2012-05-24 13:22:55 +0200
committerMichael Roth <mdroth@linux.vnet.ibm.com>2012-06-25 08:47:47 -0500
commitc63c453889d0bfbd183da686bc076590220fd44a (patch)
tree725d0fa09299ad7dad5dbbbeb11e3a2fb28a7961
parentUpdate version for 1.1.0 release (diff)
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virtio-blk: Fix geometry sector calculation
Currently the sector value for the geometry is masked, even if the user usesa command line parameter that explicitely gives a number. This breaks dasd devices on s390. A dasd device can have a physical block size of 4096 (== same for logical block size) and a typcial geometry of 15 heads and 12 sectors per cyl. The ibm partition detection relies on a correct geometry reported by the device. Unfortunately the current code changes 12 to 8. This would be necessary if the total size is not a multiple of logical sector size, but for dasd this is not the case. This patch checks the device size and only applies sector mask if necessary. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> CC: Christoph Hellwig <hch@lst.de> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> (cherry picked from commit 136be99e6e2130d3cd960b6b7d0ca86b6f011e5f) Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
-rw-r--r--hw/virtio-blk.c17
1 files changed, 16 insertions, 1 deletions
diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c
index f9e1896ea..4f5745033 100644
--- a/hw/virtio-blk.c
+++ b/hw/virtio-blk.c
@@ -489,7 +489,22 @@ static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config)
stw_raw(&blkcfg.min_io_size, s->conf->min_io_size / blk_size);
stw_raw(&blkcfg.opt_io_size, s->conf->opt_io_size / blk_size);
blkcfg.heads = heads;
- blkcfg.sectors = secs & ~s->sector_mask;
+ /*
+ * We must ensure that the block device capacity is a multiple of
+ * the logical block size. If that is not the case, lets use
+ * sector_mask to adopt the geometry to have a correct picture.
+ * For those devices where the capacity is ok for the given geometry
+ * we dont touch the sector value of the geometry, since some devices
+ * (like s390 dasd) need a specific value. Here the capacity is already
+ * cyls*heads*secs*blk_size and the sector value is not block size
+ * divided by 512 - instead it is the amount of blk_size blocks
+ * per track (cylinder).
+ */
+ if (bdrv_getlength(s->bs) / heads / secs % blk_size) {
+ blkcfg.sectors = secs & ~s->sector_mask;
+ } else {
+ blkcfg.sectors = secs;
+ }
blkcfg.size_max = 0;
blkcfg.physical_block_exp = get_physical_block_exp(s->conf);
blkcfg.alignment_offset = 0;