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virtio-scsi: Fix subtle (guest) endian bug 

The virtio-scsi config space is, by specification, in guest endian (which
is ill-defined, but there you go).  In virtio_scsi_get_config() we set up
all the fields in there, using stl_raw().  Which is a problem for the
max_channel and max_target fields, which are 16-bit, not 32-bit.  For
little-endian targets we get away with it by accident, since the first
two bytes will still be correct, and the extra two bytes written (with
zeroes) will be overwritten correctly by the next store.

But for big-endian guests, this means the max_target field ends up as zero,
which means the guest will only recognize a single disk on the virtio-scsi
bus.  This patch fixes the problem.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul 'Rusty' Russell <rusty@rustcorp.com.au>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
master
David Gibson 2012-11-26 12:33:52 +11:00 committed by Paolo Bonzini
parent 474ee55a18
commit 863d1050c9
1 changed files with 2 additions and 2 deletions
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4
hw/virtio-scsi.c
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@ -534,8 +534,8 @@ static void virtio_scsi_get_config(VirtIODevice *vdev,
stl_raw(&scsiconf->event_info_size, sizeof(VirtIOSCSIEvent));
stl_raw(&scsiconf->sense_size, s->sense_size);
stl_raw(&scsiconf->cdb_size, s->cdb_size);
stl_raw(&scsiconf->max_channel, VIRTIO_SCSI_MAX_CHANNEL);
stl_raw(&scsiconf->max_target, VIRTIO_SCSI_MAX_TARGET);
stw_raw(&scsiconf->max_channel, VIRTIO_SCSI_MAX_CHANNEL);
stw_raw(&scsiconf->max_target, VIRTIO_SCSI_MAX_TARGET);
stl_raw(&scsiconf->max_lun, VIRTIO_SCSI_MAX_LUN);
}