From patchwork Wed Nov 28 15:21:50 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [5/5] virtio-scsi: Fix subtle (guest) endian bug Date: Wed, 28 Nov 2012 05:21:50 -0000 From: Paolo Bonzini X-Patchwork-Id: 202484 Message-Id: <1354116110-28651-6-git-send-email-pbonzini@redhat.com> To: qemu-devel@nongnu.org Cc: aliguori@us.ibm.com, Paul 'Rusty' Russell , David Gibson From: David Gibson 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 Cc: Paul 'Rusty' Russell Signed-off-by: David Gibson Signed-off-by: Paolo Bonzini --- hw/virtio-scsi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/hw/virtio-scsi.c b/hw/virtio-scsi.c index 924fc69..bfe1860 100644 --- a/hw/virtio-scsi.c +++ b/hw/virtio-scsi.c @@ -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); }