From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:37176) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TcnYS-0004qB-C9 for qemu-devel@nongnu.org; Sun, 25 Nov 2012 20:32:13 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TcnYQ-0002SN-VH for qemu-devel@nongnu.org; Sun, 25 Nov 2012 20:32:12 -0500 Received: from ozlabs.org ([203.10.76.45]:56013) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TcnYQ-0002S2-K2 for qemu-devel@nongnu.org; Sun, 25 Nov 2012 20:32:10 -0500 From: David Gibson Date: Mon, 26 Nov 2012 12:33:52 +1100 Message-Id: <1353893632-22442-1-git-send-email-david@gibson.dropbear.id.au> Subject: [Qemu-devel] [PATCH] virtio-scsi: Fix subtle (guest) endian bug List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: aliguori@us.ibm.com, pbonzini@redhat.com Cc: Paul 'Rusty' Russell , qemu-devel@nongnu.org, 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 --- 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 9d27d1d..6eb2e03 100644 --- a/hw/virtio-scsi.c +++ b/hw/virtio-scsi.c @@ -533,8 +533,8 @@ 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); } -- 1.7.10.4