From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52957) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZHqDb-0004vk-Km for qemu-devel@nongnu.org; Wed, 22 Jul 2015 05:21:40 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZHqDX-0003gH-FP for qemu-devel@nongnu.org; Wed, 22 Jul 2015 05:21:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59051) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZHqDX-0003fv-9S for qemu-devel@nongnu.org; Wed, 22 Jul 2015 05:21:35 -0400 Date: Wed, 22 Jul 2015 12:21:32 +0300 From: "Michael S. Tsirkin" Message-ID: <20150722121913-mutt-send-email-mst@redhat.com> References: <1437544792-3949-1-git-send-email-jasowang@redhat.com> <1437544792-3949-3-git-send-email-jasowang@redhat.com> <20150722105843.41d22942.cornelia.huck@de.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150722105843.41d22942.cornelia.huck@de.ibm.com> Subject: Re: [Qemu-devel] [PATCH V3 2/3] virtio-blk: fail get_features when both scsi and 1.0 were set List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Cornelia Huck Cc: pbonzini@redhat.com, Jason Wang , qemu-devel@nongnu.org On Wed, Jul 22, 2015 at 10:58:43AM +0200, Cornelia Huck wrote: > On Wed, 22 Jul 2015 13:59:51 +0800 > Jason Wang wrote: > > > SCSI passthrough was no longer supported in virtio 1.0, so this patch > > fail the get_features() when both 1.0 and scsi is set. And also only > > advertise VIRTIO_BLK_F_SCSI for legacy virtio-blk device. > > > > Signed-off-by: Jason Wang > > --- > > hw/block/virtio-blk.c | 9 ++++++++- > > 1 file changed, 8 insertions(+), 1 deletion(-) > > > > diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c > > index 4c27974..4716c3e 100644 > > --- a/hw/block/virtio-blk.c > > +++ b/hw/block/virtio-blk.c > > @@ -731,7 +731,14 @@ static uint64_t virtio_blk_get_features(VirtIODevice *vdev, uint64_t features, > > virtio_add_feature(&features, VIRTIO_BLK_F_GEOMETRY); > > virtio_add_feature(&features, VIRTIO_BLK_F_TOPOLOGY); > > virtio_add_feature(&features, VIRTIO_BLK_F_BLK_SIZE); > > - virtio_add_feature(&features, VIRTIO_BLK_F_SCSI); > > + if (__virtio_has_feature(features, VIRTIO_F_VERSION_1)) { > > + if (s->conf.scsi) { > > + error_setg(errp, "Virtio 1.0 does not support scsi passthrough!"); > > + return 0; > > + } > > + } else { > > + virtio_add_feature(&features, VIRTIO_BLK_F_SCSI); > > + } > > > > if (s->conf.config_wce) { > > virtio_add_feature(&features, VIRTIO_BLK_F_CONFIG_WCE); > > Do we advertise F_SCSI even if scsi is not configured in order to keep > the same bits as before? I'm afraid I don't remember, that thread was > long :/ > > I'm asking because I'd like to depend on that bit to decide whether I > can negotiate revision 1 for ccw and subsequently offer VERSION_1. It > would be an easy thing to do, and I'd like to avoid mucking around with > device-specific configuration from the transport. > > To illustrate what I'm talking about, my current patchset for virtio-1 > on ccw is here: > > git://github.com/cohuck/qemu virtio-1-ccw-2.5 I still think you are over-engineering it. Just add a property to disable the modern interface. Anyone using scsi passthrough will have to set that, if not - above patch will make initialization fail. -- MST