From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=36880 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Q90GM-00055j-ML for qemu-devel@nongnu.org; Sun, 10 Apr 2011 15:25:35 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Q90GL-0002n4-Ha for qemu-devel@nongnu.org; Sun, 10 Apr 2011 15:25:34 -0400 Received: from hall.aurel32.net ([88.191.126.93]:37295) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Q90GL-0002mr-BZ for qemu-devel@nongnu.org; Sun, 10 Apr 2011 15:25:33 -0400 Date: Sun, 10 Apr 2011 21:25:31 +0200 From: Aurelien Jarno Subject: Re: [Qemu-devel] [PATCH 01/15] s390x: fix virtio feature bitmap Message-ID: <20110410192531.GC4551@volta.aurel32.net> References: <1301927544-32767-1-git-send-email-agraf@suse.de> <1301927544-32767-2-git-send-email-agraf@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <1301927544-32767-2-git-send-email-agraf@suse.de> List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexander Graf Cc: peter.maydell@linaro.org, QEMU-devel Developers , Richard Henderson On Mon, Apr 04, 2011 at 04:32:10PM +0200, Alexander Graf wrote: > The feature bitmap in the s390 virtio machine is little endian. To > address for that, we need to bswap the values after reading them out. > > Signed-off-by: Alexander Graf > --- > hw/s390-virtio-bus.c | 4 ++-- > 1 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/hw/s390-virtio-bus.c b/hw/s390-virtio-bus.c > index 58af164..60e0135 100644 > --- a/hw/s390-virtio-bus.c > +++ b/hw/s390-virtio-bus.c > @@ -223,7 +223,7 @@ void s390_virtio_device_sync(VirtIOS390Device *dev) > cur_offs += num_vq * VIRTIO_VQCONFIG_LEN; > > /* Sync feature bitmap */ > - stl_phys(cur_offs, dev->host_features); > + stl_phys(cur_offs, bswap32(dev->host_features)); Is bswap32 correct here for both big and little endian guests? I don't really understand the reason why a bswap is needed here, especially given that AFAIK this code was already used when using KVM. > dev->feat_offs = cur_offs + dev->feat_len; > cur_offs += dev->feat_len * 2; > @@ -246,7 +246,7 @@ void s390_virtio_device_update_status(VirtIOS390Device *dev) > > /* Update guest supported feature bitmap */ > > - features = ldl_phys(dev->feat_offs); > + features = bswap32(ldl_phys(dev->feat_offs)); > if (vdev->set_features) { > vdev->set_features(vdev, features); > } > -- > 1.6.0.2 > > > -- Aurelien Jarno GPG: 1024D/F1BCDB73 aurelien@aurel32.net http://www.aurel32.net