From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45854) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WFm8B-0000Z1-T8 for qemu-devel@nongnu.org; Tue, 18 Feb 2014 09:58:48 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WFm87-00072k-9k for qemu-devel@nongnu.org; Tue, 18 Feb 2014 09:58:43 -0500 Received: from mx1.redhat.com ([209.132.183.28]:4578) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WFm87-00072S-0K for qemu-devel@nongnu.org; Tue, 18 Feb 2014 09:58:39 -0500 Date: Tue, 18 Feb 2014 17:03:27 +0200 From: "Michael S. Tsirkin" Message-ID: <20140218150327.GA9457@redhat.com> References: <20140218123844.9849.58557.stgit@bahia.lab.toulouse-stg.fr.ibm.com> <20140218123849.9849.77875.stgit@bahia.lab.toulouse-stg.fr.ibm.com> <530372C6.70503@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <530372C6.70503@suse.de> Subject: Re: [Qemu-devel] [PATCH 1/8] virtio_get_byteswap: function for endian-ambivalent targets using virtio. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexander Graf Cc: kwolf@redhat.com, peter.maydell@linaro.org, thuth@linux.vnet.ibm.com, marc.zyngier@arm.com, rusty@rustcorp.com.au, qemu-devel@nongnu.org, stefanha@redhat.com, anthony@codemonkey.ws, pbonzini@redhat.com, afaerber@suse.de, Greg Kurz On Tue, Feb 18, 2014 at 03:48:38PM +0100, Alexander Graf wrote: > On 02/18/2014 01:38 PM, Greg Kurz wrote: > >From: Rusty Russell > > > >virtio data structures are defined as "target endian", which assumes > >that's a fixed value. In fact, that actually means it's > >platform-specific. > > > >The OASIS virtio 1.0 spec will fix this. Meanwhile, create a hook for > >little endian ppc (and potentially ARM). This is called at device > >reset time (which is done before any driver is loaded) since it > >may involve a system call to get the status when running under kvm. > > > >[ fixed checkpatch.pl error with the virtio_byteswap initialisation, > > ldq_phys() API change, Greg Kurz ] > >Signed-off-by: Rusty Russell > >Signed-off-by: Greg Kurz > >--- > > hw/virtio/virtio.c | 6 ++ > > include/hw/virtio/virtio-access.h | 132 +++++++++++++++++++++++++++++++++++++ > > include/hw/virtio/virtio.h | 2 + > > stubs/Makefile.objs | 1 > > stubs/virtio_get_byteswap.c | 6 ++ > > 5 files changed, 147 insertions(+) > > create mode 100644 include/hw/virtio/virtio-access.h > > create mode 100644 stubs/virtio_get_byteswap.c > > > >diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c > >index aeabf3a..4fd6ac2 100644 > >--- a/hw/virtio/virtio.c > >+++ b/hw/virtio/virtio.c > >@@ -19,6 +19,9 @@ > > #include "hw/virtio/virtio.h" > > #include "qemu/atomic.h" > > #include "hw/virtio/virtio-bus.h" > >+#include "hw/virtio/virtio-access.h" > >+ > >+bool virtio_byteswap; > > Could this be a virtio object property rather than a global? Imagine > an AMP guest system with a BE and an LE system running in parallel > accessing two separate virtio devices. With a single global that > would break. > > > Alex Well, how does a device know which CPU uses it? I suspect we are better off waiting for 1.0 with this one. -- MST