From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44603) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z8QRJ-0003jF-98 for qemu-devel@nongnu.org; Fri, 26 Jun 2015 06:00:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z8QRE-0006RO-7n for qemu-devel@nongnu.org; Fri, 26 Jun 2015 06:00:53 -0400 Received: from mail-wg0-x22b.google.com ([2a00:1450:400c:c00::22b]:33421) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z8QRE-0006RK-0R for qemu-devel@nongnu.org; Fri, 26 Jun 2015 06:00:48 -0400 Received: by wgck11 with SMTP id k11so84271702wgc.0 for ; Fri, 26 Jun 2015 03:00:47 -0700 (PDT) Date: Fri, 26 Jun 2015 11:00:45 +0100 From: Stefan Hajnoczi Message-ID: <20150626100045.GJ15457@stefanha-thinkpad.redhat.com> References: <20150625152609.16840.52299.stgit@bahia.lab.toulouse-stg.fr.ibm.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="yr/DzoowOgTDcSCF" Content-Disposition: inline In-Reply-To: <20150625152609.16840.52299.stgit@bahia.lab.toulouse-stg.fr.ibm.com> Subject: Re: [Qemu-devel] [PATCH] dataplane: drop copy_in_vring_desc() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Greg Kurz Cc: Cornelia Huck , qemu-devel@nongnu.org, Stefan Hajnoczi , "Michael S. Tsirkin" --yr/DzoowOgTDcSCF Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jun 25, 2015 at 05:26:09PM +0200, Greg Kurz wrote: > During early virtio 1.0 devel, there were several proposals about how to > deal endianness of the vring descriptor fields: > - convert the decriptor to host endianness in a single place, and use its > fields directly in the code > - keep the descriptor untouched and use virtio memory helpers to access i= ts > fields with the appropriate endianness >=20 > It seems like both approaches got merged: commit f5a5628cf0b6 introduces > an extra swap that negates the one brought by commit b0e5d90ebc3e. This > breaks cross-endian setups with the following error: >=20 > Failed to map descriptor addr 0x18e2517e00000000 len 268435456 >=20 > A solution could be to revert f5a5628cf0b6, but dropping copy_in_vring_de= sc() > is equivalent and gives a smaller patch. Cornelia already sent "[PATCH] Revert "dataplane: allow virtio-1 devices" to revert f5a5628cf0b. I acked it but the patch is going through Michael Tsirkin. --yr/DzoowOgTDcSCF Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAEBAgAGBQJVjSLNAAoJEJykq7OBq3PIyawH/Re7Taj0ML/lrTC4UW7B4lyW q02TywFrrIvn4Z96C5AXNYsOl6oILjD9JXPGq+fbK4M1k97vQN7pWPs7XcxZLG6o vcPL31f7guYhdHLbDxGlQbxx47fLg1b9yIX2mvluvenbsQZRTpvkRg5QjiktkX5y QBf2SqhFHUX+kluRJ7lBEVXZkS8/RhS3yFTHiPQsiwI3bl7CNOFREWIPsZuRHEMK 2PxPB8p6EQXZz94R2MxksjwcLAvMjXu+Pb5sqvJ26Sotqr0K/Q4ztDsnTFxBMGzp rENXkcE2bxOwVNv7kH0lXr9X+x8U1V88QHu06hx+WKgnw8pYHmdl6fFa7DQv/L8= =NH1Z -----END PGP SIGNATURE----- --yr/DzoowOgTDcSCF--