From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60186) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cqiaA-000715-Q6 for qemu-devel@nongnu.org; Wed, 22 Mar 2017 11:53:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cqia5-0003Sp-0e for qemu-devel@nongnu.org; Wed, 22 Mar 2017 11:53:54 -0400 Date: Wed, 22 Mar 2017 15:53:44 +0000 From: Stefan Hajnoczi Message-ID: <20170322155344.GA16717@stefanha-x1.localdomain> References: <20170228132132.20231-1-pbonzini@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="IJpNTDwzlM2Ie8A6" Content-Disposition: inline In-Reply-To: <20170228132132.20231-1-pbonzini@redhat.com> Subject: Re: [Qemu-devel] [PATCH] virtio: always use handle_aio_output if registered List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: qemu-devel@nongnu.org, qemu-stable@nongnu.org, kraxel@redhat.com, mst@redhat.com --IJpNTDwzlM2Ie8A6 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Feb 28, 2017 at 02:21:32PM +0100, Paolo Bonzini wrote: > Commit ad07cd6 ("virtio-scsi: always use dataplane path if ioeventfd is > active", 2016-10-30) and 9ffe337 ("virtio-blk: always use dataplane > path if ioeventfd is active", 2016-10-30) broke the virtio 1.0 > indirect access registers. >=20 > The indirect access registers bypass the ioeventfd, so that virtio-blk > and virtio-scsi now repeatedly try to initialize dataplane instead of > triggering the guest->host EventNotifier. Detect the situation by > checking vq->handle_aio_output; if it is not NULL, trigger the > EventNotifier, which is how the device expects to get notifications > and in fact the only thread-safe manner to deliver them. >=20 > Fixes: ad07cd6 > Fixes: 9ffe337 > Cc: qemu-stable@nongnu.org > Signed-off-by: Paolo Bonzini > --- > hw/virtio/virtio.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) Reviewed-by: Stefan Hajnoczi --IJpNTDwzlM2Ie8A6 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEcBAEBAgAGBQJY0p4IAAoJEJykq7OBq3PIolUIAK5AVQO7mBFWsyW3iaSJ2rfc QBXNu9egf39P6vcXy7PB1/cNWpogR+XlEsGiH6v5zUS1x2asIkjZqQPrzRKmP0FP TrjbWrpa+aVvc/n9rGBtRQBWJsNemtilmx7p5JoTfzbW+AqkDE41QjbV9NGEYBbo hrFZdpGb09ZfcIVG2z8RpDTeQ/1Xman3T1qtpHehzvo83UsN0NHaCYCOUHN6pZWC q0XpgI2e5r6gO7Vls2YGoR/FyF55wckbOMyo+4fINOGU3yIWyDFD+TGp2o+7cxte myreyGR908jy525/bMXqiPdU5Tf4Fqicv+w7GC/xL3N/5iNnSFOoz8LAn1DcZlw= =BXsT -----END PGP SIGNATURE----- --IJpNTDwzlM2Ie8A6--