From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Hajnoczi Subject: Re: [RFC] virtio: support VIRTIO_F_IO_BARRIER Date: Thu, 3 May 2018 10:06:52 +0100 Message-ID: <20180503090652.GB5301__25519.5499318235$1525350741$gmane$org@stefanha-x1.localdomain> References: <20180503025955.28816-1-tiwei.bie@intel.com> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============8833794240571668891==" Return-path: In-Reply-To: <20180503025955.28816-1-tiwei.bie@intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Tiwei Bie Cc: mst@redhat.com, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, zhihong.wang@intel.com, pbonzini@redhat.com List-Id: virtualization@lists.linuxfoundation.org --===============8833794240571668891== Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="qlTNgmc+xy1dBmNv" Content-Disposition: inline --qlTNgmc+xy1dBmNv Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, May 03, 2018 at 10:59:55AM +0800, Tiwei Bie wrote: > This patch introduces the support for VIRTIO_F_IO_BARRIER. > When this feature is negotiated, driver will use the barriers > suitable for hardware devices. >=20 > Signed-off-by: Tiwei Bie I should have thought of this earlier, but why is a new feature bit necessary? If a hardware virtio device is in use, then the device should already negotiate VIRTIO_F_IOMMU_PLATFORM (i.e. use DMA APIs and IOMMU callbacks). Does disabling weak_barriers when VIRTIO_F_IOMMU_PLATFORM is set solve the problem? --qlTNgmc+xy1dBmNv Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEcBAEBAgAGBQJa6tEsAAoJEJykq7OBq3PId/QIALdwBH9xWwEQVvM6d304pF6L xzcV8Swsp88sZDWASg+U4bAHqwEu7GHZV8uL5D7cL0wj/GzosiL8UXg5gRMbCewJ +WqmRO650s3yMrYWkSODwIVA1ecJ4z7ij43NCVFDYn2INVec5PbVxW0lDgtCG0KD +EU5IWUK4JMU25x4f+mQSYQkrsV89msupTw/qdxF634+qHitlj79JOL4ZmcvmOg6 DrSD11OXbpKDi8KEOJb+9KJ1ky69L9xUn29Me5YMK3mYbfte1kZYLSzE4JvQmKHS Rf68rErinhJeAxDU4txxaIb2jOq3dUwqSQLuj5MjtNf4KhJbSB3A+BkZHSY4HM0= =X31/ -----END PGP SIGNATURE----- --qlTNgmc+xy1dBmNv-- --===============8833794240571668891== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization --===============8833794240571668891==--