From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: [PATCH v1 2/4] iommu/tegra: gart: Check whether page is already mapped Date: Tue, 26 Sep 2017 13:06:36 +0200 Message-ID: <20170926110636.GA23108@ulmo> References: Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0722265706265761397==" Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Dmitry Osipenko Cc: linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Jonathan Hunter List-Id: iommu@lists.linux-foundation.org --===============0722265706265761397== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="jI8keyz6grp/JLjh" Content-Disposition: inline --jI8keyz6grp/JLjh Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Wed, Jul 05, 2017 at 07:29:46PM +0300, Dmitry Osipenko wrote: > Due to a bug, multiple devices may try to map the same IOVA region. We can > catch that case by checking that 'VALID' bit of the GART's page entry is > unset prior to mapping of the page. Due to what bug? Sounds to me like access to the GART should be exclusive, so that only a single driver can ever access it. Thierry --jI8keyz6grp/JLjh Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEEiOrDCAFJzPfAjcif3SOs138+s6EFAlnKNLkACgkQ3SOs138+ s6HJgRAAu5usJlokWcX2krlcm/Afn3LpCSM200cjMZ9rDWozN3+zhpQdbqtl2lym b0KyPRVkyNHkxHrtWjsSfWuANZt8uzJVerwgedRpAa78Wm4WtYqziHFlfOQ69M0y 0aBUAZGWaam8vjt8OOMJwzJ/kOk7LxrStM41yi4jmQav8/z3hWWgD1lIzA7Br67n dq4pgOfRcwXtfUdvXUvQXziximZzZojIY/ujAyA+YsYyQD0m4oeTRTVceZS3N8O9 9+x18W0bX+rAp2le4+YlfX7NvgSbV4Ffn708R0Ez2cVp2CUJrqpX4aSbw1HI5Pr5 goehjlmkGHZ8nDSOIwgfkOl+O8sQt2wQPbkN1IX4x4TuqY96dTmqWoV7OAsBttBu tem6VWYlIo0OpTm5vbtafaghWwg4YFbaDW89FhrOR57ccAvbAYEmyHnB7cURpbFI rt/si4zE04yD+jQ8OEWlF3Xinkm+RUc+Snu1t4UouACrERpGSlErXtQMXFN0U36R tF4U3BGsZdh0kO/QNAXDfipEPNmrzWV1ICfiUEdESAHZJft6EpSLNH6siQWxTMtR aOD89uLIEUsZJ8mHnQfs/i8vVlACaj84hddX3e1oB/UmyW/LI2iEnMQafMIArvDx bnFQ9V8MYA11o7hiZc4ezMLmSUAbeEvyUTANKA6+jBMula49A/Y= =3Bql -----END PGP SIGNATURE----- --jI8keyz6grp/JLjh-- --===============0722265706265761397== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline --===============0722265706265761397==--