From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36960) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aZGdF-00042x-CD for qemu-devel@nongnu.org; Fri, 26 Feb 2016 06:32:26 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aZGdE-0007GE-BA for qemu-devel@nongnu.org; Fri, 26 Feb 2016 06:32:25 -0500 Date: Fri, 26 Feb 2016 22:33:24 +1100 From: David Gibson Message-ID: <20160226113324.GC24457@voom.redhat.com> References: <1456486323-8047-1-git-send-email-david@gibson.dropbear.id.au> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="zCKi3GIZzVBPywwA" Content-Disposition: inline In-Reply-To: <1456486323-8047-1-git-send-email-david@gibson.dropbear.id.au> Subject: Re: [Qemu-devel] [PATCH 00/12] Allow EEH on spapr-pci-host-bridge devices List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: aik@ozlabs.ru, benh@kernel.crashing.org Cc: agraf@suse.de, qemu-devel@nongnu.org, gwshan@au1.ibm.com, mdroth@linux.vnet.ibm.com, alex.williamson@redhat.com, qemu-ppc@nongnu.org --zCKi3GIZzVBPywwA Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Feb 26, 2016 at 10:31:51PM +1100, David Gibson wrote: > For historical reasons, the spapr machine type has two PCI host bridge > implementations: spapr-pci-host-bridge, and > spapr-vfio-pci-host-bridge. The latter was (duh) designed for VFIO > devices, but later reworks mean it's not necessary for that, and VFIO > can be used on the regular host bridge. >=20 > The only remaining difference is that EEH (Enhanced Error Handling - > IBM's interface with similar purpose to AER) is only supported on the > spapr-vfio-pci-host-bridge device. >=20 > This series corrects this, allowing EEH operations on the regular host > bridge. That allows the special VFIO host bridge (we leave a stub, > for backwards compatibility). >=20 > EEH is only supported for VFIO devices, for the time being, and due to > bugs in the kernel implementation, it is only usable when the host > bridge only has devices from a single (host-side) IOMMU group > ("Partitionable Endpoint", in IBM terminology). That's an annoying > limitation which we hope to lift someday, but it's no worse than now, > since the spapr-vfio-pci-host-bridge only permits devices from a > single IOMMU group in any case (although it doesn't properly enforce > that). >=20 > I wrote these a while back, and I'm not sure why they got sidelined - > I suspect I was looking for testing from Gavin Shan, not realising > then that he was no longer working on EEH. In any case, I'm hoping we > can squeeze this change into 2.6, so we don't need to carry the broken > spapr-vfio-pci-host-bridge device any longer. Btw, Alexey. Sorry, I know this will conflict with your vfio-ddw patches. However, from my brief glance at those, it looked like you removed spapr-vfio-pci-host-bridge without properly fixing up EEH on the regular host bridge, which I'd like to avoid. --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson --zCKi3GIZzVBPywwA Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJW0DgEAAoJEGw4ysog2bOSNx8QALp76ic8cb87ZlE1Bc/9s3Sa 84f60s8K8K/BdDJW3MDBcUNoEuRHET9dYZbKnyuPQwma/SmnQX5EvW7xZdtLUePD 83NczzP1yaeyqXQ/T453UKcdPuZb9jmDiwhwAIbqf+W5x8MEPNLALWS8j8H71gxX 3zq+Cz+CRgtCr5dcaLKE7AWEnvYMA1Ei9ugnaCq5JrSmlvG1tEZScE7nidNGLcV1 v1rXyLxGO6pV1IoiZ4X1HwhPMZLFMV/ngWY7ILbOoljSsRNjxyF5c0rb0ipfIWtn z2ZTfgxn1wLrVbxa0dXOaJhWKh+Swm/byXdirXKffKI5CbMVAKuVSLjublxUMXD2 AL2XegiDtaSysrOM9IV63ShqWbLVk+6a9pRzHvloaiRUP27hrgtIZzKJsl6pMUsd QQ+j/oncxvlg4f/pdS08/al26BjXmPWMZ8OYcN6cy89NzZ64PkemzUzTNInRx7g2 l6vASIfVZ4sAxUSqPNwqCeGuZ/SeLl9C5abqyO3qbLpaQuzaYC9SkaqJpTgjDmsX q5GbNXx4Sl3LofFhK34qudoJDFSBs6zBWvz7dpJPHhz+1I91gCE88Aa1mPORuIs5 dqXw93+KmOja60cNzSMHgB4peXno1N6/zc1P6DWFd9/SJsE7HC9LbO/iFziF152k xcgdFHvJ6kALDR88Vhol =Rdmw -----END PGP SIGNATURE----- --zCKi3GIZzVBPywwA--