From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34710) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cCjuM-0002lI-Dt for qemu-devel@nongnu.org; Fri, 02 Dec 2016 04:13:31 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cCjuI-00016B-DD for qemu-devel@nongnu.org; Fri, 02 Dec 2016 04:13:30 -0500 Date: Fri, 2 Dec 2016 16:50:44 +1100 From: David Gibson Message-ID: <20161202055044.GG10089@umbus.fritz.box> References: <20161031025314.GJ18226@umbus.fritz.box> <20161101024634.GA14860@umbus.fritz.box> <1479218565.3319.18.camel@redhat.com> <3353ecef-2308-13e3-025d-df41b2e89945@ozlabs.ru> <1479457042.1391.11.camel@redhat.com> <20161123050049.GD17795@umbus.fritz.box> <1480081581.4367.65.camel@redhat.com> <20161202041835.GF10089@umbus.fritz.box> <1480655870.3459.46.camel@kernel.crashing.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="yQbNiKLmgenwUfTN" Content-Disposition: inline In-Reply-To: <1480655870.3459.46.camel@kernel.crashing.org> Subject: Re: [Qemu-devel] [Qemu-ppc] [RFC PATCH qemu] spapr_pci: Create PCI-express root bus by default List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Benjamin Herrenschmidt Cc: Andrea Bolognani , Alexey Kardashevskiy , Greg Kurz , Paolo Bonzini , Alex Williamson , qemu-ppc@nongnu.org, qemu-devel@nongnu.org, libvir-list@redhat.com, Michael Roth --yQbNiKLmgenwUfTN Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Dec 02, 2016 at 04:17:50PM +1100, Benjamin Herrenschmidt wrote: > On Fri, 2016-12-02 at 15:18 +1100, David Gibson wrote: > > But if you pass through multiple groups, things get weird.=A0 On q35, > > you'd generally expect physically separate (different slot) devices to > > appear under separate root complexes.=A0 Whereas on pseries they'll > > appear as siblings on a virtual bus (which makes no physical sense for > > point-to-point PCI-E). >=20 > It's also somewhat broken if they aren't in the same iommu domain > because the way we pass the iommu buid is via the parent node, so > a given iommu domain must reside below a common parent and not share > it. Uh.. I don't entirely follow you. From the host point of view there are multiple iommu groups (PEs), but from the guest point of view there's only one. On the guest side iommu granularity is always per-vPHB. > > I suppose we could try treating all devices on pseries as though they > > were chipset builtin devices on q35, which will appear on the root > > PCI-E bus without root complex.=A0 But I suspect that's likely to cause > > trouble with hotplug, and it will certainly need different address > > allocation from libvirt. >=20 --=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 --yQbNiKLmgenwUfTN Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBCAAGBQJYQQuxAAoJEGw4ysog2bOSUBcQAKyrg7Fs1PV4VgvUK61gDtFK Ce8M5CBcL7Yim/a+F2Y8sxufHXWW3ajQozOv9szuVCCk2ximHpoDvMhlZL8q0v7p J0M0EqZ97GexUkEGUdeT45wZiO/Xc0g6ylvr1fxPCdxPVkspX6LQJwgHpoJuuxMe c+9yatKo6glso0c4LsP+vQOA0dQ5GwPEuKmW4J85JHjQRGEmvZnixZKg4xFjU6Jz HEletFsNr/sj0XTSLvOVYiwx3OGoVsUFn4KboFD0K6Lu4sYIHldoOrZza3dc3mFl CxK4mK5Nz9I0dPYgEYKTXDjHUaQG7cn7zSAlp9uz3DAQgwC/Ai0aY97aMa7qu54q lns2uiYTUKnbRp/oZcFypT2cED6teANPsxFjWIBBUIsbQov6rxohZJWIMIBB1Uzh M/PVxTeQ6G522Uccky79VwQNIPEkEyhKcOnQ7cJCd9ob3gaAnhb78xcYJNTUemWF Wa9iqi/55DtnSvWadNKltOpgS+pfWTEFHJXgLPM3JqY6hLh2oN3nvFBWm3H5czeP m4k1AoX7CGOE8YSz26VCjjAI35HRPEA8CbilKSUmSAv1GkMHvGQ6NshiSGgK83Ip xV+V6N05ed/LH8aprcGNM5BzcutQEvuPDY84qrAzXjuXSguN7yo1XI7P/RYOJev+ BT/xe8G90PeM43gyeRPU =GRin -----END PGP SIGNATURE----- --yQbNiKLmgenwUfTN--