From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46763) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Z6rgL-0000Vb-JD for qemu-devel@nongnu.org; Sun, 21 Jun 2015 22:41:58 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Z6rgG-0004Eh-Os for qemu-devel@nongnu.org; Sun, 21 Jun 2015 22:41:54 -0400 Date: Mon, 22 Jun 2015 12:00:18 +1000 From: David Gibson Message-ID: <20150622020018.GL13352@voom.redhat.com> References: <1429964684-23872-1-git-send-email-aik@ozlabs.ru> <1429964684-23872-14-git-send-email-aik@ozlabs.ru> <20150505124940.GS14090@voom.redhat.com> <5582AD10.3070400@ozlabs.ru> <20150619014510.GI13352@voom.redhat.com> <87y4jgmbvn.fsf@blackfin.pond.sub.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="35HXvU1qzCTR5mW7" Content-Disposition: inline In-Reply-To: <87y4jgmbvn.fsf@blackfin.pond.sub.org> Subject: Re: [Qemu-devel] [PATCH qemu v7 13/14] spapr_pci/spapr_pci_vfio: Support Dynamic DMA Windows (DDW) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Markus Armbruster Cc: Alexey Kardashevskiy , Alex Williamson , qemu-ppc@nongnu.org, qemu-devel@nongnu.org, Alexander Graf --35HXvU1qzCTR5mW7 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Jun 19, 2015 at 08:49:00AM +0200, Markus Armbruster wrote: > David Gibson writes: >=20 > > On Thu, Jun 18, 2015 at 09:35:44PM +1000, Alexey Kardashevskiy wrote: > >> On 05/05/2015 10:49 PM, David Gibson wrote: > >> >On Sat, Apr 25, 2015 at 10:24:43PM +1000, Alexey Kardashevskiy wrote: > >> >>This adds support for Dynamic DMA Windows (DDW) option defined by > >> >>the SPAPR specification which allows to have additional DMA window(s) > >> >> > >> >>This implements DDW for emulated and VFIO devices. As all TCE root r= egions > >> >>are mapped at 0 and 64bit long (and actual tables are child regions), > >> >>this replaces memory_region_add_subregion() with _overlap() to make > >> >>QEMU memory API happy. > >> >> > >> >>This reserves RTAS token numbers for DDW calls. > >> >> > >> >>This implements helpers to interact with VFIO kernel interface. > >> >> > >> >>This changes the TCE table migration descriptor to support dynamic > >> >>tables as from now on, PHB will create as many stub TCE table objects > >> >>as PHB can possibly support but not all of them might be initialized= at > >> >>the time of migration because DDW might or might not be requested by > >> >>the guest. > >> >> > >> >>The "ddw" property is enabled by default on a PHB but for compatibil= ity > >> >>the pseries-2.3 machine and older disable it. > >> >> > >> >>This implements DDW for VFIO. The host kernel support is required. > >> >>This adds a "levels" property to PHB to control the number of levels > >> >>in the actual TCE table allocated by the host kernel, 0 is the defau= lt > >> >>value to tell QEMU to calculate the correct value. Current hardware > >> >>supports up to 5 levels. > >> >> > >> >>The existing linux guests try creating one additional huge DMA window > >> >>with 64K or 16MB pages and map the entire guest RAM to. If succeeded, > >> >>the guest switches to dma_direct_ops and never calls TCE hypercalls > >> >>(H_PUT_TCE,...) again. This enables VFIO devices to use the entire R= AM > >> >>and not waste time on map/unmap later. > >> >> > >> >>This adds 4 RTAS handlers: > >> >>* ibm,query-pe-dma-window > >> >>* ibm,create-pe-dma-window > >> >>* ibm,remove-pe-dma-window > >> >>* ibm,reset-pe-dma-window > >> >>These are registered from type_init() callback. > >> >> > >> >>These RTAS handlers are implemented in a separate file to avoid poll= uting > >> >>spapr_iommu.c with PCI. > >> >> > >> >>Signed-off-by: Alexey Kardashevskiy > >> > > >> >Reviewed-by: David Gibson > >>=20 > >> I saw this and decided there are no more coments but I was wrong :) > > > > Right. Note that if I add a Reviewed-by but also make comments, then > > those comments are seeking clarification and maybe suggesting later > > cleanups, but I think the problems are small enough that the patch is > > still ready to go as it is. >=20 > You can help the recipient of your comments by putting your R-by behind > the last comment. Noted for future reference. > Wouldn't be necessary if people never left reams of quoted material > at the end of their replies, but that's a pipe dream :) I do usually try to trim quoted material - looks like I forgot this time though. --=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 --35HXvU1qzCTR5mW7 Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJVh2wyAAoJEGw4ysog2bOS4T8P/1CpyFGvFO90VkeE4MWnMaXV 2628LRF6UoZcFW1NClohiUVbmk+oc2yI5c/ZX7Uk5wqEbsEtyq1fQZfMruE256DU 8ZMyqAkLomi8lmIPRdMMPpe2Jq7fBCa2bc2HSUAT9lg62CWXAMDLph0FMw9j8XGR xXHcoqiOjBk/ZF9lBPWk/cWRIMo88it00B1cqVAQb2tLPt9XpusvsxW2K7FntHby td/FWFYQf6fDWwSXLAyVk/KJU483xkwYRWXltjsFfPH9LithYV/lUSF5BI1SZzCE YBORx9WMWiKMmw010bPWvJaN8Hj+iFKhqp7NP/fvfCydPYUXBqwN2a2y/4/kdi8W BXGe9k7aT33ohxfd7PzGYIpqL+pPOnp46/T+xRawPHEdGES1bzO+2qylbCmraQ1Z 0suKW8w96nNGFoDQgKpljg+sVzh8wMbDb6dhSfx5OCETQu6/RvYFify4eeYAVVCX lai9IAokyp1FcT+JJcevCt26BmyH6OgnvYke4D4uP0VUDlkr80zE1FfH0YPAjERs UWEcMvY+/mR6eiqjUTQumhAlUIZzQcu4SbpFdLFvquRE5Vl90Nsv4ALHDrLvsJtm EhYbkbdFW7LzFEngnSW8s0UcVMJmBCiWIbGaUmQctbpOX7UZy91LI1wpIVOM3EiA A/edaTfxXPSo7AqtjgTN =pgmZ -----END PGP SIGNATURE----- --35HXvU1qzCTR5mW7--