From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:50611) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ucs4d-0001wN-DR for qemu-devel@nongnu.org; Thu, 16 May 2013 02:54:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Ucs4Z-0000IA-8Q for qemu-devel@nongnu.org; Thu, 16 May 2013 02:53:59 -0400 Date: Thu, 16 May 2013 16:53:47 +1000 From: David Gibson Message-ID: <20130516065347.GA5901@truffula.fritz.box> References: <1368522837-20747-1-git-send-email-david@gibson.dropbear.id.au> <1368522837-20747-12-git-send-email-david@gibson.dropbear.id.au> <1368551726.5520.127.camel@ul30vt.home> <20130515013346.GO14944@truffula.fritz.box> <1368586268.5520.162.camel@ul30vt.home> <20130515033250.GP14944@truffula.fritz.box> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="LZvS9be/3tNcYl/X" Content-Disposition: inline In-Reply-To: <20130515033250.GP14944@truffula.fritz.box> Subject: Re: [Qemu-devel] [Qemu-ppc] [PATCH 11/11] vfio: Add guest side IOMMU support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alex Williamson Cc: pbonzini@redhat.com, qemu-ppc@nongnu.org, qemu-devel@nongnu.org, mst@redhat.com --LZvS9be/3tNcYl/X Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, May 15, 2013 at 01:32:50PM +1000, David Gibson wrote: > On Tue, May 14, 2013 at 08:51:08PM -0600, Alex Williamson wrote: > > On Wed, 2013-05-15 at 11:33 +1000, David Gibson wrote: > > > On Tue, May 14, 2013 at 11:15:26AM -0600, Alex Williamson wrote: > > > > On Tue, 2013-05-14 at 19:13 +1000, David Gibson wrote: [snip] > > Trying to make sure I understand why guest_iommus is a list. We can > > have multiple guest iommus, but in the majority of those cases I would > > expect only one iommu per VFIOAddressSpace. So if the listener is for > > this space, we only add the relevant iommu and not all of the iommus in > > the machine. >=20 > That's what we do - we only add notifiers for iommu regions that > appear within the relevant address space. It's a list because at > least theoretically there could be more than one iommu region in the > AS, although I don't know of any real cases where that would be true. >=20 >=20 > > Actually maybe two guest iommu ranges are common for spapr > > per space, a 32bit and a 64bit range? >=20 > I think 64-bit DMA windows on PAPR are usually just mapped to RAM with > a fixed offset, rather than having TCEs (page table). That might well > introduce some extra complexities in how we mirror that into VFIO, but > it's not directly relevant to this point. So, since I wrote that I've heard from Ben that while current machines don't have multiple (translated) iommu windows, this could well be found on future machines. --=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 --LZvS9be/3tNcYl/X Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iEYEARECAAYFAlGUgnsACgkQaILKxv3ab8amHgCeIpTxELs4rtDkc6z0hWg0SACn vt4AoIBAGGMeVyjbUPQdnYK4X2+2VvQK =34l5 -----END PGP SIGNATURE----- --LZvS9be/3tNcYl/X--