From: Joerg Roedel <joro@8bytes.org>
To: David Woodhouse <dwmw2@infradead.org>
Cc: Jerome Glisse <jglisse@redhat.com>,
ksummit-discuss@lists.linuxfoundation.org
Subject: Re: [Ksummit-discuss] [CORE TOPIC] Core Kernel support for Compute-Offload Devices
Date: Mon, 3 Aug 2015 23:31:20 +0200 [thread overview]
Message-ID: <20150803213120.GN14980@8bytes.org> (raw)
In-Reply-To: <1438636374.26511.440.camel@infradead.org>
On Mon, Aug 03, 2015 at 10:12:54PM +0100, David Woodhouse wrote:
> On Mon, 2015-08-03 at 23:10 +0200, Joerg Roedel wrote:
> > AMD hardware currently implements PASIDs with 16 bits. Given that only
> > mm_structs which are used by offload devices get one, this should be
> > enough to put them into a global pool and have one PASID per mm_struct.
>
> I think there are many ARM systems which need this model because of the
> way TLB shootdowns are handled in hardware, and shared with the IOMMU?
> So we have to use the same ASID for both MMU and IOMMU there, AIUI.
Yes, I heard the same, this hardware clearly forces the one-PASID per
mm_struct model.
On x86 we probably have to look what offload devices will appear, the
ones currently available support 16 bits, which this allows the same model.
Joerg
next prev parent reply other threads:[~2015-08-03 21:31 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-30 13:00 Joerg Roedel
2015-07-30 13:31 ` David Woodhouse
2015-07-30 13:54 ` Joerg Roedel
2015-07-31 16:34 ` Jerome Glisse
2015-08-03 18:51 ` David Woodhouse
2015-08-03 19:01 ` Jerome Glisse
2015-08-03 19:07 ` Andy Lutomirski
2015-08-03 19:56 ` Jerome Glisse
2015-08-03 21:10 ` Joerg Roedel
2015-08-03 21:12 ` David Woodhouse
2015-08-03 21:31 ` Joerg Roedel [this message]
2015-08-03 21:34 ` Jerome Glisse
2015-08-03 21:51 ` David Woodhouse
2015-08-04 18:11 ` Catalin Marinas
2015-08-03 22:10 ` Benjamin Herrenschmidt
2015-07-30 22:32 ` Benjamin Herrenschmidt
2015-08-01 16:10 ` Joerg Roedel
2015-07-31 14:52 ` Rik van Riel
2015-07-31 16:13 ` Jerome Glisse
2015-08-01 15:57 ` Joerg Roedel
2015-08-01 19:08 ` Jerome Glisse
2015-08-03 16:02 ` Joerg Roedel
2015-08-03 18:28 ` Jerome Glisse
2015-08-01 20:46 ` Arnd Bergmann
2015-08-03 16:10 ` Joerg Roedel
2015-08-03 19:23 ` Arnd Bergmann
2015-08-04 15:40 ` Christoph Lameter
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