From: Benjamin Herrenschmidt <benh@kernel.crashing.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: Tue, 04 Aug 2015 08:10:38 +1000 [thread overview]
Message-ID: <1438639838.14073.116.camel@kernel.crashing.org> (raw)
In-Reply-To: <1438627862.26511.366.camel@infradead.org>
On Mon, 2015-08-03 at 19:51 +0100, David Woodhouse wrote:
> In PCIe we have 20 bits of PASID. And we are going to expect hardware
> to implement them all, even if it can only do caching for fewer PASIDs
> than that.
>
> There is also an expectation that a given MM will have the *same*
> PASID across all devices.
Unless you already have a TLB-coherent fabric keyed on a LPID/PID whose
capacity overall is larger than your 20-bit PASID. In that case your
IOMMU have remapping facilities between PASIDs and LPID/PID which could
in theory provide a different mapping for devices...
Cheers,
Ben.
next prev parent reply other threads:[~2015-08-03 22:11 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-30 13:00 [Ksummit-discuss] [CORE TOPIC] Core Kernel support for Compute-Offload Devices 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
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 [this message]
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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