From: "David S. Miller" <davem@redhat.com>
To: James Bottomley <James.Bottomley@steeleye.com>
Cc: linux-arch@vger.kernel.org
Subject: Re: Accessing memory remote across the bus in the same way as local memory
Date: Fri, 18 Jun 2004 16:32:43 -0700 [thread overview]
Message-ID: <20040618163243.26d9fcb3.davem@redhat.com> (raw)
In-Reply-To: <1087601198.2134.206.camel@mulgrave>
On 18 Jun 2004 18:26:37 -0500
James Bottomley <James.Bottomley@SteelEye.com> wrote:
> The question is given the constraints, can we pull page table tricks on
> every platform to make this bus remote memory look like real memory?
There are three issues:
1) How to form the physical address (for a PCI device we have PCI device
pointer and resource, stuff like that, we just need a translator
interface or similar to pass that info in)
2) Whether such accesses are legal. On Sparc64 one device cannot DMA
to/from the MMIO of a device behind a _DIFFERENT_ PCI controller.
3) Some logic to get page table non-cacheable bits set etc. since this
is to non-memory space.
next prev parent reply other threads:[~2004-06-18 23:33 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-06-18 23:26 Accessing memory remote across the bus in the same way as local memory James Bottomley
2004-06-18 23:32 ` David S. Miller [this message]
2004-06-18 23:43 ` James Bottomley
2004-06-19 4:05 ` Paul Mackerras
2004-06-19 14:02 ` James Bottomley
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