From: "H. Peter Anvin" <hpa@zytor.com>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: the arch/x86 maintainers <x86@kernel.org>,
"Xen-devel@lists.xensource.com" <Xen-devel@lists.xensource.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: [PATCH] x86: define arch_vm_get_page_prot to set _PAGE_IOMAP on VM_IO vmas
Date: Thu, 21 Oct 2010 15:47:52 -0700 [thread overview]
Message-ID: <4CC0C318.90401@zytor.com> (raw)
In-Reply-To: <4CC0C14E.5080205@goop.org>
On 10/21/2010 03:40 PM, Jeremy Fitzhardinge wrote:
>
> Set _PAGE_IOMAP in ptes mapping a VM_IO vma. This says that the mapping
> is of a real piece of physical hardware, and not just system memory.
>
> Xen, in particular, uses to this to inhibit the normal pfn->mfn conversion
> that would normally happen - in other words, treat the address directly
> as a machine physical address without converting it from pseudo-physical.
>
> [ Impact: make VM_IO mappings map the right thing under Xen ]
>
> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
>
Am I the only one who thinks this seems extremely odd that the guest is
trusted to make this distinction?
-hpa
next prev parent reply other threads:[~2010-10-21 22:48 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-21 22:40 [PATCH] x86: define arch_vm_get_page_prot to set _PAGE_IOMAP on VM_IO vmas Jeremy Fitzhardinge
2010-10-21 22:47 ` H. Peter Anvin [this message]
2010-10-21 23:17 ` Jeremy Fitzhardinge
2010-10-22 0:45 ` H. Peter Anvin
2010-10-22 15:08 ` Konrad Rzeszutek Wilk
2010-10-22 16:44 ` H. Peter Anvin
2010-10-22 18:02 ` Konrad Rzeszutek Wilk
2010-10-22 18:05 ` Konrad Rzeszutek Wilk
2010-10-22 19:06 ` H. Peter Anvin
2010-10-22 19:11 ` [Xen-devel] " Konrad Rzeszutek Wilk
2010-10-22 19:06 ` Jeremy Fitzhardinge
2010-10-22 19:20 ` H. Peter Anvin
2010-10-22 19:36 ` Jeremy Fitzhardinge
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