From: Avi Kivity <avi@qumranet.com>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Ingo Molnar <mingo@elte.hu>,
Xen Devel <xen-devel@lists.xensource.com>,
Andi Kleen <andi@firstfloor.org>,
linux-kernel@vger.kernel.org, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [Xen-devel] Re: [PATCH 1 of 7] x86: add _PAGE_IOMAP pte flag for IO mappings
Date: Wed, 10 Sep 2008 12:55:25 +0300 [thread overview]
Message-ID: <48C7998D.1030408@qumranet.com> (raw)
In-Reply-To: <48C68EA3.4050508@qumranet.com>
Avi Kivity wrote:
>>
>> I'm not sure; I still don't really understand how _PAGE_SPECIAL gets
>> used, other than being user-mode mapping only. But in principle,
>> _PAGE_IOMAP could be set on both kernel and user mappings (if you direct
>> map a device into a process address space), so I think they would
>> conflict then?
>>
>>
>
> It's a "don't refcount me" flag, which is not sematically the same as
> I/O, but may be close enough.
Actually it's more of a "no struct page" flag, which implies no
refcounting. And not having a struct page should correspond well to a
pte not requiring pfn->mfn conversion and being an I/O page.
--
error compiling committee.c: too many arguments to function
WARNING: multiple messages have this Message-ID (diff)
From: Avi Kivity <avi@qumranet.com>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Ingo Molnar <mingo@elte.hu>,
Xen Devel <xen-devel@lists.xensource.com>,
Andi Kleen <andi@firstfloor.org>,
linux-kernel@vger.kernel.org, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: Re: [PATCH 1 of 7] x86: add _PAGE_IOMAP pte flag for IO mappings
Date: Wed, 10 Sep 2008 12:55:25 +0300 [thread overview]
Message-ID: <48C7998D.1030408@qumranet.com> (raw)
In-Reply-To: <48C68EA3.4050508@qumranet.com>
Avi Kivity wrote:
>>
>> I'm not sure; I still don't really understand how _PAGE_SPECIAL gets
>> used, other than being user-mode mapping only. But in principle,
>> _PAGE_IOMAP could be set on both kernel and user mappings (if you direct
>> map a device into a process address space), so I think they would
>> conflict then?
>>
>>
>
> It's a "don't refcount me" flag, which is not sematically the same as
> I/O, but may be close enough.
Actually it's more of a "no struct page" flag, which implies no
refcounting. And not having a struct page should correspond well to a
pte not requiring pfn->mfn conversion and being an I/O page.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2008-09-10 9:55 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-07 22:21 [PATCH 0 of 7] x86: lay groundwork for Xen domain 0 support Jeremy Fitzhardinge
2008-09-07 22:21 ` [PATCH 1 of 7] x86: add _PAGE_IOMAP pte flag for IO mappings Jeremy Fitzhardinge
2008-09-09 13:32 ` Avi Kivity
2008-09-09 13:32 ` Avi Kivity
2008-09-09 14:47 ` Jeremy Fitzhardinge
2008-09-09 14:47 ` Jeremy Fitzhardinge
2008-09-09 14:56 ` Avi Kivity
2008-09-09 14:56 ` Avi Kivity
2008-09-09 15:29 ` [Xen-devel] " Keir Fraser
2008-09-09 15:29 ` Keir Fraser
2008-09-09 15:48 ` [Xen-devel] " Jeremy Fitzhardinge
2008-09-09 15:48 ` Jeremy Fitzhardinge
2008-09-09 16:05 ` [Xen-devel] " Keir Fraser
2008-09-09 16:05 ` Keir Fraser
2008-09-10 9:55 ` Avi Kivity [this message]
2008-09-10 9:55 ` Avi Kivity
2008-09-10 16:38 ` [Xen-devel] " Jeremy Fitzhardinge
2008-09-10 16:38 ` Jeremy Fitzhardinge
2008-09-10 16:55 ` [Xen-devel] " Nick Piggin
2008-09-10 17:27 ` Jeremy Fitzhardinge
2008-09-07 22:21 ` [PATCH 2 of 7] x86: remove duplicate early_ioremap declarations Jeremy Fitzhardinge
2008-09-07 22:21 ` Jeremy Fitzhardinge
2008-09-07 22:21 ` [PATCH 3 of 7] x86: add early_memremap() Jeremy Fitzhardinge
2008-09-07 22:21 ` Jeremy Fitzhardinge
2008-09-07 22:21 ` [PATCH 4 of 7] x86: use early_memremap() in setup.c Jeremy Fitzhardinge
2008-09-07 22:21 ` [PATCH 5 of 7] x86-64: don't check for map replacement Jeremy Fitzhardinge
2008-09-07 22:21 ` [PATCH 6 of 7] x86: use early_ioremap in __acpi_map_table Jeremy Fitzhardinge
2008-09-07 23:44 ` Andi Kleen
2008-09-08 0:03 ` Jeremy Fitzhardinge
2008-09-08 0:03 ` Jeremy Fitzhardinge
2008-09-08 14:26 ` Ingo Molnar
2008-09-08 14:26 ` Ingo Molnar
2008-09-08 16:29 ` Jeremy Fitzhardinge
2008-09-08 16:29 ` Jeremy Fitzhardinge
2008-09-08 19:41 ` Jeremy Fitzhardinge
2008-09-08 19:41 ` Jeremy Fitzhardinge
2008-09-10 11:55 ` Ingo Molnar
2008-09-10 16:49 ` Jeremy Fitzhardinge
2008-09-11 7:33 ` Ingo Molnar
2008-09-11 18:36 ` Jeremy Fitzhardinge
2008-09-11 18:56 ` Ingo Molnar
2008-09-11 20:34 ` Yinghai Lu
2008-09-11 21:07 ` Jeremy Fitzhardinge
2008-09-12 9:49 ` Ingo Molnar
2008-09-12 17:31 ` Yinghai Lu
[not found] ` <20080911125748.GA14698@elte.hu>
2008-09-11 21:33 ` [PATCH] acpi: remove final __acpi_map_table mapping before setting acpi_gbl_permanent_mmap Jeremy Fitzhardinge
2008-09-07 22:21 ` [PATCH 7 of 7] x86: always explicitly map acpi memory Jeremy Fitzhardinge
2008-09-07 23:35 ` [Xen-devel] " Yinghai Lu
2008-09-07 23:35 ` Yinghai Lu
2008-09-08 0:02 ` [Xen-devel] " Jeremy Fitzhardinge
2008-09-08 0:02 ` Jeremy Fitzhardinge
2008-09-08 0:14 ` [Xen-devel] " Yinghai Lu
2008-09-08 0:14 ` Yinghai Lu
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