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Re: [Qemu-devel] [RFC] Memory API
From: |
Jan Kiszka |
Subject: |
Re: [Qemu-devel] [RFC] Memory API |
Date: |
Thu, 19 May 2011 15:55:04 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
On 2011-05-19 15:50, Anthony Liguori wrote:
> On 05/19/2011 08:47 AM, Jan Kiszka wrote:
>> On 2011-05-19 15:44, Anthony Liguori wrote:
>>> Well......
>>>
>>> The i440fx may direct VGA accesses to RAM depending on the SMM
>>> registers. By the time the PIIX gets the I/O request, we're past the
>>> memory controller.
>>>
>>> This is my biggest concern about this whole notion of "priority". These
>>> sort of issues are not dealt with by a simple z-ordering. There is
>>> logic in each component that may be arbitrarily complex.
>>>
>>> We're going to end up having to dynamically change the "priority" based
>>> how registers are programmed. But priorities are relative so it's
>>> unclear to me how the I440FX would prioritize RAM over dispatch to PIIX
>>> (for VGA, for instance).
>>
>> But creating an extra RAM window region with higher priority than the
>> underlying mappings.
>
> But the i440fx doesn't register the VGA region. The PIIX3 (ISA bus)
> does, so how does it know what the priority of that mapping is?
Everything imported from "below" is of default priority for a bridge. So
it just has to add 1 to that prio value (or more if it needs to support
more layers).
Jan
--
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux
- Re: [Qemu-devel] [RFC] Memory API, (continued)
- Re: [Qemu-devel] [RFC] Memory API, Avi Kivity, 2011/05/20
- Re: [Qemu-devel] [RFC] Memory API, Avi Kivity, 2011/05/20
- Re: [Qemu-devel] [RFC] Memory API, Anthony Liguori, 2011/05/20
- Re: [Qemu-devel] [RFC] Memory API, Jan Kiszka, 2011/05/20
- Re: [Qemu-devel] [RFC] Memory API, Avi Kivity, 2011/05/22
- Re: [Qemu-devel] [RFC] Memory API, Anthony Liguori, 2011/05/22
- Re: [Qemu-devel] [RFC] Memory API, Avi Kivity, 2011/05/19
- Re: [Qemu-devel] [RFC] Memory API, Anthony Liguori, 2011/05/19
- Re: [Qemu-devel] [RFC] Memory API, Jan Kiszka, 2011/05/19
- Re: [Qemu-devel] [RFC] Memory API, Anthony Liguori, 2011/05/19
- Re: [Qemu-devel] [RFC] Memory API,
Jan Kiszka <=
- Re: [Qemu-devel] [RFC] Memory API, Avi Kivity, 2011/05/19
- Re: [Qemu-devel] [RFC] Memory API, Anthony Liguori, 2011/05/19
- Re: [Qemu-devel] [RFC] Memory API, Jan Kiszka, 2011/05/19
- Re: [Qemu-devel] [RFC] Memory API, Avi Kivity, 2011/05/19
- Re: [Qemu-devel] [RFC] Memory API, Edgar E. Iglesias, 2011/05/19
- Re: [Qemu-devel] [RFC] Memory API, Peter Maydell, 2011/05/19
- Re: [Qemu-devel] [RFC] Memory API, Anthony Liguori, 2011/05/18
- Re: [Qemu-devel] [RFC] Memory API, Avi Kivity, 2011/05/18
- Re: [Qemu-devel] [RFC] Memory API, Anthony Liguori, 2011/05/18
- Re: [Qemu-devel] [RFC] Memory API, Avi Kivity, 2011/05/18