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Re: [Qemu-ppc] [PATCH 6/8] target-ppc: Rework get_physical_address()
From: |
Alexander Graf |
Subject: |
Re: [Qemu-ppc] [PATCH 6/8] target-ppc: Rework get_physical_address() |
Date: |
Sat, 23 Feb 2013 13:21:19 +0100 |
On 23.02.2013, at 12:56, David Gibson wrote:
> On Sat, Feb 23, 2013 at 11:38:23AM +0100, Alexander Graf wrote:
>>
>>
>> Am 23.02.2013 um 07:28 schrieb David Gibson <address@hidden>:
>>
>>> On Fri, Feb 22, 2013 at 05:06:52PM +0100, Alexander Graf wrote:
>>>>
>>>> On 12.02.2013, at 03:00, David Gibson wrote:
>>>>
>>>>> Currently get_physical_address() first checks to see if translation is
>>>>> enabled in the MSR, then in the translation on case switches on the mmu
>>>>> type. Except that for BookE MMUs, translation is always on, and so it
>>>>> has to switch in the "translation off" case as well and do the same thing
>>>>> as the translation on path for those MMUs. Plus, even translation off
>>>>> doesn't behave exactly the same on the various MMU types so there are
>>>>> further mmu type checks in the "translation off" path.
>>>>>
>>>>> As a first step to cleaning this up, this patch moves the switch on mmu
>>>>> type to the top level, then makes the translation on/off check just for
>>>>> those mmu types where it is meaningful.
>>>>
>>>> Eventually the mmu translation should just be a class dispatched
>>>> indirect function call. I don't think it's within the scope of this
>>>> first round of cleanup though.
>>>
>>> I agree. My plan was to first push the switching all up to the top
>>> level as I've done, then replace that with a method dispatch
>>> afterwards.
>>
>> If you're convinced the path you're taking is already correct, don't
>> post patches as RFC :).
>
> Well, I'm not sure about all of it.
>
> More to the point, I'm really not sure what you're suggesting I do
> differently. We can't switch to a method invocation when there are
> mmu type dependencies scattered all through the path. So that change
> more or less has to go after what I have already.
I never disagreed. I think your patches are fine, nothing really needs to be
done differently. I just don't want the conversion to be done half-way.
I can understand if you don't feel comfortable not converting non-book3s mmus,
but I want to have it done at least completely for all book3s ones then. I'm
not a big fan of aborting a race right before the goal :)
Alex
[Qemu-ppc] [PATCH 2/8] target-ppc: Move SLB handling into a mmu-hash64.c, David Gibson, 2013/02/11
[Qemu-ppc] [PATCH 4/8] target-ppc: Disentangle 64-bit version of find_pte(), David Gibson, 2013/02/11
Re: [Qemu-ppc] [Qemu-devel] [0/8] RFC: target-ppc: Start disentangling different MMU types, Andreas Färber, 2013/02/12
Re: [Qemu-ppc] [0/8] RFC: target-ppc: Start disentangling different MMU types, Alexander Graf, 2013/02/22