Re: [Qemu-devel] [PATCH 6/6] kvm: Fix dirty tracking with large kernel page size

[Andreas Färber]

Am 04.03.2012 12:53, schrieb Benjamin Herrenschmidt:
> On Sun, 2012-03-04 at 12:49 +0200, Avi Kivity wrote:
>> On 02/28/2012 11:48 PM, Benjamin Herrenschmidt wrote:
>>> On Tue, 2012-02-28 at 14:32 +0200, Avi Kivity wrote:
>>>
>>>> What if TARGET_PAGE_SIZE > getpagesize()?  Or is that impossible?
>>>
>>> We have yet to encounter such a case. It's not currently possible on
>>> power (some old embedded chips could do 1K and 2K page sizes in the TLB
>>> iirc but we never supported that in Linux and it's being phased out in
>>> HW).
>>>
>>> I suggest that gets dealt with when/if it needs to, which means probably
>>> never :-)
>>
>> Doesn't ppc support both 4k and 64k pages?  Suppose you run a 4k guest
>> on a 64k host?
>>
>> Maybe I'm misremembering or misunderstanding something.

> TARGET_PAGE_SIZE in qemu is always 4k for powerpc, it's a compile time
> #define.

Except for ppcemb-softmmu (1k), which is irrelevant for KVM AFAIU.

Maybe just add an assert and be done with it?

For the record, I am hoping to get rid of some of those cpu.h defines in
a later stage of QOM'ification.

Andreas

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