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SubjectRe: [PATCH] kvm mmu: reduce 50% memory usage
On 04/30/2010 11:54 AM, Lai Jiangshan wrote:
> Avi Kivity wrote:
>
>> On 04/30/2010 05:25 AM, Lai Jiangshan wrote:
>>
>>>
>>>> It's unrelated to TDP, same issue with shadow. I think the calculation
>>>> is correct. For example the 4th spte for a level=2 page will yield
>>>> gfn=4*512.
>>>>
>>>>
>>> Avi, Marcelo
>>> Thank you very much.
>>>
>>> The calculation I used is correct.
>>>
>>>
>> Yes. btw, can you update the patch to also correct mmu.txt?
>>
> The corresponding content in mmu.txt are:
> role.direct:
> If set, leaf sptes reachable from this page are for a linear range.
> Examples include real mode translation, large guest pages backed by small
> host pages, and gpa->hpa translations when NPT or EPT is active.
> The linear range starts at (gfn<< PAGE_SHIFT) and its size is determined
> by role.level (2MB for first level, 1GB for second level, 0.5TB for third
> level, 256TB for fourth level)
> If clear, this page corresponds to a guest page table denoted by the gfn
> field.
>
> gfn:
> Either the guest page table containing the translations shadowed by this
> page, or the base page frame for linear translations. See role.direct.
>
> These are correct. My patch is fully base on this document.
> I think it is not need to be fixed.
>
> Did I miss something?
>
>

sp->gfns can now be NULL, so the documentation of this field needs to be
updated.

--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.



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