On 09/19/2011 06:35 PM, Alexander Graf wrote:
> + /*
> + * e500 doesn't implement the lowest tsize bit,
> + * or 1K pages.
> + */
> + tsize = max(BOOK3E_PAGESZ_4K, tsize & ~1);
> +
> + /* take the smallest page size that satisfies host and
> + guest mapping */
kernel comment style...
I don't personally care much, but this leaves a checkpatch complaint for
the next person to modify the comment. Such as to make it say "take the
largest page size that...". :-)
> + asm (PPC_CNTLZL "%0,%1" : "=r" (lz) : "r" (psize));
> + tsize = min(21 - lz, tsize);
No need to open-code the cntlz and subtract-from-21:
tsize = min(ilog2(psize) - 10, tsize);
/*
* e500 doesn't implement the lowest tsize bit,
* or 1K pages.
*/
tsize = max(BOOK3E_PAGESZ_4K, tsize & ~1);
There's still an open-coded subtraction of 10, but that relates more
straightforwardly to the definition of tsize (and could be factored out
into a size-to-tsize function).
> }
>
> up_read(¤t->mm->mmap_sem);
> }
>
> if (likely(!pfnmap)) {
> + unsigned long tsize_pages = 1 << (tsize - 2);
1 << (tsize + 10 - PAGE_SHIFT);
> pfn = gfn_to_pfn_memslot(vcpu_e500->vcpu.kvm, slot, gfn);
> + pfn &= ~(tsize_pages - 1);
> + gvaddr &= ~((tsize_pages << PAGE_SHIFT) - 1);
> if (is_error_pfn(pfn)) {
Won't the masking of pfn affect is_error_pfn()?
-Scott
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