RE: [PATCH] qemu: define and use VIRTIO_PFN_SHIFT

Hollis Blanchard wrote:
> On Thursday 06 November 2008 19:38:40 Zhang, Xiantao wrote:
>> 
>> Hi, Hollis
>> 	Currenlty, kvm-qemu only supports the only case which is host
>> page_size = 
> qemu's target page size for ia64. Does your patch meets the
> requirement ? For ia64, current linux support 4K, 16K and 64k page
> size, and 1M 16M 64M or bigger page will be supported in future, so
> if your patch consider the case, it should work for ia64.  Thanks!
> 
> Take a look at the patch and you tell me. :) I've hardcoded the PFN
> shift as 16, which matches your TARGET_PAGE_BITS, but does it *have*
> to be the same? I don't believe it does.
> Out of curiosity, if you had 4K Linux host pages, and you redefined
> TARGET_PAGE_BITS to be 12, would everything just work?

Yes, if the host linux use 4K page size, we should define TARGET_PAGE_BITS to 12 when compiling qemu. 

> Also, as long as I have you... can we use getpagesize() instead of
> 65536/4096 in qemu_vmalloc()?

We tried it at early stage, seems it can't work, because current code very depens on TARGET_PAGE_BITS. 
Xiantao