Re: [PATCH] Don't assume struct page for x86 MMU

[Avi Kivity <avi@qumranet.com>]

Anthony Liguori wrote:
> This patch introduces a gfn_to_pfn() function and corresponding functions like
> kvm_release_pfn_dirty().  Using these new functions, we can modify the x86
> MMU to no longer assume that it can always get a struct page for any given gfn.
>
> We don't want to eliminate gfn_to_page() entirely because a number of places
> assume they can do gfn_to_page() and then kmap() the results.  When we support
> IO memory, gfn_to_page() will fail for IO pages although gfn_to_pfn() will
> succeed.
>
> This does not implement support for avoiding reference counting for reserved
> RAM or for IO memory.  However, it should make those things pretty straight
> forward.
>
> Since we're only introducing new common symbols, I don't think it will break
> the non-x86 architectures but I haven't tested those.  I've tested Intel,
> AMD, NPT, and hugetlbfs with Windows and Linux guests.
>
>   

Applied, thanks.

> @ -1089,7 +1086,7 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
>  	if (largepage)
>  		spte |= PT_PAGE_SIZE_MASK;
>  
> -	spte |= page_to_phys(page);
> +	spte |= (pfn << PAGE_SHIFT);
>   

This overflows on i386 with >=4GB RAM.  I fixed it before committing.


-- 
error compiling committee.c: too many arguments to function


-------------------------------------------------------------------------
This SF.net email is sponsored by the 2008 JavaOne(SM) Conference 
Register now and save $200. Hurry, offer ends at 11:59 p.m., 
Monday, April 7! Use priority code J8TLD2. 
http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone