RE: [Xen-ia64-devel] Problem with xen-unstable cset 7937 (grant tabletransfer fix)

["Magenheimer, Dan (HP Labs Fort Collins)" <dan.magenheimer@xxxxxx>]

> No patch!

Oops!  Attached is the whole file which, since this isn't proposed
as a patch to apply yet, might be easier to peruse.

The only changes are the addition of __ia64__ conditional
compile directives.

Dan

> -----Original Message-----
> From: Keir Fraser [mailto:Keir.Fraser@xxxxxxxxxxxx] 
> Sent: Monday, November 21, 2005 10:57 PM
> To: Magenheimer, Dan (HP Labs Fort Collins)
> Cc: xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [Xen-ia64-devel] Problem with xen-unstable cset 
> 7937 (grant tabletransfer fix)
> 
> 
> On 22 Nov 2005, at 00:46, Magenheimer, Dan (HP Labs Fort 
> Collins) wrote:
> 
> > Keir, could you translate the asm statement in gnttab_transfer
> > into a cmpxchg (see include/asm-x86/system.h)?  Or is it doing
> > something that the macros can't do?
> 
> Yes, it can be. The cmpxchg is relying on count_info and 
> domain fields 
> being adjacent, by the way. And the construction of old/new values to 
> pass to cmpxchg is specific to little endian systems. It 
> might be best 
> to define an arch-specific function for atomically stealing a 
> page from 
> a domain, although we might get away with defining a 
> endian-aware macro 
> for concatenating two u32's into a u64, and turning cmpxchg8b into 
> cmpxchg().
> 
> > Also, I've attached a patch that shows the differences between
> > the x86 and ia64 versions.  If you think it would be possible
> > to merge most of these differences (and/or incorporate a
> > small number of ifdefs into common/grant_table.c), that
> > would be very helpful.
> 
> No patch!
> 
>   -- Keir
> 
>

grant_table.c
Description: grant_table.c

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