Re: [Xen-devel] [PATCH v5 10/16] xen/mm: Switch map_pages_to_xen to use MFN typesafe

[Julien Grall <julien.grall@xxxxxxx>]

Hi George,

On 15/03/18 16:50, George Dunlap wrote:
> On 03/14/2018 06:20 PM, julien.grall@xxxxxxx wrote:
> > diff --git a/xen/common/vmap.c b/xen/common/vmap.c
> > index 11785ffb0a..04f5db386d 100644
> > --- a/xen/common/vmap.c
> > +++ b/xen/common/vmap.c
> > @@ -9,6 +9,10 @@
> >   #include <xen/vmap.h>
> >   #include <asm/page.h>
> >   
> > +/* Override macros from asm/page.h to make them work with mfn_t */
> > +#undef page_to_mfn
> > +#define page_to_mfn(pg) _mfn(__page_to_mfn(pg))
> > +
> >   static DEFINE_SPINLOCK(vm_lock);
> >   static void *__read_mostly vm_base[VMAP_REGION_NR];
> >   #define vm_bitmap(x) ((unsigned long *)vm_base[x])
> > @@ -208,7 +212,7 @@ void *__vmap(const mfn_t *mfn, unsigned int granularity,
> >   
> >       for ( ; va && nr--; ++mfn, cur += PAGE_SIZE * granularity )
> >       {
> > -        if ( map_pages_to_xen(cur, mfn_x(*mfn), granularity, flags) )
> > +        if ( map_pages_to_xen(cur, *mfn, granularity, flags) )
> >           {
> >               vunmap(va);
> >               va = NULL;
> > @@ -234,7 +238,7 @@ void vunmap(const void *va)
> >   #ifndef _PAGE_NONE
> >       destroy_xen_mappings(addr, addr + PAGE_SIZE * pages);
> >   #else /* Avoid tearing down intermediate page tables. */
> > -    map_pages_to_xen(addr, 0, pages, _PAGE_NONE);
> > +    map_pages_to_xen(addr, INVALID_MFN, pages, _PAGE_NONE);
> This is a bit of a nit-pick, but shouldn't something like this have gone
> in patch 8?
patch #8 is about removing a parameter of populate_pt_range. At the same 
time, 0 is replaced by mfn_x(INVALID_MFN) for that specific use case.
It was not intended to replace all the user of map_pages_to_xen with 0 
to mfn_x(INVALID_MFN). This is done here as the caller is modified.
Cheers,

--
Julien Grall

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