On Tue, 4 Aug 2015, Julien Grall wrote:
> After the commit introducing convertion between DMA and guest address,
^ addresses
> all the callers of pfn_to_mfn are expecting to get a GFN (Guest Frame
> Number). On ARM, all the guests are auto-translated so the GFN is equal
> to the Linux PFN (Pseudo-physical Frame Number).
>
> The current implementation may return an MFN if the caller is passing a
> PFN associated to a mapped foreign grant. In pratical, I haven't seen
^ practice
> the problem on running guest but we should fix it for the sake of
> correctness.
>
> Correct the implementation by always returning the pfn passed in parameter.
>
> A follow-up patch will take care to rename pfn_to_mfn to a suitable
> name.
>
> Signed-off-by: Julien Grall <[email protected]>
> Cc: Stefano Stabellini <[email protected]>
> Cc: Russell King <[email protected]>
> Cc: [email protected]
Reviewed-by: Stefano Stabellini <[email protected]>
> arch/arm/include/asm/xen/page.h | 8 --------
> 1 file changed, 8 deletions(-)
>
> diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h
> index bc5e77c..087d86e 100644
> --- a/arch/arm/include/asm/xen/page.h
> +++ b/arch/arm/include/asm/xen/page.h
> @@ -36,14 +36,6 @@ extern struct rb_root phys_to_mach;
>
> static inline unsigned long pfn_to_mfn(unsigned long pfn)
> {
> - unsigned long mfn;
> -
> - if (phys_to_mach.rb_node != NULL) {
> - mfn = __pfn_to_mfn(pfn);
> - if (mfn != INVALID_P2M_ENTRY)
> - return mfn;
> - }
> -
> return pfn;
> }
>
> --
> 2.1.4
>
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