arm/xen: implement correctly pfn_to_mfn
After the commit introducing convertion between DMA and guest 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 pratice, I haven't seen
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 <julien.grall@citrix.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h
index 5f76a9e..911d62b 100644
--- a/arch/arm/include/asm/xen/page.h
+++ b/arch/arm/include/asm/xen/page.h
@@ -36,14 +36,6 @@
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;
}
