xen/arm: p2m: Clean-up mfn_to_p2m_entry

The physical address is computed from the machine frame number, so
checking if the physical address is page aligned is pointless.

Furthermore, directly assigned the MFN to the corresponding field in the
entry rather than converting to a physical address and orring the value.
It will avoid to rely on the field position and make the code clearer.

Signed-off-by: Julien Grall <julien.grall@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 79095f1d6f79b27db93922366c971070288e5a29..d82349c1669e2f765b43d83dbb333ff1444e475f 100644 (file)
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -327,7 +327,6 @@ static void p2m_set_permission(lpae_t *e, p2m_type_t t, p2m_access_t a)
 static lpae_t mfn_to_p2m_entry(unsigned long mfn, unsigned int mattr,
                                p2m_type_t t, p2m_access_t a)
 {
-    paddr_t pa = ((paddr_t) mfn) << PAGE_SHIFT;
     /*
      * sh, xn and write bit will be defined in the following switches
      * based on mattr and t.
@@ -359,10 +358,9 @@ static lpae_t mfn_to_p2m_entry(unsigned long mfn, unsigned int mattr,
 
     p2m_set_permission(&e, t, a);
 
-    ASSERT(!(pa & ~PAGE_MASK));
-    ASSERT(!(pa & ~PADDR_MASK));
+    ASSERT(!(pfn_to_paddr(mfn) & ~PADDR_MASK));
 
-    e.bits |= pa;
+    e.p2m.base = mfn;
 
     return e;
 }