@@ -204,6 +204,37 @@ static void p2m_flush_tlb_sync(struct p2m_domain *p2m)
}
/*
+ * Find and map the root page table. The caller is responsible for
+ * unmapping the table.
+ *
+ * The function will return NULL if the offset of the root table is
+ * invalid.
+ */
+static lpae_t *p2m_get_root_pointer(struct p2m_domain *p2m,
+ gfn_t gfn)
+{
+ unsigned int root_table;
+
+ if ( P2M_ROOT_PAGES == 1 )
+ return __map_domain_page(p2m->root);
+
+ /*
+ * Concatenated root-level tables. The table number will be the
+ * offset at the previous level. It is not possible to
+ * concatenate a level-0 root.
+ */
+ ASSERT(P2M_ROOT_LEVEL > 0);
+
+ root_table = gfn_x(gfn) >> (level_shifts[P2M_ROOT_LEVEL - 1] - PAGE_SHIFT);
+ root_table &= LPAE_ENTRY_MASK;
+
+ if ( root_table >= P2M_ROOT_PAGES )
+ return NULL;
+
+ return __map_domain_page(p2m->root + root_table);
+}
+
+/*
* Lookup the MFN corresponding to a domain's GFN.
*
* There are no processor functions to do a stage 2 only lookup therefore we
@@ -226,7 +257,7 @@ static mfn_t __p2m_lookup(struct domain *d, gfn_t gfn, p2m_type_t *t)
mfn_t mfn = INVALID_MFN;
paddr_t mask = 0;
p2m_type_t _t;
- unsigned int level, root_table;
+ unsigned int level;
ASSERT(p2m_is_locked(p2m));
BUILD_BUG_ON(THIRD_MASK != PAGE_MASK);
@@ -236,22 +267,9 @@ static mfn_t __p2m_lookup(struct domain *d, gfn_t gfn, p2m_type_t *t)
*t = p2m_invalid;
- if ( P2M_ROOT_PAGES > 1 )
- {
- /*
- * Concatenated root-level tables. The table number will be
- * the offset at the previous level. It is not possible to
- * concatenate a level-0 root.
- */
- ASSERT(P2M_ROOT_LEVEL > 0);
- root_table = offsets[P2M_ROOT_LEVEL - 1];
- if ( root_table >= P2M_ROOT_PAGES )
- goto err;
- }
- else
- root_table = 0;
-
- map = __map_domain_page(p2m->root + root_table);
+ map = p2m_get_root_pointer(p2m, gfn);
+ if ( !map )
+ return INVALID_MFN;
ASSERT(P2M_ROOT_LEVEL < 4);
@@ -286,7 +304,6 @@ static mfn_t __p2m_lookup(struct domain *d, gfn_t gfn, p2m_type_t *t)
*t = pte.p2m.type;
}
-err:
return mfn;
}
Mapping the root table is always done the same way. To avoid duplicating the code in a later patch, move the code in a separate helper. Signed-off-by: Julien Grall <julien.grall@arm.com> --- xen/arch/arm/p2m.c | 53 +++++++++++++++++++++++++++++++++++------------------ 1 file changed, 35 insertions(+), 18 deletions(-)