[Xen-devel] [PATCH 1 of 3] x86: Add conversion from a xen map to an mfn

[Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>]

 xen/include/asm-x86/page.h        |  18 +++++++++++++++++-
 xen/include/asm-x86/x86_64/page.h |   5 +++++
 2 files changed, 22 insertions(+), 1 deletions(-)


This conversion is a trivial invocation of virt_to_mfn in 64 bits.
In 32 bits it uses the linear_map.

Signed-off-by: Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>

diff -r 36aac3e56d01 -r 7b6db593bda0 xen/include/asm-x86/page.h
--- a/xen/include/asm-x86/page.h
+++ b/xen/include/asm-x86/page.h
@@ -296,8 +296,22 @@ void copy_page_sse2(void *, const void *
 #define __linear_l4_table \
  ((l4_pgentry_t *)(__linear_l3_table + l3_linear_offset(LINEAR_PT_VIRT_START)))
 
+#ifndef __ASSEMBLY__
+#ifndef __x86_64__
+/* We need to stash this here for 32 bits as it depends on constructs
+ * defined after including x86_32/page.h */
+static inline unsigned long __xen_map_to_mfn(void *va)
+{
+    l1_pgentry_t *l1e;
 
-#ifndef __ASSEMBLY__
+    ASSERT( (((unsigned long) va) >= MAPCACHE_VIRT_START) &&
+            (((unsigned long) va) <= MAPCACHE_VIRT_END) );
+    l1e = &__linear_l1_table[
+            l1_linear_offset((unsigned long) va)];
+    return l1e_get_pfn(*l1e);
+}
+#endif /* __x86_64__ */
+
 extern root_pgentry_t idle_pg_table[ROOT_PAGETABLE_ENTRIES];
 #if CONFIG_PAGING_LEVELS == 3
 extern l2_pgentry_t   idle_pg_table_l2[
@@ -317,6 +331,8 @@ void paging_init(void);
 void setup_idle_pagetable(void);
 #endif /* !defined(__ASSEMBLY__) */
 
+#define xen_map_to_mfn(va)  __xen_map_to_mfn(va)
+
 #define _PAGE_PRESENT  0x001U
 #define _PAGE_RW       0x002U
 #define _PAGE_USER     0x004U
diff -r 36aac3e56d01 -r 7b6db593bda0 xen/include/asm-x86/x86_64/page.h
--- a/xen/include/asm-x86/x86_64/page.h
+++ b/xen/include/asm-x86/x86_64/page.h
@@ -104,6 +104,11 @@ static inline void *__maddr_to_virt(unsi
                      ((ma & ma_top_mask) >> pfn_pdx_hole_shift)));
 }
 
+static inline unsigned long __xen_map_to_mfn(void *va)
+{
+    return (__virt_to_maddr((unsigned long) va) >> PAGE_SHIFT);
+}
+
 /* read access (should only be used for debug printk's) */
 typedef u64 intpte_t;
 #define PRIpte "016lx"

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