x86: Add conversion from a xen map to an mfn

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@lagarcavilla.org>
Signed-off-by: Tim Deegan <tim@xen.org>
Committed-by: Tim Deegan <tim@xen.org>

diff --git a/xen/arch/x86/x86_32/domain_page.c b/xen/arch/x86/x86_32/domain_page.c
index 4fb563d4f0fc0ba3a917c32eaf76be79f8cece8c..5e12aa7941055545289ee00d797e3bc72025ca23 100644 (file)
--- a/xen/arch/x86/x86_32/domain_page.c
+++ b/xen/arch/x86/x86_32/domain_page.c
@@ -265,3 +265,15 @@ void unmap_domain_page_global(const void *va)
     idx = (__va - IOREMAP_VIRT_START) >> PAGE_SHIFT;
     set_bit(idx, garbage);
 }
+
+/* Translate a map-domain-page'd address to the underlying MFN */
+unsigned long domain_page_map_to_mfn(void *va)
+{
+    l1_pgentry_t *l1e;
+
+    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);
+}

diff --git a/xen/include/xen/domain_page.h b/xen/include/xen/domain_page.h
index 95b939ff93aa60d520879717bb367d27e9db3bd3..a7df10b1ad93f860c732cf93d191687b110c7077 100644 (file)
--- a/xen/include/xen/domain_page.h
+++ b/xen/include/xen/domain_page.h
@@ -26,6 +26,12 @@ void *map_domain_page(unsigned long mfn);
  */
 void unmap_domain_page(const void *va);
 
+
+/* 
+ * Given a VA from map_domain_page(), return its underlying MFN.
+ */
+unsigned long domain_page_map_to_mfn(void *va);
+
 /*
  * Similar to the above calls, except the mapping is accessible in all
  * address spaces (not just within the VCPU that created the mapping). Global
@@ -102,6 +108,7 @@ domain_mmap_cache_destroy(struct domain_mmap_cache *cache)
 #define map_domain_page(mfn)                mfn_to_virt(mfn)
 #define __map_domain_page(pg)               page_to_virt(pg)
 #define unmap_domain_page(va)               ((void)(va))
+#define domain_page_map_to_mfn(va)          virt_to_mfn((unsigned long)(va))
 
 #define map_domain_page_global(mfn)         mfn_to_virt(mfn)
 #define __map_domain_page_global(pg)        page_to_virt(pg)