1 files changed, 44 insertions, 38 deletions

diff --git a/system/physmem.c b/system/physmem.c
index 6dc58b34bb..d3a3d8a45c 100644
--- a/system/physmem.c
+++ b/system/physmem.c
@@ -31,6 +31,7 @@
 #endif /* CONFIG_TCG */
 
 #include "exec/exec-all.h"
+#include "exec/page-protection.h"
 #include "exec/target_page.h"
 #include "hw/qdev-core.h"
 #include "hw/qdev-properties.h"
@@ -2188,43 +2189,28 @@ void qemu_ram_remap(ram_addr_t addr, ram_addr_t length)
 }
 #endif /* !_WIN32 */
 
-/* Return a host pointer to ram allocated with qemu_ram_alloc.
- * This should not be used for general purpose DMA.  Use address_space_map
- * or address_space_rw instead. For local memory (e.g. video ram) that the
- * device owns, use memory_region_get_ram_ptr.
+/*
+ * Return a host pointer to guest's ram.
+ * For Xen, foreign mappings get created if they don't already exist.
  *
- * Called within RCU critical section.
- */
-void *qemu_map_ram_ptr(RAMBlock *block, ram_addr_t addr)
-{
-    if (block == NULL) {
-        block = qemu_get_ram_block(addr);
-        addr -= block->offset;
-    }
-
-    if (xen_enabled() && block->host == NULL) {
-        /* We need to check if the requested address is in the RAM
-         * because we don't want to map the entire memory in QEMU.
-         * In that case just map until the end of the page.
-         */
-        if (block->offset == 0) {
-            return xen_map_cache(addr, 0, 0, false);
-        }
-
-        block->host = xen_map_cache(block->offset, block->max_length, 1, false);
-    }
-    return ramblock_ptr(block, addr);
-}
-
-/* Return a host pointer to guest's ram. Similar to qemu_map_ram_ptr
- * but takes a size argument.
+ * @block: block for the RAM to lookup (optional and may be NULL).
+ * @addr: address within the memory region.
+ * @size: pointer to requested size (optional and may be NULL).
+ *        size may get modified and return a value smaller than
+ *        what was requested.
+ * @lock: wether to lock the mapping in xen-mapcache until invalidated.
+ * @is_write: hint wether to map RW or RO in the xen-mapcache.
+ *            (optional and may always be set to true).
  *
  * Called within RCU critical section.
  */
 static void *qemu_ram_ptr_length(RAMBlock *block, ram_addr_t addr,
-                                 hwaddr *size, bool lock)
+                                 hwaddr *size, bool lock,
+                                 bool is_write)
 {
-    if (*size == 0) {
+    hwaddr len = 0;
+
+    if (size && *size == 0) {
         return NULL;
     }
 
@@ -2232,7 +2218,10 @@ static void *qemu_ram_ptr_length(RAMBlock *block, ram_addr_t addr,
         block = qemu_get_ram_block(addr);
         addr -= block->offset;
     }
-    *size = MIN(*size, block->max_length - addr);
+    if (size) {
+        *size = MIN(*size, block->max_length - addr);
+        len = *size;
+    }
 
     if (xen_enabled() && block->host == NULL) {
         /* We need to check if the requested address is in the RAM
@@ -2240,15 +2229,31 @@ static void *qemu_ram_ptr_length(RAMBlock *block, ram_addr_t addr,
          * In that case just map the requested area.
          */
         if (block->offset == 0) {
-            return xen_map_cache(addr, *size, lock, lock);
+            return xen_map_cache(block->mr, addr, len, lock, lock,
+                                 is_write);
         }
 
-        block->host = xen_map_cache(block->offset, block->max_length, 1, lock);
+        block->host = xen_map_cache(block->mr, block->offset,
+                                    block->max_length, 1,
+                                    lock, is_write);
     }
 
     return ramblock_ptr(block, addr);
 }
 
+/*
+ * Return a host pointer to ram allocated with qemu_ram_alloc.
+ * This should not be used for general purpose DMA.  Use address_space_map
+ * or address_space_rw instead. For local memory (e.g. video ram) that the
+ * device owns, use memory_region_get_ram_ptr.
+ *
+ * Called within RCU critical section.
+ */
+void *qemu_map_ram_ptr(RAMBlock *ram_block, ram_addr_t addr)
+{
+    return qemu_ram_ptr_length(ram_block, addr, NULL, false, true);
+}
+
 /* Return the offset of a hostpointer within a ramblock */
 ram_addr_t qemu_ram_block_host_offset(RAMBlock *rb, void *host)
 {
@@ -2756,7 +2761,7 @@ static MemTxResult flatview_write_continue_step(MemTxAttrs attrs,
     } else {
         /* RAM case */
         uint8_t *ram_ptr = qemu_ram_ptr_length(mr->ram_block, mr_addr, l,
-                                               false);
+                                               false, true);
 
         memmove(ram_ptr, buf, *l);
         invalidate_and_set_dirty(mr, mr_addr, *l);
@@ -2849,7 +2854,7 @@ static MemTxResult flatview_read_continue_step(MemTxAttrs attrs, uint8_t *buf,
     } else {
         /* RAM case */
         uint8_t *ram_ptr = qemu_ram_ptr_length(mr->ram_block, mr_addr, l,
-                                               false);
+                                               false, false);
 
         memcpy(buf, ram_ptr, *l);
 
@@ -3243,7 +3248,7 @@ void *address_space_map(AddressSpace *as,
     *plen = flatview_extend_translation(fv, addr, len, mr, xlat,
                                         l, is_write, attrs);
     fuzz_dma_read_cb(addr, *plen, mr);
-    return qemu_ram_ptr_length(mr->ram_block, xlat, plen, true);
+    return qemu_ram_ptr_length(mr->ram_block, xlat, plen, true, is_write);
 }
 
 /* Unmaps a memory region previously mapped by address_space_map().
@@ -3339,7 +3344,8 @@ int64_t address_space_cache_init(MemoryRegionCache *cache,
         l = flatview_extend_translation(cache->fv, addr, len, mr,
                                         cache->xlat, l, is_write,
                                         MEMTXATTRS_UNSPECIFIED);
-        cache->ptr = qemu_ram_ptr_length(mr->ram_block, cache->xlat, &l, true);
+        cache->ptr = qemu_ram_ptr_length(mr->ram_block, cache->xlat, &l, true,
+                                         is_write);
     } else {
         cache->ptr = NULL;
     }