commit 1240be24357ee292f8d05aa2abfdba75dd0ca25d
author Michael S. Tsirkin <mst@redhat.com> Wed Nov 12 11:44:41 2014 +0200
committer Amit Shah <amit.shah@redhat.com> Tue Dec 16 17:47:35 2014 +0530
tree 377ce51d512e0916fc18b25b2fce85ce352e9ab4
parent 68a5e38a7e428c05610fdbced7e7320a7aea3dc2

exec: add wrapper for host pointer access

host pointer accesses force pointer math, let's
add a wrapper to make them safer.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Amos Kong <akong@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>

exec.c

diff --git a/exec.c b/exec.c
index 71ac104..963481a 100644
--- a/exec.c
+++ b/exec.c
@@ -840,7 +840,7 @@
 
     block = qemu_get_ram_block(start);
     assert(block == qemu_get_ram_block(end - 1));
-    start1 = (uintptr_t)block->host + (start - block->offset);
+    start1 = (uintptr_t)ramblock_ptr(block, start - block->offset);
     cpu_tlb_reset_dirty_all(start1, length);
 }
 
@@ -1500,7 +1500,7 @@
     QTAILQ_FOREACH(block, &ram_list.blocks, next) {
         offset = addr - block->offset;
         if (offset < block->length) {
-            vaddr = block->host + offset;
+            vaddr = ramblock_ptr(block, offset);
             if (block->flags & RAM_PREALLOC) {
                 ;
             } else if (xen_enabled()) {
@@ -1551,7 +1551,7 @@
 {
     RAMBlock *block = qemu_get_ram_block(addr);
 
-    return block->host;
+    return ramblock_ptr(block, 0);
 }
 
 /* Return a host pointer to ram allocated with qemu_ram_alloc.
@@ -1578,7 +1578,7 @@
                 xen_map_cache(block->offset, block->length, 1);
         }
     }
-    return block->host + (addr - block->offset);
+    return ramblock_ptr(block, addr - block->offset);
 }
 
 /* Return a host pointer to guest's ram. Similar to qemu_get_ram_ptr
@@ -1597,7 +1597,7 @@
             if (addr - block->offset < block->length) {
                 if (addr - block->offset + *size > block->length)
                     *size = block->length - addr + block->offset;
-                return block->host + (addr - block->offset);
+                return ramblock_ptr(block, addr - block->offset);
             }
         }
 

include/exec/cpu-all.h

diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h
index c085804..9d8d408 100644
--- a/include/exec/cpu-all.h
+++ b/include/exec/cpu-all.h
@@ -313,6 +313,11 @@
     int fd;
 } RAMBlock;
 
+static inline void *ramblock_ptr(RAMBlock *block, ram_addr_t offset)
+{
+    return (char *)block->host + offset;
+}
+
 typedef struct RAMList {
     QemuMutex mutex;
     /* Protected by the iothread lock.  */