[Qemu-devel] [PATCH v2 2/3] CPUPhysMemoryClient: Pass guest physical address not region offset

[Alex Williamson]

When we're trying to get a newly registered phys memory client updated
with the current page mappings, we end up passing the region offset
(a ram_addr_t) as the start address rather than the actual guest
physical memory address (target_phys_addr_t).  If your guest has less
than 3.5G of memory, these are coincidentally the same thing.  If
there's more, the region offset for the memory above 4G starts over
at 0, so the set_memory client will overwrite it's lower memory entries.

Instead, keep track of the guest phsyical address as we're walking the
tables and pass that to the set_memory client.

Signed-off-by: Alex Williamson <address@hidden>
Acked-by: Michael S. Tsirkin <address@hidden>
---

 exec.c |   16 ++++++++++++----
 1 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/exec.c b/exec.c
index 8790ad8..bbd5c86 100644
--- a/exec.c
+++ b/exec.c
@@ -1741,8 +1741,14 @@ static int cpu_notify_migration_log(int enable)
     return 0;
 }
 
+/* The l1_phys_map provides the upper P_L1_BITs of the guest physical
+ * address.  Each intermediate table provides the next L2_BITs of guest
+ * physical address space.  The number of levels vary based on host and
+ * guest configuration, making it efficient to build the final guest
+ * physical address by seeding the L1 offset and shifting and adding in
+ * each L2 offset as we recurse through them. */
 static void phys_page_for_each_1(CPUPhysMemoryClient *client,
-                                 int level, void **lp)
+                                 int level, void **lp, target_phys_addr_t addr)
 {
     int i;
 
@@ -1751,16 +1757,18 @@ static void phys_page_for_each_1(CPUPhysMemoryClient 
*client,
     }
     if (level == 0) {
         PhysPageDesc *pd = *lp;
+        addr <<= L2_BITS + TARGET_PAGE_BITS;
         for (i = 0; i < L2_SIZE; ++i) {
             if (pd[i].phys_offset != IO_MEM_UNASSIGNED) {
-                client->set_memory(client, pd[i].region_offset,
+                client->set_memory(client, addr | i << TARGET_PAGE_BITS,
                                    TARGET_PAGE_SIZE, pd[i].phys_offset);
             }
         }
     } else {
         void **pp = *lp;
         for (i = 0; i < L2_SIZE; ++i) {
-            phys_page_for_each_1(client, level - 1, pp + i);
+            phys_page_for_each_1(client, level - 1, pp + i,
+                                 (addr << L2_BITS) | i);
         }
     }
 }
@@ -1770,7 +1778,7 @@ static void phys_page_for_each(CPUPhysMemoryClient 
*client)
     int i;
     for (i = 0; i < P_L1_SIZE; ++i) {
         phys_page_for_each_1(client, P_L1_SHIFT / L2_BITS - 1,
-                             l1_phys_map + i);
+                             l1_phys_map + i, i);
     }
 }