commit ce4adc0b6e6167091373389ef8befd379c61fddb
author David Hildenbrand <david@redhat.com> Fri Apr 03 11:18:27 2020 +0100
committer Michael S. Tsirkin <mst@redhat.com> Mon Apr 13 06:55:54 2020 -0400
tree 9ad77918a4d67e924f6a1b3a706ae31385cdd4c1
parent 394f0f72fd94595e656af62f079b7680cdbe8add

exec: Fix for qemu_ram_resize() callback

Summarizing the issue:
1. Memory regions contain ram blocks with a different size,  if the
   size is  not properly aligned. While memory regions can have an
   unaligned size, ram blocks can't. This is true when creating
   resizable memory region with  an unaligned size.
2. When resizing a ram block/memory region, the size of the memory
   region  is set to the aligned size. The callback is called with
   the aligned size. The unaligned piece is lost.

Because of the above, if ACPI blob length modifications happens
after the initial virt_acpi_build() call, and the changed blob
length is within the PAGE size boundary, then the revised size
is not seen by the firmware on Guest reboot.

Hence make sure callback is called if memory region size is changed,
irrespective of aligned or not.

Signed-off-by: David Hildenbrand <david@redhat.com>
[Shameer: added commit log]
Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20200403101827.30664-4-shameerali.kolothum.thodi@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

exec.c

diff --git a/exec.c b/exec.c
index de9d949..2874bb5 100644
--- a/exec.c
+++ b/exec.c
@@ -2074,11 +2074,23 @@
  */
 int qemu_ram_resize(RAMBlock *block, ram_addr_t newsize, Error **errp)
 {
+    const ram_addr_t unaligned_size = newsize;
+
     assert(block);
 
     newsize = HOST_PAGE_ALIGN(newsize);
 
     if (block->used_length == newsize) {
+        /*
+         * We don't have to resize the ram block (which only knows aligned
+         * sizes), however, we have to notify if the unaligned size changed.
+         */
+        if (unaligned_size != memory_region_size(block->mr)) {
+            memory_region_set_size(block->mr, unaligned_size);
+            if (block->resized) {
+                block->resized(block->idstr, unaligned_size, block->host);
+            }
+        }
         return 0;
     }
 
@@ -2102,9 +2114,9 @@
     block->used_length = newsize;
     cpu_physical_memory_set_dirty_range(block->offset, block->used_length,
                                         DIRTY_CLIENTS_ALL);
-    memory_region_set_size(block->mr, newsize);
+    memory_region_set_size(block->mr, unaligned_size);
     if (block->resized) {
-        block->resized(block->idstr, newsize, block->host);
+        block->resized(block->idstr, unaligned_size, block->host);
     }
     return 0;
 }