[PATCH 02/16] hw/arm/boot: let a board preset initrd_start

[Kyle Fox <kylefoxaustin.github@gmail.com>]

Allow a board to place the initrd itself (honour a pre-set
info->initrd_start) so a board with a reserved-memory carveout can keep
the initrd clear of it.

Signed-off-by: Kyle Fox <kylefoxaustin.github@gmail.com>
---
 hw/arm/boot.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/hw/arm/boot.c b/hw/arm/boot.c
index 9b7553dde5e..4bfb0d8264b 100644
--- a/hw/arm/boot.c
+++ b/hw/arm/boot.c
@@ -997,8 +997,16 @@ static void arm_setup_direct_kernel_boot(ARMCPU *cpu,
      * don't tell us their exact size (eg self-decompressing 32-bit kernels)
      * we might still make a bad choice here.
      */
-    info->initrd_start = info->loader_start +
-        MIN(info->ram_size / 2, 128 * MiB);
+    /*
+     * Boards may preset info->initrd_start to force a placement (e.g. to
+     * dodge a guest reserved-memory carveout that happens to sit where the
+     * default heuristic would land the initrd). Only compute a default when
+     * the board left it unset.
+     */
+    if (!info->initrd_start) {
+        info->initrd_start = info->loader_start +
+            MIN(info->ram_size / 2, 128 * MiB);
+    }
     if (image_high_addr) {
         info->initrd_start = MAX(info->initrd_start, image_high_addr);
     }
-- 
2.34.1