vga: do not dynamically allocate chain4_alias

Instead, add a boolean variable to indicate the presence of the region.
This avoids a repeated malloc/free (later we can also avoid the
add_child/unparent by changing the offset/size of the alias).

Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/hw/display/vga_int.h b/hw/display/vga_int.h
index 5320abdc07..641f8f41d2 100644
--- a/hw/display/vga_int.h
+++ b/hw/display/vga_int.h
@@ -94,7 +94,8 @@ typedef struct VGACommonState {
     uint32_t vram_size;
     uint32_t vram_size_mb; /* property */
     uint32_t latch;
-    MemoryRegion *chain4_alias;
+    bool has_chain4_alias;
+    MemoryRegion chain4_alias;
     uint8_t sr_index;
     uint8_t sr[256];
     uint8_t gr_index;