[PULL 28/29] hw/arm/vexpress: Avoid trivial memory leak of 'flashalias'

[Peter Maydell <peter.maydell@linaro.org>]

In the vexpress board code, we allocate a new MemoryRegion at the top
of vexpress_common_init() but only set it up and use it inside the
"if (map[VE_NORFLASHALIAS] != -1)" conditional, so we leak it if not.
This isn't a very interesting leak as it's a tiny amount of memory
once at startup, but it's easy to fix.

We could silence Coverity simply by moving the g_new() into the
if() block, but this use of g_new(MemoryRegion, 1) is a legacy from
when this board model was originally written; we wouldn't do that
if we wrote it today. The MemoryRegions are conceptually a part of
the board and must not go away until the whole board is done with
(at the end of the simulation), so they belong in its state struct.

This machine already has a VexpressMachineState struct that extends
MachineState, so statically put the MemoryRegions in there instead of
dynamically allocating them separately at runtime.

Spotted by Coverity (CID 1509083).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20230512170223.3801643-3-peter.maydell@linaro.org
---
 hw/arm/vexpress.c | 40 ++++++++++++++++++++--------------------
 1 file changed, 20 insertions(+), 20 deletions(-)

diff --git a/hw/arm/vexpress.c b/hw/arm/vexpress.c
index 34b012b528b..56abadd9b8b 100644
--- a/hw/arm/vexpress.c
+++ b/hw/arm/vexpress.c
@@ -173,6 +173,11 @@ struct VexpressMachineClass {
 
 struct VexpressMachineState {
     MachineState parent;
+    MemoryRegion vram;
+    MemoryRegion sram;
+    MemoryRegion flashalias;
+    MemoryRegion lowram;
+    MemoryRegion a15sram;
     bool secure;
     bool virt;
 };
@@ -182,7 +187,7 @@ struct VexpressMachineState {
 #define TYPE_VEXPRESS_A15_MACHINE   MACHINE_TYPE_NAME("vexpress-a15")
 OBJECT_DECLARE_TYPE(VexpressMachineState, VexpressMachineClass, VEXPRESS_MACHINE)
 
-typedef void DBoardInitFn(const VexpressMachineState *machine,
+typedef void DBoardInitFn(VexpressMachineState *machine,
                           ram_addr_t ram_size,
                           const char *cpu_type,
                           qemu_irq *pic);
@@ -263,14 +268,13 @@ static void init_cpus(MachineState *ms, const char *cpu_type,
     }
 }
 
-static void a9_daughterboard_init(const VexpressMachineState *vms,
+static void a9_daughterboard_init(VexpressMachineState *vms,
                                   ram_addr_t ram_size,
                                   const char *cpu_type,
                                   qemu_irq *pic)
 {
     MachineState *machine = MACHINE(vms);
     MemoryRegion *sysmem = get_system_memory();
-    MemoryRegion *lowram = g_new(MemoryRegion, 1);
     ram_addr_t low_ram_size;
 
     if (ram_size > 0x40000000) {
@@ -287,9 +291,9 @@ static void a9_daughterboard_init(const VexpressMachineState *vms,
      * address space should in theory be remappable to various
      * things including ROM or RAM; we always map the RAM there.
      */
-    memory_region_init_alias(lowram, NULL, "vexpress.lowmem", machine->ram,
-                             0, low_ram_size);
-    memory_region_add_subregion(sysmem, 0x0, lowram);
+    memory_region_init_alias(&vms->lowram, NULL, "vexpress.lowmem",
+                             machine->ram, 0, low_ram_size);
+    memory_region_add_subregion(sysmem, 0x0, &vms->lowram);
     memory_region_add_subregion(sysmem, 0x60000000, machine->ram);
 
     /* 0x1e000000 A9MPCore (SCU) private memory region */
@@ -348,14 +352,13 @@ static VEDBoardInfo a9_daughterboard = {
     .init = a9_daughterboard_init,
 };
 
-static void a15_daughterboard_init(const VexpressMachineState *vms,
+static void a15_daughterboard_init(VexpressMachineState *vms,
                                    ram_addr_t ram_size,
                                    const char *cpu_type,
                                    qemu_irq *pic)
 {
     MachineState *machine = MACHINE(vms);
     MemoryRegion *sysmem = get_system_memory();
-    MemoryRegion *sram = g_new(MemoryRegion, 1);
 
     {
         /* We have to use a separate 64 bit variable here to avoid the gcc
@@ -386,9 +389,9 @@ static void a15_daughterboard_init(const VexpressMachineState *vms,
     /* 0x2b060000: SP805 watchdog: not modelled */
     /* 0x2b0a0000: PL341 dynamic memory controller: not modelled */
     /* 0x2e000000: system SRAM */
-    memory_region_init_ram(sram, NULL, "vexpress.a15sram", 0x10000,
+    memory_region_init_ram(&vms->a15sram, NULL, "vexpress.a15sram", 0x10000,
                            &error_fatal);
-    memory_region_add_subregion(sysmem, 0x2e000000, sram);
+    memory_region_add_subregion(sysmem, 0x2e000000, &vms->a15sram);
 
     /* 0x7ffb0000: DMA330 DMA controller: not modelled */
     /* 0x7ffd0000: PL354 static memory controller: not modelled */
@@ -547,10 +550,6 @@ static void vexpress_common_init(MachineState *machine)
     I2CBus *i2c;
     ram_addr_t vram_size, sram_size;
     MemoryRegion *sysmem = get_system_memory();
-    MemoryRegion *vram = g_new(MemoryRegion, 1);
-    MemoryRegion *sram = g_new(MemoryRegion, 1);
-    MemoryRegion *flashalias = g_new(MemoryRegion, 1);
-    MemoryRegion *flash0mem;
     const hwaddr *map = daughterboard->motherboard_map;
     int i;
 
@@ -662,24 +661,25 @@ static void vexpress_common_init(MachineState *machine)
 
     if (map[VE_NORFLASHALIAS] != -1) {
         /* Map flash 0 as an alias into low memory */
+        MemoryRegion *flash0mem;
         flash0mem = sysbus_mmio_get_region(SYS_BUS_DEVICE(pflash0), 0);
-        memory_region_init_alias(flashalias, NULL, "vexpress.flashalias",
+        memory_region_init_alias(&vms->flashalias, NULL, "vexpress.flashalias",
                                  flash0mem, 0, VEXPRESS_FLASH_SIZE);
-        memory_region_add_subregion(sysmem, map[VE_NORFLASHALIAS], flashalias);
+        memory_region_add_subregion(sysmem, map[VE_NORFLASHALIAS], &vms->flashalias);
     }
 
     dinfo = drive_get(IF_PFLASH, 0, 1);
     ve_pflash_cfi01_register(map[VE_NORFLASH1], "vexpress.flash1", dinfo);
 
     sram_size = 0x2000000;
-    memory_region_init_ram(sram, NULL, "vexpress.sram", sram_size,
+    memory_region_init_ram(&vms->sram, NULL, "vexpress.sram", sram_size,
                            &error_fatal);
-    memory_region_add_subregion(sysmem, map[VE_SRAM], sram);
+    memory_region_add_subregion(sysmem, map[VE_SRAM], &vms->sram);
 
     vram_size = 0x800000;
-    memory_region_init_ram(vram, NULL, "vexpress.vram", vram_size,
+    memory_region_init_ram(&vms->vram, NULL, "vexpress.vram", vram_size,
                            &error_fatal);
-    memory_region_add_subregion(sysmem, map[VE_VIDEORAM], vram);
+    memory_region_add_subregion(sysmem, map[VE_VIDEORAM], &vms->vram);
 
     /* 0x4e000000 LAN9118 Ethernet */
     if (nd_table[0].used) {
-- 
2.34.1