Re: [RFC PATCH] hw/i2c/aspeed_i2c: Make AspeedI2CClass::gap an plain unsigned type

[Cédric Le Goater]

On 4/23/25 14:05, Philippe Mathieu-Daudé wrote:

Convert AspeedI2CClass::gap to plain unsigned, using '0'
as "no gap" to avoid the followin UBSan warnings:

   SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior 
../../hw/i2c/aspeed_i2c.c:1559:16
   SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior 
../../hw/i2c/aspeed_i2c.c:1583:16
   SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior 
../../hw/i2c/aspeed_i2c.c:1608:16
   hw/i2c/aspeed_i2c.c:1608:16: runtime error: implicit conversion from type 
'int' of value
                                -1 (32-bit, signed) to type 'uint8_t' (aka 
'unsigned char')
                                changed the value to 255 (8-bit, unsigned)

Signed-off-by: Philippe Mathieu-Daudé <phi...@linaro.org>

Looks fine.


Reviewed-by: Cédric Le Goater <c...@redhat.com>

Thanks,

C.

---
  include/hw/i2c/aspeed_i2c.h | 2 +-
  hw/i2c/aspeed_i2c.c         | 5 +----
  2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/include/hw/i2c/aspeed_i2c.h b/include/hw/i2c/aspeed_i2c.h
index 2c4c81bd209..098356e5bac 100644
--- a/include/hw/i2c/aspeed_i2c.h
+++ b/include/hw/i2c/aspeed_i2c.h
@@ -290,7 +290,7 @@ struct AspeedI2CClass {
      uint8_t num_busses;
      uint8_t reg_size;
      uint32_t reg_gap_size;
-    uint8_t gap;
+    unsigned gap;
      qemu_irq (*bus_get_irq)(AspeedI2CBus *);

uint64_t pool_size;

diff --git a/hw/i2c/aspeed_i2c.c b/hw/i2c/aspeed_i2c.c
index a8fbb9f44a1..a45a4fd6cb7 100644
--- a/hw/i2c/aspeed_i2c.c
+++ b/hw/i2c/aspeed_i2c.c
@@ -1215,7 +1215,7 @@ static void aspeed_i2c_realize(DeviceState *dev, Error 
**errp)

for (i = 0; i < aic->num_busses; i++) {

          Object *bus = OBJECT(&s->busses[i]);
-        int offset = i < aic->gap ? 1 : 5;
+        unsigned offset = i < aic->gap ? 1 : 5;

if (!object_property_set_link(bus, "controller", OBJECT(s), errp)) {

              return;
@@ -1556,7 +1556,6 @@ static void aspeed_2600_i2c_class_init(ObjectClass 
*klass, void *data)

aic->num_busses = 16;

      aic->reg_size = 0x80;
-    aic->gap = -1; /* no gap */
      aic->bus_get_irq = aspeed_2600_i2c_bus_get_irq;
      aic->pool_size = 0x20;
      aic->pool_base = 0xC00;
@@ -1580,7 +1579,6 @@ static void aspeed_1030_i2c_class_init(ObjectClass 
*klass, void *data)

aic->num_busses = 14;

      aic->reg_size = 0x80;
-    aic->gap = -1; /* no gap */
      aic->bus_get_irq = aspeed_2600_i2c_bus_get_irq;
      aic->pool_size = 0x20;
      aic->pool_base = 0xC00;
@@ -1605,7 +1603,6 @@ static void aspeed_2700_i2c_class_init(ObjectClass 
*klass, void *data)
      aic->num_busses = 16;
      aic->reg_size = 0x80;
      aic->reg_gap_size = 0x80;
-    aic->gap = -1; /* no gap */
      aic->bus_get_irq = aspeed_2600_i2c_bus_get_irq;
      aic->pool_size = 0x20;
      aic->pool_gap_size = 0xe0;