[Qemu-devel] [PATCH v3] register: fix incorrect read mask

["Philippe Mathieu-Daudé" <f4bug@amsat.org>]

The register_read() and register_write() functions expect a bitmask argument.
To avoid duplicated code, a new inlined function register_enabled_mask() is
introduced.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Alistair Francis <alistair.francis@xilinx.com>
---

 v3: clarify functions affected in the commit message.
 v2: squashed together both previous commits as suggested by Francis Alistair.

 hw/core/register.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/hw/core/register.c b/hw/core/register.c
index 4bfbc508de..482e3f827a 100644
--- a/hw/core/register.c
+++ b/hw/core/register.c
@@ -59,6 +59,15 @@ static inline uint64_t register_read_val(RegisterInfo *reg)
     return 0; /* unreachable */
 }
 
+static inline uint64_t register_enabled_mask(int data_size, unsigned size)
+{
+    if (data_size < size) {
+        size = data_size;
+    }
+
+    return MAKE_64BIT_MASK(0, size * 8);
+}
+
 void register_write(RegisterInfo *reg, uint64_t val, uint64_t we,
                     const char *prefix, bool debug)
 {
@@ -192,11 +201,7 @@ void register_write_memory(void *opaque, hwaddr addr,
     }
 
     /* Generate appropriate write enable mask */
-    if (reg->data_size < size) {
-        we = MAKE_64BIT_MASK(0, reg->data_size * 8);
-    } else {
-        we = MAKE_64BIT_MASK(0, size * 8);
-    }
+    we = register_enabled_mask(reg->data_size, size);
 
     register_write(reg, value, we, reg_array->prefix,
                    reg_array->debug);
@@ -208,6 +213,7 @@ uint64_t register_read_memory(void *opaque, hwaddr addr,
     RegisterInfoArray *reg_array = opaque;
     RegisterInfo *reg = NULL;
     uint64_t read_val;
+    uint64_t re;
     int i;
 
     for (i = 0; i < reg_array->num_elements; i++) {
@@ -223,7 +229,10 @@ uint64_t register_read_memory(void *opaque, hwaddr addr,
         return 0;
     }
 
-    read_val = register_read(reg, size * 8, reg_array->prefix,
+    /* Generate appropriate read enable mask */
+    re = register_enabled_mask(reg->data_size, size);
+
+    read_val = register_read(reg, re, reg_array->prefix,
                              reg_array->debug);
 
     return extract64(read_val, 0, size * 8);
-- 
2.11.0