[PATCH] hw/misc: Fix invalid size assertions in exynos4210_rng read/write functions

[Zheyu Ma <zheyuma97@gmail.com>]

This commit updates the exynos4210_rng_read() and exynos4210_rng_write()
functions to handle cases where the size is not 4 bytes. Instead of
asserting, which causes the program to abort, the functions now log an
error message and return a default value for reads or do nothing for
writes when the size is invalid.

Reproducer:
cat << EOF | qemu-system-aarch64 -display none \
-machine accel=qtest, -m 512M -machine smdkc210 -qtest stdio
readb 0x10830454
EOF

Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
---
 hw/misc/exynos4210_rng.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/hw/misc/exynos4210_rng.c b/hw/misc/exynos4210_rng.c
index 0756bd3205..307d4eea43 100644
--- a/hw/misc/exynos4210_rng.c
+++ b/hw/misc/exynos4210_rng.c
@@ -146,7 +146,12 @@ static uint64_t exynos4210_rng_read(void *opaque, hwaddr offset,
     Exynos4210RngState *s = (Exynos4210RngState *)opaque;
     uint32_t val = 0;
 
-    assert(size == 4);
+    if (size != 4) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: invalid read size %u at offset 0x%" HWADDR_PRIx
+                      "\n", __func__, size, offset);
+        return 0;
+    }
 
     switch (offset) {
     case EXYNOS4210_RNG_CONTROL_1:
@@ -181,7 +186,12 @@ static void exynos4210_rng_write(void *opaque, hwaddr offset,
 {
     Exynos4210RngState *s = (Exynos4210RngState *)opaque;
 
-    assert(size == 4);
+    if (size != 4) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: invalid write size %u at offset 0x%" HWADDR_PRIx
+                      "\n", __func__, size, offset);
+        return;
+    }
 
     switch (offset) {
     case EXYNOS4210_RNG_CONTROL_1:
-- 
2.34.1