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[Qemu-devel] [PATCH] memory: don't sign-extend 32-bit writes
From: |
Ladi Prosek |
Subject: |
[Qemu-devel] [PATCH] memory: don't sign-extend 32-bit writes |
Date: |
Thu, 26 Jan 2017 15:22:37 +0100 |
ldl_p has a signed return type so assigning it to uint64_t implicitly
sign-extends the value. This results in devices with min_access_size = 8
seeing unexpected values passed to their write handlers.
Example: guest performs a 32-bit write of 0x80000000 to an mmio region
and the handler receives 0xFFFFFFFF80000000 in its value argument.
Signed-off-by: Ladi Prosek <address@hidden>
---
exec.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/exec.c b/exec.c
index f2bed92..b05c5d2 100644
--- a/exec.c
+++ b/exec.c
@@ -2630,7 +2630,7 @@ static MemTxResult
address_space_write_continue(AddressSpace *as, hwaddr addr,
break;
case 4:
/* 32 bit write access */
- val = ldl_p(buf);
+ val = (uint32_t)ldl_p(buf);
result |= memory_region_dispatch_write(mr, addr1, val, 4,
attrs);
break;
--
2.7.4
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