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[PATCH] hw: misc: edu: fix 2 off-by-one errors
From: |
Christopher Friedt |
Subject: |
[PATCH] hw: misc: edu: fix 2 off-by-one errors |
Date: |
Sat, 8 Jan 2022 21:37:28 -0500 |
In the case that size1 was zero, because of the explicit
'end1 > addr' check, the range check would fail and the error
message would read as shown below. The correct comparison
is 'end1 >= addr' (or 'addr <= end1').
EDU: DMA range 0x40000-0x3ffff out of bounds (0x40000-0x3ffff)!
At the opposite end, in the case that size1 was 4096, within()
would fail because of the non-inclusive check 'end1 < end2',
which should have been 'end1 <= end2'. The error message would
previously say
EDU: DMA range 0x40000-0x40fff out of bounds (0x40000-0x40fff)!
The solution is to use non-inclusive ranges e.g. [begin,end).
Signed-off-by: Christopher Friedt <chrisfriedt@gmail.com>
---
hw/misc/edu.c | 16 ++++++----------
1 file changed, 6 insertions(+), 10 deletions(-)
diff --git a/hw/misc/edu.c b/hw/misc/edu.c
index e935c418d4..73e97a54e7 100644
--- a/hw/misc/edu.c
+++ b/hw/misc/edu.c
@@ -103,25 +103,21 @@ static void edu_lower_irq(EduState *edu, uint32_t val)
}
}
-static bool within(uint64_t addr, uint64_t start, uint64_t end)
-{
- return start <= addr && addr < end;
-}
-
static void edu_check_range(uint64_t addr, uint64_t size1, uint64_t start,
uint64_t size2)
{
uint64_t end1 = addr + size1;
uint64_t end2 = start + size2;
- if (within(addr, start, end2) &&
- end1 > addr && within(end1, start, end2)) {
+ if (start <= addr && addr < end2 &&
+ addr <= end1 &&
+ start <= end1 && end1 <= end2) {
return;
}
- hw_error("EDU: DMA range 0x%016"PRIx64"-0x%016"PRIx64
- " out of bounds (0x%016"PRIx64"-0x%016"PRIx64")!",
- addr, end1 - 1, start, end2 - 1);
+ hw_error("EDU: DMA range [0x%016"PRIx64", 0x%016"PRIx64")"
+ " out of bounds [0x%016"PRIx64", 0x%016"PRIx64")!",
+ addr, end1, start, end2);
}
static dma_addr_t edu_clamp_addr(const EduState *edu, dma_addr_t addr)
--
2.30.2
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