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'.
EDU: DMA range 0x40000-0x3ffff out of bounds (0x40000-0x40fff)! 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)! Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1254 Signed-off-by: Chris Friedt <cfri...@meta.com> --- hw/misc/edu.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) diff --git a/hw/misc/edu.c b/hw/misc/edu.c index e935c418d4..b3de8d206a 100644 --- a/hw/misc/edu.c +++ b/hw/misc/edu.c @@ -103,19 +103,18 @@ 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) +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)) { + /* + * 1. ensure we aren't overflowing + * 2. ensure that [addr, end1) is within [start, size2) + */ + if (end2 >= start && end1 >= addr && + addr >= start && end1 <= end2) { return; } -- 2.36.1
