Another issue is that 145 uses $TEST_IMG as follows: SYSEMU_DRIVE_ARG=if=none,file="$TEST_IMG",driver=$IMGFMT
That doesn't work when json: contains a comma, since commas need to be doubled up to escape them. This fails: $ qemu-system-x86_64 -drive 'if=none,file=json:{"driver":"io_uring","filename":"test.img"}' qemu-system-x86_64: -drive if=none,file=json:{"driver":"io_uring","filename":"test.img"}: warning: short-form boolean option '"filename":"test.img"}' deprecated Please use "filename":"test.img"}=on instead This works: qemu-system-x86_64 -drive 'if=none,file=json:{"driver":"io_uring",,"filename":"test.img"}' Maybe it's simply not possible to use TEST_IMG=json: in qemu-iotests? The alternative is to always set IMGOPTSSYNTAX=true and then find the test cases that fail because they contain non-IMGOPTSSYNTAX commands. Stefan