Re: [PATCH for-6.2 0/2] target/sparc: Drop use of gen_io_end()

[Peter Maydell]

On Sat, 24 Jul 2021 at 14:49, Peter Maydell <peter.maydell@linaro.org> wrote:
> There is a slight difficulty here with testing this: icount
> doesn't seem to work for sparc Linux guests in master at the
> moment. For instance if you get the advent calendar image from
>   https://www.qemu-advent-calendar.org/2018/download/day11.tar.xz
> it will boot without icount with a command line like
>   qemu-system-sparc -display none -vga none -machine SS-20 -serial stdio 
> -kernel /tmp/day11/zImage.elf
> But if you add '-icount auto' it will get as far as
> "bootconsole [earlyprom0] disabled" and then apparently hang.
> I'm not sure what's going on here :-(
> (I filed this as https://gitlab.com/qemu-project/qemu/-/issues/499)

This turns out to be a recent regression, caused by commit 78ff82bb
("accel/tcg: Reduce CF_COUNT_MASK to match TCG_MAX_INSNS"). It's
an intermittent rather than a 100% reproducible hang.

-- PMM