Re: [Qemu-arm] [PATCH v1 05/23] semihosting: enable chardev backed output

[Peter Maydell]

On Fri, 10 May 2019 at 17:59, Alex Bennée <address@hidden> wrote:
>
>
> Peter Maydell <address@hidden> writes:
>
> > On Thu, 9 May 2019 at 17:59, Alex Bennée <address@hidden> wrote:
> >>
> >> For running system tests we want to be able to re-direct output to a
> >> file like we do with serial output. This does the wiring to allow us
> >> to treat semihosting like just another character output device.
> >>
> >> diff --git a/qemu-options.hx b/qemu-options.hx
> >> index 51802cbb266..6aa3a08c2fb 100644
> >> --- a/qemu-options.hx
> >> +++ b/qemu-options.hx
> >> @@ -3975,12 +3975,12 @@ STEXI
> >>  Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II only).
> >>  ETEXI
> >>  DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config,
> >> -    "-semihosting-config 
> >> [enable=on|off][,target=native|gdb|auto][,arg=str[,...]]\n" \
> >> +    "-semihosting-config 
> >> [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]\n" \
> >>      "                semihosting configuration\n",
> >>  QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | QEMU_ARCH_LM32 |
> >>  QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2)
> >
> > As you can see in the docs here, semihosting is supported on
> > five guest architectures, so we should implement this new
> > feature for all of them, not just arm.
>
> As I've introduced this for testing I see no reason not to add support
> for other architectures. However I was hoping this is something that
> could be done organically as other system tests get enabled.

IME transitions done "organically" really means "slowly, and
nobody ever gets round to actually completing them".
Semihosting is a user-facing feature, so if we want to add
the user feature of allowing output to go to a chardev we
should add it properly, I think.

thanks
-- PMM