Re: [PATCH 3/4] target/riscv/kvm: add kvm-aia bools props

[Andrew Jones <ajones@ventanamicro.com>]

On Wed, Oct 30, 2024 at 11:40:57AM +1000, Alistair Francis wrote:
> On Fri, Oct 11, 2024 at 9:19 PM Daniel Henrique Barboza
...
> > In case someone tries it out with multiple -accel options, this doesn't work. Only
> > the first '-accel <type>' are parsed. This happens due to a known command line
> > parsing/accel globals issue that I tried to fix in [1] and [2].
> >
> > For now, using the existing 'riscv-aia' string option:
> >
> > -accel kvm,riscv-aia=emul -accel kvm,riscv-aia=hwaccel -accel kvm,riscv-aia=auto
> >
> > This will set riscv-aia to "emul" because all other "-accel kvm" options aren't
> > being parsed. You can do silly stuff like:
> >
> > -accel kvm,riscv-aia=emul -accel kvm,riscv-aia=this_is_not_an_option
> >
> > And the guest will boot normally, setting riscv-aia to 'emul'.
> 
> Both of those are unfortunate, but I do at least feel that reading
> them it's clear that something is wrong as the user has listed `-accel
> kvm...` multiple times.
>

I wish that multiple '-accel kvm...' would work since scripts can be
written to set reasonable defaults, e.g.

 qemu-script.sh:
 qemu-system-riscv64 -cpu max -accel kvm,riscv-aia=auto ... $@

but then anything the user tacks on through $@ would override those
defaults. For example, 'qemu-script.sh -cpu max,some-ext=off' overrides
the '-cpu max' in the script, disabling an extension. However,
'qemu-script.sh -accel kvm,riscv-aia=emul' will not force KVM to use
use AIA=emul mode since the tacked on '-accel' is ignored.

Thanks,
drew