Re: [PATCH] hw/riscv: virt: Warn the user if -bios is provided when using KVM

["Daniel P. Berrangé" <berrange@redhat.com>]

On Wed, Mar 23, 2022 at 06:13:46PM +0100, Ralf Ramsauer wrote:
> The -bios option is silently ignored if used in combination with -enable-kvm.
> The reason is that the machine starts in S-Mode, and the bios typically runs in
> M-Mode.
> 
> Warn the user that the bios won't be loaded.
> 
> Signed-off-by: Ralf Ramsauer <ralf.ramsauer@oth-regensburg.de>
> ---
>  hw/riscv/virt.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c
> index 4496a15346..a4d13114ee 100644
> --- a/hw/riscv/virt.c
> +++ b/hw/riscv/virt.c
> @@ -1312,6 +1312,9 @@ static void virt_machine_init(MachineState *machine)
>       * when KVM is enabled.
>       */
>      if (kvm_enabled()) {
> +        if (machine->firmware && strcmp(machine->firmware, "none"))
> +            warn_report("BIOS is not supported in combination with KVM. "
> +                        "Ignoring BIOS.");

If the usage scenario isn't supportable, then ultimately we should be
raising an error and immediately exiting.

If you know of common usage that is already mistakenly passing -bios,
then we could start with a warning and list it as deprecated, then
change to an error_report 2 releases later. If we don't thing people
are often mistakenly passing -bios, then go straight for error_report
and exit.

>          g_free(machine->firmware);
>          machine->firmware = g_strdup("none");
>      }
> -- 
> 2.32.0
> 
> 

With regards,
Daniel
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