Re: [PATCH 65/65] hw/arm/virt: Allow user to select GICv5

[Jonathan Cameron via <qemu-arm@nongnu.org>]

On Mon, 23 Feb 2026 17:02:12 +0000
Peter Maydell <peter.maydell@linaro.org> wrote:

> Allow the user to select a GICv5 via '-machine gic-version=x-5', and
> document this.  The 'x-' prefix indicates that the emulation is still
> in an "experimental" state as far as QEMU is concerned; the
> documentation describes what "experimental" means for the user and
> what parts are not yet implemented.
> 
> We do not make 'gic-version=max' enable GICv5 here because:
> 
>  * the GICv5 architectural spec is still at the EAC level and
>    could have minor changes between now and its final version;
>    only users who specifically want to start working with the
>    GICv5 should select it
>  * QEMU's implementation here is still not fully featured,
>    and selecting it instead of GICv3 will mean losing
>    functionality such as MSIs
>  * the GICv5 is not backwards compatible with the GICv3/GICv4
>    for system software, so silently "upgrading" an existing
>    command line to GICv5 is just going to break existing guest
>    kernels
> 
> The last one in particular suggests that even when the emulation
> moves out of "experimental" status we will probably not want to
> change "max".
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>

Nice start, looking forward to the ITS, ACPI bit and hopefully
eventually IWB as all useful for testing purposes.

Thanks,

Jonathan