Re: [Qemu-devel] [PATCH 1/3] arm: gic: add GICType

[Andrea Bolognani <abologna@redhat.com>]

On Tue, 2016-02-23 at 18:52 +0800, Peter Xu wrote:
> A new enum type is added to define ARM GIC types.
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  qapi-schema.json | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 8d04897..81654bd 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -4083,3 +4083,20 @@
>  ##
>  { 'enum': 'ReplayMode',
>    'data': [ 'none', 'record', 'play' ] }
> +
> +##
> +# @GICType:
> +#
> +# An enumeration of GIC types
> +#
> +# @gicv2:     GICv2 support without kernel irqchip
> +#
> +# @gicv3:     GICv3 support without kernel irqchip
> +#
> +# @gicv2-kvm: GICv3 support with kernel irqchip
> +#
> +# @gicv3-kvm: GICv3 support with kernel irqchip
> +#
> +# Since: 2.6
> +##
> +{ 'enum': 'GICType', 'data': [ 'gicv2', 'gicv3', 'gicv2-kvm', 'gicv3-kvm' ] }

Wouldn't this conflate the use of accel= and kernel_irqchip= options?

IIUC, depending on the hardware, you might find yourself in the
following situation:

  accel=tcg,gic-version=3                     unavailable
  accel=kvm,kernel_irqchip=off,gic-version=3  unavailable
  accel=kvm,gic-version=3                     available

so I'd expect the output to be something like

  [ "v2": { "tcg": true,
            "kvm-without-kernel-irqchip": true,
            "kvm": true },
    "v3": { "tcg": false,
            "kvm-without-kernel-irqchip": false,
            "kvm": true } ]

Since libvirt currently doesn't have support for the
kernel_irqchip= option, it would only take the "tcg" and "kvm"
values into account; on the other hand, if at some point
libvirt will grow support for that option it would be able to
retrieve all the required information.

Cheers.

-- 
Andrea Bolognani
Software Engineer - Virtualization Team