Re: [PATCH v4 11/18] KVM: arm64: selftests: Add basic GICv3 support

[Oliver Upton]

On Thu, Sep 09, 2021 at 01:38:11AM +0000, Raghavendra Rao Ananta wrote:
> Add basic support for ARM Generic Interrupt Controller v3.
> The support provides guests to setup interrupts.
> 
> The work is inspired from kvm-unit-tests and the kernel's
> GIC driver (drivers/irqchip/irq-gic-v3.c).
> 
> Signed-off-by: Raghavendra Rao Ananta <rananta@xxxxxxxxxx>
> Reviewed-by: Andrew Jones <drjones@xxxxxxxxxx>
> ---
>  tools/testing/selftests/kvm/Makefile          |   2 +-
>  .../selftests/kvm/include/aarch64/gic.h       |  21 ++
>  tools/testing/selftests/kvm/lib/aarch64/gic.c |  93 +++++++
>  .../selftests/kvm/lib/aarch64/gic_private.h   |  21 ++
>  .../selftests/kvm/lib/aarch64/gic_v3.c        | 240 ++++++++++++++++++
>  .../selftests/kvm/lib/aarch64/gic_v3.h        |  70 +++++
>  6 files changed, 446 insertions(+), 1 deletion(-)
>  create mode 100644 tools/testing/selftests/kvm/include/aarch64/gic.h
>  create mode 100644 tools/testing/selftests/kvm/lib/aarch64/gic.c
>  create mode 100644 tools/testing/selftests/kvm/lib/aarch64/gic_private.h
>  create mode 100644 tools/testing/selftests/kvm/lib/aarch64/gic_v3.c
>  create mode 100644 tools/testing/selftests/kvm/lib/aarch64/gic_v3.h
> 

[...]

> +static void
> +gic_dist_init(enum gic_type type, unsigned int nr_cpus, void *dist_base)
> +{
> +	const struct gic_common_ops *gic_ops;

does this need to be initialized? I haven't tried compiling, but it
seems it should trigger a compiler warning as it is only initialized if
type == GIC_V3.

> +	spin_lock(&gic_lock);
> +
> +	/* Distributor initialization is needed only once per VM */
> +	if (gic_common_ops) {
> +		spin_unlock(&gic_lock);
> +		return;
> +	}
> +
> +	if (type == GIC_V3)
> +		gic_ops = &gicv3_ops;
> +
> +	gic_ops->gic_init(nr_cpus, dist_base);
> +	gic_common_ops = gic_ops;
> +
> +	/* Make sure that the initialized data is visible to all the vCPUs */
> +	dsb(sy);
> +
> +	spin_unlock(&gic_lock);
> +}