Re: [PATCH] kselftest: kvm/arm64: Skip tests if we can't create a vgic-v3

From: Shuah Khan <skhan@linuxfoundation•org>
To: Mark Brown <broonie@kernel•org>, Marc Zyngier <maz@kernel•org>,
	Shuah Khan <shuah@kernel•org>
Cc: James Morse <james.morse@arm•com>,
	Alexandru Elisei <alexandru.elisei@arm•com>,
	Suzuki K Poulose <suzuki.poulose@arm•com>,
	linux-arm-kernel@lists•infradead.org,
	kvmarm@lists•cs.columbia.edu, linux-kselftest@vger•kernel.org,
	Shuah Khan <skhan@linuxfoundation•org>
Subject: Re: [PATCH] kselftest: kvm/arm64: Skip tests if we can't create a vgic-v3
Date: Tue, 25 Jan 2022 12:48:00 -0700	[thread overview]
Message-ID: <a7215f00-2ffd-d3ec-eb02-e7fc8e527715@linuxfoundation.org> (raw)
In-Reply-To: <20220125192851.3907611-1-broonie@kernel.org>

On 1/25/22 12:28 PM, Mark Brown wrote:
> The arch_timer and vgic_irq kselftests assume that they can create a
> vgic-v3, using the library function vgic_v3_setup() which aborts with a
> test failure if it is not possible to do so. Since vgic-v3 can only be
> instantiated on systems where the host has GICv3 this leads to false
> positives on older systems where that is not the case.
> 
> Fix this by changing vgic_v3_setup() to return an error if the vgic can't
> be instantiated and have the callers skip if this happens. We could also
> exit flagging a skip in vgic_v3_setup() but this would prevent future test
> cases conditionally deciding which GIC to use or generally doing more
> complex output.
> 
> Signed-off-by: Mark Brown <broonie@kernel•org>
> ---
>   tools/testing/selftests/kvm/aarch64/arch_timer.c | 7 ++++++-
>   tools/testing/selftests/kvm/aarch64/vgic_irq.c   | 5 +++++
>   tools/testing/selftests/kvm/lib/aarch64/vgic.c   | 4 +++-
>   3 files changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/selftests/kvm/aarch64/arch_timer.c b/tools/testing/selftests/kvm/aarch64/arch_timer.c
> index 9ad38bd360a4..791d38404652 100644
> --- a/tools/testing/selftests/kvm/aarch64/arch_timer.c
> +++ b/tools/testing/selftests/kvm/aarch64/arch_timer.c
> @@ -366,6 +366,7 @@ static struct kvm_vm *test_vm_create(void)
>   {
>   	struct kvm_vm *vm;
>   	unsigned int i;
> +	int ret;
>   	int nr_vcpus = test_args.nr_vcpus;
>   
>   	vm = vm_create_default_with_vcpus(nr_vcpus, 0, 0, guest_code, NULL);
> @@ -382,7 +383,11 @@ static struct kvm_vm *test_vm_create(void)
>   
>   	ucall_init(vm, NULL);
>   	test_init_timer_irq(vm);
> -	vgic_v3_setup(vm, nr_vcpus, 64, GICD_BASE_GPA, GICR_BASE_GPA);
> +	ret = vgic_v3_setup(vm, nr_vcpus, 64, GICD_BASE_GPA, GICR_BASE_GPA);
> +	if (ret < 0) {
> +		pr_info("Failed to create vgic-v3, skipping\n");
> +		exit(KSFT_SKIP);
> +	}
>   
>   	/* Make all the test's cmdline args visible to the guest */
>   	sync_global_to_guest(vm, test_args);
> diff --git a/tools/testing/selftests/kvm/aarch64/vgic_irq.c b/tools/testing/selftests/kvm/aarch64/vgic_irq.c
> index e6c7d7f8fbd1..8c6b61b8e6aa 100644
> --- a/tools/testing/selftests/kvm/aarch64/vgic_irq.c
> +++ b/tools/testing/selftests/kvm/aarch64/vgic_irq.c
> @@ -761,6 +761,11 @@ static void test_vgic(uint32_t nr_irqs, bool level_sensitive, bool eoi_split)
>   
>   	gic_fd = vgic_v3_setup(vm, 1, nr_irqs,
>   			GICD_BASE_GPA, GICR_BASE_GPA);
> +	if (gic_fd < 0) {
> +		pr_info("Failed to create vgic-v3, skipping\n");
> +		exit(KSFT_SKIP);
> +	}
> +
>   
>   	vm_install_exception_handler(vm, VECTOR_IRQ_CURRENT,
>   		guest_irq_handlers[args.eoi_split][args.level_sensitive]);
> diff --git a/tools/testing/selftests/kvm/lib/aarch64/vgic.c b/tools/testing/selftests/kvm/lib/aarch64/vgic.c
> index b3a0fca0d780..647c18733e1b 100644
> --- a/tools/testing/selftests/kvm/lib/aarch64/vgic.c
> +++ b/tools/testing/selftests/kvm/lib/aarch64/vgic.c
> @@ -52,7 +52,9 @@ int vgic_v3_setup(struct kvm_vm *vm, unsigned int nr_vcpus, uint32_t nr_irqs,
>   			nr_vcpus, nr_vcpus_created);
>   
>   	/* Distributor setup */
> -	gic_fd = kvm_create_device(vm, KVM_DEV_TYPE_ARM_VGIC_V3, false);
> +	gic_fd = kvm_create_device(vm, KVM_DEV_TYPE_ARM_VGIC_V3, true);

Assume the flag change is intentional. The reason isn't obvious in the
change log

> +	if (gic_fd == -1)
> +		return -1;
>   
>   	kvm_device_access(gic_fd, KVM_DEV_ARM_VGIC_GRP_NR_IRQS,
>   			0, &nr_irqs, true);
> 

Looks good to me otherwise - thanks for adding the skips

Reviewed-by: Shuah Khan <skhan@linuxfoundation•org>

thanks,
-- Shuah

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