[PATCH v3 5/5] KVM: arm64: selftests: Test for setting ID register from usersapce

[Cornelia Huck]

On Tue, Oct 17 2023, Oliver Upton <oliver.upton at linux.dev> wrote:

> On Mon, Oct 16, 2023 at 05:30:06PM +0200, Cornelia Huck wrote:
>> On Wed, Oct 11 2023, Oliver Upton <oliver.upton at linux.dev> wrote:
>> 
>> > From: Jing Zhang <jingzhangos at google.com>
>> >
>> > Add tests to verify setting ID registers from userspace is handled
>> > correctly by KVM. Also add a test case to use ioctl
>> > KVM_ARM_GET_REG_WRITABLE_MASKS to get writable masks.
>> >
>> > Signed-off-by: Jing Zhang <jingzhangos at google.com>
>> > Signed-off-by: Oliver Upton <oliver.upton at linux.dev>
>> > ---
>> >  tools/testing/selftests/kvm/Makefile          |   1 +
>> >  .../selftests/kvm/aarch64/set_id_regs.c       | 479 ++++++++++++++++++
>> >  2 files changed, 480 insertions(+)
>> >  create mode 100644 tools/testing/selftests/kvm/aarch64/set_id_regs.c
>> 
>> (...)
>> 
>> > +static void test_user_set_reg(struct kvm_vcpu *vcpu, bool aarch64_only)
>> > +{
>> > +	uint64_t masks[KVM_ARM_FEATURE_ID_RANGE_SIZE];
>> > +	struct reg_mask_range range = {
>> > +		.addr = (__u64)masks,
>> > +	};
>> > +	int ret;
>> > +
>> > +	/* KVM should return error when reserved field is not zero */
>> > +	range.reserved[0] = 1;
>> > +	ret = __vm_ioctl(vcpu->vm, KVM_ARM_GET_REG_WRITABLE_MASKS, &range);
>> > +	TEST_ASSERT(ret, "KVM doesn't check invalid parameters.");
>> 
>> I think the code should first check for
>> KVM_CAP_ARM_SUPPORTED_REG_MASK_RANGES -- newer kselftests are supposed
>> to be able to run on older kernels, and we should just skip all of this
>> if the API isn't there.
>
> Ah, thanks! I'll apply the following on top:
>
> diff --git a/tools/testing/selftests/kvm/aarch64/set_id_regs.c b/tools/testing/selftests/kvm/aarch64/set_id_regs.c
> index 5c0718fd1705..bac05210b539 100644
> --- a/tools/testing/selftests/kvm/aarch64/set_id_regs.c
> +++ b/tools/testing/selftests/kvm/aarch64/set_id_regs.c
> @@ -452,6 +452,8 @@ int main(void)
>  	uint64_t val, el0;
>  	int ftr_cnt;
>  
> +	TEST_REQUIRE(kvm_has_cap(KVM_CAP_ARM_SUPPORTED_REG_MASK_RANGES));
> +
>  	vm = vm_create_with_one_vcpu(&vcpu, guest_code);
>  
>  	/* Check for AARCH64 only system */

Thanks, LGTM.