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

[Oliver Upton]

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,
Oliver