kselftest/arm64: Validate that changing one VL type does not affect another

On a system with both SVE and SME when we change one of the VLs this should
not result in a change in the other VL. Add a check that this is in fact
the case to vec-syscfg.

Signed-off-by: Mark Brown <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Will Deacon <[e-mail]>

tools/testing/selftests/arm64/fp/vec-syscfg.c

···
 /* For each VQ verify that setting via prctl() does the right thing */
 static void prctl_set_all_vqs(struct vec_data *data)
 {
-	int ret, vq, vl, new_vl;
+	int ret, vq, vl, new_vl, i;
+	int orig_vls[ARRAY_SIZE(vec_data)];
 	int errors = 0;
 
 	if (!data->min_vl || !data->max_vl) {
···
 				      data->name);
 		return;
 	}
+
+	for (i = 0; i < ARRAY_SIZE(vec_data); i++)
+		orig_vls[i] = vec_data[i].rdvl();
 
 	for (vq = SVE_VQ_MIN; vq <= SVE_VQ_MAX; vq++) {
 		vl = sve_vl_from_vq(vq);
···
 			ksft_print_msg("Set %s VL %d but RDVL reports %d\n",
 				       data->name, new_vl, data->rdvl());
 			errors++;
+		}
+
+		/* Did any other VLs change? */
+		for (i = 0; i < ARRAY_SIZE(vec_data); i++) {
+			if (&vec_data[i] == data)
+				continue;
+
+			if (!(getauxval(vec_data[i].hwcap_type) & vec_data[i].hwcap))
+				continue;
+
+			if (vec_data[i].rdvl() != orig_vls[i]) {
+				ksft_print_msg("%s VL changed from %d to %d\n",
+					       vec_data[i].name, orig_vls[i],
+					       vec_data[i].rdvl());
+				errors++;
+			}
 		}
 
 		/* Was that the VL we asked for? */