Re: [PATCH v9 1/3] KVM: selftests: arm64: Report set_id_reg reads of test registers as tests

[Sebastian Ott]

On Tue, 3 Nov 2026, Mark Brown wrote:
> Currently when we run guest code to validate that the values we wrote to
> the registers are seen by the guest we assert that these values match using
> a KVM selftests level assert, resulting in unclear diagnostics if the test
> fails. Replace this assert with reporting a kselftest test per register.
>
> In order to support getting the names of the registers we repaint the array
> of ID_ registers to store the names and open code the rest.
>
> Reviewed-by: Ben Horgan <ben.horgan@xxxxxxx>
> Reviewed-by: Lorenzo Stoakes (ARM) <ljs@xxxxxxxxxx>
> Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
[...]
> @@ -684,11 +719,20 @@ static void test_guest_reg_read(struct kvm_vcpu *vcpu)
> 			REPORT_GUEST_ASSERT(uc);
> 			break;
> 		case UCALL_SYNC:
> -			val = test_reg_vals[encoding_to_range_idx(uc.args[2])];
> -			val = reset_mutable_bits(uc.args[2], val);
> +			expected_val = test_reg_vals[encoding_to_range_idx(uc.args[2])];
> +			expected_val = reset_mutable_bits(uc.args[2], expected_val);
>
> 			/* Make sure the written values are seen by guest */
> -			TEST_ASSERT_EQ(val, reset_mutable_bits(uc.args[2], uc.args[3]));
> +			reg_id = uc.args[2];
                        ^
Minor nit: this could be moved above and be used in 3 more places.

> +			guest_val = reset_mutable_bits(uc.args[2], uc.args[3]);
> +
> +			match = expected_val == guest_val;
> +			if (!match)
> +				ksft_print_msg("%lx != %lx\n",
> +					       expected_val, guest_val);
> +			ksft_test_result(match,
> +					 "%s value seen in guest\n",
> +					 get_reg_name(reg_id));
> 			break;
> 		case UCALL_DONE:
> 			done = true;