linux-kernel - [PATCH 3/3] KVM: selftests: arm64: Make set_id_regs bitfield validatity checks non-fatal

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Message-Id: <20251030-kvm-arm64-set-id-regs-aarch64-v1-3-96fe0d2b178e@kernel.org>
Date: Thu, 30 Oct 2025 15:42:49 +0000
From: Mark Brown <broonie@...nel.org>
To: Marc Zyngier <maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>, 
 Joey Gouly <joey.gouly@....com>, Suzuki K Poulose <suzuki.poulose@....com>, 
 Paolo Bonzini <pbonzini@...hat.com>, Shuah Khan <shuah@...nel.org>
Cc: linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev, 
 kvm@...r.kernel.org, linux-kselftest@...r.kernel.org, 
 linux-kernel@...r.kernel.org, Mark Brown <broonie@...nel.org>
Subject: [PATCH 3/3] KVM: selftests: arm64: Make set_id_regs bitfield
 validatity checks non-fatal

Currently when set_id_regs encounters a problem checking validation of
writes to feature registers it uses an immediately fatal assert to report
the problem. This is not idiomatic for kselftest, and it is also not great
for usability. The affected bitfield is not clearly reported and further
tests do not have their results reported.

Switch to using standard kselftest result reporting for the two asserts
we do, these are non-fatal asserts so allow the program to continue and the
test names include the affected field.

Signed-off-by: Mark Brown <broonie@...nel.org>
---
 tools/testing/selftests/kvm/arm64/set_id_regs.c | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/kvm/arm64/set_id_regs.c b/tools/testing/selftests/kvm/arm64/set_id_regs.c
index 1a53f3a4be8d..abe97f9293c9 100644
--- a/tools/testing/selftests/kvm/arm64/set_id_regs.c
+++ b/tools/testing/selftests/kvm/arm64/set_id_regs.c
@@ -405,6 +405,7 @@ static uint64_t test_reg_set_success(struct kvm_vcpu *vcpu, uint64_t reg,
 	uint8_t shift = ftr_bits->shift;
 	uint64_t mask = ftr_bits->mask;
 	uint64_t val, new_val, ftr;
+	bool match;
 
 	val = vcpu_get_reg(vcpu, reg);
 	ftr = (val & mask) >> shift;
@@ -417,7 +418,10 @@ static uint64_t test_reg_set_success(struct kvm_vcpu *vcpu, uint64_t reg,
 
 	vcpu_set_reg(vcpu, reg, val);
 	new_val = vcpu_get_reg(vcpu, reg);
-	TEST_ASSERT_EQ(new_val, val);
+	match = new_val == val;
+	if (!match)
+		ksft_print_msg("%lx != %lx\n", new_val, val);
+	ksft_test_result(match, "%s valid write succeeded\n", ftr_bits->name);
 
 	return new_val;
 }
@@ -429,6 +433,7 @@ static void test_reg_set_fail(struct kvm_vcpu *vcpu, uint64_t reg,
 	uint64_t mask = ftr_bits->mask;
 	uint64_t val, old_val, ftr;
 	int r;
+	bool match;
 
 	val = vcpu_get_reg(vcpu, reg);
 	ftr = (val & mask) >> shift;
@@ -445,7 +450,10 @@ static void test_reg_set_fail(struct kvm_vcpu *vcpu, uint64_t reg,
 		    "Unexpected KVM_SET_ONE_REG error: r=%d, errno=%d", r, errno);
 
 	val = vcpu_get_reg(vcpu, reg);
-	TEST_ASSERT_EQ(val, old_val);
+	match = val == old_val;
+	if (!match)
+		ksft_print_msg("%lx != %lx\n", val, old_val);
+	ksft_test_result(match, "%s invalid write rejected\n", ftr_bits->name);
 }
 
 static uint64_t test_reg_vals[KVM_ARM_FEATURE_ID_RANGE_SIZE];
@@ -485,7 +493,11 @@ static void test_vm_ftr_id_regs(struct kvm_vcpu *vcpu, bool aarch64_only)
 		for (int j = 0;  ftr_bits[j].type != FTR_END; j++) {
 			/* Skip aarch32 reg on aarch64 only system, since they are RAZ/WI. */
 			if (aarch64_only && sys_reg_CRm(reg_id) < 4) {
-				ksft_test_result_skip("%s on AARCH64 only system\n",
+				ksft_print_msg("%s on AARCH64 only system\n",
+					       ftr_bits[j].name);
+				ksft_test_result_skip("%s invalid write rejected\n",
+						      ftr_bits[j].name);
+				ksft_test_result_skip("%s valid write succeeded\n",
 						      ftr_bits[j].name);
 				continue;
 			}
@@ -497,8 +509,6 @@ static void test_vm_ftr_id_regs(struct kvm_vcpu *vcpu, bool aarch64_only)
 
 			test_reg_vals[idx] = test_reg_set_success(vcpu, reg,
 								  &ftr_bits[j]);
-
-			ksft_test_result_pass("%s\n", ftr_bits[j].name);
 		}
 	}
 }
@@ -835,7 +845,7 @@ int main(void)
 		ID_REG_RESET_UNCHANGED_TEST;
 	for (i = 0; i < ARRAY_SIZE(test_regs); i++)
 		for (j = 0; test_regs[i].ftr_bits[j].type != FTR_END; j++)
-			test_cnt++;
+			test_cnt += 2;
 
 	ksft_set_plan(test_cnt);
 

-- 
2.47.2