KVM: selftests: arm64: Test vCPU-scoped feature ID registers

Test that CLIDR_EL1 and MPIDR_EL1 are modifiable from userspace and that
the values are preserved across a vCPU reset like the other feature ID
registers.

Signed-off-by: Oliver Upton <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Marc Zyngier <[email protected]>

tools/testing/selftests/kvm/aarch64/set_id_regs.c

@@ -457,6 +457,53 @@ static void test_guest_reg_read(struct kvm_vcpu *vcpu)
  }
 }
 
+/* Politely lifted from arch/arm64/include/asm/cache.h */
+/* Ctypen, bits[3(n - 1) + 2 : 3(n - 1)], for n = 1 to 7 */
+#define CLIDR_CTYPE_SHIFT(level) (3 * (level - 1))
+#define CLIDR_CTYPE_MASK(level) (7 << CLIDR_CTYPE_SHIFT(level))
+#define CLIDR_CTYPE(clidr, level) \
+ (((clidr) & CLIDR_CTYPE_MASK(level)) >> CLIDR_CTYPE_SHIFT(level))
+
+static void test_clidr(struct kvm_vcpu *vcpu)
+{
+ uint64_t clidr;
+ int level;
+
+ vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(SYS_CLIDR_EL1), &clidr);
+
+ /* find the first empty level in the cache hierarchy */
+ for (level = 1; level < 7; level++) {
+ if (!CLIDR_CTYPE(clidr, level))
+ break;
+ }
+
+ /*
+ * If you have a mind-boggling 7 levels of cache, congratulations, you
+ * get to fix this.
+ */
+ TEST_ASSERT(level <= 7, "can't find an empty level in cache hierarchy");
+
+ /* stick in a unified cache level */
+ clidr |= BIT(2) << CLIDR_CTYPE_SHIFT(level);
+
+ vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_CLIDR_EL1), clidr);
+ test_reg_vals[encoding_to_range_idx(SYS_CLIDR_EL1)] = clidr;
+}
+
+static void test_vcpu_ftr_id_regs(struct kvm_vcpu *vcpu)
+{
+ u64 val;
+
+ test_clidr(vcpu);
+
+ vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(SYS_MPIDR_EL1), &val);
+ val++;
+ vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_MPIDR_EL1), val);
+
+ test_reg_vals[encoding_to_range_idx(SYS_MPIDR_EL1)] = val;
+ ksft_test_result_pass("%s\n", __func__);
+}
+
 static void test_assert_id_reg_unchanged(struct kvm_vcpu *vcpu, uint32_t encoding)
 {
  size_t idx = encoding_to_range_idx(encoding);
@@ -477,6 +524,8 @@ static void test_reset_preserves_id_regs(struct kvm_vcpu *vcpu)
  for (int i = 0; i < ARRAY_SIZE(test_regs); i++)
  test_assert_id_reg_unchanged(vcpu, test_regs[i].reg);
 
+ test_assert_id_reg_unchanged(vcpu, SYS_CLIDR_EL1);
+
  ksft_test_result_pass("%s\n", __func__);
 }
 
@@ -504,11 +553,13 @@ int main(void)
  ARRAY_SIZE(ftr_id_aa64isar2_el1) + ARRAY_SIZE(ftr_id_aa64pfr0_el1) +
  ARRAY_SIZE(ftr_id_aa64mmfr0_el1) + ARRAY_SIZE(ftr_id_aa64mmfr1_el1) +
  ARRAY_SIZE(ftr_id_aa64mmfr2_el1) + ARRAY_SIZE(ftr_id_aa64zfr0_el1) -
- ARRAY_SIZE(test_regs) + 1;
+ ARRAY_SIZE(test_regs) + 2;
 
  ksft_set_plan(test_cnt);
 
  test_vm_ftr_id_regs(vcpu, aarch64_only);
+ test_vcpu_ftr_id_regs(vcpu);
+
  test_guest_reg_read(vcpu);
 
  test_reset_preserves_id_regs(vcpu);