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 <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240502233529.1958459-8-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>

diff --git a/tools/testing/selftests/kvm/aarch64/set_id_regs.c b/tools/testing/selftests/kvm/aarch64/set_id_regs.c
index 24b248c78f5d5a66257c9d3165cf0c30eafd0efc..a7de39fa2a0a23c018d729bafd0b48059fe152db 100644 (file)
--- a/tools/testing/selftests/kvm/aarch64/set_id_regs.c
+++ b/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);