KVM: arm64: selftests: Test for setting ID register from usersapce
authorJing Zhang <jingzhangos@google.com>
Wed, 11 Oct 2023 19:57:40 +0000 (19:57 +0000)
committerOliver Upton <oliver.upton@linux.dev>
Wed, 18 Oct 2023 23:37:33 +0000 (23:37 +0000)
Add tests to verify setting ID registers from userspace is handled
correctly by KVM. Also add a test case to use ioctl
KVM_ARM_GET_REG_WRITABLE_MASKS to get writable masks.

Signed-off-by: Jing Zhang <jingzhangos@google.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231011195740.3349631-6-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
tools/testing/selftests/kvm/Makefile
tools/testing/selftests/kvm/aarch64/set_id_regs.c [new file with mode: 0644]

index 07b3f4dc1a77560eea832389efaa17c233885454..4f4f6ad025f4b424b555988f641880f6a4255970 100644 (file)
@@ -156,6 +156,7 @@ TEST_GEN_PROGS_aarch64 += aarch64/debug-exceptions
 TEST_GEN_PROGS_aarch64 += aarch64/hypercalls
 TEST_GEN_PROGS_aarch64 += aarch64/page_fault_test
 TEST_GEN_PROGS_aarch64 += aarch64/psci_test
+TEST_GEN_PROGS_aarch64 += aarch64/set_id_regs
 TEST_GEN_PROGS_aarch64 += aarch64/smccc_filter
 TEST_GEN_PROGS_aarch64 += aarch64/vcpu_width_config
 TEST_GEN_PROGS_aarch64 += aarch64/vgic_init
diff --git a/tools/testing/selftests/kvm/aarch64/set_id_regs.c b/tools/testing/selftests/kvm/aarch64/set_id_regs.c
new file mode 100644 (file)
index 0000000..bac0521
--- /dev/null
@@ -0,0 +1,481 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * set_id_regs - Test for setting ID register from usersapce.
+ *
+ * Copyright (c) 2023 Google LLC.
+ *
+ *
+ * Test that KVM supports setting ID registers from userspace and handles the
+ * feature set correctly.
+ */
+
+#include <stdint.h>
+#include "kvm_util.h"
+#include "processor.h"
+#include "test_util.h"
+#include <linux/bitfield.h>
+
+enum ftr_type {
+       FTR_EXACT,                      /* Use a predefined safe value */
+       FTR_LOWER_SAFE,                 /* Smaller value is safe */
+       FTR_HIGHER_SAFE,                /* Bigger value is safe */
+       FTR_HIGHER_OR_ZERO_SAFE,        /* Bigger value is safe, but 0 is biggest */
+       FTR_END,                        /* Mark the last ftr bits */
+};
+
+#define FTR_SIGNED     true    /* Value should be treated as signed */
+#define FTR_UNSIGNED   false   /* Value should be treated as unsigned */
+
+struct reg_ftr_bits {
+       char *name;
+       bool sign;
+       enum ftr_type type;
+       uint8_t shift;
+       uint64_t mask;
+       int64_t safe_val;
+};
+
+struct test_feature_reg {
+       uint32_t reg;
+       const struct reg_ftr_bits *ftr_bits;
+};
+
+#define __REG_FTR_BITS(NAME, SIGNED, TYPE, SHIFT, MASK, SAFE_VAL)      \
+       {                                                               \
+               .name = #NAME,                                          \
+               .sign = SIGNED,                                         \
+               .type = TYPE,                                           \
+               .shift = SHIFT,                                         \
+               .mask = MASK,                                           \
+               .safe_val = SAFE_VAL,                                   \
+       }
+
+#define REG_FTR_BITS(type, reg, field, safe_val) \
+       __REG_FTR_BITS(reg##_##field, FTR_UNSIGNED, type, reg##_##field##_SHIFT, \
+                      reg##_##field##_MASK, safe_val)
+
+#define S_REG_FTR_BITS(type, reg, field, safe_val) \
+       __REG_FTR_BITS(reg##_##field, FTR_SIGNED, type, reg##_##field##_SHIFT, \
+                      reg##_##field##_MASK, safe_val)
+
+#define REG_FTR_END                                    \
+       {                                               \
+               .type = FTR_END,                        \
+       }
+
+static const struct reg_ftr_bits ftr_id_aa64dfr0_el1[] = {
+       S_REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64DFR0_EL1, PMUVer, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64DFR0_EL1, DebugVer, 0),
+       REG_FTR_END,
+};
+
+static const struct reg_ftr_bits ftr_id_dfr0_el1[] = {
+       S_REG_FTR_BITS(FTR_LOWER_SAFE, ID_DFR0_EL1, PerfMon, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_DFR0_EL1, CopDbg, 0),
+       REG_FTR_END,
+};
+
+static const struct reg_ftr_bits ftr_id_aa64isar0_el1[] = {
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR0_EL1, RNDR, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR0_EL1, TLB, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR0_EL1, TS, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR0_EL1, FHM, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR0_EL1, DP, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR0_EL1, SM4, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR0_EL1, SM3, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR0_EL1, SHA3, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR0_EL1, RDM, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR0_EL1, TME, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR0_EL1, ATOMIC, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR0_EL1, CRC32, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR0_EL1, SHA2, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR0_EL1, SHA1, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR0_EL1, AES, 0),
+       REG_FTR_END,
+};
+
+static const struct reg_ftr_bits ftr_id_aa64isar1_el1[] = {
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR1_EL1, LS64, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR1_EL1, XS, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR1_EL1, I8MM, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR1_EL1, DGH, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR1_EL1, BF16, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR1_EL1, SPECRES, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR1_EL1, SB, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR1_EL1, FRINTTS, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR1_EL1, LRCPC, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR1_EL1, FCMA, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR1_EL1, JSCVT, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR1_EL1, DPB, 0),
+       REG_FTR_END,
+};
+
+static const struct reg_ftr_bits ftr_id_aa64isar2_el1[] = {
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR2_EL1, BC, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR2_EL1, RPRES, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ISAR2_EL1, WFxT, 0),
+       REG_FTR_END,
+};
+
+static const struct reg_ftr_bits ftr_id_aa64pfr0_el1[] = {
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64PFR0_EL1, CSV3, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64PFR0_EL1, CSV2, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64PFR0_EL1, DIT, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64PFR0_EL1, SEL2, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64PFR0_EL1, EL3, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64PFR0_EL1, EL2, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64PFR0_EL1, EL1, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64PFR0_EL1, EL0, 0),
+       REG_FTR_END,
+};
+
+static const struct reg_ftr_bits ftr_id_aa64mmfr0_el1[] = {
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR0_EL1, ECV, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR0_EL1, EXS, 0),
+       S_REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR0_EL1, TGRAN4, 0),
+       S_REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR0_EL1, TGRAN64, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR0_EL1, TGRAN16, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR0_EL1, BIGENDEL0, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR0_EL1, SNSMEM, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR0_EL1, BIGEND, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR0_EL1, ASIDBITS, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR0_EL1, PARANGE, 0),
+       REG_FTR_END,
+};
+
+static const struct reg_ftr_bits ftr_id_aa64mmfr1_el1[] = {
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR1_EL1, TIDCP1, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR1_EL1, AFP, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR1_EL1, ETS, 0),
+       REG_FTR_BITS(FTR_HIGHER_SAFE, ID_AA64MMFR1_EL1, SpecSEI, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR1_EL1, PAN, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR1_EL1, LO, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR1_EL1, HPDS, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR1_EL1, HAFDBS, 0),
+       REG_FTR_END,
+};
+
+static const struct reg_ftr_bits ftr_id_aa64mmfr2_el1[] = {
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR2_EL1, E0PD, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR2_EL1, BBM, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR2_EL1, TTL, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR2_EL1, AT, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR2_EL1, ST, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR2_EL1, VARange, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR2_EL1, IESB, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR2_EL1, LSM, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR2_EL1, UAO, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64MMFR2_EL1, CnP, 0),
+       REG_FTR_END,
+};
+
+static const struct reg_ftr_bits ftr_id_aa64zfr0_el1[] = {
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ZFR0_EL1, F64MM, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ZFR0_EL1, F32MM, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ZFR0_EL1, I8MM, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ZFR0_EL1, SM4, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ZFR0_EL1, SHA3, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ZFR0_EL1, BF16, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ZFR0_EL1, BitPerm, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ZFR0_EL1, AES, 0),
+       REG_FTR_BITS(FTR_LOWER_SAFE, ID_AA64ZFR0_EL1, SVEver, 0),
+       REG_FTR_END,
+};
+
+#define TEST_REG(id, table)                    \
+       {                                       \
+               .reg = id,                      \
+               .ftr_bits = &((table)[0]),      \
+       }
+
+static struct test_feature_reg test_regs[] = {
+       TEST_REG(SYS_ID_AA64DFR0_EL1, ftr_id_aa64dfr0_el1),
+       TEST_REG(SYS_ID_DFR0_EL1, ftr_id_dfr0_el1),
+       TEST_REG(SYS_ID_AA64ISAR0_EL1, ftr_id_aa64isar0_el1),
+       TEST_REG(SYS_ID_AA64ISAR1_EL1, ftr_id_aa64isar1_el1),
+       TEST_REG(SYS_ID_AA64ISAR2_EL1, ftr_id_aa64isar2_el1),
+       TEST_REG(SYS_ID_AA64PFR0_EL1, ftr_id_aa64pfr0_el1),
+       TEST_REG(SYS_ID_AA64MMFR0_EL1, ftr_id_aa64mmfr0_el1),
+       TEST_REG(SYS_ID_AA64MMFR1_EL1, ftr_id_aa64mmfr1_el1),
+       TEST_REG(SYS_ID_AA64MMFR2_EL1, ftr_id_aa64mmfr2_el1),
+       TEST_REG(SYS_ID_AA64ZFR0_EL1, ftr_id_aa64zfr0_el1),
+};
+
+#define GUEST_REG_SYNC(id) GUEST_SYNC_ARGS(0, id, read_sysreg_s(id), 0, 0);
+
+static void guest_code(void)
+{
+       GUEST_REG_SYNC(SYS_ID_AA64DFR0_EL1);
+       GUEST_REG_SYNC(SYS_ID_DFR0_EL1);
+       GUEST_REG_SYNC(SYS_ID_AA64ISAR0_EL1);
+       GUEST_REG_SYNC(SYS_ID_AA64ISAR1_EL1);
+       GUEST_REG_SYNC(SYS_ID_AA64ISAR2_EL1);
+       GUEST_REG_SYNC(SYS_ID_AA64PFR0_EL1);
+       GUEST_REG_SYNC(SYS_ID_AA64MMFR0_EL1);
+       GUEST_REG_SYNC(SYS_ID_AA64MMFR1_EL1);
+       GUEST_REG_SYNC(SYS_ID_AA64MMFR2_EL1);
+       GUEST_REG_SYNC(SYS_ID_AA64ZFR0_EL1);
+
+       GUEST_DONE();
+}
+
+/* Return a safe value to a given ftr_bits an ftr value */
+uint64_t get_safe_value(const struct reg_ftr_bits *ftr_bits, uint64_t ftr)
+{
+       uint64_t ftr_max = GENMASK_ULL(ARM64_FEATURE_FIELD_BITS - 1, 0);
+
+       if (ftr_bits->type == FTR_UNSIGNED) {
+               switch (ftr_bits->type) {
+               case FTR_EXACT:
+                       ftr = ftr_bits->safe_val;
+                       break;
+               case FTR_LOWER_SAFE:
+                       if (ftr > 0)
+                               ftr--;
+                       break;
+               case FTR_HIGHER_SAFE:
+                       if (ftr < ftr_max)
+                               ftr++;
+                       break;
+               case FTR_HIGHER_OR_ZERO_SAFE:
+                       if (ftr == ftr_max)
+                               ftr = 0;
+                       else if (ftr != 0)
+                               ftr++;
+                       break;
+               default:
+                       break;
+               }
+       } else if (ftr != ftr_max) {
+               switch (ftr_bits->type) {
+               case FTR_EXACT:
+                       ftr = ftr_bits->safe_val;
+                       break;
+               case FTR_LOWER_SAFE:
+                       if (ftr > 0)
+                               ftr--;
+                       break;
+               case FTR_HIGHER_SAFE:
+                       if (ftr < ftr_max - 1)
+                               ftr++;
+                       break;
+               case FTR_HIGHER_OR_ZERO_SAFE:
+                       if (ftr != 0 && ftr != ftr_max - 1)
+                               ftr++;
+                       break;
+               default:
+                       break;
+               }
+       }
+
+       return ftr;
+}
+
+/* Return an invalid value to a given ftr_bits an ftr value */
+uint64_t get_invalid_value(const struct reg_ftr_bits *ftr_bits, uint64_t ftr)
+{
+       uint64_t ftr_max = GENMASK_ULL(ARM64_FEATURE_FIELD_BITS - 1, 0);
+
+       if (ftr_bits->type == FTR_UNSIGNED) {
+               switch (ftr_bits->type) {
+               case FTR_EXACT:
+                       ftr = max((uint64_t)ftr_bits->safe_val + 1, ftr + 1);
+                       break;
+               case FTR_LOWER_SAFE:
+                       ftr++;
+                       break;
+               case FTR_HIGHER_SAFE:
+                       ftr--;
+                       break;
+               case FTR_HIGHER_OR_ZERO_SAFE:
+                       if (ftr == 0)
+                               ftr = ftr_max;
+                       else
+                               ftr--;
+                       break;
+               default:
+                       break;
+               }
+       } else if (ftr != ftr_max) {
+               switch (ftr_bits->type) {
+               case FTR_EXACT:
+                       ftr = max((uint64_t)ftr_bits->safe_val + 1, ftr + 1);
+                       break;
+               case FTR_LOWER_SAFE:
+                       ftr++;
+                       break;
+               case FTR_HIGHER_SAFE:
+                       ftr--;
+                       break;
+               case FTR_HIGHER_OR_ZERO_SAFE:
+                       if (ftr == 0)
+                               ftr = ftr_max - 1;
+                       else
+                               ftr--;
+                       break;
+               default:
+                       break;
+               }
+       } else {
+               ftr = 0;
+       }
+
+       return ftr;
+}
+
+static void test_reg_set_success(struct kvm_vcpu *vcpu, uint64_t reg,
+                                const struct reg_ftr_bits *ftr_bits)
+{
+       uint8_t shift = ftr_bits->shift;
+       uint64_t mask = ftr_bits->mask;
+       uint64_t val, new_val, ftr;
+
+       vcpu_get_reg(vcpu, reg, &val);
+       ftr = (val & mask) >> shift;
+
+       ftr = get_safe_value(ftr_bits, ftr);
+
+       ftr <<= shift;
+       val &= ~mask;
+       val |= ftr;
+
+       vcpu_set_reg(vcpu, reg, val);
+       vcpu_get_reg(vcpu, reg, &new_val);
+       TEST_ASSERT_EQ(new_val, val);
+}
+
+static void test_reg_set_fail(struct kvm_vcpu *vcpu, uint64_t reg,
+                             const struct reg_ftr_bits *ftr_bits)
+{
+       uint8_t shift = ftr_bits->shift;
+       uint64_t mask = ftr_bits->mask;
+       uint64_t val, old_val, ftr;
+       int r;
+
+       vcpu_get_reg(vcpu, reg, &val);
+       ftr = (val & mask) >> shift;
+
+       ftr = get_invalid_value(ftr_bits, ftr);
+
+       old_val = val;
+       ftr <<= shift;
+       val &= ~mask;
+       val |= ftr;
+
+       r = __vcpu_set_reg(vcpu, reg, val);
+       TEST_ASSERT(r < 0 && errno == EINVAL,
+                   "Unexpected KVM_SET_ONE_REG error: r=%d, errno=%d", r, errno);
+
+       vcpu_get_reg(vcpu, reg, &val);
+       TEST_ASSERT_EQ(val, old_val);
+}
+
+static void test_user_set_reg(struct kvm_vcpu *vcpu, bool aarch64_only)
+{
+       uint64_t masks[KVM_ARM_FEATURE_ID_RANGE_SIZE];
+       struct reg_mask_range range = {
+               .addr = (__u64)masks,
+       };
+       int ret;
+
+       /* KVM should return error when reserved field is not zero */
+       range.reserved[0] = 1;
+       ret = __vm_ioctl(vcpu->vm, KVM_ARM_GET_REG_WRITABLE_MASKS, &range);
+       TEST_ASSERT(ret, "KVM doesn't check invalid parameters.");
+
+       /* Get writable masks for feature ID registers */
+       memset(range.reserved, 0, sizeof(range.reserved));
+       vm_ioctl(vcpu->vm, KVM_ARM_GET_REG_WRITABLE_MASKS, &range);
+
+       for (int i = 0; i < ARRAY_SIZE(test_regs); i++) {
+               const struct reg_ftr_bits *ftr_bits = test_regs[i].ftr_bits;
+               uint32_t reg_id = test_regs[i].reg;
+               uint64_t reg = KVM_ARM64_SYS_REG(reg_id);
+               int idx;
+
+               /* Get the index to masks array for the idreg */
+               idx = KVM_ARM_FEATURE_ID_RANGE_IDX(sys_reg_Op0(reg_id), sys_reg_Op1(reg_id),
+                                                  sys_reg_CRn(reg_id), sys_reg_CRm(reg_id),
+                                                  sys_reg_Op2(reg_id));
+
+               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",
+                                                     ftr_bits[j].name);
+                               continue;
+                       }
+
+                       /* Make sure the feature field is writable */
+                       TEST_ASSERT_EQ(masks[idx] & ftr_bits[j].mask, ftr_bits[j].mask);
+
+                       test_reg_set_fail(vcpu, reg, &ftr_bits[j]);
+                       test_reg_set_success(vcpu, reg, &ftr_bits[j]);
+
+                       ksft_test_result_pass("%s\n", ftr_bits[j].name);
+               }
+       }
+}
+
+static void test_guest_reg_read(struct kvm_vcpu *vcpu)
+{
+       bool done = false;
+       struct ucall uc;
+       uint64_t val;
+
+       while (!done) {
+               vcpu_run(vcpu);
+
+               switch (get_ucall(vcpu, &uc)) {
+               case UCALL_ABORT:
+                       REPORT_GUEST_ASSERT(uc);
+                       break;
+               case UCALL_SYNC:
+                       /* Make sure the written values are seen by guest */
+                       vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(uc.args[2]), &val);
+                       TEST_ASSERT_EQ(val, uc.args[3]);
+                       break;
+               case UCALL_DONE:
+                       done = true;
+                       break;
+               default:
+                       TEST_FAIL("Unexpected ucall: %lu", uc.cmd);
+               }
+       }
+}
+
+int main(void)
+{
+       struct kvm_vcpu *vcpu;
+       struct kvm_vm *vm;
+       bool aarch64_only;
+       uint64_t val, el0;
+       int ftr_cnt;
+
+       TEST_REQUIRE(kvm_has_cap(KVM_CAP_ARM_SUPPORTED_REG_MASK_RANGES));
+
+       vm = vm_create_with_one_vcpu(&vcpu, guest_code);
+
+       /* Check for AARCH64 only system */
+       vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(SYS_ID_AA64PFR0_EL1), &val);
+       el0 = FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_EL0), val);
+       aarch64_only = (el0 == ID_AA64PFR0_EL1_ELx_64BIT_ONLY);
+
+       ksft_print_header();
+
+       ftr_cnt = ARRAY_SIZE(ftr_id_aa64dfr0_el1) + ARRAY_SIZE(ftr_id_dfr0_el1) +
+                 ARRAY_SIZE(ftr_id_aa64isar0_el1) + ARRAY_SIZE(ftr_id_aa64isar1_el1) +
+                 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);
+
+       ksft_set_plan(ftr_cnt);
+
+       test_user_set_reg(vcpu, aarch64_only);
+       test_guest_reg_read(vcpu);
+
+       kvm_vm_free(vm);
+
+       ksft_finished();
+}