@@ -915,6 +915,7 @@ static inline unsigned int get_vmid_bits(u64 mmfr1)
return 8;
}
+s64 arm64_ftr_safe_value(const struct arm64_ftr_bits *ftrp, s64 new, s64 cur);
struct arm64_ftr_reg *get_arm64_ftr_reg(u32 sys_id);
extern struct arm64_ftr_override id_aa64mmfr1_override;
@@ -798,7 +798,7 @@ static u64 arm64_ftr_set_value(const struct arm64_ftr_bits *ftrp, s64 reg,
return reg;
}
-static s64 arm64_ftr_safe_value(const struct arm64_ftr_bits *ftrp, s64 new,
+s64 arm64_ftr_safe_value(const struct arm64_ftr_bits *ftrp, s64 new,
s64 cur)
{
s64 ret = 0;
@@ -41,6 +41,7 @@
* 64bit interface.
*/
+static int set_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, u64 val);
static u64 kvm_arm_read_id_reg(const struct kvm_vcpu *vcpu, u32 id);
static u64 sys_reg_to_index(const struct sys_reg_desc *reg);
@@ -1194,6 +1195,86 @@ static bool access_arch_timer(struct kvm_vcpu *vcpu,
return true;
}
+static s64 kvm_arm64_ftr_safe_value(u32 id, const struct arm64_ftr_bits *ftrp,
+ s64 new, s64 cur)
+{
+ struct arm64_ftr_bits kvm_ftr = *ftrp;
+
+ /* Some features have different safe value type in KVM than host features */
+ switch (id) {
+ case SYS_ID_AA64DFR0_EL1:
+ if (kvm_ftr.shift == ID_AA64DFR0_EL1_PMUVer_SHIFT)
+ kvm_ftr.type = FTR_LOWER_SAFE;
+ break;
+ case SYS_ID_DFR0_EL1:
+ if (kvm_ftr.shift == ID_DFR0_EL1_PerfMon_SHIFT)
+ kvm_ftr.type = FTR_LOWER_SAFE;
+ break;
+ }
+
+ return arm64_ftr_safe_value(&kvm_ftr, new, cur);
+}
+
+/**
+ * arm64_check_features() - Check if a feature register value constitutes
+ * a subset of features indicated by the idreg's KVM sanitised limit.
+ *
+ * This function will check if each feature field of @val is the "safe" value
+ * against idreg's KVM sanitised limit return from reset() callback.
+ * If a field value in @val is the same as the one in limit, it is always
+ * considered the safe value regardless For register fields that are not in
+ * writable, only the value in limit is considered the safe value.
+ *
+ * Return: 0 if all the fields are safe. Otherwise, return negative errno.
+ */
+static int arm64_check_features(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd,
+ u64 val)
+{
+ const struct arm64_ftr_reg *ftr_reg;
+ const struct arm64_ftr_bits *ftrp = NULL;
+ u32 id = reg_to_encoding(rd);
+ u64 writable_mask = rd->val;
+ u64 limit = 0;
+ u64 mask = 0;
+
+ /* For hidden and unallocated idregs without reset, only val = 0 is allowed. */
+ if (rd->reset) {
+ limit = rd->reset(vcpu, rd);
+ ftr_reg = get_arm64_ftr_reg(id);
+ if (!ftr_reg)
+ return -EINVAL;
+ ftrp = ftr_reg->ftr_bits;
+ }
+
+ for (; ftrp && ftrp->width; ftrp++) {
+ s64 f_val, f_lim, safe_val;
+ u64 ftr_mask;
+
+ ftr_mask = arm64_ftr_mask(ftrp);
+ if ((ftr_mask & writable_mask) != ftr_mask)
+ continue;
+
+ f_val = arm64_ftr_value(ftrp, val);
+ f_lim = arm64_ftr_value(ftrp, limit);
+ mask |= ftr_mask;
+
+ if (f_val == f_lim)
+ safe_val = f_val;
+ else
+ safe_val = kvm_arm64_ftr_safe_value(id, ftrp, f_val, f_lim);
+
+ if (safe_val != f_val)
+ return -E2BIG;
+ }
+
+ /* For fields that are not writable, values in limit are the safe values. */
+ if ((val & ~mask) != (limit & ~mask))
+ return -E2BIG;
+
+ return 0;
+}
+
static u8 vcpu_pmuver(const struct kvm_vcpu *vcpu)
{
if (kvm_vcpu_has_pmu(vcpu))
@@ -1244,7 +1325,6 @@ static u64 kvm_arm_read_id_reg(const struct kvm_vcpu *vcpu, u32 id)
case SYS_ID_AA64PFR0_EL1:
if (!vcpu_has_sve(vcpu))
val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_SVE);
- val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_AMU);
if (kvm_vgic_global_state.type == VGIC_V3) {
val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_GIC);
val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_GIC), 1);
@@ -1271,15 +1351,10 @@ static u64 kvm_arm_read_id_reg(const struct kvm_vcpu *vcpu, u32 id)
val &= ~ARM64_FEATURE_MASK(ID_AA64ISAR2_EL1_WFxT);
break;
case SYS_ID_AA64DFR0_EL1:
- /* Limit debug to ARMv8.0 */
- val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer);
- val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer), 6);
/* Set PMUver to the required version */
val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer),
vcpu_pmuver(vcpu));
- /* Hide SPE from guests */
- val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMSVer);
break;
case SYS_ID_DFR0_EL1:
val &= ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon);
@@ -1378,14 +1453,40 @@ static unsigned int sve_visibility(const struct kvm_vcpu *vcpu,
return REG_HIDDEN;
}
+static u64 read_sanitised_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd)
+{
+ u64 val;
+ u32 id = reg_to_encoding(rd);
+
+ val = read_sanitised_ftr_reg(id);
+ /*
+ * The default is to expose CSV2 == 1 if the HW isn't affected.
+ * Although this is a per-CPU feature, we make it global because
+ * asymmetric systems are just a nuisance.
+ *
+ * Userspace can override this as long as it doesn't promise
+ * the impossible.
+ */
+ if (arm64_get_spectre_v2_state() == SPECTRE_UNAFFECTED) {
+ val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2);
+ val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2), 1);
+ }
+ if (arm64_get_meltdown_state() == SPECTRE_UNAFFECTED) {
+ val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3);
+ val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3), 1);
+ }
+
+ val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_AMU);
+
+ return val;
+}
+
static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
const struct sys_reg_desc *rd,
u64 val)
{
- struct kvm_arch *arch = &vcpu->kvm->arch;
- u64 sval = val;
u8 csv2, csv3;
- int ret = 0;
/*
* Allow AA64PFR0_EL1.CSV2 to be set from userspace as long as
@@ -1403,26 +1504,30 @@ static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
(csv3 && arm64_get_meltdown_state() != SPECTRE_UNAFFECTED))
return -EINVAL;
- mutex_lock(&arch->config_lock);
- /* We can only differ with CSV[23], and anything else is an error */
- val ^= read_id_reg(vcpu, rd);
- val &= ~(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2) |
- ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3));
- if (val) {
- ret = -EINVAL;
- goto out;
- }
+ return set_id_reg(vcpu, rd, val);
+}
- /* Only allow userspace to change the idregs before VM running */
- if (test_bit(KVM_ARCH_FLAG_HAS_RAN_ONCE, &vcpu->kvm->arch.flags)) {
- if (sval != read_id_reg(vcpu, rd))
- ret = -EBUSY;
- } else {
- IDREG(vcpu->kvm, reg_to_encoding(rd)) = sval;
- }
-out:
- mutex_unlock(&arch->config_lock);
- return ret;
+static u64 read_sanitised_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd)
+{
+ u64 val;
+ u32 id = reg_to_encoding(rd);
+
+ val = read_sanitised_ftr_reg(id);
+ /* Limit debug to ARMv8.0 */
+ val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer);
+ val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_DebugVer), 6);
+ /*
+ * Initialise the default PMUver before there is a chance to
+ * create an actual PMU.
+ */
+ val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
+ val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer),
+ kvm_arm_pmu_get_pmuver_limit());
+ /* Hide SPE from guests */
+ val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMSVer);
+
+ return val;
}
static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
@@ -1432,7 +1537,6 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
struct kvm_arch *arch = &vcpu->kvm->arch;
u8 pmuver, host_pmuver;
bool valid_pmu;
- u64 sval = val;
int ret = 0;
host_pmuver = kvm_arm_pmu_get_pmuver_limit();
@@ -1454,40 +1558,61 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
return -EINVAL;
mutex_lock(&arch->config_lock);
- /* We can only differ with PMUver, and anything else is an error */
- val ^= read_id_reg(vcpu, rd);
- val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
- if (val) {
- ret = -EINVAL;
- goto out;
- }
-
/* Only allow userspace to change the idregs before VM running */
if (test_bit(KVM_ARCH_FLAG_HAS_RAN_ONCE, &vcpu->kvm->arch.flags)) {
- if (sval != read_id_reg(vcpu, rd))
+ if (val != read_id_reg(vcpu, rd))
ret = -EBUSY;
- } else {
- if (valid_pmu) {
- val = IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1);
- val &= ~ID_AA64DFR0_EL1_PMUVer_MASK;
- val |= FIELD_PREP(ID_AA64DFR0_EL1_PMUVer_MASK, pmuver);
- IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) = val;
-
- val = IDREG(vcpu->kvm, SYS_ID_DFR0_EL1);
- val &= ~ID_DFR0_EL1_PerfMon_MASK;
- val |= FIELD_PREP(ID_DFR0_EL1_PerfMon_MASK, pmuver_to_perfmon(pmuver));
- IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) = val;
- } else {
- assign_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags,
- pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF);
- }
+ goto out;
}
+ if (!valid_pmu) {
+ /*
+ * Ignore the PMUVer filed in @val. The PMUVer would be determined
+ * by arch flags bit KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU,
+ */
+ pmuver = FIELD_GET(ID_AA64DFR0_EL1_PMUVer_MASK,
+ IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1));
+ val &= ~ID_AA64DFR0_EL1_PMUVer_MASK;
+ val |= FIELD_PREP(ID_AA64DFR0_EL1_PMUVer_MASK, pmuver);
+ }
+
+ ret = arm64_check_features(vcpu, rd, val);
+ if (ret)
+ goto out;
+
+ IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) = val;
+
+ val = IDREG(vcpu->kvm, SYS_ID_DFR0_EL1);
+ val &= ~ID_DFR0_EL1_PerfMon_MASK;
+ val |= FIELD_PREP(ID_DFR0_EL1_PerfMon_MASK, pmuver_to_perfmon(pmuver));
+ IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) = val;
+
+ if (!valid_pmu)
+ assign_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags,
+ pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF);
+
out:
mutex_unlock(&arch->config_lock);
return ret;
}
+static u64 read_sanitised_id_dfr0_el1(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd)
+{
+ u64 val;
+ u32 id = reg_to_encoding(rd);
+
+ val = read_sanitised_ftr_reg(id);
+ /*
+ * Initialise the default PMUver before there is a chance to
+ * create an actual PMU.
+ */
+ val &= ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon);
+ val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon), kvm_arm_pmu_get_pmuver_limit());
+
+ return val;
+}
+
static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
const struct sys_reg_desc *rd,
u64 val)
@@ -1495,7 +1620,6 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
struct kvm_arch *arch = &vcpu->kvm->arch;
u8 perfmon, host_perfmon;
bool valid_pmu;
- u64 sval = val;
int ret = 0;
host_perfmon = pmuver_to_perfmon(kvm_arm_pmu_get_pmuver_limit());
@@ -1518,35 +1642,39 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
return -EINVAL;
mutex_lock(&arch->config_lock);
- /* We can only differ with PerfMon, and anything else is an error */
- val ^= read_id_reg(vcpu, rd);
- val &= ~ARM64_FEATURE_MASK(ID_DFR0_EL1_PerfMon);
- if (val) {
- ret = -EINVAL;
- goto out;
- }
-
/* Only allow userspace to change the idregs before VM running */
if (test_bit(KVM_ARCH_FLAG_HAS_RAN_ONCE, &vcpu->kvm->arch.flags)) {
- if (sval != read_id_reg(vcpu, rd))
+ if (val != read_id_reg(vcpu, rd))
ret = -EBUSY;
- } else {
- if (valid_pmu) {
- val = IDREG(vcpu->kvm, SYS_ID_DFR0_EL1);
- val &= ~ID_DFR0_EL1_PerfMon_MASK;
- val |= FIELD_PREP(ID_DFR0_EL1_PerfMon_MASK, perfmon);
- IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) = val;
-
- val = IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1);
- val &= ~ID_AA64DFR0_EL1_PMUVer_MASK;
- val |= FIELD_PREP(ID_AA64DFR0_EL1_PMUVer_MASK, perfmon_to_pmuver(perfmon));
- IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) = val;
- } else {
- assign_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags,
- perfmon == ID_DFR0_EL1_PerfMon_IMPDEF);
- }
+ goto out;
}
+ if (!valid_pmu) {
+ /*
+ * Ignore the PerfMon filed in @val. The PerfMon would be determined
+ * by arch flags bit KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU,
+ */
+ perfmon = FIELD_GET(ID_DFR0_EL1_PerfMon_MASK,
+ IDREG(vcpu->kvm, SYS_ID_DFR0_EL1));
+ val &= ~ID_DFR0_EL1_PerfMon_MASK;
+ val |= FIELD_PREP(ID_DFR0_EL1_PerfMon_MASK, perfmon);
+ }
+
+ ret = arm64_check_features(vcpu, rd, val);
+ if (ret)
+ goto out;
+
+ IDREG(vcpu->kvm, SYS_ID_DFR0_EL1) = val;
+
+ val = IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1);
+ val &= ~ID_AA64DFR0_EL1_PMUVer_MASK;
+ val |= FIELD_PREP(ID_AA64DFR0_EL1_PMUVer_MASK, perfmon_to_pmuver(perfmon));
+ IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1) = val;
+
+ if (!valid_pmu)
+ assign_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags,
+ perfmon == ID_DFR0_EL1_PerfMon_IMPDEF);
+
out:
mutex_unlock(&arch->config_lock);
return ret;
@@ -1574,11 +1702,23 @@ static int get_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
static int set_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
u64 val)
{
- /* This is what we mean by invariant: you can't change it. */
- if (val != read_id_reg(vcpu, rd))
- return -EINVAL;
+ struct kvm_arch *arch = &vcpu->kvm->arch;
+ u32 id = reg_to_encoding(rd);
+ int ret = 0;
- return 0;
+ mutex_lock(&arch->config_lock);
+ /* Only allow userspace to change the idregs before VM running */
+ if (test_bit(KVM_ARCH_FLAG_HAS_RAN_ONCE, &vcpu->kvm->arch.flags)) {
+ if (val != read_id_reg(vcpu, rd))
+ ret = -EBUSY;
+ } else {
+ ret = arm64_check_features(vcpu, rd, val);
+ if (!ret)
+ IDREG(vcpu->kvm, id) = val;
+ }
+ mutex_unlock(&arch->config_lock);
+
+ return ret;
}
static int get_raz_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
@@ -1929,9 +2069,13 @@ static const struct sys_reg_desc sys_reg_descs[] = {
/* CRm=1 */
AA32_ID_SANITISED(ID_PFR0_EL1),
AA32_ID_SANITISED(ID_PFR1_EL1),
- { SYS_DESC(SYS_ID_DFR0_EL1), .access = access_id_reg,
- .get_user = get_id_reg, .set_user = set_id_dfr0_el1,
- .visibility = aa32_id_visibility, },
+ { SYS_DESC(SYS_ID_DFR0_EL1),
+ .access = access_id_reg,
+ .get_user = get_id_reg,
+ .set_user = set_id_dfr0_el1,
+ .visibility = aa32_id_visibility,
+ .reset = read_sanitised_id_dfr0_el1,
+ .val = ID_DFR0_EL1_PerfMon_MASK, },
ID_HIDDEN(ID_AFR0_EL1),
AA32_ID_SANITISED(ID_MMFR0_EL1),
AA32_ID_SANITISED(ID_MMFR1_EL1),
@@ -1960,8 +2104,12 @@ static const struct sys_reg_desc sys_reg_descs[] = {
/* AArch64 ID registers */
/* CRm=4 */
- { SYS_DESC(SYS_ID_AA64PFR0_EL1), .access = access_id_reg,
- .get_user = get_id_reg, .set_user = set_id_aa64pfr0_el1, },
+ { SYS_DESC(SYS_ID_AA64PFR0_EL1),
+ .access = access_id_reg,
+ .get_user = get_id_reg,
+ .set_user = set_id_aa64pfr0_el1,
+ .reset = read_sanitised_id_aa64pfr0_el1,
+ .val = ID_AA64PFR0_EL1_CSV2_MASK | ID_AA64PFR0_EL1_CSV3_MASK, },
ID_SANITISED(ID_AA64PFR1_EL1),
ID_UNALLOCATED(4,2),
ID_UNALLOCATED(4,3),
@@ -1971,8 +2119,12 @@ static const struct sys_reg_desc sys_reg_descs[] = {
ID_UNALLOCATED(4,7),
/* CRm=5 */
- { SYS_DESC(SYS_ID_AA64DFR0_EL1), .access = access_id_reg,
- .get_user = get_id_reg, .set_user = set_id_aa64dfr0_el1, },
+ { SYS_DESC(SYS_ID_AA64DFR0_EL1),
+ .access = access_id_reg,
+ .get_user = get_id_reg,
+ .set_user = set_id_aa64dfr0_el1,
+ .reset = read_sanitised_id_aa64dfr0_el1,
+ .val = ID_AA64DFR0_EL1_PMUVer_MASK, },
ID_SANITISED(ID_AA64DFR1_EL1),
ID_UNALLOCATED(5,2),
ID_UNALLOCATED(5,3),
@@ -3494,38 +3646,6 @@ void kvm_arm_init_id_regs(struct kvm *kvm)
idreg++;
id = reg_to_encoding(idreg);
}
-
- /*
- * The default is to expose CSV2 == 1 if the HW isn't affected.
- * Although this is a per-CPU feature, we make it global because
- * asymmetric systems are just a nuisance.
- *
- * Userspace can override this as long as it doesn't promise
- * the impossible.
- */
- val = IDREG(kvm, SYS_ID_AA64PFR0_EL1);
-
- if (arm64_get_spectre_v2_state() == SPECTRE_UNAFFECTED) {
- val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2);
- val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV2), 1);
- }
- if (arm64_get_meltdown_state() == SPECTRE_UNAFFECTED) {
- val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3);
- val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_CSV3), 1);
- }
-
- IDREG(kvm, SYS_ID_AA64PFR0_EL1) = val;
- /*
- * Initialise the default PMUver before there is a chance to
- * create an actual PMU.
- */
- val = IDREG(kvm, SYS_ID_AA64DFR0_EL1);
-
- val &= ~ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer);
- val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer),
- kvm_arm_pmu_get_pmuver_limit());
-
- IDREG(kvm, SYS_ID_AA64DFR0_EL1) = val;
}
int __init kvm_sys_reg_table_init(void)
Refactor writings for ID_AA64PFR0_EL1.[CSV2|CSV3], ID_AA64DFR0_EL1.PMUVer and ID_DFR0_ELF.PerfMon based on utilities specific to ID register. Signed-off-by: Jing Zhang <jingzhangos@google.com> --- arch/arm64/include/asm/cpufeature.h | 1 + arch/arm64/kernel/cpufeature.c | 2 +- arch/arm64/kvm/sys_regs.c | 362 ++++++++++++++++++---------- 3 files changed, 243 insertions(+), 122 deletions(-)