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@xxxxxxxxxx>
---
arch/arm64/include/asm/cpufeature.h | 1 +
arch/arm64/kernel/cpufeature.c | 2 +-
arch/arm64/kvm/sys_regs.c | 291 +++++++++++++++++++---------
3 files changed, 203 insertions(+), 91 deletions(-)
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 6bf013fb110d..dc769c2eb7a4 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -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;
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 7d7128c65161..3317a7b6deac 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -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;
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 1a534e0fc4ca..50d4e25f42d3 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -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 encoding);
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))
@@ -1231,9 +1312,17 @@ static u8 pmuver_to_perfmon(u8 pmuver)
}
}
-static void pmuver_update(struct kvm_vcpu *vcpu, u8 pmuver, bool valid_pmu)
+static int pmuver_update(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd,
+ u64 val,
+ u8 pmuver,
+ bool valid_pmu)
{
- u64 val;
+ int ret;
+
+ ret = set_id_reg(vcpu, rd, val);
+ if (ret)
+ return ret;
if (valid_pmu) {
val = IDREG(vcpu->kvm, SYS_ID_AA64DFR0_EL1);
@@ -1249,6 +1338,8 @@ static void pmuver_update(struct kvm_vcpu *vcpu, u8 pmuver, bool valid_pmu)
assign_bit(KVM_ARCH_FLAG_VCPU_HAS_IMP_DEF_PMU, &vcpu->kvm->arch.flags,
pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF);
}
+
+ return 0;
}
static u64 general_read_kvm_sanitised_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd)
@@ -1264,7 +1355,6 @@ static u64 kvm_arm_read_id_reg(const struct kvm_vcpu *vcpu, u32 encoding)
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);
@@ -1291,15 +1381,10 @@ static u64 kvm_arm_read_id_reg(const struct kvm_vcpu *vcpu, u32 encoding)
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);
@@ -1398,38 +1483,56 @@ static unsigned int sve_visibility(const struct kvm_vcpu *vcpu,
return REG_HIDDEN;
}
-static int set_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
- const struct sys_reg_desc *rd,
- u64 val)
+static u64 read_sanitised_id_aa64pfr0_el1(struct kvm_vcpu *vcpu,
+ const struct sys_reg_desc *rd)
{
- u64 new_val = val;
- u8 csv2, csv3;
+ u64 val;
+ u32 id = reg_to_encoding(rd);
+ val = read_sanitised_ftr_reg(id);
/*
- * Allow AA64PFR0_EL1.CSV2 to be set from userspace as long as
- * it doesn't promise more than what is actually provided (the
- * guest could otherwise be covered in ectoplasmic residue).
+ * 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.
*/
- csv2 = cpuid_feature_extract_unsigned_field(val, ID_AA64PFR0_EL1_CSV2_SHIFT);
- if (csv2 > 1 ||
- (csv2 && arm64_get_spectre_v2_state() != SPECTRE_UNAFFECTED))
- return -EINVAL;
+ 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);
+ }
- /* Same thing for CSV3 */
- csv3 = cpuid_feature_extract_unsigned_field(val, ID_AA64PFR0_EL1_CSV3_SHIFT);
- if (csv3 > 1 ||
- (csv3 && arm64_get_meltdown_state() != SPECTRE_UNAFFECTED))
- return -EINVAL;
+ val &= ~ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_AMU);
- /* 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)
- return -EINVAL;
+ return val;
+}
- IDREG(vcpu->kvm, reg_to_encoding(rd)) = new_val;
- return 0;
+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,
@@ -1457,14 +1560,35 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
if (kvm_vcpu_has_pmu(vcpu) != valid_pmu)
return -EINVAL;
- /* 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)
- return -EINVAL;
+ if (!valid_pmu) {
+ /*
+ * Ignore the PMUVer field 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);
+ }
- pmuver_update(vcpu, pmuver, valid_pmu);
- return 0;
+ return pmuver_update(vcpu, rd, val, pmuver, valid_pmu);
+}
+
+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,
@@ -1493,14 +1617,18 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
if (kvm_vcpu_has_pmu(vcpu) != valid_pmu)
return -EINVAL;
- /* 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)
- return -EINVAL;
+ if (!valid_pmu) {
+ /*
+ * Ignore the PerfMon field 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);
+ }
- pmuver_update(vcpu, perfmon_to_pmuver(perfmon), valid_pmu);
- return 0;
+ return pmuver_update(vcpu, rd, val, perfmon_to_pmuver(perfmon), valid_pmu);
}
/*
@@ -1520,11 +1648,14 @@ 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;
+ u32 id = reg_to_encoding(rd);
+ int ret = 0;
- return 0;
+ ret = arm64_check_features(vcpu, rd, val);
+ if (!ret)
+ IDREG(vcpu->kvm, id) = val;
+
+ return ret;
}
static int get_raz_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
@@ -1875,9 +2006,13 @@ 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),
@@ -1906,8 +2041,12 @@ 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_reg,
+ .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),
@@ -1917,8 +2056,12 @@ 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),
@@ -3454,38 +3597,6 @@ 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)
--
2.41.0.rc0.172.g3f132b7071-goog
