On Thu, Aug 13, 2020 at 06:26:51PM +0800, Peng Liang wrote: > The Arm architecture specifies a number of ID registers that are > characterized as comprising a set of 4-bit ID fields. Each ID field > identifies the presence, and possibly the level of support for, a > particular feature in an implementation of the architecture. [1] > > For most of the ID fields, there is a minimum presence value, equal to > or higher than which means the corresponding CPU feature is implemented. > Hence, we can use the minimum presence value to determine whether a CPU > feature is enabled and enable a CPU feature. > > To disable a CPU feature, setting the corresponding ID field to 0x0/0xf > (for unsigned/signed field) seems as a good idea. However, it maybe > lead to some problems. For example, ID_AA64PFR0_EL1.FP is a signed ID > field. ID_AA64PFR0_EL1.FP == 0x0 represents the implementation of FP > (floating-point) and ID_AA64PFR0_EL1.FP == 0x1 represents the > implementation of FPHP (half-precision floating-point). If > ID_AA64PFR0_EL1.FP is set to 0xf when FPHP is disabled (which is also > disable FP), guest kernel maybe stuck. Hence, we add a ni_value (means > not-implemented value) to disable a CPU feature safely. > > [1] D13.1.3 Principles of the ID scheme for fields in ID registers in > DDI.0487 > > Signed-off-by: zhanghailiang <zhang.zhanghaili...@huawei.com> > Signed-off-by: Peng Liang <liangpen...@huawei.com> > --- > target/arm/cpu.c | 343 +++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 343 insertions(+) > > diff --git a/target/arm/cpu.c b/target/arm/cpu.c > index 79d7a6b45c..113cf4a9e7 100644 > --- a/target/arm/cpu.c > +++ b/target/arm/cpu.c > @@ -1146,6 +1146,348 @@ unsigned int gt_cntfrq_period_ns(ARMCPU *cpu) > NANOSECONDS_PER_SECOND / cpu->gt_cntfrq_hz : 1; > } > > +/** > + * CPUFeatureInfo: > + * @reg: The ID register where the ID field is in. > + * @name: The name of the CPU feature. > + * @length: The bit length of the ID field. > + * @shift: The bit shift of the ID field in the ID register. > + * @min_value: The minimum value equal to or larger than which means the CPU > + * feature is implemented. > + * @ni_value: Not-implemented value. It will be set to the ID field when > + * disabling the CPU feature. Usually, it's min_value - 1. > + * @sign: Whether the ID field is signed. > + * @is_32bit: Whether the CPU feature is for 32-bit. > + * > + * In ARM, a CPU feature is described by an ID field, which is a 4-bit field > in > + * an ID register. > + */ > +typedef struct CPUFeatureInfo { > + CPUIDReg reg; > + const char *name; > + int length; > + int shift; > + int min_value; > + int ni_value; > + bool sign; > + bool is_32bit; > +} CPUFeatureInfo; > + > +#define FIELD_INFO(id_reg, field, s, min_val, ni_val, is32bit) { \ > + .reg = id_reg, \ > + .length = R_ ## id_reg ## _ ## field ## _LENGTH, \ > + .shift = R_ ## id_reg ## _ ## field ## _SHIFT, \ > + .sign = s, \ > + .min_value = min_val, \ > + .ni_value = ni_val, \ > + .name = #field, \ > + .is_32bit = is32bit, \ > +} > + > +static struct CPUFeatureInfo cpu_features[] = { > + FIELD_INFO(ID_ISAR0, SWAP, false, 1, 0, true), > + FIELD_INFO(ID_ISAR0, BITCOUNT, false, 1, 0, true), > + FIELD_INFO(ID_ISAR0, BITFIELD, false, 1, 0, true), > + FIELD_INFO(ID_ISAR0, CMPBRANCH, false, 1, 0, true), > + FIELD_INFO(ID_ISAR0, COPROC, false, 1, 0, true), > + FIELD_INFO(ID_ISAR0, DEBUG, false, 1, 0, true), > + FIELD_INFO(ID_ISAR0, DIVIDE, false, 1, 0, true), > + > + FIELD_INFO(ID_ISAR1, ENDIAN, false, 1, 0, true), > + FIELD_INFO(ID_ISAR1, EXCEPT, false, 1, 0, true), > + FIELD_INFO(ID_ISAR1, EXCEPT_AR, false, 1, 0, true), > + FIELD_INFO(ID_ISAR1, EXTEND, false, 1, 0, true), > + FIELD_INFO(ID_ISAR1, IFTHEN, false, 1, 0, true), > + FIELD_INFO(ID_ISAR1, IMMEDIATE, false, 1, 0, true), > + FIELD_INFO(ID_ISAR1, INTERWORK, false, 1, 0, true), > + FIELD_INFO(ID_ISAR1, JAZELLE, false, 1, 0, true), > + > + FIELD_INFO(ID_ISAR2, LOADSTORE, false, 1, 0, true), > + FIELD_INFO(ID_ISAR2, MEMHINT, false, 1, 0, true), > + FIELD_INFO(ID_ISAR2, MULTIACCESSINT, false, 1, 0, true), > + FIELD_INFO(ID_ISAR2, MULT, false, 1, 0, true), > + FIELD_INFO(ID_ISAR2, MULTS, false, 1, 0, true), > + FIELD_INFO(ID_ISAR2, MULTU, false, 1, 0, true), > + FIELD_INFO(ID_ISAR2, PSR_AR, false, 1, 0, true), > + FIELD_INFO(ID_ISAR2, REVERSAL, false, 1, 0, true), > + > + FIELD_INFO(ID_ISAR3, SATURATE, false, 1, 0, true), > + FIELD_INFO(ID_ISAR3, SIMD, false, 1, 0, true), > + FIELD_INFO(ID_ISAR3, SVC, false, 1, 0, true), > + FIELD_INFO(ID_ISAR3, SYNCHPRIM, false, 1, 0, true), > + FIELD_INFO(ID_ISAR3, TABBRANCH, false, 1, 0, true), > + FIELD_INFO(ID_ISAR3, T32COPY, false, 1, 0, true), > + FIELD_INFO(ID_ISAR3, TRUENOP, false, 1, 0, true), > + FIELD_INFO(ID_ISAR3, T32EE, false, 1, 0, true), > + > + FIELD_INFO(ID_ISAR4, UNPRIV, false, 1, 0, true), > + FIELD_INFO(ID_ISAR4, WITHSHIFTS, false, 1, 0, true), > + FIELD_INFO(ID_ISAR4, WRITEBACK, false, 1, 0, true), > + FIELD_INFO(ID_ISAR4, SMC, false, 1, 0, true), > + FIELD_INFO(ID_ISAR4, BARRIER, false, 1, 0, true), > + FIELD_INFO(ID_ISAR4, SYNCHPRIM_FRAC, false, 1, 0, true), > + FIELD_INFO(ID_ISAR4, PSR_M, false, 1, 0, true), > + FIELD_INFO(ID_ISAR4, SWP_FRAC, false, 1, 0, true), > + > + FIELD_INFO(ID_ISAR5, SEVL, false, 1, 0, true), > + FIELD_INFO(ID_ISAR5, AES, false, 1, 0, true), > + FIELD_INFO(ID_ISAR5, SHA1, false, 1, 0, true), > + FIELD_INFO(ID_ISAR5, SHA2, false, 1, 0, true), > + FIELD_INFO(ID_ISAR5, CRC32, false, 1, 0, true), > + FIELD_INFO(ID_ISAR5, RDM, false, 1, 0, true), > + FIELD_INFO(ID_ISAR5, VCMA, false, 1, 0, true), > + > + FIELD_INFO(ID_ISAR6, JSCVT, false, 1, 0, true), > + FIELD_INFO(ID_ISAR6, DP, false, 1, 0, true), > + FIELD_INFO(ID_ISAR6, FHM, false, 1, 0, true), > + FIELD_INFO(ID_ISAR6, SB, false, 1, 0, true), > + FIELD_INFO(ID_ISAR6, SPECRES, false, 1, 0, true), > + > + FIELD_INFO(ID_MMFR3, CMAINTVA, false, 1, 0, true), > + FIELD_INFO(ID_MMFR3, CMAINTSW, false, 1, 0, true), > + FIELD_INFO(ID_MMFR3, BPMAINT, false, 1, 0, true), > + FIELD_INFO(ID_MMFR3, MAINTBCST, false, 1, 0, true), > + FIELD_INFO(ID_MMFR3, PAN, false, 1, 0, true), > + FIELD_INFO(ID_MMFR3, COHWALK, false, 1, 0, true), > + FIELD_INFO(ID_MMFR3, CMEMSZ, false, 1, 0, true), > + FIELD_INFO(ID_MMFR3, SUPERSEC, false, 1, 0, true), > + > + FIELD_INFO(ID_MMFR4, SPECSEI, false, 1, 0, true), > + FIELD_INFO(ID_MMFR4, AC2, false, 1, 0, true), > + FIELD_INFO(ID_MMFR4, XNX, false, 1, 0, true), > + FIELD_INFO(ID_MMFR4, CNP, false, 1, 0, true), > + FIELD_INFO(ID_MMFR4, HPDS, false, 1, 0, true), > + FIELD_INFO(ID_MMFR4, LSM, false, 1, 0, true), > + FIELD_INFO(ID_MMFR4, CCIDX, false, 1, 0, true), > + FIELD_INFO(ID_MMFR4, EVT, false, 1, 0, true), > + > + FIELD_INFO(MVFR0, SIMDREG, false, 1, 0, true), > + FIELD_INFO(MVFR0, FPSP, false, 1, 0, true), > + FIELD_INFO(MVFR0, FPDP, false, 1, 0, true), > + FIELD_INFO(MVFR0, FPTRAP, false, 1, 0, true), > + FIELD_INFO(MVFR0, FPDIVIDE, false, 1, 0, true), > + FIELD_INFO(MVFR0, FPSQRT, false, 1, 0, true), > + FIELD_INFO(MVFR0, FPSHVEC, false, 1, 0, true), > + FIELD_INFO(MVFR0, FPROUND, false, 1, 0, true), > + > + FIELD_INFO(MVFR1, FPFTZ, false, 1, 0, true), > + FIELD_INFO(MVFR1, FPDNAN, false, 1, 0, true), > + FIELD_INFO(MVFR1, SIMDLS, false, 1, 0, true), > + FIELD_INFO(MVFR1, SIMDINT, false, 1, 0, true), > + FIELD_INFO(MVFR1, SIMDSP, false, 1, 0, true), > + FIELD_INFO(MVFR1, SIMDHP, false, 1, 0, true), > + FIELD_INFO(MVFR1, FPHP, false, 1, 0, true), > + FIELD_INFO(MVFR1, SIMDFMAC, false, 1, 0, true), > + > + FIELD_INFO(MVFR2, SIMDMISC, false, 1, 0, true), > + FIELD_INFO(MVFR2, FPMISC, false, 1, 0, true), > + > + FIELD_INFO(ID_DFR0, COPDBG, false, 1, 0, true), > + FIELD_INFO(ID_DFR0, COPSDBG, false, 1, 0, true), > + FIELD_INFO(ID_DFR0, MMAPDBG, false, 1, 0, true), > + FIELD_INFO(ID_DFR0, COPTRC, false, 1, 0, true), > + FIELD_INFO(ID_DFR0, MMAPTRC, false, 1, 0, true), > + FIELD_INFO(ID_DFR0, MPROFDBG, false, 1, 0, true), > + FIELD_INFO(ID_DFR0, PERFMON, false, 1, 0, true), > + FIELD_INFO(ID_DFR0, TRACEFILT, false, 1, 0, true), > + > + FIELD_INFO(ID_AA64ISAR0, AES, false, 1, 0, false), > + FIELD_INFO(ID_AA64ISAR0, SHA1, false, 1, 0, false), > + FIELD_INFO(ID_AA64ISAR0, SHA2, false, 1, 0, false), > + FIELD_INFO(ID_AA64ISAR0, CRC32, false, 1, 0, false), > + FIELD_INFO(ID_AA64ISAR0, ATOMIC, false, 1, 0, false), > + FIELD_INFO(ID_AA64ISAR0, RDM, false, 1, 0, false), > + FIELD_INFO(ID_AA64ISAR0, SHA3, false, 1, 0, false), > + FIELD_INFO(ID_AA64ISAR0, SM3, false, 1, 0, false), > + FIELD_INFO(ID_AA64ISAR0, SM4, false, 1, 0, false), > + FIELD_INFO(ID_AA64ISAR0, DP, false, 1, 0, false), > + FIELD_INFO(ID_AA64ISAR0, FHM, false, 1, 0, false), > + FIELD_INFO(ID_AA64ISAR0, TS, false, 1, 0, false), > + FIELD_INFO(ID_AA64ISAR0, TLB, false, 1, 0, false), > + FIELD_INFO(ID_AA64ISAR0, RNDR, false, 1, 0, false), > + > + FIELD_INFO(ID_AA64ISAR1, DPB, false, 1, 0, false), > + FIELD_INFO(ID_AA64ISAR1, APA, false, 1, 0, false), > + FIELD_INFO(ID_AA64ISAR1, API, false, 1, 0, false), > + FIELD_INFO(ID_AA64ISAR1, JSCVT, false, 1, 0, false), > + FIELD_INFO(ID_AA64ISAR1, FCMA, false, 1, 0, false), > + FIELD_INFO(ID_AA64ISAR1, LRCPC, false, 1, 0, false), > + FIELD_INFO(ID_AA64ISAR1, GPA, false, 1, 0, false), > + FIELD_INFO(ID_AA64ISAR1, GPI, false, 1, 0, false), > + FIELD_INFO(ID_AA64ISAR1, FRINTTS, false, 1, 0, false), > + FIELD_INFO(ID_AA64ISAR1, SB, false, 1, 0, false), > + FIELD_INFO(ID_AA64ISAR1, SPECRES, false, 1, 0, false), > + > + FIELD_INFO(ID_AA64PFR0, EL0, false, 1, 0, false), > + FIELD_INFO(ID_AA64PFR0, EL1, false, 1, 0, false), > + FIELD_INFO(ID_AA64PFR0, EL2, false, 1, 0, false), > + FIELD_INFO(ID_AA64PFR0, EL3, false, 1, 0, false), > + FIELD_INFO(ID_AA64PFR0, FP, true, 0, 0xf, false), > + FIELD_INFO(ID_AA64PFR0, ADVSIMD, true, 0, 0xf, false), > + FIELD_INFO(ID_AA64PFR0, GIC, false, 1, 0, false), > + FIELD_INFO(ID_AA64PFR0, RAS, false, 1, 0, false), > + FIELD_INFO(ID_AA64PFR0, SVE, false, 1, 0, false), > + > + FIELD_INFO(ID_AA64PFR1, BT, false, 1, 0, false), > + FIELD_INFO(ID_AA64PFR1, SBSS, false, 1, 0, false), > + FIELD_INFO(ID_AA64PFR1, MTE, false, 1, 0, false), > + FIELD_INFO(ID_AA64PFR1, RAS_FRAC, false, 1, 0, false), > + > + FIELD_INFO(ID_AA64MMFR0, PARANGE, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR0, ASIDBITS, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR0, BIGEND, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR0, SNSMEM, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR0, BIGENDEL0, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR0, TGRAN16, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR0, TGRAN64, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR0, TGRAN4, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR0, TGRAN16_2, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR0, TGRAN64_2, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR0, TGRAN4_2, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR0, EXS, false, 1, 0, false), > + > + FIELD_INFO(ID_AA64MMFR1, HAFDBS, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR1, VMIDBITS, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR1, VH, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR1, HPDS, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR1, LO, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR1, PAN, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR1, SPECSEI, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR1, XNX, false, 1, 0, false), > + > + FIELD_INFO(ID_AA64MMFR2, CNP, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR2, UAO, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR2, LSM, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR2, IESB, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR2, VARANGE, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR2, CCIDX, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR2, NV, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR2, ST, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR2, AT, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR2, IDS, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR2, FWB, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR2, TTL, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR2, BBM, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR2, EVT, false, 1, 0, false), > + FIELD_INFO(ID_AA64MMFR2, E0PD, false, 1, 0, false), > + > + FIELD_INFO(ID_AA64DFR0, DEBUGVER, false, 1, 0, false), > + FIELD_INFO(ID_AA64DFR0, TRACEVER, false, 1, 0, false), > + FIELD_INFO(ID_AA64DFR0, PMUVER, false, 1, 0, false), > + FIELD_INFO(ID_AA64DFR0, BRPS, false, 1, 0, false), > + FIELD_INFO(ID_AA64DFR0, WRPS, false, 1, 0, false), > + FIELD_INFO(ID_AA64DFR0, CTX_CMPS, false, 1, 0, false), > + FIELD_INFO(ID_AA64DFR0, PMSVER, false, 1, 0, false), > + FIELD_INFO(ID_AA64DFR0, DOUBLELOCK, false, 1, 0, false), > + FIELD_INFO(ID_AA64DFR0, TRACEFILT, false, 1, 0, false), > + > + { > + .reg = ID_AA64PFR0, .length = R_ID_AA64PFR0_FP_LENGTH, > + .shift = R_ID_AA64PFR0_FP_SHIFT, .sign = true, .min_value = 1, > + .ni_value = 0, .name = "FPHP", .is_32bit = false, > + }, > + { > + .reg = ID_AA64PFR0, .length = R_ID_AA64PFR0_ADVSIMD_LENGTH, > + .shift = R_ID_AA64PFR0_ADVSIMD_SHIFT, .sign = true, .min_value = 1, > + .ni_value = 0, .name = "ADVSIMDHP", .is_32bit = false, > + }, > + { > + .reg = ID_AA64ISAR0, .length = R_ID_AA64ISAR0_AES_LENGTH, > + .shift = R_ID_AA64ISAR0_AES_SHIFT, .sign = false, .min_value = 2, > + .ni_value = 1, .name = "PMULL", .is_32bit = false, > + }, > + { > + .reg = ID_AA64ISAR0, .length = R_ID_AA64ISAR0_SHA2_LENGTH, > + .shift = R_ID_AA64ISAR0_SHA2_SHIFT, .sign = false, .min_value = 2, > + .ni_value = 1, .name = "SHA512", .is_32bit = false, > + }, > + { > + .reg = ID_AA64ISAR0, .length = R_ID_AA64ISAR0_TS_LENGTH, > + .shift = R_ID_AA64ISAR0_TS_SHIFT, .sign = false, .min_value = 2, > + .ni_value = 1, .name = "FLAGM2", .is_32bit = false, > + }, > + { > + .reg = ID_AA64ISAR1, .length = R_ID_AA64ISAR1_DPB_LENGTH, > + .shift = R_ID_AA64ISAR1_DPB_SHIFT, .sign = false, .min_value = 2, > + .ni_value = 1, .name = "DCPODP", .is_32bit = false, > + }, > + { > + .reg = ID_AA64ISAR1, .length = R_ID_AA64ISAR1_LRCPC_LENGTH, > + .shift = R_ID_AA64ISAR1_LRCPC_SHIFT, .sign = false, .min_value = 2, > + .ni_value = 1, .name = "ILRCPC", .is_32bit = false, > + }, > +}; > + > +static void arm_cpu_get_bit_prop(Object *obj, Visitor *v, const char *name, > + void *opaque, Error **errp) > +{ > + ARMCPU *cpu = ARM_CPU(obj); > + CPUFeatureInfo *feat = opaque; > + int field_value = feat->sign ? sextract64(cpu->isar.regs[feat->reg], > + feat->shift, feat->length) : > + extract64(cpu->isar.regs[feat->reg], > + feat->shift, feat->length); > + bool value = field_value >= feat->min_value; > + > + visit_type_bool(v, name, &value, errp); > +} > + > +static void arm_cpu_set_bit_prop(Object *obj, Visitor *v, const char *name, > + void *opaque, Error **errp) > +{ > + DeviceState *dev = DEVICE(obj); > + ARMCPU *cpu = ARM_CPU(obj); > + ARMISARegisters *isar = &cpu->isar; > + CPUFeatureInfo *feat = opaque; > + Error *local_err = NULL; > + bool value; > + > + if (dev->realized) { > + qdev_prop_set_after_realize(dev, name, errp); > + return; > + } > + > + visit_type_bool(v, name, &value, &local_err); > + if (local_err) { > + error_propagate(errp, local_err); > + return; > + } > + > + if (value) { > + isar->regs[feat->reg] = deposit64(isar->regs[feat->reg], > + feat->shift, feat->length, > + feat->min_value); > + } else { > + isar->regs[feat->reg] = deposit64(isar->regs[feat->reg], > + feat->shift, feat->length, > + feat->ni_value); > + } > +} > + > +static void arm_cpu_register_feature_props(ARMCPU *cpu) > +{ > + int i; > + int num = sizeof(cpu_features) / sizeof(cpu_features[i]); > + ObjectProperty *op; > + CPUARMState *env = &cpu->env; > + > + for (i = 0; i < num; i++) { > + if ((arm_feature(env, ARM_FEATURE_AARCH64) && > cpu_features[i].is_32bit) > + || (!arm_feature(env, ARM_FEATURE_AARCH64) && > + cpu_features[i].is_32bit)) { > + continue; > + } > + op = object_property_find(OBJECT(cpu), cpu_features[i].name, NULL); > + if (!op) { > + error_report("register name %s", cpu_features[i].name); > + object_property_add(OBJECT(cpu), cpu_features[i].name, "bool", > + arm_cpu_get_bit_prop, > + arm_cpu_set_bit_prop, > + NULL, &cpu_features[i]);
So we're adding properties for every CPU feature? How many of these make sense for the user to change? What happens when a user selects an invalid combination? Thanks, drew > + } > + } > +} > + > void arm_cpu_post_init(Object *obj) > { > ARMCPU *cpu = ARM_CPU(obj); > @@ -1271,6 +1613,7 @@ void arm_cpu_post_init(Object *obj) > } > } > #endif > + arm_cpu_register_feature_props(cpu); > } > > static void arm_cpu_finalizefn(Object *obj) > -- > 2.18.4 >