SPMDEVAFF_EL1 System Performance Monitors Device Affinity Register when FEAT_SPMU is implemented and FEAT_AA64 is implemented For additional information, see the CoreSight Architecture Specification. For a System PMU that has affinity with a single PE or a group of PEs, SPMDEVAFF_EL1 is a copy of MPIDR_EL1 or part of MPIDR_EL1: If the System PMU has affinity with a single PE, then the affinity level is 0 and SPMDEVAFF_EL1 reads the same value as MPIDR_EL1, and SPMDEVAFF_EL1.F0V reads-as-one to indicate affinity level 0. If the System PMU has affinity with a group of PEs, then the affinity level is 1, 2, or 3, parts of SPMDEVAFF_EL1 reads the same value as parts of MPIDR_EL1, and the rest of SPMDEVAFF_EL1 indicates the level. For example, if the group of PEs is a subset of the PEs at affinity level 1, then all of the following are true: All the PEs in the group have the same values in MPIDR_EL1.{Aff3,Aff2}, and these values are equal to SPMDEVAFF_EL1.{Aff3,Aff2}. SPMDEVAFF_EL1.Aff1 is nonzero and not 0x80, and SPMDEVAFF_EL1.{Aff0,F0V} read-as-zero, to indicate at least affinity level 1. The subset of PEs at level 1 that the System PMU has affinity with is indicated by the least-significant set bit in SPMDEVAFF_EL1.Aff1. In this example, if SPMDEVAFF_EL1.Aff1[2:0] is 0b100, then the System PMU has affinity with the up-to 8 PEs that have MPIDR_EL1.Aff1[7:3] == SPMDEVAFF_EL1.Aff1[7:3]. Depending on the IMPLEMENTATION DEFINED nature of the system, it might be possible that SPMDEVAFF_EL1 is read before system firmware has configured the System PMU and/or the PE or group of PEs that the System PMU has affinity with. When this is the case, SPMDEVAFF_EL1 reads-as-zero. Unknown SPMDEVAFF_EL1 is a 64-bit register. 63 40 63:40 Reserved, RES0. Aff3 39 32 39:32 PE affinity level 3. The MPIDR_EL1.Aff3 field, viewed from the highest Exception level of the associated PE or PEs. This field has an IMPLEMENTATION DEFINED value. RO F0V 31 31 31 Indicates that the SPMDEVAFF_EL1.Aff0 field is valid. 0b0 SPMDEVAFF_EL1.Aff0 is not valid, and the PE affinity is above level 0 or a subset of level 0. 0b1 SPMDEVAFF_EL1.Aff0 is valid, and the PE affinity is at level 0. RO U 30 30 0 Uniprocessor. The MPIDR_EL1.U field, viewed from the highest Exception level of the associated PE. This field has an IMPLEMENTATION DEFINED value. RO When SPMDEVAFF_EL1.F0V == '1' 30 30 30 Reserved, UNKNOWN. Otherwise 29 25 29:25 Reserved, RES0. MT 24 24 0 Multithreaded. The MPIDR_EL1.MT field, viewed from the highest Exception level of the associated PE. This field has an IMPLEMENTATION DEFINED value. RO When SPMDEVAFF_EL1.F0V == '1' 24 24 24 Reserved, UNKNOWN. Otherwise Aff2 23 16 7:0 PE affinity level 2. The MPIDR_EL1.Aff2 field, viewed from the highest Exception level of the associated PE or PEs. This field has an IMPLEMENTATION DEFINED value. RO When affine with a PE or PEs at affinity level 2 or below Aff2 23 16 7:0 PE affinity level 2. Defines part of the MPIDR_EL1.Aff2 field, viewed from the highest Exception level of the associated PEs. 0bxxxxxxx1 SPMDEVAFF_EL1.Aff2[7:1] is the value of MPIDR_EL1.Aff2[7:1], viewed from the highest Exception level of the associated PEs. 0bxxxxxx10 SPMDEVAFF_EL1.Aff2[7:2] is the value of MPIDR_EL1.Aff2[7:2], viewed from the highest Exception level of the associated PEs. 0bxxxxx100 SPMDEVAFF_EL1.Aff2[7:3] is the value of MPIDR_EL1.Aff2[7:3], viewed from the highest Exception level of the associated PEs. 0bxxxx1000 SPMDEVAFF_EL1.Aff2[7:4] is the value of MPIDR_EL1.Aff2[7:4], viewed from the highest Exception level of the associated PEs. 0bxxx10000 SPMDEVAFF_EL1.Aff2[7:5] is the value of MPIDR_EL1.Aff2[7:5], viewed from the highest Exception level of the associated PEs. 0bxx100000 SPMDEVAFF_EL1.Aff2[7:6] is the value of MPIDR_EL1.Aff2[7:6], viewed from the highest Exception level of the associated PEs. 0bx1000000 SPMDEVAFF_EL1.Aff2[7] is the value of MPIDR_EL1.Aff2[7], viewed from the highest Exception level of the associated PEs. RO When affine with a sub-set of PEs at affinity level 2 Aff2 23 16 7:0 PE affinity level NOT DEFINED. Indicates whether the PE affinity is at level 3. All other values are reserved. 0x80 PE affinity is at level 3. RO Otherwise Aff1 15 8 7:0 PE affinity level 1. The MPIDR_EL1.Aff1 field, viewed from the highest Exception level of the associated PE or PEs. This field has an IMPLEMENTATION DEFINED value. RO When affine with a PE or PEs at affinity level 1 or below Aff1 15 8 7:0 PE affinity level 1. Defines part of the MPIDR_EL1.Aff1 field, viewed from the highest Exception level of the associated PEs. 0bxxxxxxx1 SPMDEVAFF_EL1.Aff1[7:1] is the value of MPIDR_EL1.Aff1[7:1], viewed from the highest Exception level of the associated PEs. 0bxxxxxx10 SPMDEVAFF_EL1.Aff1[7:2] is the value of MPIDR_EL1.Aff1[7:2], viewed from the highest Exception level of the associated PEs. 0bxxxxx100 SPMDEVAFF_EL1.Aff1[7:3] is the value of MPIDR_EL1.Aff1[7:3], viewed from the highest Exception level of the associated PEs. 0bxxxx1000 SPMDEVAFF_EL1.Aff1[7:4] is the value of MPIDR_EL1.Aff1[7:4], viewed from the highest Exception level of the associated PEs. 0bxxx10000 SPMDEVAFF_EL1.Aff1[7:5] is the value of MPIDR_EL1.Aff1[7:5], viewed from the highest Exception level of the associated PEs. 0bxx100000 SPMDEVAFF_EL1.Aff1[7:6] is the value of MPIDR_EL1.Aff1[7:6], viewed from the highest Exception level of the associated PEs. 0bx1000000 SPMDEVAFF_EL1.Aff1[7] is the value of MPIDR_EL1.Aff1[7], viewed from the highest Exception level of the associated PEs. RO When affine with a sub-set of PEs at affinity level 1 Aff1 15 8 7:0 PE affinity level 1. Indicates whether the PE affinity is at level 2. 0x00 PE affinity is above level 2 or a subset of level 2. 0x80 PE affinity is at level 2. RO Otherwise Aff0 7 0 7:0 PE affinity level 0. The MPIDR_EL1.Aff0 field, viewed from the highest Exception level of the associated PE. This field has an IMPLEMENTATION DEFINED value. RO When affine with a PE at affinity level 0 Aff0 7 0 7:0 PE affinity level 0. Defines part of the MPIDR_EL1.Aff0 field, viewed from the highest Exception level of the associated PEs. 0bxxxxxxx1 SPMDEVAFF_EL1.Aff0[7:1] is the value of MPIDR_EL1.Aff0[7:1], viewed from the highest Exception level of the associated PEs. 0bxxxxxx10 SPMDEVAFF_EL1.Aff0[7:2] is the value of MPIDR_EL1.Aff0[7:2], viewed from the highest Exception level of the associated PEs. 0bxxxxx100 SPMDEVAFF_EL1.Aff0[7:3] is the value of MPIDR_EL1.Aff0[7:3], viewed from the highest Exception level of the associated PEs. 0bxxxx1000 SPMDEVAFF_EL1.Aff0[7:4] is the value of MPIDR_EL1.Aff0[7:4], viewed from the highest Exception level of the associated PEs. 0bxxx10000 SPMDEVAFF_EL1.Aff0[7:5] is the value of MPIDR_EL1.Aff0[7:5], viewed from the highest Exception level of the associated PEs. 0bxx100000 SPMDEVAFF_EL1.Aff0[7:6] is the value of MPIDR_EL1.Aff0[7:6], viewed from the highest Exception level of the associated PEs. 0bx1000000 SPMDEVAFF_EL1.Aff0[7] is the value of MPIDR_EL1.Aff0[7], viewed from the highest Exception level of the associated PEs. RO When affine with a sub-set of PEs at affinity level 0 Aff0 7 0 7:0 PE affinity level 0. Indicates whether the PE affinity is at level 1. 0x00 PE affinity is above level 1 or a subset of level 1. 0x80 PE affinity is at level 1. RO Otherwise Reads of SPMDEVAFF_EL1 are not affected by the value of VMPIDR_EL2 at any Exception level. If System PMU <s> has affinity only with this PE, then it is IMPLEMENTATION DEFINED whether SPMDEVAFF_EL1 reads-as-zero or reads the same value as MPIDR_EL1. To access SPMDEVAFF_EL1 for System PMU <s>, set SPMSELR_EL0.SYSPMUSEL to s. SPMDEVAFF_EL1 reads-as-zero if any of the following are true: System PMU <s> is not implemented. System PMU <s> has no affinity with the PE or cluster of PEs. MRS <Xt>, SPMDEVAFF_EL1 if !(IsFeatureImplemented(FEAT_SPMU) && IsFeatureImplemented(FEAT_AA64)) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().EnPM2 == '0' then Undefined(); elsif HaveEL(EL3) && EL3SDDUndefPriority() && SPMACCESSR_EL3()[UInt(SPMSELR_EL0().SYSPMUSEL) * 2+:2] == '00' then Undefined(); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT2) && ((HaveEL(EL3) && SCR_EL3().FGTEn2 == '0') || HDFGRTR2_EL2().nSPMDEVAFF_EL1 == '0') then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && MDCR_EL2().EnSPM == '0' then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && SPMACCESSR_EL2()[UInt(SPMSELR_EL0().SYSPMUSEL) * 2+:2] == '00' then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && MDCR_EL3().EnPM2 == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif HaveEL(EL3) && SPMACCESSR_EL3()[UInt(SPMSELR_EL0().SYSPMUSEL) * 2+:2] == '00' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else X{64}(t) = SPMDEVAFF_EL1(UInt(SPMSELR_EL0().SYSPMUSEL)); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && MDCR_EL3().EnPM2 == '0' then Undefined(); elsif HaveEL(EL3) && EL3SDDUndefPriority() && SPMACCESSR_EL3()[UInt(SPMSELR_EL0().SYSPMUSEL) * 2+:2] == '00' then Undefined(); elsif HaveEL(EL3) && MDCR_EL3().EnPM2 == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif HaveEL(EL3) && SPMACCESSR_EL3()[UInt(SPMSELR_EL0().SYSPMUSEL) * 2+:2] == '00' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else X{64}(t) = SPMDEVAFF_EL1(UInt(SPMSELR_EL0().SYSPMUSEL)); end; elsif PSTATE.EL == EL3 then X{64}(t) = SPMDEVAFF_EL1(UInt(SPMSELR_EL0().SYSPMUSEL)); end; 2026-03-26 20:27:25 2026-03_rel