MPAMBWIDR_EL1 MPAM PE-side Bandwidth Controls ID Register when FEAT_MPAM_PE_BW_CTRL is implemented Indicates the supported PE-side memory bandwidth parameter values. MPAM MPAMBWIDR_EL1 is a 64-bit register. HAS_HW_SCALE 63 63 63 Indicates whether hardware support for auto-scaling of MPAMBWn_ELx.MAX, MPAMBWSM_EL1.MAX and MPAMBWCAP_EL2.CAP limits is available. 0b0 Hardware support for auto-scaling is not implemented. 0b1 Hardware support for auto-scaling is implemented. RO 62 32 62:32 Reserved, RES0. MAX_LIM 31 30 31:30 Indicates the implemented maximum bandwidth limit partitioning behaviors. 0b00 Both soft limit and hard limit behaviors are implemented. 0b01 Soft limit behavior is implemented. 0b10 Hard limit behavior is implemented. 0b11 Reserved. RO 29 6 29:6 Reserved, RES0. BWA_WD 5 0 5:0 Indicates the number of implemented bits in the bandwidth allocation fields MPAMBWn_ELx.MAX, MPAMBWSM_EL1.MAX and MPAMBWCAP_EL2.CAP. 0b000001..0b010000 Number of implemented bits in the bandwidth allocation fields. RO MRS <Xt>, MPAMBWIDR_EL1 if !IsFeatureImplemented(FEAT_MPAM_PE_BW_CTRL) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if HaveEL(EL3) && EL3SDDUndefPriority() && (IsFeatureImplemented(FEAT_MPAMv0p1) || IsFeatureImplemented(FEAT_MPAMv1p0)) && MPAM3_EL3().TRAPLOWER == '1' then Undefined(); elsif HaveEL(EL3) && EL3SDDUndefPriority() && MPAMBW3_EL3().nTRAPLOWER == '0' then Undefined(); elsif HaveEL(EL3) && (IsFeatureImplemented(FEAT_MPAMv0p1) || IsFeatureImplemented(FEAT_MPAMv1p0)) && MPAM3_EL3().TRAPLOWER == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif HaveEL(EL3) && MPAMBW3_EL3().nTRAPLOWER == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif EL2Enabled() && MPAMBW2_EL2().nTRAP_MPAMBWIDR_EL1 == '0' then AArch64_SystemAccessTrap(EL2, 0x18); else X{64}(t) = MPAMBWIDR_EL1(); end; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && (IsFeatureImplemented(FEAT_MPAMv0p1) || IsFeatureImplemented(FEAT_MPAMv1p0)) && MPAM3_EL3().TRAPLOWER == '1' then Undefined(); elsif HaveEL(EL3) && EL3SDDUndefPriority() && MPAMBW3_EL3().nTRAPLOWER == '0' then Undefined(); elsif HaveEL(EL3) && (IsFeatureImplemented(FEAT_MPAMv0p1) || IsFeatureImplemented(FEAT_MPAMv1p0)) && MPAM3_EL3().TRAPLOWER == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif HaveEL(EL3) && MPAMBW3_EL3().nTRAPLOWER == '0' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; else X{64}(t) = MPAMBWIDR_EL1(); end; elsif PSTATE.EL == EL3 then X{64}(t) = MPAMBWIDR_EL1(); end; 2026-03-26 20:27:25 2026-03_rel