← Home

ICV_IGRPEN1_EL1

Interrupt Controller Virtual Interrupt Group 1 Enable Register

Controls whether virtual Group 1 interrupts are enabled for the current Security state.

Configuration

AArch64 System register ICV_IGRPEN1_EL1 bits [31:0] are architecturally mapped to AArch32 System register ICV_IGRPEN1[31:0].

This register is present only when (GICv3 is implemented or FEAT_GCIE_LEGACY is implemented), EL2 is implemented, and FEAT_AA64 is implemented. Otherwise, direct accesses to ICV_IGRPEN1_EL1 are UNDEFINED.

Attributes

ICV_IGRPEN1_EL1 is a 64-bit register.

Field descriptions

6362616059585756555453525150494847464544434241403938373635343332
313029282726252423222120191817161514131211109876543210
RES0
RES0Enable

Bits [63:1]:

Reserved, RES0.

Enable, bit [0]:

Enables virtual Group 1 interrupts.

EnableMeaning
0b0

Virtual Group 1 interrupts are disabled.

0b1

Virtual Group 1 interrupts are enabled.

The reset behavior of this field is:

Access Instructions

Accesses to this register use the following encodings in the System register encoding space:

MRS <Xt>, ICC_IGRPEN1_EL1

(op0 = 0b11, op1 = 0b000, CRn = 0b1100, CRm = 0b1100, op2 = 0b111)

if !((IsFeatureImplemented(FEAT_GICv3) || IsFeatureImplemented(FEAT_GCIE_LEGACY)) && IsFeatureImplemented(FEAT_AA64)) then Undefined(); elsif HaveEL(EL3) && !(EffectivelyAtEL0InHost() || EffectivelyAtEL0NotInHost() || PSTATE.EL == EL3) && EL3SDDUndefPriority() && SCR_EL3().IRQ == '1' then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if IsFeatureImplemented(FEAT_GCIE_LEGACY) && (ICH_VCTLR_EL2().V3 == '0' || !EL2Enabled() || !((IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3().FGTEn == '1') && HFGRTR_EL2().ICC_IGRPENn_EL1 == '1') || ICH_HCR_EL2().TALL1 == '1' || HCR_EL2().IMO == '1')) then Undefined(); elsif ICC_SRE_EL1().SRE == '0' then AArch64_SystemAccessTrap(EL1, 0x18); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3().FGTEn == '1') && HFGRTR_EL2().ICC_IGRPENn_EL1 == '1' then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && ICH_HCR_EL2().TALL1 == '1' then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && HCR_EL2().IMO == '1' then X{64}(t) = ICV_IGRPEN1_EL1(); elsif HaveEL(EL3) && SCR_EL3().IRQ == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif HaveEL(EL3) then if EffectiveSCR_EL3_NS() == '0' then X{64}(t) = ICC_IGRPEN1_EL1_S(); else X{64}(t) = ICC_IGRPEN1_EL1_NS(); end; else X{64}(t) = ICC_IGRPEN1_EL1(); end; elsif PSTATE.EL == EL2 then if IsFeatureImplemented(FEAT_GCIE_LEGACY) then Undefined(); elsif ICC_SRE_EL2().SRE == '0' then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && SCR_EL3().IRQ == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif HaveEL(EL3) then if EffectiveSCR_EL3_NS() == '0' then X{64}(t) = ICC_IGRPEN1_EL1_S(); else X{64}(t) = ICC_IGRPEN1_EL1_NS(); end; else X{64}(t) = ICC_IGRPEN1_EL1(); end; elsif PSTATE.EL == EL3 then if IsFeatureImplemented(FEAT_GCIE_LEGACY) then Undefined(); elsif ICC_SRE_EL3().SRE == '0' then AArch64_SystemAccessTrap(EL3, 0x18); else if EffectiveSCR_EL3_NS() == '0' then X{64}(t) = ICC_IGRPEN1_EL1_S(); else X{64}(t) = ICC_IGRPEN1_EL1_NS(); end; end; end;

MSR ICC_IGRPEN1_EL1, <Xt>

(op0 = 0b11, op1 = 0b000, CRn = 0b1100, CRm = 0b1100, op2 = 0b111)

if !((IsFeatureImplemented(FEAT_GICv3) || IsFeatureImplemented(FEAT_GCIE_LEGACY)) && IsFeatureImplemented(FEAT_AA64)) then Undefined(); elsif HaveEL(EL3) && !(EffectivelyAtEL0InHost() || EffectivelyAtEL0NotInHost() || PSTATE.EL == EL3) && EL3SDDUndefPriority() && SCR_EL3().IRQ == '1' then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then if IsFeatureImplemented(FEAT_GCIE_LEGACY) && (ICH_VCTLR_EL2().V3 == '0' || !EL2Enabled() || !((IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3().FGTEn == '1') && HFGWTR_EL2().ICC_IGRPENn_EL1 == '1') || ICH_HCR_EL2().TALL1 == '1' || HCR_EL2().IMO == '1')) then Undefined(); elsif ICC_SRE_EL1().SRE == '0' then AArch64_SystemAccessTrap(EL1, 0x18); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3().FGTEn == '1') && HFGWTR_EL2().ICC_IGRPENn_EL1 == '1' then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && ICH_HCR_EL2().TALL1 == '1' then AArch64_SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && HCR_EL2().IMO == '1' then ICV_IGRPEN1_EL1() = X{64}(t); elsif HaveEL(EL3) && SCR_EL3().IRQ == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif HaveEL(EL3) then if EffectiveSCR_EL3_NS() == '0' then ICC_IGRPEN1_EL1_S() = X{64}(t); else ICC_IGRPEN1_EL1_NS() = X{64}(t); end; else ICC_IGRPEN1_EL1() = X{64}(t); end; elsif PSTATE.EL == EL2 then if IsFeatureImplemented(FEAT_GCIE_LEGACY) then Undefined(); elsif ICC_SRE_EL2().SRE == '0' then AArch64_SystemAccessTrap(EL2, 0x18); elsif HaveEL(EL3) && SCR_EL3().IRQ == '1' then if EL3SDDUndef() then Undefined(); else AArch64_SystemAccessTrap(EL3, 0x18); end; elsif HaveEL(EL3) then if EffectiveSCR_EL3_NS() == '0' then ICC_IGRPEN1_EL1_S() = X{64}(t); else ICC_IGRPEN1_EL1_NS() = X{64}(t); end; else ICC_IGRPEN1_EL1() = X{64}(t); end; elsif PSTATE.EL == EL3 then if IsFeatureImplemented(FEAT_GCIE_LEGACY) then Undefined(); elsif ICC_SRE_EL3().SRE == '0' then AArch64_SystemAccessTrap(EL3, 0x18); else if EffectiveSCR_EL3_NS() == '0' then ICC_IGRPEN1_EL1_S() = X{64}(t); else ICC_IGRPEN1_EL1_NS() = X{64}(t); end; end; end;


Version 2026.06 — Copyright © 2010-2026 Arm Limited or its affiliates.

This site is provided as a community resource and is NOT affiliated with nor endorsed by Arm Limited.