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HFGRTR2_EL2: Hypervisor Fine-Grained Read Trap Register 2

Purpose

Provides controls for traps of MRRS, MRS and MRC reads of System registers.

Configuration

This register is present only when FEAT_FGT2 is implemented. Otherwise, direct accesses to HFGRTR2_EL2 are UNDEFINED.

If EL2 is not implemented, this register is RES0 from EL3.

Attributes

HFGRTR2_EL2 is a 64-bit register.

Field descriptions

6362616059585756555453525150494847464544434241403938373635343332
313029282726252423222120191817161514131211109876543210
RES0
RES0nRCWSMASK_EL1nERXGSR_EL1nPFAR_EL1

Bits [63:3]

Reserved, RES0.

nRCWSMASK_EL1, bit [2]

When FEAT_THE is implemented:

Trap MRS or MRRS reads of RCWSMASK_EL1 at EL1 using AArch64 to EL2.

nRCWSMASK_EL1Meaning
0b0

If EL2 is implemented and enabled in the current Security state, then MRS or MRRS reads of RCWSMASK_EL1 at EL1 using AArch64 are trapped to EL2 and reported with EC syndrome value 0x18 for 64-bit access and 0x14 for 128-bit access, unless the read generates a higher priority exception.

0b1

MRS or MRRS reads of RCWSMASK_EL1 are not trapped by this mechanism.

This field is ignored by the PE and treated as zero when all of the following are true:

The reset behavior of this field is:



Otherwise:

Reserved, RES0.

nERXGSR_EL1, bit [1]

When FEAT_RASv2 is implemented:

Trap MRS reads of ERXGSR_EL1 at EL1 using AArch64 to EL2.

nERXGSR_EL1Meaning
0b0

If EL2 is implemented and enabled in the current Security state, then MRS reads of ERXGSR_EL1 at EL1 using AArch64 are trapped to EL2 and reported with EC syndrome value 0x18, unless the read generates a higher priority exception.

0b1

MRS reads of ERXGSR_EL1 are not trapped by this mechanism.

This field is ignored by the PE and treated as zero when all of the following are true:

Accessing this field has the following behavior:

The reset behavior of this field is:



Otherwise:

Reserved, RES0.

nPFAR_EL1, bit [0]

When FEAT_PFAR is implemented:

Trap MRS reads of PFAR_EL1 at EL1 using AArch64 to EL2.

nPFAR_EL1Meaning
0b0

If EL2 is implemented and enabled in the current Security state, then MRS reads of PFAR_EL1 at EL1 using AArch64 are trapped to EL2 and reported with EC syndrome value 0x18, unless the read generates a higher priority exception.

0b1

MRS reads of PFAR_EL1 are not trapped by this mechanism.

This field is ignored by the PE and treated as zero when all of the following are true:

The reset behavior of this field is:



Otherwise:

Reserved, RES0.

Accessing HFGRTR2_EL2

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

MRS <Xt>, HFGRTR2_EL2

op0op1CRnCRmop2
0b110b1000b00110b00010b010

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EffectiveHCR_EL2_NVx() IN {'1x1'} then X[t, 64] = NVMem[0x2C0]; elsif EffectiveHCR_EL2_NVx() IN {'xx1'} then AArch64.SystemAccessTrap(EL2, 0x18); else UNDEFINED; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && SCR_EL3.FGTEn2 == '0' then UNDEFINED; elsif HaveEL(EL3) && SCR_EL3.FGTEn2 == '0' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else X[t, 64] = HFGRTR2_EL2; elsif PSTATE.EL == EL3 then X[t, 64] = HFGRTR2_EL2;

MSR HFGRTR2_EL2, <Xt>

op0op1CRnCRmop2
0b110b1000b00110b00010b010

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EffectiveHCR_EL2_NVx() IN {'1x1'} then NVMem[0x2C0] = X[t, 64]; elsif EffectiveHCR_EL2_NVx() IN {'xx1'} then AArch64.SystemAccessTrap(EL2, 0x18); else UNDEFINED; elsif PSTATE.EL == EL2 then if HaveEL(EL3) && EL3SDDUndefPriority() && SCR_EL3.FGTEn2 == '0' then UNDEFINED; elsif HaveEL(EL3) && SCR_EL3.FGTEn2 == '0' then if EL3SDDUndef() then UNDEFINED; else AArch64.SystemAccessTrap(EL3, 0x18); else HFGRTR2_EL2 = X[t, 64]; elsif PSTATE.EL == EL3 then HFGRTR2_EL2 = X[t, 64];