HPFAR_EL2, Hypervisor IPA Fault Address Register

The HPFAR_EL2 characteristics are:

Purpose

Holds the faulting IPA for some aborts on a stage 2 translation taken to EL2.

Configuration

AArch64 System register HPFAR_EL2 bits [31:0] are architecturally mapped to AArch32 System register HPFAR[31:0].

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

This register has no effect if EL2 is not enabled in the current Security state.

The HPFAR_EL2 is written for:

For all other exceptions taken to EL2, this register is UNKNOWN.

Note

The address held in this register is an address accessed by the instruction fetch or data access that caused the exception that gave rise to the instruction or data abort. It is the lowest address that gave rise to the fault. Where different faults from different addresses arise from the same instruction, such as for an instruction that loads or stores a mis-aligned address that crosses a page boundary, the architecture does not prioritize between those different faults.

Attributes

HPFAR_EL2 is a 64-bit register.

Field descriptions

6362616059585756555453525150494847464544434241403938373635343332
313029282726252423222120191817161514131211109876543210
NSRES0FIPA
FIPARES0

Execution at EL1 or EL0 makes HPFAR_EL2 become UNKNOWN.

NS, bit [63]
When FEAT_SEL2 is implemented:

Faulting IPA address space.

NSMeaning
0b0

Faulting IPA is from the Secure IPA space.

0b1

Faulting IPA is from the Non-secure IPA space.

For Data Aborts or Instruction Aborts taken to Non-secure EL2:

For Data Aborts or Instruction Aborts taken to Realm EL2:

The reset behaviour of this field is:


Otherwise:

Reserved, RES0.

Bits [62:44]

Reserved, RES0.

FIPA, bits [43:4]

FIPA encoding when FEAT_LPA is implemented

38373635343332313029282726252423222120191817161514131211109876543210
FIPA

FIPA, bits [38:0]

Faulting Intermediate Physical Address.

When 52-bit addresses are in use for stage 1 translation, FIPA[38:35] forms the upper part of the address value.

When 52-bit addresses are not in use for stage 1 translation, FIPA[38:35] is RES0.

The reset behaviour of this field is:

  • On a Warm reset, this field resets to an architecturally UNKNOWN value.

FIPA encoding when FEAT_LPA is not implemented

38373635343332313029282726252423222120191817161514131211109876543210
RES0FIPA

Bits [38:35]

Reserved, RES0.

FIPA, bits [34:0]

Faulting Intermediate Physical Address.

For implementations with fewer than 48 physical address bits, the corresponding upper bits in this field are RES0.

The reset behaviour of this field is:

  • On a Warm reset, this field resets to an architecturally UNKNOWN value.

Bits [3:0]

Reserved, RES0.

Accessing HPFAR_EL2

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

MRS <Xt>, HPFAR_EL2

op0op1CRnCRmop2
0b110b1000b01100b00000b100

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && HCR_EL2.NV == '1' then AArch64.SystemAccessTrap(EL2, 0x18); else UNDEFINED; elsif PSTATE.EL == EL2 then return HPFAR_EL2; elsif PSTATE.EL == EL3 then return HPFAR_EL2;

MSR HPFAR_EL2, <Xt>

op0op1CRnCRmop2
0b110b1000b01100b00000b100

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EL2Enabled() && HCR_EL2.NV == '1' then AArch64.SystemAccessTrap(EL2, 0x18); else UNDEFINED; elsif PSTATE.EL == EL2 then HPFAR_EL2 = X[t]; elsif PSTATE.EL == EL3 then HPFAR_EL2 = X[t];


30/06/2021 15:21; 2a17f7750cfd1ab239f20f6cf29877ba8041794f

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