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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.

RW fields in this register reset to architecturally UNKNOWN values.

Attributes

HPFAR_EL2 is a 64-bit register.

Field descriptions

The HPFAR_EL2 bit assignments are:

6362616059585756555453525150494847464544434241403938373635343332
NSRES0FIPA[51:48]FIPA[47:12]
FIPA[47:12]RES0
313029282726252423222120191817161514131211109876543210

Execution at EL1 or EL0 makes HPFAR_EL2 become UNKNOWN.

NS, bit [63]

From Armv8.4:

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 or instruction aborts taken to Non-secure EL2, this field is RES0.

This field resets to an architecturally UNKNOWN value.


Otherwise:

Reserved, RES0.

Bits [62:44]

Reserved, RES0.

FIPA[51:48], bits [43:40]

From Armv8.2, or if ARMv8.2-LPA is implemented:

Extension to FIPA[47:12]. See FIPA[47:12] for more details.

This field resets to an architecturally UNKNOWN value.


Otherwise:

Reserved, RES0.

FIPA[47:12], bits [39:4]

Bits [47:12] of the faulting intermediate physical address.

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

When ARMv8.2-LPA is implemented, and 52-bit addresses and a 64KB translation granule are in use for the stage 1 translation, the FIPA[51:48] bits form the upper part of the address value. For implementations or stage 1 translation granules with fewer than 52 physical address bits the FIPA[51:48] bits are RES0.

The HPFAR_EL2 is written for:

  • Translation or Access faults in the second stage of translation.
  • An abort in the second stage of translation performed during the translation table walk of a first stage translation, caused by a Translation fault, an Access flag fault, or a Permission fault.
  • A stage 2 Address size fault.
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.

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

This field resets to an architecturally UNKNOWN value.

Bits [3:0]

Reserved, RES0.

Accessing the HPFAR_EL2

Accesses to this register use the following encodings:

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];
              


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