APAS

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APAS, Associate PA space

Purpose

Associate a location with a specified PA space, for locations that are protected by a memory-side PAS filter.

Configuration

This instruction is present only when FEAT_RME_GPC3 is implemented and FEAT_AA64 is implemented. Otherwise, direct accesses to APAS are UNDEFINED.

Attributes

Field descriptions

NS, bit [63]

Together with the NSE field, selects the target physical address space.

NSE	NS	Meaning
0b0	0b0	When Secure state is implemented, Secure. Otherwise reserved.
0b0	0b1	Non-secure.
0b1	0b0	Root.
0b1	0b1	Realm.

NSE, bit [62]

Together with the NS field, selects the target physical address space.

For a description of the values derived by evaluating NS and NSE together, see APAS.NS.

Bits [61:56]

PA, bits [55:6]

Bits [55:6] of the Physical Address.

Bits of Xt corresponding to physical address bits above the implemented physical address size indicated in ID_AA64MMFR0_EL1.PARange are RES0. For example, if 44 bits of PA space are implemented, then Xt[55:44] are RES0.

Bits [5:3]

TargetAttributes, bits [2:0]

The Target Attributes field is encoded as follows:

TargetAttributes	Meaning
0b000	Default behavior applies.
0b001..0b111	IMPLEMENTATION DEFINED.

Executing APAS

This instruction is not subject to any translation, permission checks, or granule protection checks.

This system instruction is an alias of the SYS instruction.

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

APAS <Xt>

op0	op1	CRn	CRm	op2
0b01	0b110	0b0111	0b0000	0b000

if !(IsFeatureImplemented(FEAT_RME_GPC3) && IsFeatureImplemented(FEAT_AA64)) then Undefined(); elsif PSTATE.EL == EL0 then Undefined(); elsif PSTATE.EL == EL1 then Undefined(); elsif PSTATE.EL == EL2 then Undefined(); elsif PSTATE.EL == EL3 then AArch64_APAS(X{64}(t)); end;

63	62	61	60	59	58	57	56	55	54	53	52	51	50	49	48	47	46	45	44	43	42	41	40	39	38	37	36	35	34	33	32
31	30	29	28	27	26	25	24	23	22	21	20	19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
NS	NSE	RES0						PA
PA																										RES0			TargetAttributes