VBAR_EL1

AArch64 System register VBAR_EL1 bits [31:0] are architecturally mapped to AArch32 System register VBAR[31:0].

Attributes

Field descriptions

Bits [63:11]

Vector Base Address. Base address of the exception vectors for exceptions taken to EL1.

Note

If the implementation supports FEAT_LVA3, then:

If tagged addresses are not being used, bits [63:56] of VBAR_EL1 must be the same or else the use of the vector address will result in a recursive exception.

Otherwise:

If the implementation supports FEAT_LVA, then:

If tagged addresses are being used, bits [55:52] of VBAR_EL1 must be the same or else the use of the vector address will result in a recursive exception.
If tagged addresses are not being used, bits [63:52] of VBAR_EL1 must be the same or else the use of the vector address will result in a recursive exception.

If the implementation does not support FEAT_LVA, then:

If tagged addresses are being used, bits [55:48] of VBAR_EL1 must be the same or else the use of the vector address will result in a recursive exception.
If tagged addresses are not being used, bits [63:48] of VBAR_EL1 must be the same or else the use of the vector address will result in a recursive exception.

The reset behavior of this field is:

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

Bits [10:0]

Accessing VBAR_EL1

When the Effective value of HCR_EL2.E2H is 1, without explicit synchronization, accesses from EL3 using the accessor name VBAR_EL1 or VBAR_EL12 are not guaranteed to be ordered with respect to accesses using the other accessor name.

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

MRS <Xt>, VBAR_EL1

op0	op1	CRn	CRm	op2
0b11	0b000	0b1100	0b0000	0b000

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EffectiveHCR_EL2_NVx() == '011' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HFGRTR_EL2.VBAR_EL1 == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EffectiveHCR_EL2_NVx() IN {'111'} then X[t, 64] = NVMem[0x250]; else X[t, 64] = VBAR_EL1; elsif PSTATE.EL == EL2 then if ELIsInHost(EL2) then X[t, 64] = VBAR_EL2; else X[t, 64] = VBAR_EL1; elsif PSTATE.EL == EL3 then X[t, 64] = VBAR_EL1;

MSR VBAR_EL1, <Xt>

op0	op1	CRn	CRm	op2
0b11	0b000	0b1100	0b0000	0b000

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EffectiveHCR_EL2_NVx() == '011' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EL2Enabled() && IsFeatureImplemented(FEAT_FGT) && (!HaveEL(EL3) || SCR_EL3.FGTEn == '1') && HFGWTR_EL2.VBAR_EL1 == '1' then AArch64.SystemAccessTrap(EL2, 0x18); elsif EffectiveHCR_EL2_NVx() IN {'111'} then NVMem[0x250] = X[t, 64]; else VBAR_EL1 = X[t, 64]; elsif PSTATE.EL == EL2 then if ELIsInHost(EL2) then VBAR_EL2 = X[t, 64]; else VBAR_EL1 = X[t, 64]; elsif PSTATE.EL == EL3 then VBAR_EL1 = X[t, 64];

MRS <Xt>, VBAR_EL12

op0	op1	CRn	CRm	op2
0b11	0b101	0b1100	0b0000	0b000

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EffectiveHCR_EL2_NVx() == '101' then X[t, 64] = NVMem[0x250]; elsif EffectiveHCR_EL2_NVx() IN {'xx1'} then AArch64.SystemAccessTrap(EL2, 0x18); else UNDEFINED; elsif PSTATE.EL == EL2 then if ELIsInHost(EL2) then X[t, 64] = VBAR_EL1; else UNDEFINED; elsif PSTATE.EL == EL3 then if ELIsInHost(EL2) then X[t, 64] = VBAR_EL1; else UNDEFINED;

MSR VBAR_EL12, <Xt>

op0	op1	CRn	CRm	op2
0b11	0b101	0b1100	0b0000	0b000

if PSTATE.EL == EL0 then UNDEFINED; elsif PSTATE.EL == EL1 then if EffectiveHCR_EL2_NVx() == '101' then NVMem[0x250] = X[t, 64]; elsif EffectiveHCR_EL2_NVx() IN {'xx1'} then AArch64.SystemAccessTrap(EL2, 0x18); else UNDEFINED; elsif PSTATE.EL == EL2 then if ELIsInHost(EL2) then VBAR_EL1 = X[t, 64]; else UNDEFINED; elsif PSTATE.EL == EL3 then if ELIsInHost(EL2) then VBAR_EL1 = X[t, 64]; else UNDEFINED;

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
Vector Base Address
Vector Base Address																					RES0

VBAR_EL1, Vector Base Address Register (EL1)

Purpose

Configuration