hvc

Hypervisor Call

HVC #<imm>

Generates a Hypervisor Call exception to EL2.

Pseudocode Operation

exception ← HypervisorCall
ESR_ELx.ISS ← imm16
Branch to EL2 exception handler

Example

HVC #16

Encoding

Binary Layout

11010100

31:24

000

23:21

imm16

20:5

000

4:2

1:0

Format Exception

Opcode 0xD4000002

Extension System

Operands

imm
ID

Other forms of hvc

hvc Hypervisor Call (Thumb)
hvc Hypervisor Call (A32)

Reference

View in Arm A64 ISA Reference ↗ Arm A64 ISA

Instruction Forms

Encoding	Instruction		ISA		Bit pattern
0xD4000002	HVC #<imm>		A64		11010100 \| 000 \| imm16 \| 000 \| 10

Description

Hypervisor Call causes an exception to EL2. Software executing at EL1 can use this instruction to call the hypervisor to request a service. The HVC instruction is UNDEFINED: On executing an HVC instruction, the PE records the exception as a Hypervisor Call exception in ESR_ELx, using the EC value 0x16, and the value of the immediate argument.

Operation

if !HaveEL(EL2) || PSTATE.EL == EL0 || (PSTATE.EL == EL1 && !EL2Enabled()) then
    UNDEFINED;

bits(1) hvc_enable = if HaveEL(EL3) then SCR_EL3.HCE else NOT(HCR_EL2.HCD);

if hvc_enable == '0' then
    UNDEFINED;
else
    AArch64.CallHypervisor(imm16);

hvc