RISC-V htinst CSR Register

Address 0x64APrivilege HypervisorAccess HRW / HSXLENHypervisor and virtualization CSRs

htinst is a Hypervisor trap-instruction CSR.

Related Search Terms

htinst CSR htinst 0x64A transformed instruction or pseudoinstruction information Hypervisor

Bit Overview

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bit 3 = only bit 3; bits 12..11 = bits 12 down to 11

MSBLSB

TRANSFORMED_INSTRUCTION_OR_PSEUDOINSTRUCTION_INFORMATION63:0RW

Field Map

Understand htinst By Bit Fields

1 key fields

HSXLEN-1:0

TRANSFORMED_INSTRUCTION_OR_PSEUDOINSTRUCTION_INFORMATION

The transformed instruction or pseudoinstruction information of htinst.

TRANSFORMED_INSTRUCTION_OR_PSEUDOINSTRUCTION_INFORMATION (bits HSXLEN-1:0) — The transformed instruction or pseudoinstruction information of htinst.

What This Field Controls

- The transformed instruction or pseudoinstruction information of htinst.

Common Values

This field is better understood together with surrounding context than as a fixed memorized enumeration.

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Official Basis & Search Notes

htinst is a Hypervisor trap-instruction CSR. It is HS/M-side hypervisor state, not a VS supervisor CSR copy; guest access is governed by the H extension and relevant state-enable, AIA, Sstc, or Smcsrind rules.

htinst address, access class, and width are checked against the official CSR tables: 0x64A, HRW, HSXLEN.

htinst fields are interpreted by the corresponding Hypervisor extension section; unimplemented fields must not be treated as fixed writable bits.

When writing, modify only officially defined fields; handle WARL, WLRL, WPRI, and reserved fields according to the official specification and implementation behavior.

RISC-V Privileged Architecture Manual - CSR table RISC-V Privileged Architecture Manual - Hypervisor extension

What To Check First When Reading This CSR

- htinst is a Hypervisor-level CSR; its separate address is in the official HRW access class.
- Guest/VS software does not reach this H-level CSR through a supervisor CSR alias; access is controlled by the H extension and relevant optional-extension rules.

Risk Checks Before Writing

- When writing htinst, modify only officially defined target fields and preserve WPRI, reserved, and unchanged fields.

Put It Back Into A Real Flow

Confirm the current software is in an M/HS context that may access Hypervisor CSRs.

Confirm that the H, AIA, Sstc, Smstateen, Smcsrind, or other defining extension is implemented.

Read or write only official fields; whether guest-related access succeeds or traps is controlled by the corresponding extension rules and state-enable state.

FAQ

Can htinst be accessed through a supervisor CSR alias?

Do not treat htinst as a VS CSR copy. It is an H-level CSR; whether guest/VS access to related functionality traps is defined by the H extension and the relevant optional extension.