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CSR Bit Fields

RISC-V vstval CSR Register

Address 0x243Privilege Hypervisor direct / VS aliasAccess HRW / VSXLENHypervisor and virtualization CSRs

vstval holds VS trap auxiliary value as the VS copy of the corresponding supervisor CSR.

Related Search Terms
vstval CSRvstval 0x243vstval VS copydirect HRW accessguest supervisor state
Bit Overview
bit 3 = only bit 3; bits 12..11 = bits 12 down to 11
MSBLSB
TVAL63:0RW
Field Map

Understand vstval By Bit Fields

1 key fields
VSXLEN-1:0

TVAL

RW

vstval VS trap auxiliary value; exact fields follow the corresponding supervisor CSR semantics for the VS copy.

TVAL (bits VSXLEN-1:0) — vstval VS trap auxiliary value; exact fields follow the corresponding supervisor CSR semantics for the VS copy.

What This Field Controls

  • - vstval VS trap auxiliary value; exact fields follow the corresponding supervisor CSR semantics for the VS copy.

Common Values

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

↗Open Official Manual
Official Basis & Search Notes

vstval is a VS supervisor state or trap CSR. The separate CSR address is for M/HS-side management; when V=1, guest access to the corresponding supervisor CSR is substituted with VS state unless an extension specifies otherwise.

vstval address, access class, and width are checked against the official CSR tables: 0x243, HRW, VSXLEN.
The H extension specifies that, when V=1, access to the corresponding supervisor CSR is substituted with the VS CSR.
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 tableRISC-V Privileged Architecture Manual - Hypervisor extension

What To Check First When Reading This CSR

  • - vstval's separate CSR address is in the official HRW access class; a VS/VU guest normally reaches VS state through the corresponding supervisor CSR alias.
  • - Before reading it, confirm that the defining extension such as H, AIA, Sstc, Smstateen, or Smcsrind is implemented.

Risk Checks Before Writing

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

Put It Back Into A Real Flow

1

M/HS software may access the VS copy through the separate CSR address.

2

When V=1, guest access to the corresponding supervisor CSR aliases to VS state; direct access to the separate VS CSR address raises a virtual-instruction exception.

3

Update only official fields and do not treat VS state as ordinary HS supervisor state.

FAQ

Can VS-mode directly access vstval's separate CSR address?

No. The H extension substitutes VS state for the corresponding supervisor CSR when V=1; direct access to the separate VS CSR address raises a virtual-instruction exception.

What does vstval mainly hold?

vstval holds VS trap auxiliary value, allowing the hypervisor to manage guest-supervisor trap, status, or execution context.