"Ssdbltrp" Double Trap Extension, Version 1.0

The Ssdbltrp extension addresses a double trap (See Double Trap Control in mstatus Register) privilege modes lower than M. It enables HS-mode to invoke a critical error handler in a virtual machine on a double trap in VS-mode. It also allows M-mode to invoke a critical error handler in the OS/Hypervisor on a double trap in S/HS-mode.

The Ssdbltrp extension adds the menvcfg.DTE (See Machine Environment Configuration (menvcfg) Register) and the sstatus.SDT fields (See Supervisor Status (sstatus) Register). If the hypervisor extension is additionally implemented, then the extension adds the henvcfg.DTE (See Hypervisor Environment Configuration Register (henvcfg)) and the vsstatus.SDT fields (See Virtual Supervisor Status (vsstatus) Register).

See Double Trap Control in sstatus Register for the operational details.