CVSROOT: /cvs
Module name: src
Changes by: bl...@cvs.openbsd.org 2025/05/28 01:59:05
Modified files:
sys/arch/amd64/amd64: vmm_machdep.c
sys/arch/amd64/include: ghcb.h
Log message:
Handle AMD SEV-ES GHCB MSR protocol for CPUID in vmm(4).
When a SEV-ES guest is in locore0, it will not be able yet to use
a GHCB to communicate with vmm(4). Therefore, AMD specifies a "GHCB
MSR protocol" that uses the lower 12 bits of the GHCB MSR to request
services from vmm(4). Guest writes to the GHCB MSR will show up
in the v_ghcb_gpa member of the VMCB and are thus accesible by
vmm(4). The response of vmm(4) can be provided by writing it to
the VMCB.
In locore0 a SEV-ES guest will need to request CPUID from vmm(4)
using the GHCB MSR protocol. This commit provides vmm(4) implementation.
from hshoexer@; OK mlarkin@
