CVS commit: src/sys/dev/nvmm

["Taylor R Campbell" <riastradh%netbsd.org@localhost>]

Module Name:    src
Committed By:   riastradh
Date:           Tue Sep 13 20:10:04 UTC 2022

Modified Files:
        src/sys/dev/nvmm: nvmm.c nvmm_internal.h
        src/sys/dev/nvmm/x86: nvmm_x86_vmx.c

Log Message:
nvmm(4): Add suspend/resume support.

New MD nvmm_impl callbacks:

- .suspend_interrupt forces all VMs on all physical CPUs to exit.
- .vcpu_suspend suspends an individual vCPU on a machine.
- .machine_suspend suspends an individual machine.
- .suspend suspends the whole system.
- .resume resumes the whole system.
- .machine_resume resumes an individual machine.
- .vcpu_resume resumes an indidivudal vCPU on a machine.

Suspending nvmm:

1. causes new VM operations (ioctl and close) to block until resumed,
2. uses .suspend_interrupt to interrupt any concurrent and force them
   to return early, and then
3. uses the various suspend callbacks to suspend all vCPUs, machines,
   and the whole system -- all vCPUs before the machine they're on,
   and all machines before the system.

Resuming nvmm does the reverse of (3) -- resume system, resume each
machine and then the vCPUs on that machine -- and then unblocks
operations.

Implemented only for x86-vmx for now:

- suspend_interrupt triggers a TLB IPI to cause VM exits;
- vcpu_suspend issues VMCLEAR to force any in-CPU state to be written
  to memory;
- machine_suspend does nothing;
- suspend does VMXOFF on all CPUs;
- resume does VMXON on all CPUs;
- machine_resume does nothing; and
- vcpu_resume just marks each vCPU as valid but inactive so
  subsequent use will clear it and load it with vmptrld.

x86-svm left as an exercise for the reader.


To generate a diff of this commit:
cvs rdiff -u -r1.46 -r1.47 src/sys/dev/nvmm/nvmm.c
cvs rdiff -u -r1.20 -r1.21 src/sys/dev/nvmm/nvmm_internal.h
cvs rdiff -u -r1.84 -r1.85 src/sys/dev/nvmm/x86/nvmm_x86_vmx.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.