vmm: Avoid embedding cpuset_t ioctl ABIs

[jhb]

sys/amd64/include/vmm.h

758

It's really tempting to remove the dmask pointer entirely. My one suggestion here removes the remaining in-kernel use. For userspace you might just need to pass the 'struct vm_run` to the exit handlers instead of vm_exit and then you could kill this entirely.

sys/amd64/vmm/io/vlapic.c

1149–1150

sys/amd64/vmm/vmm_dev.c

97

Maybe 's/old/13'? E.g. vm_exit_ipi_13 and VM_RUN_13?

620

I would do this fixup in libvmmapi perhaps rather than in the kernel.

usr.sbin/bhyve/bhyverun.c

1008

I don't think you need the zero? We don't memset vme to 0 here either.

[markj]

• Move cpuset_t entirely out of struct vm_exit.
• Modify bhyve exitcode handlers to take a vmrun structure.
• Rename compat ioctls/structures to use a more precise suffix.

[markj]

Fix a typo.

[jhb]

Thanks for doing the other changes.

usr.sbin/bhyve/bhyverun.c

1008

So I think I was wrong, you do need the CPU_ZERO, but maybe with a comment to explain why. Doing the zero here ensures that if the kernel is using a smaller cpuset_t size than userspace, that the kernel doesn't have to explicitly zero out the extra bits each time. Otherwise you will need to patch the VM_RUN ioctl in the kernel to copy out zeroes to the "extra" cpuset_t bits.

[markj]

sys/amd64/include/vmm.h

758

Yeah, that's a better idea. I didn't do that initially just out of laziness.

sys/amd64/vmm/vmm_dev.c

97

"old" is what we say elsewhere, but yeah it's better to be specific.

usr.sbin/bhyve/bhyverun.c

1008

Since userspace is doing the work to provide us with its view of the cpusetsize anyway, I think it's a bit tidier if the kernel takes take of zeroing the rest. That's what cpuset syscalls do too.