bhyve and legacy

[John Baldwin]

On Wednesday, January 22, 2014 7:54:47 pm Tycho Nightingale wrote:
> 
> Hi,
> 
> Interest?  Yes!  Matter of fact, I have some scraps of 8259 support lying 
around here if you are keen to have a starting point.

I think most of 8259A could live in the hypervisor in userland.  I think all
that would be needed in vmm.ko would be a way to do the equivalent of 
asserting ExtInt with a specific IDT vector value and having the VMM code
honor the mask bits on lapic LINT0 and the I/O APIC ExtInt pins for deciding
when to deliver it to a CPU.

> Now with respect to bhyveload, while it certainly does have some FreeBSD-
specific uses, it is a bit of a barrier to supporting non-FreeBSD guests and 
furthermore supporting them well e.g. reboot without bhyve exiting.  If 'true' 
support existed for booting from an iso, then with a quick 'mkisofs' you could 
achieve the same kernel-to-VM turnaround without bhyveload.

Well, not quite as nice, but close.  One nice thing about the current host0:
approach is I can actually use 'nextboot -e bootfile=foo' inside the VM to
trigger a boot of a test kernel similar to using 'nextboot -k foo' on real
hardware.  That's not quite as easy to arrange in the ISO case given that
ISO's generally only show up if you boot from them.  What would be interesting
perhaps would be a way to PXE boot from the host.  That would be a closer
approximation to how bhyveload -H works.

-- 
John Baldwin