No-downtime ROM upgrades

[Andrey Korolyov <andrey@xdel.ru>]

Hello,

As it shows up, upgrading of any system ROMs loaded to the emulator
initially is not possible without complete restart of the emulator
itself, as live migration refuses to complete with different payload at
both ends. Assuming that the guest side payload for vga/ethernet can be
actually re-read via powering off and on corresponding PCI devices at
the runtime, it`s hard to say of what to do with BIOS itself. Does
anyone have an idea if such kind of upgrades are discussed/implemented
somewhere? Though ROMs are very unlikely to be buggy, some additional
features may come in over couple of releases adding necessity of
relaunching virtual machine (like upcoming PNP080 update for example).
And, of course, there are business-driven cases where such thing must be
avoided. :)

Thanks!