Re: [9fans] I/O load crashes Qemu

[Bakul Shah <bakul+plan9@bitblocks.com>]

On Fri, 13 Jun 2008 19:52:22 EDT erik quanstrom <quanstro@quanstro.net>  wrote:
> > You don't need this sort of code in a virtualizable processor.
> > See for example
> >   http://en.wikipedia.org/wiki/Popek_and_Goldberg_virtualization_requiremen
> ts
>
> i'm not convinced that the illusion that the virtualized environment
> is in every way equivalent to the bare iron is always useful or worth
> the effort.  why should a virtualized operating system need to worry
> about what nic the machine has?

Well the URL was more to get the point across.  Whether your
virtual OS uses simplified virtual devices or emulated real
devices, you shouldn't have to emulate each instruction in
software!

I won't argue with "worth the effort" but it can be useful
(e.g. running dusty decks, debugging etc).

My argument is more that real device intefaces should be
designed to make virtualization efficient.

> for example vmware doesn't provide this sort of virtualized environment.
> it provides the same virtual network card interface regardless of
> what hardware the machine has.

It is doable but it took them years to get there and provide
good efficiency.  May be even more years that VM/370?!