lkml.org 
[lkml]   [2008]   [Oct]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC] CPUID usage for interaction between Hypervisors and Linux.
H. Peter Anvin wrote:
> With a sufficiently large block, we could use fixed points, e.g. by
> having each vendor create interfaces in the 0x40SSSSXX range, where
> SSSS is the PCI ID they use for PCI devices.

Sure, you could do that, but you'd still want to have a signature in
0x40SSSS00 to positively identify the chunk. And what if you wanted
more than 256 leaves?

> Note that I said "create interfaces". It's important that all about
> this is who specified the interface -- for "what hypervisor is this"
> just use 0x40000000 and disambiguate based on that.

"What hypervisor is this?" isn't a very interesting question; if you're
even asking it then it suggests that something has gone wrong. Its much
more useful to ask "what interfaces does this hypervisor support?", and
enumerating a smallish range of well-known leaves looking for signatures
is the simplest way to do that. (We could use signatures derived from
the PCI vendor IDs which would help with managing that namespace.)

J


\
 
 \ /
  Last update: 2008-10-01 20:39    [W:0.074 / U:0.356 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site