Re: Standardizing an MSR or other hypercall to get an RNG seed?

Gleb Natapov
2014-09-19T17:15:45Z

On Fri, Sep 19, 2014 at 10:08:20AM -0700, H. Peter Anvin wrote:
> On 09/19/2014 09:53 AM, Gleb Natapov wrote:
> > On Fri, Sep 19, 2014 at 09:40:07AM -0700, H. Peter Anvin wrote:
> >> On 09/19/2014 09:37 AM, Gleb Natapov wrote:
> >>>
> >>> Linux detects what hypervior it runs on very early
> >>
> >> Not anywhere close to early enough. We're talking for uses like kASLR.
> >>
> > Still to early to do:
> >
> > h = cpuid(HYPERVIOR_SIGNATURE)
> > if (h == KVMKVMKVM) {
> > if (cpuid(kvm_features) & kvm_rnd)
> > rdmsr(kvm_rnd)
> > else (h == HyperV) {
> > if (cpuid(hv_features) & hv_rnd)
> > rdmsr(hv_rnd)
> > else (h == XenXenXen) {
> > if (cpuid(xen_features) & xen_rnd)
> > rdmsr(xen_rnd)
> > }
> >
>
> If we need to do chase loops, especially not so...
>
What loops exactly? As a non native English speaker I fail to understand
if your answer is "yes" or "no" ;)

--
Gleb.