Re: GET_RNG_SEED hypercall ABI? (Re: [PATCH v5 0/5] random,x86,kvm: Rework arch RNG seeds and get some from kvm)

From: Paolo Bonzini
Date: Fri Aug 29 2014 - 02:37:24 EST

Il 29/08/2014 02:13, Andy Lutomirski ha scritto:
> Hmm. Then, assuming that someone manages to allocate a
> cross-hypervisor MSR number for this, what am I supposed to do in the
> KVM code? Just make it available unconditionally? I don't see why
> that wouldn't work reliably, but it seems like an odd design.

The odd part of it is what Gleb mentioned.

> Also, the one and only native feature flag I tested (rdtscp) actually
> does work: RDTSCP seems to send #UD if QEMU is passed -cpu
> host,-rdtscp.

True, and I'm not sure why. There are a couple others. I was thinking
more of things like SSE, AVX or DE (that affects the availability of a
bit in CR4).

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