Re: [PATCH 3/3] KVM: PPC: Book3S: Add support for hwrng found on some powernv systems

Benjamin Herrenschmidt
2013-10-02T22:07:52Z

On Wed, 2013-10-02 at 13:02 +0300, Gleb Natapov wrote:

> Yes, I alluded to it in my email to Paul and Paolo asked also. How this
> interface is disabled? Also hwrnd is MMIO in a host why guest needs to
> use hypercall instead of emulating the device (in kernel or somewhere
> else?). Another things is that on a host hwrnd is protected from
> direct userspace access by virtue of been a device, but guest code (event
> kernel mode) is userspace as far as hosts security model goes, so by
> implementing this hypercall in a way that directly access hwrnd you
> expose hwrnd to a userspace unconditionally. Why is this a good idea?

BTW. Is this always going to be like this ?

Every *single* architectural or design decision we make for our
architecture has to be justified 30 times over, every piece of code bike
shedded to oblivion for month, etc... ?

Do we always have to finally get to some kind of agreement on design, go
to the 6 month bike-shedding phase, just to have somebody else come up
and start re-questioning the whole original design (without any
understanding of our specific constraints of course) ?

You guys are the most horrendous community I have ever got to work with.
It's simply impossible to get anything done in any reasonable time
frame .

At this stage, it would have taken us an order of magnitude less time to
simply rewrite an entire hypervisor from scratch.

This is sad.

Ben.