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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20131001092320.GA2000@iris.ozlabs.ibm.com>
Date:	Tue, 1 Oct 2013 19:23:20 +1000
From:	Paul Mackerras <paulus@...ba.org>
To:	Gleb Natapov <gleb@...hat.com>
Cc:	Michael Ellerman <michael@...erman.id.au>,
	Paolo Bonzini <pbonzini@...hat.com>,
	linux-kernel@...r.kernel.org,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	agraf@...e.de, mpm@...enic.com, herbert@...dor.hengli.com.au,
	linuxppc-dev@...abs.org, kvm@...r.kernel.org,
	kvm-ppc@...r.kernel.org, tytso@....edu
Subject: Re: [PATCH 3/3] KVM: PPC: Book3S: Add support for hwrng found on
 some powernv systems

On Tue, Oct 01, 2013 at 11:39:08AM +0300, Gleb Natapov wrote:
> On Tue, Oct 01, 2013 at 06:34:26PM +1000, Michael Ellerman wrote:
> > On Thu, Sep 26, 2013 at 11:06:59AM +0200, Paolo Bonzini wrote:
> > > Il 26/09/2013 08:31, Michael Ellerman ha scritto:
> > > > Some powernv systems include a hwrng. Guests can access it via the
> > > > H_RANDOM hcall.
> > > 
> > > Is there any reason to do this in the kernel?  
> > 
> > It's less code, and it's faster :)
> > 
> > > It does not have to be a particularly fast path;
> > 
> > Sure, but do we have to make it slow on purpose?
> > 
> We do not put non performance critical devices into the kernel.

It's not a device, it's a single hypercall, specified by PAPR, which
is the moral equivalent of x86's RDRAND.

Paul.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/