From: Gleb Natapov <gleb@redhat.com>
To: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <michael@ellerman.id.au>,
Paolo Bonzini <pbonzini@redhat.com>,
linux-kernel@vger.kernel.org,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
agraf@suse.de, mpm@selenic.com, herbert@gondor.hengli.com.au,
linuxppc-dev@ozlabs.org, kvm@vger.kernel.org,
kvm-ppc@vger.kernel.org, tytso@mit.edu
Subject: Re: [PATCH 3/3] KVM: PPC: Book3S: Add support for hwrng found on some powernv systems
Date: Tue, 01 Oct 2013 09:57:59 +0000 [thread overview]
Message-ID: <20131001095759.GA1308@redhat.com> (raw)
In-Reply-To: <20131001092320.GA2000@iris.ozlabs.ibm.com>
On Tue, Oct 01, 2013 at 07:23:20PM +1000, Paul Mackerras wrote:
> 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.
>
OK. A couple of general questions. How guest knows when this hypercall
is available? Is QEMU enable it when KVM_CAP_PPC_HWRNG is available (I
haven't seen userspace patch that uses KVM_CAP_PPC_HWRNG)? What about
QEMU TCG does it implement this hypercall or it emulates hwrng directly?
--
Gleb.
WARNING: multiple messages have this Message-ID (diff)
From: Gleb Natapov <gleb@redhat.com>
To: Paul Mackerras <paulus@samba.org>
Cc: tytso@mit.edu, kvm@vger.kernel.org, linuxppc-dev@ozlabs.org,
agraf@suse.de, kvm-ppc@vger.kernel.org,
linux-kernel@vger.kernel.org, herbert@gondor.hengli.com.au,
mpm@selenic.com, Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH 3/3] KVM: PPC: Book3S: Add support for hwrng found on some powernv systems
Date: Tue, 1 Oct 2013 12:57:59 +0300 [thread overview]
Message-ID: <20131001095759.GA1308@redhat.com> (raw)
In-Reply-To: <20131001092320.GA2000@iris.ozlabs.ibm.com>
On Tue, Oct 01, 2013 at 07:23:20PM +1000, Paul Mackerras wrote:
> 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.
>
OK. A couple of general questions. How guest knows when this hypercall
is available? Is QEMU enable it when KVM_CAP_PPC_HWRNG is available (I
haven't seen userspace patch that uses KVM_CAP_PPC_HWRNG)? What about
QEMU TCG does it implement this hypercall or it emulates hwrng directly?
--
Gleb.
WARNING: multiple messages have this Message-ID (diff)
From: Gleb Natapov <gleb@redhat.com>
To: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <michael@ellerman.id.au>,
Paolo Bonzini <pbonzini@redhat.com>,
linux-kernel@vger.kernel.org,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
agraf@suse.de, mpm@selenic.com, herbert@gondor.hengli.com.au,
linuxppc-dev@ozlabs.org, kvm@vger.kernel.org,
kvm-ppc@vger.kernel.org, tytso@mit.edu
Subject: Re: [PATCH 3/3] KVM: PPC: Book3S: Add support for hwrng found on some powernv systems
Date: Tue, 1 Oct 2013 12:57:59 +0300 [thread overview]
Message-ID: <20131001095759.GA1308@redhat.com> (raw)
In-Reply-To: <20131001092320.GA2000@iris.ozlabs.ibm.com>
On Tue, Oct 01, 2013 at 07:23:20PM +1000, Paul Mackerras wrote:
> 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.
>
OK. A couple of general questions. How guest knows when this hypercall
is available? Is QEMU enable it when KVM_CAP_PPC_HWRNG is available (I
haven't seen userspace patch that uses KVM_CAP_PPC_HWRNG)? What about
QEMU TCG does it implement this hypercall or it emulates hwrng directly?
--
Gleb.
next prev parent reply other threads:[~2013-10-01 9:57 UTC|newest]
Thread overview: 146+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-26 6:31 [PATCH 1/3] powerpc: Implement arch_get_random_long/int() for powernv Michael Ellerman
2013-09-26 6:31 ` Michael Ellerman
2013-09-26 6:31 ` Michael Ellerman
2013-09-26 6:31 ` Michael Ellerman
2013-09-26 6:31 ` [PATCH 2/3] hwrng: Add a driver for the hwrng found in power7+ systems Michael Ellerman
2013-09-26 6:31 ` Michael Ellerman
2013-09-26 6:31 ` Michael Ellerman
2013-09-26 6:31 ` Michael Ellerman
2013-09-26 8:01 ` Benjamin Herrenschmidt
2013-09-26 8:01 ` Benjamin Herrenschmidt
2013-09-26 8:01 ` Benjamin Herrenschmidt
2013-10-01 8:25 ` Michael Ellerman
2013-10-01 8:25 ` Michael Ellerman
2013-10-01 8:25 ` Michael Ellerman
2013-09-26 6:31 ` [PATCH 3/3] KVM: PPC: Book3S: Add support for hwrng found on some powernv systems Michael Ellerman
2013-09-26 6:31 ` Michael Ellerman
2013-09-26 6:31 ` Michael Ellerman
2013-09-26 6:31 ` Michael Ellerman
2013-09-26 9:06 ` Paolo Bonzini
2013-09-26 9:06 ` Paolo Bonzini
2013-09-26 9:06 ` Paolo Bonzini
2013-09-26 9:06 ` Paolo Bonzini
2013-10-01 8:34 ` Michael Ellerman
2013-10-01 8:34 ` Michael Ellerman
2013-10-01 8:34 ` Michael Ellerman
2013-10-01 8:34 ` Michael Ellerman
2013-10-01 8:39 ` Gleb Natapov
2013-10-01 8:39 ` Gleb Natapov
2013-10-01 8:39 ` Gleb Natapov
2013-10-01 9:23 ` Paul Mackerras
2013-10-01 9:23 ` Paul Mackerras
2013-10-01 9:23 ` Paul Mackerras
2013-10-01 9:57 ` Gleb Natapov [this message]
2013-10-01 9:57 ` Gleb Natapov
2013-10-01 9:57 ` Gleb Natapov
2013-10-01 10:00 ` Alexander Graf
2013-10-01 10:00 ` Alexander Graf
2013-10-01 10:00 ` Alexander Graf
2013-10-01 9:38 ` Benjamin Herrenschmidt
2013-10-01 9:38 ` Benjamin Herrenschmidt
2013-10-01 9:38 ` Benjamin Herrenschmidt
2013-10-01 11:19 ` Paolo Bonzini
2013-10-01 11:19 ` Paolo Bonzini
2013-10-01 11:19 ` Paolo Bonzini
2013-10-01 21:44 ` Benjamin Herrenschmidt
2013-10-01 21:44 ` Benjamin Herrenschmidt
2013-10-01 21:44 ` Benjamin Herrenschmidt
2013-10-02 8:38 ` Paolo Bonzini
2013-10-02 8:38 ` Paolo Bonzini
2013-10-02 8:38 ` Paolo Bonzini
2013-10-02 5:09 ` Paul Mackerras
2013-10-02 5:09 ` Paul Mackerras
2013-10-02 5:09 ` Paul Mackerras
2013-10-02 8:46 ` Paolo Bonzini
2013-10-02 8:46 ` Paolo Bonzini
2013-10-02 8:46 ` Paolo Bonzini
2013-10-02 9:06 ` Benjamin Herrenschmidt
2013-10-02 9:06 ` Benjamin Herrenschmidt
2013-10-02 9:06 ` Benjamin Herrenschmidt
2013-10-02 9:11 ` Alexander Graf
2013-10-02 9:11 ` Alexander Graf
2013-10-02 9:11 ` Alexander Graf
2013-10-02 9:50 ` Alexander Graf
2013-10-02 9:50 ` Alexander Graf
2013-10-02 9:50 ` Alexander Graf
2013-10-02 10:02 ` Gleb Natapov
2013-10-02 10:02 ` Gleb Natapov
2013-10-02 10:02 ` Gleb Natapov
2013-10-02 13:57 ` Michael Ellerman
2013-10-02 13:57 ` Michael Ellerman
2013-10-02 13:57 ` Michael Ellerman
2013-10-02 14:08 ` Alexander Graf
2013-10-02 14:08 ` Alexander Graf
2013-10-02 14:08 ` Alexander Graf
2013-10-02 14:33 ` Paolo Bonzini
2013-10-02 14:33 ` Paolo Bonzini
2013-10-02 14:33 ` Paolo Bonzini
2013-10-02 14:36 ` Alexander Graf
2013-10-02 14:36 ` Alexander Graf
2013-10-02 14:36 ` Alexander Graf
2013-10-02 14:38 ` Paolo Bonzini
2013-10-02 14:38 ` Paolo Bonzini
2013-10-02 14:38 ` Paolo Bonzini
2013-10-02 22:45 ` Paul Mackerras
2013-10-02 22:45 ` Paul Mackerras
2013-10-02 22:45 ` Paul Mackerras
2013-10-03 5:48 ` Gleb Natapov
2013-10-03 5:48 ` Gleb Natapov
2013-10-03 5:48 ` Gleb Natapov
2013-10-03 10:06 ` Paul Mackerras
2013-10-03 10:06 ` Paul Mackerras
2013-10-03 10:06 ` Paul Mackerras
2013-10-03 12:08 ` Gleb Natapov
2013-10-03 12:08 ` Gleb Natapov
2013-10-03 12:08 ` Gleb Natapov
2013-10-02 14:37 ` Gleb Natapov
2013-10-02 14:37 ` Gleb Natapov
2013-10-02 14:37 ` Gleb Natapov
2013-10-02 22:21 ` Benjamin Herrenschmidt
2013-10-02 22:21 ` Benjamin Herrenschmidt
2013-10-02 22:21 ` Benjamin Herrenschmidt
2013-10-03 6:08 ` Gleb Natapov
2013-10-03 6:08 ` Gleb Natapov
2013-10-03 6:08 ` Gleb Natapov
2013-10-02 22:13 ` Benjamin Herrenschmidt
2013-10-02 22:13 ` Benjamin Herrenschmidt
2013-10-02 22:13 ` Benjamin Herrenschmidt
2013-10-02 14:10 ` Gleb Natapov
2013-10-02 14:10 ` Gleb Natapov
2013-10-02 14:10 ` Gleb Natapov
2013-10-02 22:15 ` Benjamin Herrenschmidt
2013-10-02 22:15 ` Benjamin Herrenschmidt
2013-10-02 22:15 ` Benjamin Herrenschmidt
2013-10-02 22:02 ` Benjamin Herrenschmidt
2013-10-02 22:02 ` Benjamin Herrenschmidt
2013-10-02 22:02 ` Benjamin Herrenschmidt
2013-10-03 5:43 ` Gleb Natapov
2013-10-03 5:43 ` Gleb Natapov
2013-10-03 5:43 ` Gleb Natapov
2013-10-03 7:22 ` Benjamin Herrenschmidt
2013-10-03 7:22 ` Benjamin Herrenschmidt
2013-10-03 7:22 ` Benjamin Herrenschmidt
2013-10-02 22:07 ` Benjamin Herrenschmidt
2013-10-02 22:07 ` Benjamin Herrenschmidt
2013-10-02 22:07 ` Benjamin Herrenschmidt
2013-10-03 6:28 ` Gleb Natapov
2013-10-03 6:28 ` Gleb Natapov
2013-10-03 6:28 ` Gleb Natapov
2013-10-02 21:58 ` Benjamin Herrenschmidt
2013-10-02 21:58 ` Benjamin Herrenschmidt
2013-10-02 21:58 ` Benjamin Herrenschmidt
2013-10-01 9:58 ` Paolo Bonzini
2013-10-01 9:58 ` Paolo Bonzini
2013-10-01 9:58 ` Paolo Bonzini
2013-10-01 9:58 ` Paolo Bonzini
2013-09-27 14:15 ` Anshuman Khandual
2013-09-27 14:27 ` Anshuman Khandual
2013-09-27 14:15 ` Anshuman Khandual
2013-09-27 14:15 ` Anshuman Khandual
2013-10-01 8:36 ` Michael Ellerman
2013-10-01 8:36 ` Michael Ellerman
2013-10-01 8:36 ` Michael Ellerman
2013-10-01 8:36 ` Michael Ellerman
2013-09-26 7:58 ` [PATCH 1/3] powerpc: Implement arch_get_random_long/int() for powernv Benjamin Herrenschmidt
2013-09-26 7:58 ` Benjamin Herrenschmidt
2013-09-26 7:58 ` Benjamin Herrenschmidt
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