On Thu, Oct 03, 2013 at 08:06:30PM +1000, Paul Mackerras wrote:
> On Thu, Oct 03, 2013 at 08:48:03AM +0300, Gleb Natapov wrote:
> > On Thu, Oct 03, 2013 at 08:45:42AM +1000, Paul Mackerras wrote:
> > > On Wed, Oct 02, 2013 at 04:36:05PM +0200, Alexander Graf wrote:
> > > >
> > > > On 02.10.2013, a
On Thu, Oct 03, 2013 at 08:48:03AM +0300, Gleb Natapov wrote:
> On Thu, Oct 03, 2013 at 08:45:42AM +1000, Paul Mackerras wrote:
> > On Wed, Oct 02, 2013 at 04:36:05PM +0200, Alexander Graf wrote:
> > >
> > > On 02.10.2013, at 16:33, Paolo Bonzini wrote:
> > >
> > > > Il 02/10/2013 16:08, Alexande
On Thu, 2013-10-03 at 08:43 +0300, Gleb Natapov wrote:
> Why it can be a bad idea? User can drain hwrng continuously making other
> users of it much slower, or even worse, making them fall back to another
> much less reliable, source of entropy.
Not in a very significant way, we generate entropy a
On Thu, Oct 03, 2013 at 08:07:22AM +1000, Benjamin Herrenschmidt wrote:
> 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 hypercal
On Thu, Oct 03, 2013 at 08:21:20AM +1000, Benjamin Herrenschmidt wrote:
> On Wed, 2013-10-02 at 17:37 +0300, Gleb Natapov wrote:
> > On Wed, Oct 02, 2013 at 04:33:18PM +0200, Paolo Bonzini wrote:
> > > Il 02/10/2013 16:08, Alexander Graf ha scritto:
> > > > > The hwrng is accessible by host userspa
On Thu, Oct 03, 2013 at 08:45:42AM +1000, Paul Mackerras wrote:
> On Wed, Oct 02, 2013 at 04:36:05PM +0200, Alexander Graf wrote:
> >
> > On 02.10.2013, at 16:33, Paolo Bonzini wrote:
> >
> > > Il 02/10/2013 16:08, Alexander Graf ha scritto:
> > >>> The hwrng is accessible by host userspace via /
On Thu, Oct 03, 2013 at 08:02:20AM +1000, Benjamin Herrenschmidt wrote:
> 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 hypercal
On Wed, Oct 02, 2013 at 04:36:05PM +0200, Alexander Graf wrote:
>
> On 02.10.2013, at 16:33, Paolo Bonzini wrote:
>
> > Il 02/10/2013 16:08, Alexander Graf ha scritto:
> >>> The hwrng is accessible by host userspace via /dev/mem.
> >>
> >> A guest should live on the same permission level as a us
On Wed, 2013-10-02 at 17:37 +0300, Gleb Natapov wrote:
> On Wed, Oct 02, 2013 at 04:33:18PM +0200, Paolo Bonzini wrote:
> > Il 02/10/2013 16:08, Alexander Graf ha scritto:
> > > > The hwrng is accessible by host userspace via /dev/mem.
> > >
> > > A guest should live on the same permission level a
On Wed, 2013-10-02 at 17:10 +0300, Gleb Natapov wrote:
> > The hwrng is accessible by host userspace via /dev/mem.
> >
> Regular user has no access to /dev/mem, but he can start kvm guest and
> gain access to the device.
Seriously. You guys are really trying hard to make our life hell or
what ? T
On Wed, 2013-10-02 at 16:08 +0200, Alexander Graf wrote:
> A guest should live on the same permission level as a user space
> application. If you run QEMU as UID 1000 without access to /dev/mem,
> why should the guest suddenly be able to directly access a memory
> location (MMIO) it couldn't access
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
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?).
Migration wil
On Wed, 2013-10-02 at 11:11 +0200, Alexander Graf wrote:
> Right, and the difference for the patch in question is really whether
> we handle in in kernel virtual mode or in QEMU, so the bulk of the
> overhead (kicking threads out of guest context, switching MMU
> context, etc) happens either way.
Il 02/10/2013 16:36, Alexander Graf ha scritto:
>> >
>> > With Michael's earlier patch in this series, the hwrng is accessible by
>> > host userspace via /dev/hwrng, no?
> Yes, but there's not token from user space that gets passed into the
> kernel to check whether access is ok or not. So while Q
On Wed, Oct 02, 2013 at 04:33:18PM +0200, Paolo Bonzini wrote:
> Il 02/10/2013 16:08, Alexander Graf ha scritto:
> > > The hwrng is accessible by host userspace via /dev/mem.
> >
> > A guest should live on the same permission level as a user space
> > application. If you run QEMU as UID 1000 witho
On 02.10.2013, at 16:33, Paolo Bonzini wrote:
> Il 02/10/2013 16:08, Alexander Graf ha scritto:
>>> The hwrng is accessible by host userspace via /dev/mem.
>>
>> A guest should live on the same permission level as a user space
>> application. If you run QEMU as UID 1000 without access to /dev/me
Il 02/10/2013 16:08, Alexander Graf ha scritto:
> > The hwrng is accessible by host userspace via /dev/mem.
>
> A guest should live on the same permission level as a user space
> application. If you run QEMU as UID 1000 without access to /dev/mem, why
> should the guest suddenly be able to directl
On Wed, Oct 02, 2013 at 11:57:55PM +1000, Michael Ellerman wrote:
> On Wed, 2013-10-02 at 13:02 +0300, Gleb Natapov wrote:
> > On Wed, Oct 02, 2013 at 11:50:50AM +0200, Alexander Graf wrote:
> > >
> > > On 02.10.2013, at 11:11, Alexander Graf wrote:
> > >
> > > So how do you solve live migration
On 02.10.2013, at 15:57, Michael Ellerman wrote:
> On Wed, 2013-10-02 at 13:02 +0300, Gleb Natapov wrote:
>> On Wed, Oct 02, 2013 at 11:50:50AM +0200, Alexander Graf wrote:
>>>
>>> On 02.10.2013, at 11:11, Alexander Graf wrote:
>>>
>>> So how do you solve live migration between a kernel that ha
On Wed, 2013-10-02 at 13:02 +0300, Gleb Natapov wrote:
> On Wed, Oct 02, 2013 at 11:50:50AM +0200, Alexander Graf wrote:
> >
> > On 02.10.2013, at 11:11, Alexander Graf wrote:
> >
> > So how do you solve live migration between a kernel that has this patch and
> > one that doesn't?
> >
> Yes, I
On Wed, Oct 02, 2013 at 11:50:50AM +0200, Alexander Graf wrote:
>
> On 02.10.2013, at 11:11, Alexander Graf wrote:
>
> >
> > On 02.10.2013, at 11:06, Benjamin Herrenschmidt wrote:
> >
> >> On Wed, 2013-10-02 at 10:46 +0200, Paolo Bonzini wrote:
> >>
> >>>
> >>> Thanks. Any chance you can giv
On 02.10.2013, at 11:11, Alexander Graf wrote:
>
> On 02.10.2013, at 11:06, Benjamin Herrenschmidt wrote:
>
>> On Wed, 2013-10-02 at 10:46 +0200, Paolo Bonzini wrote:
>>
>>>
>>> Thanks. Any chance you can give some numbers of a kernel hypercall and
>>> a userspace hypercall on Power, so we h
On 02.10.2013, at 11:06, Benjamin Herrenschmidt wrote:
> On Wed, 2013-10-02 at 10:46 +0200, Paolo Bonzini wrote:
>
>>
>> Thanks. Any chance you can give some numbers of a kernel hypercall and
>> a userspace hypercall on Power, so we have actual data? For example a
>> hypercall that returns H_
On Wed, 2013-10-02 at 10:46 +0200, Paolo Bonzini wrote:
>
> Thanks. Any chance you can give some numbers of a kernel hypercall and
> a userspace hypercall on Power, so we have actual data? For example a
> hypercall that returns H_PARAMETER as soon as possible.
I don't have (yet) numbers at han
Il 02/10/2013 07:09, Paul Mackerras ha scritto:
> On Tue, Oct 01, 2013 at 01:19:06PM +0200, Paolo Bonzini wrote:
>
>> Anyhow, I would like to know more about this hwrng and hypercall.
>>
>> Does the hwrng return random numbers (like rdrand) or real entropy (like
>> rdseed that Intel will add in Br
Il 01/10/2013 23:44, Benjamin Herrenschmidt ha scritto:
> On Tue, 2013-10-01 at 13:19 +0200, Paolo Bonzini wrote:
>> Il 01/10/2013 11:38, Benjamin Herrenschmidt ha scritto:
>>> So for the sake of that dogma you are going to make us do something that
>>> is about 100 times slower ? (and possibly inv
On Tue, Oct 01, 2013 at 01:19:06PM +0200, Paolo Bonzini wrote:
> Anyhow, I would like to know more about this hwrng and hypercall.
>
> Does the hwrng return random numbers (like rdrand) or real entropy (like
> rdseed that Intel will add in Broadwell)? What about the hypercall?
Well, firstly, yo
On Tue, 2013-10-01 at 13:19 +0200, Paolo Bonzini wrote:
> Il 01/10/2013 11:38, Benjamin Herrenschmidt ha scritto:
> > So for the sake of that dogma you are going to make us do something that
> > is about 100 times slower ? (and possibly involves more lines of code)
>
> If it's 100 times slower the
Il 01/10/2013 11:38, Benjamin Herrenschmidt ha scritto:
> So for the sake of that dogma you are going to make us do something that
> is about 100 times slower ? (and possibly involves more lines of code)
If it's 100 times slower there is something else that's wrong. It's
most likely not 100 times
On 10/01/2013 11:23 AM, 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 p
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, Mic
Il 01/10/2013 10:34, Michael Ellerman ha scritto:
>> If you really want to have the hypercall, implementing it in QEMU means
>> that you can support it on all systems, in fact even when running
>> without KVM.
>
> Sure, I can add a fallback to /dev/hwrng for full emulation.
>
>> The QEMU comman
On Tue, 2013-10-01 at 11:39 +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
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.
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 a
On Fri, Sep 27, 2013 at 07:45:45PM +0530, Anshuman Khandual wrote:
> On 09/26/2013 12:01 PM, Michael Ellerman wrote:
> > +int powernv_hwrng_present(void)
> > +{
> > + return __raw_get_cpu_var(powernv_rng) != NULL;
> > +}
> > +
> > static unsigned long rng_whiten(struct powernv_rng *rng, unsigned
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 :)
> I
On 09/26/2013 12:01 PM, Michael Ellerman wrote:
> +int powernv_hwrng_present(void)
> +{
> + return __raw_get_cpu_var(powernv_rng) != NULL;
> +}
> +
> static unsigned long rng_whiten(struct powernv_rng *rng, unsigned long val)
> {
> unsigned long parity;
> @@ -42,6 +48,17 @@ static unsig
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.
>
> We add a real mode implementation of H_RANDOM when a hwrng is found.
> Userspace can detect the presence of the hwrng by quering the
> KVM_CAP_PPC_HWRNG capa
Some powernv systems include a hwrng. Guests can access it via the
H_RANDOM hcall.
We add a real mode implementation of H_RANDOM when a hwrng is found.
Userspace can detect the presence of the hwrng by quering the
KVM_CAP_PPC_HWRNG capability.
Signed-off-by: Michael Ellerman
---
arch/powerpc/in
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