From: Jeff Garzik <jeff@garzik.org>
To: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
virtualization@lists.osdl.org,
Rusty Russell <rusty@rustcorp.com.au>,
jeremy@xensource.com, Herbert Xu <herbert@gondor.apana.org.au>,
Avi Kivity <avi@qumranet.com>,
dor.laor@qumranet.com
Subject: Re: Virt RNG?
Date: Thu, 15 May 2008 16:44:56 -0400 [thread overview]
Message-ID: <482CA0C8.7020808@garzik.org> (raw)
In-Reply-To: <200805152231.56967.borntraeger@de.ibm.com>
Christian Borntraeger wrote:
> Am Donnerstag, 15. Mai 2008 schrieb Jeff Garzik:
>> Has anyone yet written a "hw" RNG module for virt, that reads the host's
>> random number pool?
>>
>> All this talk[1] about IRQF_SAMPLE_RANDOM in network drivers reminds me
>> that virt guest instances should be grabbing random numbers from the
>> host, especially if the host has a hardware RNG.
>
> Yes, there was a drivers/char/hw_random/virtio-rng.c in Rusty's lguest
> repository.
> http://www.mail-archive.com/virtualization%40lists.linux-foundation.org/msg02902.html
>
> I have tested this driver with this fix
> https://lists.linux-foundation.org/pipermail/virtualization/2008-January/009737.html
> and it worked.
Nice!
> As it transfers only 4 byte per hypercall it is not mindblowingly fast, but I
> guess it is fast enough.
A limitation of the hw-random API. However, I'd say the virtio rng
driver could (and should) buffer bigger chunks, say at least a
cacheline's worth of data, to return via hw-random's 32-bit data request
API.
Jeff
next prev parent reply other threads:[~2008-05-15 20:44 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-15 18:48 Virt RNG? Jeff Garzik
2008-05-15 19:53 ` Jeremy Fitzhardinge
2008-05-15 19:53 ` Jeremy Fitzhardinge
2008-05-15 20:26 ` Dor Laor
2008-05-15 20:31 ` Christian Borntraeger
2008-05-15 20:44 ` Jeff Garzik [this message]
2008-05-15 20:43 ` Jeff Dike
2008-05-15 23:43 ` Rusty Russell
2008-05-16 0:07 ` Henrique de Moraes Holschuh
2008-05-16 5:31 ` [PATCH 1/2] virtio: hardware random device Rusty Russell
2008-05-16 5:39 ` [PATCH 2/2] lguest: virtio-rng support Rusty Russell
2008-05-16 5:39 ` Rusty Russell
2008-05-16 5:39 ` Rusty Russell
2008-05-16 10:49 ` Johannes Berg
2008-05-16 10:49 ` Johannes Berg
2008-05-16 20:25 ` H. Peter Anvin
2008-05-16 20:25 ` H. Peter Anvin
2008-05-17 4:46 ` Rusty Russell
2008-05-17 4:50 ` H. Peter Anvin
2008-05-17 4:50 ` H. Peter Anvin
2008-05-17 6:28 ` Rusty Russell
2008-05-17 6:28 ` Rusty Russell
2008-05-17 6:43 ` Herbert Xu
2008-05-17 6:43 ` Herbert Xu
2008-05-17 7:43 ` Christian Borntraeger
2008-05-17 7:43 ` Christian Borntraeger
2008-05-17 15:56 ` H. Peter Anvin
2008-05-17 15:56 ` H. Peter Anvin
2008-05-17 7:47 ` Jeremy Fitzhardinge
2008-05-17 7:47 ` Jeremy Fitzhardinge
2008-05-19 9:05 ` Rusty Russell
2008-05-19 9:05 ` Rusty Russell
2008-05-19 9:10 ` Jeremy Fitzhardinge
2008-05-19 9:28 ` Rusty Russell
2008-05-19 9:28 ` Rusty Russell
2008-05-19 9:45 ` Jeremy Fitzhardinge
2008-05-19 9:45 ` Jeremy Fitzhardinge
2008-05-19 9:10 ` Jeremy Fitzhardinge
2008-05-17 15:57 ` H. Peter Anvin
2008-05-17 15:57 ` H. Peter Anvin
2008-05-17 4:46 ` Rusty Russell
2008-05-16 7:31 ` [PATCH 1/2] virtio: hardware random device Christian Borntraeger
2008-05-16 7:31 ` Christian Borntraeger
2008-05-16 5:31 ` Rusty Russell
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