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Re: [Qemu-devel] [PATCH v2] rng-builtin: add an RNG backend that uses qe
From: |
Daniel P . Berrangé |
Subject: |
Re: [Qemu-devel] [PATCH v2] rng-builtin: add an RNG backend that uses qemu_guest_getrandom() |
Date: |
Fri, 10 May 2019 16:32:27 +0100 |
User-agent: |
Mutt/1.11.4 (2019-03-13) |
On Fri, May 10, 2019 at 02:37:41PM +0200, Laurent Vivier wrote:
> On 10/05/2019 14:27, Markus Armbruster wrote:
> > Laurent Vivier <address@hidden> writes:
> > The new rng-builtin is considerably simpler than both rng-random and
> > rng-egd. Moreover, it just works, whereas rng-random is limited to
> > CONFIG_POSIX, and rng-egd needs egd running (which I suspect basically
> > nobody does). Have we considered deprecating these two backends in
> > favor of rng-builtin?
>
> I have several bugzilla involving these backends: as there are blocking, the
> virtio-rng device in the guest can hang, or crash during hot-unplug. From my
> point of view, life would be easier without them...
Are you sure about that ?
The EGD impl looks like it is requesting entropy in an async manner.
Any problem with rng-random would also affect rng-builtin, as depending
on platform / build options, rng-builtin may just use /dev/urandom
directly. It should only block with /dev/random really and that's only
with Linux's impl of /dev/random - some OS effectively have /dev/random
behave identically to /dev/urandom.
Regards,
Daniel
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