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Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver
From: |
Willy Tarreau |
Subject: |
Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver |
Date: |
Sat, 17 Oct 2020 09:17:21 +0200 |
User-agent: |
Mutt/1.6.1 (2016-04-27) |
On Sat, Oct 17, 2020 at 08:55:34AM +0200, Jann Horn wrote:
> My suggestion is to use a counter *in the UAPI*, not in the hypervisor
> protocol. (And as long as that counter can only miss increments in a
> cryptographically negligible fraction of cases, everything's fine.)
OK I got it now and I agree.
> > If what is sought is pure
> > randomness (in the sense that it's unpredictable, which I don't think
> > is needed here), then randoms are better.
>
> And this is what *the hypervisor protocol* gives us (which could be
> very useful for reseeding the kernel RNG).
As an external source, yes very likely, as long as it's not trivially
observable by everyone under the same hypervisor :-)
> > Now the initial needs in the forwarded message are not entirely clear
> > to me but I wanted to rule out the apparent mismatch between the expressed
> > needs for uniqueness and the proposed solutions solely based on randomness.
>
> Sure, from a theoretical standpoint, it would be a little bit nicer if
> the hypervisor protocol included a generation number along with the
> 128-bit random value. But AFAIU it doesn't, so if we want this to just
> work under Microsoft's existing hypervisor, we'll have to make do with
> checking whether the random value changed. :P
OK got it, thanks for the explanation!
Willy
- Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver, (continued)
- Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver, Jann Horn, 2020/10/16
- Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver, Willy Tarreau, 2020/10/17
- Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver, Jann Horn, 2020/10/17
- Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver, Colm MacCarthaigh, 2020/10/17
- Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver, Jann Horn, 2020/10/17
- Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver, Colm MacCarthaigh, 2020/10/17
- Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver, Willy Tarreau, 2020/10/17
- Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver, Jann Horn, 2020/10/17
- Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver, Willy Tarreau, 2020/10/17
- Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver, Jann Horn, 2020/10/17
- Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver,
Willy Tarreau <=
- Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver, Jason A. Donenfeld, 2020/10/17
- Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver, Catangiu, Adrian Costin, 2020/10/17
- Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver, Alexander Graf, 2020/10/17
- Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver, Jann Horn, 2020/10/17
- Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver, Christian Borntraeger, 2020/10/20
- Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver, Alexander Graf, 2020/10/20
- Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver, Catangiu, Adrian Costin, 2020/10/20
- Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver, Colm MacCarthaigh, 2020/10/17
- Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver, Michael S. Tsirkin, 2020/10/18
- Re: [PATCH] drivers/virt: vmgenid: add vm generation id driver, Andy Lutomirski, 2020/10/18