Re: [PATCH RFC v1 0/2] VM fork detection for RNG

Jason A. Donenfeld
2022-02-23T16:08:21Z

On Wed, Feb 23, 2022 at 2:12 PM Jason A. Donenfeld <Jason@zx2c4.com> wrote:
> second patch is the reason this is just an RFC: it's a cleanup of the
> ACPI driver from last year, and I don't really have much experience
> writing, testing, debugging, or maintaining these types of drivers.
> Ideally this thread would yield somebody saying, "I see the intent of
> this; I'm happy to take over ownership of this part." That way, I can
> focus on the RNG part, and whoever steps up for the paravirt ACPI part
> can focus on that.

I actually managed to test this in QEMU, and it seems to work quite well. Steps:

$ qemu-system-x86_64 ... -device vmgenid,guid=auto -monitor stdio
(qemu) savevm blah
(qemu) quit
$ qemu-system-x86_64 ... -device vmgenid,guid=auto -monitor stdio
(qemu) loadvm blah

Doing this successfully triggers the function to reinitialize the RNG
with the new GUID. (It appears there's a bug in QEMU which prevents
the GUID from being reinitialized when running `loadvm` without
quitting first; I suppose this should be discussed with QEMU
upstream.)

So that's very positive. But I would appreciate hearing from some
ACPI/Virt/Amazon people about this.

Jason