Re: [DISCUSSION] Allow ACPI default OEM ID and OEM table ID fields to be set.

[Antoine Damhet]

On Wed, Nov 25, 2020 at 11:04:55AM -0500, Michael S. Tsirkin wrote:
> On Wed, Nov 25, 2020 at 01:32:51PM +0000, Richard W.M. Jones wrote:
> > On Wed, Nov 25, 2020 at 02:27:11PM +0100, Antoine Damhet wrote:
> > > Hello,
> > > 
> > > We recently found out that some softwares are effectively crashing
> > > when they detect qemu's `OEM ID` or `OEM table ID` in the ACPI tables.
> > > 
> > > I see no reason not to expose the setting to the user/command-line. A
> > > previous patch has been submitted in 2015[1] but did not get through
> > > because (if I understand correctly) using the IDs on the `SLIC`, `BXPC`
> > > and `RSDT` tables were enough at the time.
> > > 
> > > If you agree, I am willing to forward port the patches of M. Jones but I
> > > need to ask how it would work `Signed-Off`-wise ?
> > 
> > On this point, the patch I sent was actually written by
> > Michael Tokarev, I was only trying to get them upstream.
> > 
> > Rich.
> 
> I think at least one of the issues is that e.g. UEFI at least
> seems to assume unique OEM table IDs e.g. for SSDTs.
> 
> So let's try to be more specific please, which software
> crashes, what does it want to see and in which table.

I'm sorry I cannot give you the name of the crashing software due to a
company policy. But I can tell you that if either `BOCHS ` or `BXPC` is
present in any of the tables it will crash. Any (or at least the few
that I threw at it) other string will work so it seems it's some kind
of DRM-related hypervisor detection.

As for the uniqueness of the table IDs, I guess it would be sane to keep
the same pattern (id+table sig) but allowing the first 4 bytes to be
overridden.

[...]

-- 
Antoine 'xdbob' Damhet