ACPI VFCT table too short on PVH dom0 (was: Re: E820 memory allocation issue on Threadripper platforms)

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Thu, Jan 18, 2024 at 10:46:26AM +0100, Roger Pau Monné wrote:
> On Thu, Jan 18, 2024 at 03:34:13AM -0500, Patrick Plenefisch wrote:
> > On Thu, Jan 18, 2024 at 3:27 AM Roger Pau Monné <roger.pau@xxxxxxxxxx>
> > wrote:
> > 
> > > On Thu, Jan 18, 2024 at 01:23:56AM -0500, Patrick Plenefisch wrote:
> > > > On Wed, Jan 17, 2024 at 3:46 AM Jan Beulich <jbeulich@xxxxxxxx> wrote:
> > > >
> > > > > On 17.01.2024 07:12, Patrick Plenefisch wrote:
> > > > > > On Tue, Jan 16, 2024 at 4:33 AM Jan Beulich <jbeulich@xxxxxxxx>
> > > wrote:
> > > > > >
> > > > > >> On 16.01.2024 01:22, Patrick Plenefisch wrote:
> > > > For the two logs that actually boooted (linuxoffset), I truncated them
> > > > during pcie initialization, but they did go all the way to give me a
> > > login
> > > > screen
> > >
> > > I'm not seeing any Linux output on the provided logs, they just seem
> > > to contain Xen output ...
> > >
> > > > >
> > > > > > As someone who hasn't built a kernel in over a decade, should I
> > > figure
> > > > > out
> > > > > > how to do a kernel build with CONFIG_PHYSICAL_START=0x2000000 and
> > > report
> > > > > > back?
> > > > >
> > > > > That was largely a suggestion to perhaps allow you to gain some
> > > > > workable setup. It would be of interest to us largely for 
> > > > > completeness.
> > > > >
> > > >
> > > > Typo aside, setting the boot to 2MiB works! It works better for PV, 
> > > > while
> > > > PVH has some graphics card issues, namely that I have to interact over
> > > > serial and dmesg has some concerning radeon errors
> > >
> > > ... and so the radeon error mentioned here seem to be missing.  IIRC
> > > for radeon cards to work on PVH dom0 you will need an hypervisor with
> > > the following commit:
> > >
> > >
> > > https://xenbits.xen.org/gitweb/?p=xen.git;a=commit;h=f69c5991595c92756860d038346569464c1b9ea1
> > >
> > > (included in 4.18)
> > >
> > 
> > hmm.. that would mean I was running with them as I used 4.18 for that run
> > 
> > 
> > >
> > > There where also some changes not long ago in order to propagate the
> > > video console information from Xen into dom0, those are also included
> > > in 4.18, but I don't recall in which Linux version they landed.
> > >
> > > Anyway, would be good if you can provide the full Xen + Linux logs
> > > when the radeon issue happens.
> > >
> > 
> > Luckily linux logs are mercifully short. Append this to
> > xen-4.18p_grub_linuxoffset_pvh.log:
> > 
> > [    0.778770] i2c_designware AMDI0010:00: Unknown Synopsys component type:
> > 0xffffffff
> > [    0.914664] amd_gpio AMDI0030:00: error -EINVAL: IRQ index 0 not found
> > [    0.930112] xen_mcelog: Failed to get CPU numbers
> > [    8.324907] ccp 0000:06:00.5: pcim_iomap_regions failed (-16)
> > [    8.338604] sp5100-tco sp5100-tco: Watchdog hardware is disabled
> > [    8.909366] [drm:radeon_get_bios [radeon]] *ERROR* ACPI VFCT table
> > present but broken (too short #2)
> 
> Hm, interesting.  I will have to add more debug in order to check
> what's going on here, seems like the table is corrupted somehow.

>From that environment (PVH dom0) can you see if you can dump the
contents of the VFCT table?  I don't have a system with that table, so
not sure if this will work (because iasl is unlikely to know how to
decode it):

# acpidump -n VFCT -o table.dump
# acpixtract -a table.dump
# iasl -d vfct.dat
# cat vfct.dsl

Would be good if you can compare the output from what you get on a PV
dom0 or when running native Linux.

I'm also adding some AMD folks, as IIRC they did some fixes to Linux
in order to get some AMD graphics cards running on a PVH dom0, maybe
they can provide some additional input.

Thanks, Roger.