Re: E820 memory allocation issue on Threadripper platforms

["Roger Pau Monné" <roger.pau@citrix.com>]

On Wed, Jan 17, 2024 at 01:12:30AM -0500, Patrick Plenefisch wrote:
> On Tue, Jan 16, 2024 at 4:33 AM Jan Beulich <jbeulich@suse.com> wrote:
> 
> > On 16.01.2024 01:22, Patrick Plenefisch wrote:
> > It remains to be seen in how far it is reasonably possible to work
> > around this in the kernel. While (sadly) still unsupported, in the
> > meantime you may want to consider running Dom0 in PVH mode.
> >
> 
> I tried this by adding dom0=pvh, and instead got this boot error:
> 
> (XEN) xenoprof: Initialization failed. AMD processor family 25 is not
> supported
> (XEN) NX (Execute Disable) protection active
> (XEN) Dom0 has maximum 1400 PIRQs
> (XEN) *** Building a PVH Dom0 ***
> (XEN) Failed to load kernel: -1
> (XEN) Xen dom0 kernel broken ELF: <NULL>
> (XEN) Failed to load Dom0 kernel
> (XEN)
> (XEN) ****************************************
> (XEN) Panic on CPU 0:
> (XEN) Could not construct domain 0
> (XEN) ****************************************
> (XEN)
> (XEN) Reboot in five seconds...

PVH dom0 also re-uses the host memory map in order to build the dom0
memory map, and will fail to load the kernel if the ELF program
headers physical addresses are not between RAM regions (or destination
guest physical addresses where hvm_copy_to_guest_phys() returns
failure).

Roger.