Re: [PATCH] revert "hvmloader: PA range 0xfc000000-0xffffffff should be UC"

[Anthony PERARD <anthony.perard@citrix.com>]

On Thu, Dec 16, 2021 at 11:17:12AM +0000, Andrew Cooper wrote:
> What should happen is the domain builder place OVMF there directly. 
> OVMF is linked to run there, and there ought to be no hvmloader involved
> for UEFI guests, and there shouldn't be any copying into place
> required.  That was a very short sited move on behalf of the OVMF
> support logic, and I guarantee you that it creates more problems than it
> allegedly solves.

FYI, OVMF been copied there is due to how KVM/QEMU make use of OVMF, so
it was probably the easiest thing to do at the time.

Now, we have OvmfXen with support for PVH (still a few thing to fix),
which doesn't need to be loaded from hvmloader, and doesn't need to run
from that address (~4GB). Most of OVMF is linked to run at 8MB anyway (I
think, if I remember the address).

We aren't far from been able to run UEFI HVM guests without hvmloader,
we need to fix the logic in OVMF to take care of the PCI bars, and maybe
one or two other things, then load OVMF as a PVH kernel and hopefully no
more hvmloader on HVM guests.

Cheers,

-- 
Anthony PERARD