Re: [PATCH] xen/arm: acpi: Support memory reserve configuration table

[Leo Yan <leo.yan@xxxxxxxxxx>]

On Tue, Sep 06, 2022 at 03:27:47PM +0800, Leo Yan wrote:
> On Tue, Sep 06, 2022 at 09:22:00AM +0200, Ard Biesheuvel wrote:
> 
> [...]
> 
> > > IIUC, you consider the general flow from architecture view, so you prefer
> > > to ask Xen to implement EFI stub to comply the general flow for EFI
> > > booting sequence, right?
> > >
> > > If the conclusion is to change Xen for support EFI stub, then this
> > > would be fine for me and I will hold on and leave Xen developers to work
> > > on it.
> > >
> > 
> > As I mentioned before, proper EFI boot support in Xen would be nice.
> > *However*, I don't think it makes sense to go through all the trouble
> > of implementing that just to shut up a warning that doesn't affect Xen
> > to begin with.
> 
> Another option is we can set a bit for xen feature, so Linux kernel
> can read out the xen feature and make decision if need to reserve
> memory for RD tables based on the new feature bit.  This is somehow
> a solution is to create a general protocol between Xen and Linux kernel.
> 
> How about you think for this?

Just supplement info.  I tried to set flag EFI_PARAVIRT in Linux
kernel, but kernel cannot boot up successfully on Arm64.  Seems
the Linux kernel will not map memory correctly after settting
this flag.

This is why I didn't move forward with this flag.

Thanks,
Leo