Re: [edk2-devel] [RFC PATCH 08/11] MdeModulePkg/DxeIpl: Relocate and remap XIP capable DXE drivers

["Ard Biesheuvel" <ardb@kernel.org>]

On Tue, 30 May 2023 at 10:02, Ni, Ray <ray.ni@intel.com> wrote:
>
>
>
> > -----Original Message-----
> > From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Ard
> > Biesheuvel
> > Sent: Tuesday, May 30, 2023 3:58 PM
> > To: devel@edk2.groups.io; Ni, Ray <ray.ni@intel.com>
> > Cc: Yao, Jiewen <jiewen.yao@intel.com>; Gerd Hoffmann <kraxel@redhat.com>;
> > Taylor Beebe <t@taylorbeebe.com>; Oliver Smith-Denny <osd@smith-
> > denny.com>; Bi, Dandan <dandan.bi@intel.com>; Gao, Liming
> > <gaoliming@byosoft.com.cn>; Kinney, Michael D <michael.d.kinney@intel.com>;
> > Leif Lindholm <quic_llindhol@quicinc.com>; Michael Kubacki
> > <mikuback@linux.microsoft.com>
> > Subject: Re: [edk2-devel] [RFC PATCH 08/11] MdeModulePkg/DxeIpl: Relocate
> > and remap XIP capable DXE drivers
> >
> > On Tue, 30 May 2023 at 08:45, Ni, Ray <ray.ni@intel.com> wrote:
> > >
> > > 1. is it possible that a PE image sits in the right location but the
> > SectionAlignment is larger than FileAlignment so each section still needs to be
> > copied to the aligned memory location?
> > >
> >
> > That is a good question. Currently, the ELF toolchains rely on GenFw
> > to construct the PE images in a way that permits execution in place,
> > but I have no idea how this works with native PE/COFF toolchains.
> >
> > > 2. PeCoffLoaderRelocateImage() might not be called for XIP
> > >
> >
> > Are you saying it is not permitted? Or that it may not happen?
> >
> > In any case, relocating the image in place is exactly what the
> > BaseTools do for XIP PEIMs, so I think applying the same logic here is
> > reasonable.
>
> But when the image is in SPI flash (MMIO device, rather in physical memory), relocating the image in place should not be performed.
> Or you require platform build strips the relocation section for drivers XIP in SPI flash?
>

This code only operates on EFI_FV_FILETYPE_DRIVER, which does not
cover the PEI core or PEIMs.

But we should probably only operate on FVs that are covered by PEI
permanent memory anyway.