Re: [edk2-devel] [PATCH resend] MdeModulePkg/EsrtDxe: allocate ESRT table from RtServicesData memory

["Michael D Kinney" <michael.d.kinney@intel.com>]

Ard,

I think skipping the nested check at runtime is a good
idea.  No need for ESRT at RT and no need to cache GUIDs
at EBS.

Mike

> -----Original Message-----
> From: Ard Biesheuvel [mailto:ard.biesheuvel@linaro.org]
> Sent: Friday, April 19, 2019 11:43 AM
> To: Kinney, Michael D <michael.d.kinney@intel.com>
> Cc: devel@edk2.groups.io; ming.huang@linaro.org; Wu,
> Hao A <hao.a.wu@intel.com>; Wang, Jian J
> <jian.j.wang@intel.com>
> Subject: Re: [edk2-devel] [PATCH resend]
> MdeModulePkg/EsrtDxe: allocate ESRT table from
> RtServicesData memory
> 
> On Fri, 19 Apr 2019 at 20:38, Ard Biesheuvel
> <ard.biesheuvel@linaro.org> wrote:
> >
> > On Fri, 19 Apr 2019 at 20:23, Kinney, Michael D
> > <michael.d.kinney@intel.com> wrote:
> > >
> > > Ard,
> > >
> > > Let's see if we can remove the ESRT access from
> those
> > > paths.  That would be the better fix.
> > >
> >
> > I am not that familiar with this code, but it seems
> that the only
> > reason we access the ESRT at runtime is to check
> whether a capsule is
> > a nested FMP capsule, where the outer GUID is cross
> referenced against
> > the ESRT before checking whether the inner GUID is
> the FMP guid.
> >
> > Could we relax this check? FMP capsule can only be
> dispatched across a
> > reboot anyway, and so the runtime capsule handling
> could accept any
> > capsule that has an inner FMP guid.
> >
> > If not, it means we do need to read the ESRT at
> runtime, in which case
> > my patch is the simplest solution. We would have to
> clarify the spec
> > though.
> >
> 
> Actually, I might be able to cache just the list of
> GUIDs at
> ReadyToBoot, so we can do the comparisons at runtime.