Re: [PATCH] Use EfiACPIReclaimMemory for ESRT

[Demi Marie Obenour <demi@xxxxxxxxxxxxxxxxxxxxxx>]

On Tue, Oct 04, 2022 at 10:31:25AM +0200, Jan Beulich wrote:
> On 30.09.2022 23:02, Demi Marie Obenour wrote:
> > As discussed on xen-devel, using EfiRuntimeServicesData for more than is
> > absolutely necessary is a bad idea.
> > ---
> >  xen/common/efi/boot.c | 19 +++++++++++--------
> >  1 file changed, 11 insertions(+), 8 deletions(-)
> > 
> > diff --git a/xen/common/efi/boot.c b/xen/common/efi/boot.c
> > index 
> > db0340c8e2628314226c618dda11ede4c62fdf3b..dba23439758d1e842d267dcd19448e0f9113b115
> >  100644
> > --- a/xen/common/efi/boot.c
> > +++ b/xen/common/efi/boot.c
> > @@ -601,11 +601,13 @@ static size_t __init get_esrt_size(const 
> > EFI_MEMORY_DESCRIPTOR *desc)
> >      if ( physical_start > esrt || esrt - physical_start >= len )
> >          return 0;
> >      /*
> > -     * The specification requires EfiBootServicesData, but accept
> > -     * EfiRuntimeServicesData, which is a more logical choice.
> > +     * The specification requires EfiBootServicesData, but also accept
> > +     * EfiRuntimeServicesData (for compatibility) and EfiACPIReclaimMemory
> > +     * (which will contain the tables after successful kexec).
> 
> What's the compatibility concern here? We haven't released any Xen
> version yet where the table would be moved to EfiRuntimeServicesData.

Old buggy firmware.
-- 
Sincerely,
Demi Marie Obenour (she/her/hers)
Invisible Things Lab

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