Re: [PATCH 0/3] iommu/vt-d bad RMRR workarounds

[Chen, Yian]

On 12/13/2019 5:52 PM, Lu Baolu wrote:
> On 12/13/19 10:31 PM, Barret Rhoden wrote:
> > On 12/11/19 9:43 PM, Lu Baolu wrote:
> > > The VT-d spec defines the BIOS considerations about RMRR in section 
> > > 8.4:
> > >
> > > "
> > > BIOS must report the RMRR reported memory addresses as reserved (or as
> > > EFI runtime) in the system memory map returned through methods such as
> > > INT15, EFI GetMemoryMap etc.
> > > "
> > >
> > > So we should treat it as firmware bug if the RMRR range is not 
> > > mapped as
> > > RESERVED in the system memory map table.
> > >
> > > As for how should the driver handle this case, ignoring buggy RMRR with
> > > a warning message might be a possible choice.
> >
> > Agreed, firmware should not be doing this. My first patch just skips 
> > those entries, instead of aborting DMAR processing, and keeps the 
> > warning.
>
> Hi Yian,
>
> Does this work for you?
>
> Best regards,
> baolu
I made a comment in the the patch email "[PATCH 1/3] iommu/vt-d: skip 
RMRR entries that fail the sanity check "
thanks,
Yian

> > So long as the machine still boots in a safe manner, I'm reasonably 
> > happy.
> >
> > Thanks,
> >
> > Barret