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

[Lu Baolu]

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


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