> From: Lu Baolu
> Sent: Saturday, January 16, 2021 11:54 AM
>
> Hi Jean,
>
> On 2021/1/15 0:41, Jean-Philippe Brucker wrote:
> > I guess detailing what's needed for nested IOPF can help the discussion,
> > although I haven't seen any concrete plan about implementing it, and it
> > still seems
IOMMU Extended Feature Register (EFR) is used to communicate
the supported features for each IOMMU to the IOMMU driver.
This is normally read from the PCI MMIO register offset 0x30,
and used by the iommu_feature() helper function.
However, there are certain scenarios where the information is
