Re: Failure to shutdown/reboot with intel_iommu=on

[Joerg Roedel]

Hi Lenny,

On Tue, May 12, 2020 at 04:00:26PM -0400, Lenny Szubowicz wrote:
> Some Lenovo laptops provide an ACPI DMAR RMRR that identifies the memory
> range that the kernel should open up for permissable DMA access
> for this purpose. Unfortunately, the PCI device that performs these
> DMA operations is hidden from the kernel by the BIOS. Given that the
> associated PCI device is hidden, the Linux kernel does not act upon
> the associated DMAR RMRR.

That sounds aweful. We should add to the VT-d driver that it sets up
RMRR mappings for request-ids which are not present as a PCI device, to
fix the Laptops which have it.

For the others, is the region the TPM talks to via DMA known so that we
can add a quirk?


	Joerg