Enabling VT-d on pre-QS silicon may have issues like rendering the
Thunderbolt driver useless. This change will ensure that VT-d is
disabled for pre-QS silicon and enabled for QS.
BUG=b:152242800,161215918,158519322
TEST=Validated VT-d is disabled for pre-QS (cpu:0x806c0) and enabled for
QS (cpu:0x806c1). Kernel walks through ACPI tables. If VT-d is disabled
and no DMAR table exists, IOMMU will not be enabled.
Signed-off-by: John Zhao <john.zhao@intel.com>
Change-Id: I98a9f6df185002a4e68eaa910f867acd0b96ec2b
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43657
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>
7417bb0e5a