PMR enabling set by pre-boot DMA protection is cleared by RC when boot guard is enabled. Pre-boot DMA protection should only reset VT-d BAR when it is 0 and reset PMR region when it is not programmed to protect all memory address. PlatformVTdInfoSamplePei driver installs the null root entry table ppi. BIOS uses TE with a null root entry table to block VT-d engine access to block any DMA traffic in pre-memory phase.
REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2867 Cc: Ray Ni <ray...@intel.com> Cc: Rangasai V Chaganty <rangasai.v.chaga...@intel.com> Sheng Wei (2): PlatformVTdInfoSamplePei: Install Null Root Entry Table PPI IntelVTdPmrPei: Fix PMR enabling setting confilct .../Feature/VTd/IntelVTdPmrPei/IntelVTdPmrPei.c | 14 ++++++ .../Feature/VTd/IntelVTdPmrPei/IntelVTdPmrPei.h | 15 +++++++ .../Feature/VTd/IntelVTdPmrPei/VtdReg.c | 50 ++++++++++++++++++++++ .../PlatformVTdInfoSamplePei.c | 16 +++++++ 4 files changed, 95 insertions(+) -- 2.16.2.windows.1 -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#63440): https://edk2.groups.io/g/devel/message/63440 Mute This Topic: https://groups.io/mt/75861786/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
