When build in DEBUG, the code asserts that 5LPage support is there when the physical address width is larger than 48. In a RELEASE build it will just force LA57 to 1 in CR4 even if CPUID(7).ECX[16] says it is not supported.
The hang (in the ASSERT) in DEBUG is not warranted as there are legal configurations with CPUID(7).ECX[16](==LA57)=0 and with a physical address width of larger than 48 (like 52). This is also supported by this code: https://github.com/tianocore/edk2/blob/master/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c#L221 There (as long as physical address width is smaller or equal to 52) any address width above 48 will be reduced to 48 and the system can and will work without 5LPaging. The forced setting of LA57 in CR4 (in the absence of LA57 in CPUID(7).ECX) is a spec violation and should not happen. Hence the proposed fix a) removes the assert. b) only returns TRUE from Is5LevelPagingNeeded if 5LPaging is actually supported by HW. Signed-off-by: Robert Guenzel mailto:robert.guen...@intel.com --- UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c index 6587212f4e..f8b1ac31f1 100644 --- a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c +++ b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c @@ -104,8 +104,8 @@ Is5LevelPagingNeeded ( ExtFeatureEcx.Bits.FiveLevelPage )); - if (VirPhyAddressSize.Bits.PhysicalAddressBits > 4 * 9 + 12) { - ASSERT (ExtFeatureEcx.Bits.FiveLevelPage == 1); + if ((VirPhyAddressSize.Bits.PhysicalAddressBits > 4 * 9 + 12) && + (ExtFeatureEcx.Bits.FiveLevelPage == 1)) { return TRUE; } else { return FALSE; -- 2.34.1 Intel Deutschland GmbH Registered Address: Am Campeon 10, 85579 Neubiberg, Germany Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de> Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva Chairperson of the Supervisory Board: Nicole Lau Registered Office: Munich Commercial Register: Amtsgericht Muenchen HRB 186928 -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#96192): https://edk2.groups.io/g/devel/message/96192 Mute This Topic: https://groups.io/mt/94935896/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
