+UefiCpuPkg maintainers/reviewers.
> -----Original Message----- > From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Guenzel, Robert > Sent: Thursday, November 10, 2022 5:51 AM > To: devel@edk2.groups.io > Subject: [edk2-devel] [PATCH] UefiCpuPkg: Bug fix in 5LPage handling > > 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 (#96408): https://edk2.groups.io/g/devel/message/96408 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] -=-=-=-=-=-=-=-=-=-=-=-