The patch resolves an issue in Boot Guard enabled system that NEM is already enabled by Boot Guard, disabling cache evicts all cache content which is unexpected.
Reviewed-by: Ray Ni <ray...@intel.com> > -----Original Message----- > From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Ni, Ray > Sent: Wednesday, July 26, 2023 5:56 PM > To: Xue, Shengfeng <xueshengf...@byosoft.com.cn>; devel@edk2.groups.io; > Dong, Eric <eric.d...@intel.com>; Kumar, Rahul R <rahul.r.ku...@intel.com>; > kra...@redhat.com; De, Debkumar <debkumar...@intel.com>; West, Catharine > <catharine.w...@intel.com> > Cc: Wu, MingliangX <mingliangx...@intel.com> > Subject: Re: [edk2-devel] [PATCH V1 1/1] UefiCpuPkg/ResetVector: Cache > Disable should not be set by default in CR0 > > This patch is not right. > > Intel SDM explicitly says the initial CR0 value is 6000_0010. CD bit is set. > > So the ResetVector code that still sets CD bit should be good. > > If you are facing NEM enable failure, can you change your NEM enable logic to > explicitly clear CD bit instead of changing here? > > Thanks, > Ray > > > > -----Original Message----- > > From: xueshengfeng <xueshengf...@byosoft.com.cn> > > Sent: Wednesday, July 26, 2023 5:48 PM > > To: devel@edk2.groups.io; Dong, Eric <eric.d...@intel.com>; Ni, Ray > > <ray...@intel.com>; Kumar, Rahul R <rahul.r.ku...@intel.com>; > > kra...@redhat.com; De, Debkumar <debkumar...@intel.com>; West, Catharine > > <catharine.w...@intel.com> > > Cc: Wu, MingliangX <mingliangx...@intel.com>; Wu > > Subject: [PATCH V1 1/1] UefiCpuPkg/ResetVector: Cache Disable should not be > > set by default in CR0 > > > > From: "Wu, MingliangX" <mingliangx...@intel.com> > > > > REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4511 > > > > With 64 bit build we are seeing the CD in control register CR 0 set. > > This causes the NEM to disabled for some specific bios profiles. > > > > Cc: Eric Dong <eric.d...@intel.com> > > Cc: Ray Ni <ray...@intel.com> > > Cc: Rahul Kumar <rahul1.ku...@intel.com> > > Cc: Gerd Hoffmann <kra...@redhat.com> > > Cc: Debkumar De <debkumar...@intel.com> > > Cc: Catharine West <catharine.w...@intel.com> > > Signed-off-by: Wu, Mingliang <mingliangx...@intel.com> > > --- > > UefiCpuPkg/ResetVector/Vtf0/Ia16/Real16ToFlat32.asm | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/UefiCpuPkg/ResetVector/Vtf0/Ia16/Real16ToFlat32.asm > > b/UefiCpuPkg/ResetVector/Vtf0/Ia16/Real16ToFlat32.asm > > index f59fc6ead4ba..4af2e875c31c 100644 > > --- a/UefiCpuPkg/ResetVector/Vtf0/Ia16/Real16ToFlat32.asm > > +++ b/UefiCpuPkg/ResetVector/Vtf0/Ia16/Real16ToFlat32.asm > > @@ -7,7 +7,7 @@ > > ; > > > > ;------------------------------------------------------------------------------ > > > > -%define SEC_DEFAULT_CR0 0x40000023 > > +%define SEC_DEFAULT_CR0 0x00000023 > > %define SEC_DEFAULT_CR4 0x640 > > > > BITS 16 > > -- > > 2.26.2.windows.1 > > > > > > > -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#107527): https://edk2.groups.io/g/devel/message/107527 Mute This Topic: https://groups.io/mt/100367559/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/leave/9847357/21656/1706620634/xyzzy [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
