On 11/20/19 21:06, Lendacky, Thomas wrote: > BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=2198 > > An SEV-ES guest will generate a #VC exception when it encounters a > non-automatic exit (NAE) event. It is expected that the #VC exception > handler will communicate with the hypervisor using the GHCB to handle > the NAE event. > > NAE events can occur during the Sec phase, so initialize exception > handling early in the OVMF Sec support. > > Cc: Jordan Justen <jordan.l.jus...@intel.com> > Cc: Laszlo Ersek <ler...@redhat.com> > Cc: Ard Biesheuvel <ard.biesheu...@linaro.org> > Signed-off-by: Tom Lendacky <thomas.lenda...@amd.com> > --- > OvmfPkg/Sec/SecMain.inf | 1 + > OvmfPkg/Sec/SecMain.c | 29 ++++++++++++++++------------- > 2 files changed, 17 insertions(+), 13 deletions(-) > > diff --git a/OvmfPkg/Sec/SecMain.inf b/OvmfPkg/Sec/SecMain.inf > index 63ba4cb555fb..7f53845f5436 100644 > --- a/OvmfPkg/Sec/SecMain.inf > +++ b/OvmfPkg/Sec/SecMain.inf > @@ -50,6 +50,7 @@ [LibraryClasses] > PeCoffExtraActionLib > ExtractGuidedSectionLib > LocalApicLib > + CpuExceptionHandlerLib > > [Ppis] > gEfiTemporaryRamSupportPpiGuid # PPI ALWAYS_PRODUCED > diff --git a/OvmfPkg/Sec/SecMain.c b/OvmfPkg/Sec/SecMain.c > index bae9764577f0..db319030ee58 100644 > --- a/OvmfPkg/Sec/SecMain.c > +++ b/OvmfPkg/Sec/SecMain.c > @@ -24,6 +24,7 @@ > #include <Library/PeCoffExtraActionLib.h> > #include <Library/ExtractGuidedSectionLib.h> > #include <Library/LocalApicLib.h> > +#include <Library/CpuExceptionHandlerLib.h> > > #include <Ppi/TemporaryRamSupport.h> > > @@ -737,6 +738,21 @@ SecCoreStartupWithStack ( > Table[Index] = 0; > } > > + // > + // Initialize IDT > + // > + IdtTableInStack.PeiService = NULL; > + for (Index = 0; Index < SEC_IDT_ENTRY_COUNT; Index ++) { > + CopyMem (&IdtTableInStack.IdtTable[Index], &mIdtEntryTemplate, sizeof > (mIdtEntryTemplate)); > + } > + > + IdtDescriptor.Base = (UINTN)&IdtTableInStack.IdtTable; > + IdtDescriptor.Limit = (UINT16)(sizeof (IdtTableInStack.IdtTable) - 1); > + > + AsmWriteIdtr (&IdtDescriptor); > + > + InitializeCpuExceptionHandlers (NULL); > + > ProcessLibraryConstructorList (NULL, NULL); > > DEBUG ((EFI_D_INFO,
(1) The problem here is that we call multiple library APIs before calling ProcessLibraryConstructorList() -- namely CopyMem(), AsmWriteIdtr(), and InitializeCpuExceptionHandlers(). (See also the "SetMem" reference in the leading context, in the source file -- it is not quoted in this patch.) Thus, would it be possible to move all the "+" lines, quoted above, just below the ProcessLibraryConstructorList() call? (2) If possible I'd like to restrict the InitializeCpuExceptionHandlers() call to SevEsIsEnabled(). (Unless you're implying that InitializeCpuExceptionHandlers() is useful even without SEV-ES -- but then the commit message should be reworded accordingly.) If you agree to that restriction, then I further suggest reordering this patch against the next one: [edk2-devel] [RFC PATCH v3 31/43] OvmfPkg/Sec: Enable cache early to speed up booting Namely, if you put that patch first, then in the present patch you can extend the already existing SevEsIsEnabled()-dependent scope, with a call to InitializeCpuExceptionHandlers(). The end result would be something like: ProcessLibraryConstructorList(); // // Initialize IDT // ... // if (SevEsIsEnabled()) { // // non-automatic exit events (NAE) can occur during SEC ... // InitializeCpuExceptionHandlers (NULL); // // Under SEV-ES, the hypervisor can't modify CR0 ... // AsmEnableCache (); } What's your opinion? Thanks! Laszlo > @@ -751,19 +767,6 @@ SecCoreStartupWithStack ( > // > InitializeFloatingPointUnits (); > > - // > - // Initialize IDT > - // > - IdtTableInStack.PeiService = NULL; > - for (Index = 0; Index < SEC_IDT_ENTRY_COUNT; Index ++) { > - CopyMem (&IdtTableInStack.IdtTable[Index], &mIdtEntryTemplate, sizeof > (mIdtEntryTemplate)); > - } > - > - IdtDescriptor.Base = (UINTN)&IdtTableInStack.IdtTable; > - IdtDescriptor.Limit = (UINT16)(sizeof (IdtTableInStack.IdtTable) - 1); > - > - AsmWriteIdtr (&IdtDescriptor); > - > #if defined (MDE_CPU_X64) > // > // ASSERT that the Page Tables were set by the reset vector code to > -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#51052): https://edk2.groups.io/g/devel/message/51052 Mute This Topic: https://groups.io/mt/60973137/21656 Mute #vc: https://groups.io/mk?hashtag=vc&subid=3846945 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-