On October 26, 2021 6:25 PM, Gerd Hoffmann wrote: > Hi, > > > > > So it has to be implemented inside the exception lib. > > > > > > Well, no, you can also change the code to avoid triggering an exception. > > > > > > Adding a new lib for the exception means the lib must be added into > > > each and every *.dsc file (either the tdx impl or the null variant), > > > not only in the tianocore core itself but also all projects depending on > tianocore. > > > > > > So IMHO it is worth checking out how much effort it would be to > > > avoid early (before component registration) exceptions. > > > > > > Which early exception do actually happen? > > > > > RegisterCpuInterfaceHandler() is not supported in SEC/PEI phase. But there > are still some scenarios in SEC/PEI which will trigger #VE. > > CPUID is the sample. See below call chain in CpuMpPei. > > InitializeCpuMpWorker --> CollectBitsDataFromPpi --> > > MpInitLibGetProcessorInfo --> GetProcessorLocationByApicId() > > Bad example ;) > > TDX needs its own Mp implementations anyway, so that one specifically should > be quite easy to avoid. > > > Actually #VE handler follows the same way as #VC handler (by SEV). See > discussions in below link. > > https://edk2.groups.io/g/devel/topic/73201885 > > I guess the list of instructions which trap on tdx is quite simliar to sev? > cpuid, > msr access, io instructions? > > I suspect there isn't an easy way around that then (as discussed at length in > the > email thread linked, thanks for that). > > How about adding the tdx exception handler to the existing library, so we > don't > have the churn of adding a new library everywhere *again*? Do you mean add the VmTdExitVeHandler.c/VmTdExitLibNull.c in CpuExceptionHandlerLib, then include the corresponding source file in each *CpuExceptionHandlerLib.inf? If this is the case, then the implementation of #VE handler (TDX) will be in-consistent with #VC handler (SEV). Shall we keep these 2 implementation consistent? Or will SEV agree to update the #VC handler in the same way?
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