On Wed, Oct 20, 2021 at 10:23:06PM +0800, Tianyu Lan wrote: > This follows Joreg's previous comment and I implemented similar version in > the V! patchset([PATCH 05/13] HV: Add Write/Read MSR registers via ghcb page > https://lkml.org/lkml/2021/7/28/668). > "Instead, factor out a helper function which contains what Hyper-V needs and > use that in sev_es_ghcb_hv_call() and Hyper-V code." > > https://lkml.org/lkml/2021/8/2/375 If you wanna point to mails on a mailing list, you simply do https://lore.kernel.org/r/<Message-id> No need to use some random, unreliable web pages. As to Joerg's suggestion, in the version I'm seeing, you're checking the *context* - and the one you sent today, avoids the __pa(ghcb) MSR write. So which is it? Because your current version will look at the context too, see return verify_exception_info(ghcb, ctxt); at the end of the function. So is the issue what Tom said that "the paravisor uses the same GHCB MSR and GHCB protocol, it just can't use __pa() to get the address of the GHCB."? If that is the case and the only thing you want is to avoid the GHCB PA write, then, in the future, we might drop that MSR write altogether on the enlightened Linux guests too and then the same function will be used by your paravisor and the Linux guest. So please explain in detail what exactly you want to avoid from sev_es_ghcb_hv_call()'s current version and why. As I said before, I don't want to export any random details of the SEV implementation in the kernel without any justification for it. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette
