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Date:   Mon, 14 Jun 2021 21:03:03 +0200
From:   Borislav Petkov <bp@alien8.de>
To:     Brijesh Singh <brijesh.singh@amd.com>
Cc:     x86@kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        linux-efi@vger.kernel.org, platform-driver-x86@vger.kernel.org,
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        linux-crypto@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Joerg Roedel <jroedel@suse.de>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Ard Biesheuvel <ardb@kernel.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <seanjc@google.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Andy Lutomirski <luto@kernel.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Sergio Lopez <slp@redhat.com>, Peter Gonda <pgonda@google.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
        David Rientjes <rientjes@google.com>, tony.luck@intel.com,
        npmccallum@redhat.com
Subject: Re: [PATCH Part1 RFC v3 11/22] x86/sev: Add helper for validating
 pages in early enc attribute changes
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On Mon, Jun 14, 2021 at 07:45:11AM -0500, Brijesh Singh wrote:
> IMO, there is no need to add a warning. This case should happen if its
> either a hypervisor bug or hypervisor does not follow the GHCB
> specification. I followed the SEV-ES vmgexit handling  and it does not
> warn if the hypervisor returns a wrong response code. We simply
> terminate the guest.

This brings my regular user-friendliness question: will the guest user
know what happened or will the guest simply disappear/freeze without any
hint as to what has happened so that a post-mortem analysis would turn
out hard to decipher?

> I did thought about reusing the VMGEXIT defined macro
> SNP_PAGE_STATE_{PRIVATE, SHARED} but I was not sure if you will be okay
> with that.

Yeah, I think that makes stuff simpler. Unless there's something
speaking against it which we both are not thinking of right now.

> Additionally now both the function name and macro name will
> include the "SNP". The call will look like this:
> 
> snp_prep_memory(paddr, SNP_PAGE_STATE_PRIVATE)

Yap, looks ok to me.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette