Message-ID: <b30d6f61-2dc9-4c4f-dbdb-a48c186745d3@amd.com>
Date:   Tue, 24 Jan 2023 16:07:46 +0530
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Subject: Re: [PATCH kernel v3 3/3] x86/sev: Do not handle #VC for DR7
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To:     Alexey Kardashevskiy <aik@amd.com>
Cc:     kvm@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org,
        Yury Norov <yury.norov@gmail.com>,
        Venu Busireddy <venu.busireddy@oracle.com>,
        Tony Luck <tony.luck@intel.com>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Sean Christopherson <seanjc@google.com>,
        Sandipan Das <sandipan.das@amd.com>,
        Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Michael Roth <michael.roth@amd.com>,
        Mario Limonciello <mario.limonciello@amd.com>,
        Kim Phillips <kim.phillips@amd.com>,
        Kees Cook <keescook@chromium.org>,
        Juergen Gross <jgross@suse.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Ingo Molnar <mingo@redhat.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Daniel Sneddon <daniel.sneddon@linux.intel.com>,
        Brijesh Singh <brijesh.singh@amd.com>,
        Borislav Petkov <bp@alien8.de>,
        Arnaldo Carvalho de Melo <acme@redhat.com>,
        Andrew Cooper <andrew.cooper3@citrix.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        "Peter Zijlstra (Intel)" <peterz@infradead.org>,
        "Jason A. Donenfeld" <Jason@zx2c4.com>,
        "H. Peter Anvin" <hpa@zytor.com>
References: <20230120031047.628097-1-aik@amd.com>
 <20230120031047.628097-4-aik@amd.com>
 <adc11ed3-de89-a389-e629-3c951257469c@amd.com>
 <533c5c83-b68b-eff0-d36d-9963194ab844@amd.com>
From:   "Nikunj A. Dadhania" <nikunj@amd.com>
In-Reply-To: <533c5c83-b68b-eff0-d36d-9963194ab844@amd.com>
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On 20/01/23 15:53, Alexey Kardashevskiy wrote:
> It is MSR_AMD64_SEV_DEBUG_SWAP (SEV, not SNP), it is an SEV-ES thing. 

Yes, noticed that, earlier analysis was that Debug Swap shouldn't need any guest side changes, but it does need it.

> Why is that feature negotiation SNP-only and not SEV?

As per the spec, GHCB termination request: reason code: 0x2 is SNP features specific.

Regards
Nikunj