From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.skyhub.de (mail.skyhub.de [5.9.137.197]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 27E06173 for ; Wed, 16 Jun 2021 12:03:17 +0000 (UTC) Received: from zn.tnic (p200300ec2f0c2b00ec25a986a17212ee.dip0.t-ipconnect.de [IPv6:2003:ec:2f0c:2b00:ec25:a986:a172:12ee]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 3BAEE1EC03E4; Wed, 16 Jun 2021 14:03:16 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1623844996; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=qK3Y1DHOt57Qig7xfqZFQT3ydoFk9JaEiyImUpf/4h4=; b=mPkX1WjdJx43H98yJ0xojjxpLkY44F46gfmAvHgRhvQxPBJMGtuYOk9hA3L8aJwckyEYjZ 5rQCCG8gEnwy45fVBV3wv3aILo7Xjvo6F5qham5jpiWltLR6fF3pok4WGqWjxdq/L0DgZ2 ArwOn584uWA7wywbnefvHhDirxUBCUM= Date: Wed, 16 Jun 2021 14:03:05 +0200 From: Borislav Petkov To: Brijesh Singh Cc: x86@kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-efi@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-coco@lists.linux.dev, linux-mm@kvack.org, linux-crypto@vger.kernel.org, Thomas Gleixner , Ingo Molnar , Joerg Roedel , Tom Lendacky , "H. Peter Anvin" , Ard Biesheuvel , Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Andy Lutomirski , Dave Hansen , Sergio Lopez , Peter Gonda , Peter Zijlstra , Srinivas Pandruvada , David Rientjes , 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 Message-ID: References: <20210602140416.23573-1-brijesh.singh@amd.com> <20210602140416.23573-12-brijesh.singh@amd.com> <70db789d-b1aa-c355-2d16-51ace4666b3f@amd.com> X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: On Wed, Jun 16, 2021 at 06:00:09AM -0500, Brijesh Singh wrote: > I am trying to be consistent with previous VMGEXIT implementations. If > the command itself failed then use the command specific error code to > tell hypervisor why we terminated but if the hypervisor violated the > GHCB specification then use the "general request termination". I feel like we're running in circles here: I ask about debuggability and telling the user what exactly failed and you're giving me some explanation about what the error codes mean. I can see what they mean. So let me try again: Imagine you're a guest owner and you haven't written the SNP code and you don't know how it works. You start a guest in the public cloud and it fails because the hypervisor violates the GHCB protocol and all that guest prints before it dies is "general request termination" How are you - the guest owner - going to find out what exactly happened? Call support? -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette