From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D68F0C4338F for ; Mon, 23 Aug 2021 04:49:43 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4420F6135A for ; Mon, 23 Aug 2021 04:49:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 4420F6135A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=alien8.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 5A4A88D0001; Mon, 23 Aug 2021 00:49:41 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5557E6B0072; Mon, 23 Aug 2021 00:49:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 443268D0001; Mon, 23 Aug 2021 00:49:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0072.hostedemail.com [216.40.44.72]) by kanga.kvack.org (Postfix) with ESMTP id 282446B006C for ; Mon, 23 Aug 2021 00:49:41 -0400 (EDT) Received: from smtpin39.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id B32E6267E4 for ; Mon, 23 Aug 2021 04:49:40 +0000 (UTC) X-FDA: 78505117320.39.5659C79 Received: from mail.skyhub.de (mail.skyhub.de [5.9.137.197]) by imf18.hostedemail.com (Postfix) with ESMTP id 32CAA400208F for ; Mon, 23 Aug 2021 04:49:38 +0000 (UTC) Received: from zn.tnic (p200300ec2f07d90037f6d6bcf935006e.dip0.t-ipconnect.de [IPv6:2003:ec:2f07:d900:37f6:d6bc:f935:6e]) (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 510D11EC0464; Mon, 23 Aug 2021 06:49:32 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1629694172; 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=Wemuc7ifFKY1JG/J29bORf/DK0p/Jh7ow0XTFAR5vaQ=; b=GWFpORbvrZ8l8jHKGAzgi+Cz1txdHdZz8F9sjQY9xBZvlXhqDXf+r0vx5NE81Hj6mQ8dlo +IAvWd5e/mO995J1rlhjfLNvLK6UguEzHzL5ps2RT1YPXRl84mVgESeSiD7AG2hGH8zBHe mNWAN3/Z4gJGd5z3iKn0CHCn+yqr8j0= Date: Mon, 23 Aug 2021 06:50:06 +0200 From: Borislav Petkov To: Michael Roth Cc: Brijesh Singh , 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 , Dov Murik , Tobin Feldman-Fitzthum , Vlastimil Babka , tony.luck@intel.com, brijesh.ksingh@gmail.com Subject: Re: [PATCH Part1 RFC v4 22/36] x86/sev: move MSR-based VMGEXITs for CPUID to helper Message-ID: References: <20210707181506.30489-1-brijesh.singh@amd.com> <20210707181506.30489-23-brijesh.singh@amd.com> <20210819153741.h6yloeihz5vl6hvu@amd.com> <20210820032908.vqnptvjqnp7xxa6i@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210820032908.vqnptvjqnp7xxa6i@amd.com> Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=alien8.de header.s=dkim header.b=GWFpORbv; spf=pass (imf18.hostedemail.com: domain of bp@alien8.de designates 5.9.137.197 as permitted sender) smtp.mailfrom=bp@alien8.de; dmarc=pass (policy=none) header.from=alien8.de X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 32CAA400208F X-Stat-Signature: qwoqz4dpapo1fi65ut3149xtg5bg7rh1 X-HE-Tag: 1629694178-339176 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Aug 19, 2021 at 10:29:08PM -0500, Michael Roth wrote: > The select cases where we still fetch CPUID values from hypervisor in > SNP need careful consideration, so for the purposes of auditing the code > for security, or just noticing things in patches, I think it's important > to make it clear what is the "normal" SNP case (not trusting hypervisor > CPUID values) and what are exceptional cases (getting select values from > hypervisor). If something got added in the future, I think something > like: > > +sev_cpuid_hv(0x8000001f, ...) > > would be more likely to raise eyebrows and get more scrutiny than: > > +sev_cpuid(0x8000001f, ...) > > where it might get lost in the noise or mistaken as similar to > sev_snp_cpuid(). > > Maybe a bit contrived, and probably not a big deal in practice, but > conveying the source it in the naming does seem at least seem slightly > better than not doing so. Ok, makes sense. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette