Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
IronPort-SDR: idi5OjpwaChbrxSejeuAXluS3XRoQ7TxMESJCdOOZix/rcebJ0Zkiamg+iZAZkUietKUQyvxaB
 f+6qp1hAa79A==
IronPort-SDR: hdKBHocW4cw+bhpRa3+aukcMxVuVu4cR1A0degMe8prXywHn0vswyAprdKpmN2AzgF2DsA2YRq
 hjrBXjSYvIgg==
Date:   Fri, 11 Jun 2021 14:37:32 -0700
From:   Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
To:     Borislav Petkov <bp@alien8.de>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Jonathan Corbet <corbet@lwn.net>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@redhat.com>,
        Namhyung Kim <namhyung@kernel.org>, x86@kernel.org,
        "H. Peter Anvin" <hpa@zytor.com>,
        "Paul E. McKenney" <paulmck@kernel.org>,
        Randy Dunlap <rdunlap@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Maciej W. Rozycki" <macro@orcam.me.uk>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        Tony Luck <tony.luck@intel.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <seanjc@google.com>,
        Kyung Min Park <kyung.min.park@intel.com>,
        Fenghua Yu <fenghua.yu@intel.com>,
        Ricardo Neri <ricardo.neri-calderon@linux.intel.com>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        Juergen Gross <jgross@suse.com>,
        Krish Sadhukhan <krish.sadhukhan@oracle.com>,
        Kan Liang <kan.liang@linux.intel.com>,
        Joerg Roedel <jroedel@suse.de>,
        Victor Ding <victording@google.com>,
        Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
        Brijesh Singh <brijesh.singh@amd.com>,
        Dave Hansen <dave.hansen@intel.com>,
        Mike Rapoport <rppt@kernel.org>,
        Anthony Steinhauser <asteinhauser@google.com>,
        Anand K Mistry <amistry@google.com>,
        Andi Kleen <ak@linux.intel.com>,
        Miguel Ojeda <ojeda@kernel.org>, Joe Perches <joe@perches.com>,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-perf-users@vger.kernel.org
Subject: Re: [PATCH 4/4] x86/tsx: Add cmdline tsx=fake to not clear CPUID
 bits RTM and HLE
Message-ID: <20210611213732.wdriyvmrkcu32fv7@gupta-dev2.localdomain>
References: <cover.2d906c322f72ec1420955136ebaa7a4c5073917c.1623272033.git-series.pawan.kumar.gupta@linux.intel.com>
 <de6b97a567e273adff1f5268998692bad548aa10.1623272033.git-series.pawan.kumar.gupta@linux.intel.com>
 <YMM1wUjg/REXCkQQ@zn.tnic>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Disposition: inline
In-Reply-To: <YMM1wUjg/REXCkQQ@zn.tnic>
Precedence: bulk

On 11.06.2021 12:06, Borislav Petkov wrote:
>On Wed, Jun 09, 2021 at 02:14:39PM -0700, Pawan Gupta wrote:
>> On CPUs that deprecated TSX, clearing the enumeration bits CPUID.RTM and
>> CPUID.HLE may not be desirable in some corner cases. Like a saved guest
>> would refuse to resume if it was saved before the microcode update
>> that deprecated TSX.
>
>That corner case needs a lot more justification. Otherwise this is just
>silly.

Agree, chances of hitting the save/resume guest condition described
above is low. I am okay with dropping this patch.

Thanks,
Pawan