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([2a10:bac0:b000:75b8:7285:c2ff:fedd:7e3a]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-a93c2946bddsm869783366b.123.2024.10.02.07.54.14 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 02 Oct 2024 07:54:15 -0700 (PDT) Message-ID: Date: Wed, 2 Oct 2024 17:54:14 +0300 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 6/6] x86/bugs: Clean-up verw mitigations To: Daniel Sneddon , Jonathan Corbet , Thomas Gleixner , Borislav Petkov , Peter Zijlstra , Josh Poimboeuf , Ingo Molnar , Dave Hansen , x86@kernel.org Cc: hpa@zytor.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, pawan.kumar.gupta@linux.intel.com References: <20240924223140.1054918-1-daniel.sneddon@linux.intel.com> <20240924223140.1054918-7-daniel.sneddon@linux.intel.com> From: Nikolay Borisov Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 2.10.24 г. 17:46 ч., Daniel Sneddon wrote: > On 10/2/24 07:20, Nikolay Borisov wrote: >>> + if (boot_cpu_has_bug(X86_BUG_MDS)) { >>> mds_mitigation = MDS_MITIGATION_FULL; >>> mds_select_mitigation(); >>> + } else { >>> + mds_mitigation = MDS_MITIGATION_OFF; >>> } >> >> BUt with this logic if CONFIG_MITIGATION_MDS is deselected meaning >> mds_mitigations will have the value MDS_MITIGATION_OFF, yet now you will >> set it to _FULL thereby overriding the compile-time value of the user. >> So shouldn't this condition be augmented to alsoo consider >> CONFIG_MITIGATION_MDS compile time value? > > CONFIG_MITIGATION_MDS is used to set the value of the mds_mitigation variable. > Same goes for all the other mitigations touched here. Those variables are > checked in verw_mitigations_disabled() which is called just before this code. If > all of them are configured off, we return without enabling any of the mitigations. Ah, indeed. Reviewed-by: Nikolay Borisov