From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 4E49033D50F; Fri, 9 Jan 2026 11:45:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767959103; cv=none; b=b4pu0Uph1eVAU1HJTo+lt1pnOWKCXh59k5IWjUXwjb43fDWNcQjbRq1FRJJ8aV1g6f+TFnJOFVjucbS+GNcTvMJZzh7KDQj96lvPGMhqLLT9O8p5RgV6bezkb192K+HvdQxFKtMyvd/BciXcWejNJZcbgmYfn729y1TP3h0MaPg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767959103; c=relaxed/simple; bh=VuNbK6IddF/rdbWqXWLyR3Ta+ijLfxVsqBq/ESkywKw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WbnnTiK5CSoZ989Q6+Sp6ZMIxbPIBKjHpQIeWIA4+JvSdB9XZUA9/VWHYIXTuf4PLErKs/iO3FLYzDiLORI+b+qNuKU6VFtRXghSH3UgmK9DAkMpF8RT6xElGbJ+9//Q5o0AttFcfH063Etid4/rPEfTse7vWBt4Ol0aWakAshk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=yAwOrY1z; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="yAwOrY1z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0D7D8C4CEF1; Fri, 9 Jan 2026 11:45:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1767959102; bh=VuNbK6IddF/rdbWqXWLyR3Ta+ijLfxVsqBq/ESkywKw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yAwOrY1zbmZL7ab0ojyUnQMsEMdi+AACrt8FsreO2Y2x2JRZvT5MzT9g8U+eyR7Pr dhpFzXol9qmIxdjevDn6ygokHHJbim9yNSW6YSHbeRNVRHwNUiTr/Mi6N5z1vTJOLf cicd7/T4ZCOrMA0ezLJ5SI8bYyGuuPoq37urIC6w= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Aaron Rainbolt , Srinivas Pandruvada , "Rafael J. Wysocki" , Richa Bharti Subject: [PATCH 6.12 09/16] cpufreq: intel_pstate: Check IDA only before MSR_IA32_PERF_CTL writes Date: Fri, 9 Jan 2026 12:43:50 +0100 Message-ID: <20260109111951.774773967@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260109111951.415522519@linuxfoundation.org> References: <20260109111951.415522519@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Richa Bharti [ Upstream commit 4b747cc628d8f500d56cf1338280eacc66362ff3 ] Commit ac4e04d9e378 ("cpufreq: intel_pstate: Unchecked MSR aceess in legacy mode") introduced a check for feature X86_FEATURE_IDA to verify turbo mode support. Although this is the correct way to check for turbo mode support, it causes issues on some platforms that disable turbo during OS boot, but enable it later [1]. Before adding this feature check, users were able to get turbo mode frequencies by writing 0 to /sys/devices/system/cpu/intel_pstate/no_turbo post-boot. To restore the old behavior on the affected systems while still addressing the unchecked MSR issue on some Skylake-X systems, check X86_FEATURE_IDA only immediately before updates of MSR_IA32_PERF_CTL that may involve setting the Turbo Engage Bit (bit 32). Fixes: ac4e04d9e378 ("cpufreq: intel_pstate: Unchecked MSR aceess in legacy mode") Reported-by: Aaron Rainbolt Closes: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2122531 [1] Tested-by: Aaron Rainbolt Signed-off-by: Srinivas Pandruvada [ rjw: Subject adjustment, changelog edits ] Link: https://patch.msgid.link/20251111010840.141490-1-srinivas.pandruvada@linux.intel.com Signed-off-by: Rafael J. Wysocki [ richa: Backport to 6.12.y with context adjustments ] Signed-off-by: Richa Bharti Signed-off-by: Greg Kroah-Hartman --- drivers/cpufreq/intel_pstate.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -600,9 +600,6 @@ static bool turbo_is_disabled(void) { u64 misc_en; - if (!cpu_feature_enabled(X86_FEATURE_IDA)) - return true; - rdmsrl(MSR_IA32_MISC_ENABLE, misc_en); return !!(misc_en & MSR_IA32_MISC_ENABLE_TURBO_DISABLE); @@ -2018,7 +2015,8 @@ static u64 atom_get_val(struct cpudata * u32 vid; val = (u64)pstate << 8; - if (READ_ONCE(global.no_turbo) && !READ_ONCE(global.turbo_disabled)) + if (READ_ONCE(global.no_turbo) && !READ_ONCE(global.turbo_disabled) && + cpu_feature_enabled(X86_FEATURE_IDA)) val |= (u64)1 << 32; vid_fp = cpudata->vid.min + mul_fp( @@ -2183,7 +2181,8 @@ static u64 core_get_val(struct cpudata * u64 val; val = (u64)pstate << 8; - if (READ_ONCE(global.no_turbo) && !READ_ONCE(global.turbo_disabled)) + if (READ_ONCE(global.no_turbo) && !READ_ONCE(global.turbo_disabled) && + cpu_feature_enabled(X86_FEATURE_IDA)) val |= (u64)1 << 32; return val;