From nobody Fri Dec 19 05:00:13 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C9D04C0015E for ; Sat, 12 Aug 2023 20:06:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231218AbjHLUGj (ORCPT ); Sat, 12 Aug 2023 16:06:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41120 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231185AbjHLUGb (ORCPT ); Sat, 12 Aug 2023 16:06:31 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6527C1BD2 for ; Sat, 12 Aug 2023 13:06:05 -0700 (PDT) Message-ID: <20230812195729.151791844@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1691870360; 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: references:references; bh=2kqLUw1a4gV9FrIDWZ/O+PSOOuBOB0W9vRdpe8yDcXg=; b=1Z1lw9Ww3BM9YXEw1BzRvEWs/3vjeiRnep1e0b18O1h3e7/54fwoOtvgkG7UkaxqpLk/oa sdtYLEYQAAnxcl88ABdTn3eh08lHjNOTCkgECUDsfckza313teaJrKvKbRtsq03o6R9N1k Qz1/R+nARgME7/sOgr4eIpFilkYAybZUfIx2QwVbm1woF+OyhO5Gg0Cz/vTc5kGdE1vthK UXTH0+esHfJY3HQye4REWXVlzjqfVYkKYvbZe/auaxghnBgXoVntspJB7luBNDQoWqWAme 6dkAAP+Ieri1AG39TXW0RxHYwb6jjLnYgyHWWNiA2mDUwB0hLCMI+UKbwVfc/g== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1691870360; 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: references:references; bh=2kqLUw1a4gV9FrIDWZ/O+PSOOuBOB0W9vRdpe8yDcXg=; b=vUrkC1ippGLhba5Q8lhTClaptrOpApv0nxztTG+iEF2D0BVUzIBScyVrwverfaFESnoPEp Gw1soY2IdAougYCg== From: Thomas Gleixner To: LKML Cc: x86@kernel.org, Borislav Petkov , Ashok Raj , Arjan van de Ven , Nikolay Borisov Subject: [patch V2 28/37] x86/microcode: Add per CPU result state References: <20230812194003.682298127@linutronix.de> MIME-Version: 1.0 Date: Sat, 12 Aug 2023 21:59:20 +0200 (CEST) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Thomas Gleixner The microcode rendevouz is purely acting on global state, which does not allow to analyze fails in a coherent way. Introduce per CPU state where the results are written into, which allows to analyze the return codes of the individual CPUs. Initialize the state when walking the cpu_present_mask in the online check to avoid another for_each_cpu() loop. Enhance the result print out with that. The structure is intentionally named ucode_ctrl as it will gain control fields in subsequent changes. Signed-off-by: Thomas Gleixner --- arch/x86/kernel/cpu/microcode/core.c | 108 ++++++++++++++++++--------= ----- arch/x86/kernel/cpu/microcode/internal.h | 1=20 2 files changed, 65 insertions(+), 44 deletions(-) --- --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -324,6 +324,11 @@ static struct platform_device *microcode * requirement can be relaxed in the future. Right now, this is conserva= tive * and good. */ +struct ucode_ctrl { + enum ucode_state result; +}; + +static DEFINE_PER_CPU(struct ucode_ctrl, ucode_ctrl); static atomic_t late_cpus_in, late_cpus_out; =20 static bool wait_for_cpus(atomic_t *cnt) @@ -344,23 +349,19 @@ static bool wait_for_cpus(atomic_t *cnt) return false; } =20 -/* - * Returns: - * < 0 - on error - * 0 - success (no update done or microcode was updated) - */ -static int __reload_late(void *info) +static int ucode_load_cpus_stopped(void *unused) { int cpu =3D smp_processor_id(); - enum ucode_state err; - int ret =3D 0; + enum ucode_state ret; =20 /* * Wait for all CPUs to arrive. A load will not be attempted unless all * CPUs show up. * */ - if (!wait_for_cpus(&late_cpus_in)) - return -1; + if (!wait_for_cpus(&late_cpus_in)) { + this_cpu_write(ucode_ctrl.result, UCODE_TIMEOUT); + return 0; + } =20 /* * On an SMT system, it suffices to load the microcode on one sibling of @@ -369,17 +370,11 @@ static int __reload_late(void *info) * loading attempts happen on multiple threads of an SMT core. See * below. */ - if (cpumask_first(topology_sibling_cpumask(cpu)) =3D=3D cpu) - err =3D microcode_ops->apply_microcode(cpu); - else + if (cpumask_first(topology_sibling_cpumask(cpu)) !=3D cpu) goto wait_for_siblings; =20 - if (err >=3D UCODE_NFOUND) { - if (err =3D=3D UCODE_ERROR) { - pr_warn("Error reloading microcode on CPU %d\n", cpu); - ret =3D -1; - } - } + ret =3D microcode_ops->apply_microcode(cpu); + this_cpu_write(ucode_ctrl.result, ret); =20 wait_for_siblings: if (!wait_for_cpus(&late_cpus_out)) @@ -391,19 +386,18 @@ static int __reload_late(void *info) * per-cpu cpuinfo can be updated with right microcode * revision. */ - if (cpumask_first(topology_sibling_cpumask(cpu)) !=3D cpu) - err =3D microcode_ops->apply_microcode(cpu); + if (cpumask_first(topology_sibling_cpumask(cpu)) =3D=3D cpu) + return 0; =20 - return ret; + ret =3D microcode_ops->apply_microcode(cpu); + this_cpu_write(ucode_ctrl.result, ret); + return 0; } =20 -/* - * Reload microcode late on all CPUs. Wait for a sec until they - * all gather together. - */ -static int microcode_reload_late(void) +static int ucode_load_late_stop_cpus(void) { - int old =3D boot_cpu_data.microcode, ret; + unsigned int cpu, updated =3D 0, failed =3D 0, timedout =3D 0, siblings = =3D 0; + int old_rev =3D boot_cpu_data.microcode; struct cpuinfo_x86 prev_info; =20 pr_err("Attempting late microcode loading - it is dangerous and taints th= e kernel.\n"); @@ -418,26 +412,47 @@ static int microcode_reload_late(void) */ store_cpu_caps(&prev_info); =20 - ret =3D stop_machine_cpuslocked(__reload_late, NULL, cpu_online_mask); + stop_machine_cpuslocked(ucode_load_cpus_stopped, NULL, cpu_online_mask); + + /* Analyze the results */ + for_each_cpu_and(cpu, cpu_present_mask, &cpus_booted_once_mask) { + switch (per_cpu(ucode_ctrl.result, cpu)) { + case UCODE_UPDATED: updated++; break; + case UCODE_TIMEOUT: timedout++; break; + case UCODE_OK: siblings++; break; + default: failed++; break; + } + } =20 if (microcode_ops->finalize_late_load) - microcode_ops->finalize_late_load(ret); + microcode_ops->finalize_late_load(!updated); =20 - if (!ret) { - pr_info("Reload succeeded, microcode revision: 0x%x -> 0x%x\n", - old, boot_cpu_data.microcode); - microcode_check(&prev_info); - add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK); - } else { - pr_info("Reload failed, current microcode revision: 0x%x\n", - boot_cpu_data.microcode); + if (!updated) { + /* Nothing changed. */ + if (!failed && !timedout) + return 0; + pr_err("Microcode update failed: %u CPUs failed %u CPUs timed out\n", + failed, timedout); + return -EIO; } - return ret; + + add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK); + pr_info("Microcode load: updated on %u primary CPUs with %u siblings\n", = updated, siblings); + if (failed || timedout) { + pr_err("Microcode load incomplete. %u CPUs timed out or failed\n", + num_online_cpus() - (updated + siblings)); + } + pr_info("Microcode revision: 0x%x -> 0x%x\n", old_rev, boot_cpu_data.micr= ocode); + microcode_check(&prev_info); + + return updated + siblings =3D=3D num_online_cpus() ? 0 : -EIO; } =20 /* - * Ensure that all required CPUs which are present and have been booted - * once are online. + * This function does two things: + * + * 1) Ensure that all required CPUs which are present and have been booted + * once are online. * * To pass this check, all primary threads must be online. * @@ -448,9 +463,12 @@ static int microcode_reload_late(void) * behaviour is undefined. The default play_dead() implementation on * modern CPUs is using MWAIT, which is also not guaranteed to be safe * against a microcode update which affects MWAIT. + * + * 2) Initialize the per CPU control structure */ -static bool ensure_cpus_are_online(void) +static bool ucode_setup_cpus(void) { + struct ucode_ctrl ctrl =3D { .result =3D -1, }; unsigned int cpu; =20 for_each_cpu_and(cpu, cpu_present_mask, &cpus_booted_once_mask) { @@ -460,6 +478,8 @@ static bool ensure_cpus_are_online(void) return false; } } + /* Initialize the per CPU state */ + per_cpu(ucode_ctrl, cpu) =3D ctrl; } return true; } @@ -468,13 +488,13 @@ static int ucode_load_late_locked(void) { int ret; =20 - if (!ensure_cpus_are_online()) + if (!ucode_setup_cpus()) return -EBUSY; =20 ret =3D microcode_ops->request_microcode_fw(0, µcode_pdev->dev); if (ret !=3D UCODE_NEW) return ret =3D=3D UCODE_NFOUND ? -ENOENT : -EBADFD; - return microcode_reload_late(); + return ucode_load_late_stop_cpus(); } =20 static ssize_t reload_store(struct device *dev, --- a/arch/x86/kernel/cpu/microcode/internal.h +++ b/arch/x86/kernel/cpu/microcode/internal.h @@ -16,6 +16,7 @@ enum ucode_state { UCODE_UPDATED, UCODE_NFOUND, UCODE_ERROR, + UCODE_TIMEOUT, }; =20 struct microcode_ops {