From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x227884cz9s0dvvJUzonEEU6U/Sh2AY3JP+lKqZc4+xFfaSKccSYLLtXan7cazM2bataoSsXl ARC-Seal: i=1; a=rsa-sha256; t=1518863592; cv=none; d=google.com; s=arc-20160816; b=ynjZMB4/cXFCtwElO7P1yRpiYw1NemK287q0goyC+Da7+3prnvzCZTnvIsPn9E7eRW Y6hkqPYdAICuCYenp9wGYM6z4clTdeZcRZGsjw/9aXPXxdMRnawqIoFYtVOkvqug4xNn frtkDmoKmrNgrmCX8otGMFZQydovDWBug4KjurTE4GxUJaDZl2THxj6hyQdw/x1XeMMQ 49xtCf63mLvt/M4FQonvDcJRg0/xiXWBAC75E31ezEQnl2srB1zgp93o8FBG+KtOQSVP xaYt10eujmvq8F/IleQ/IzHnE17RlMYIbVRbJy1LlX7Aa8DFjmhUzFmGRNDbnZQkp+f4 QObQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=precedence:content-disposition:content-transfer-encoding :mime-version:robot-unsubscribe:robot-id:git-commit-id:subject:to :references:in-reply-to:reply-to:cc:message-id:from:sender:date :arc-authentication-results; bh=npa8zYN0xrs35jlO6x7l1Dh0uSaYh4zX/5mqZB1DmE0=; b=jMVqkbbIxvQzH1f7JS3qoLxx7prMJjVplRW8hSwBumd7bjzMrMG+2WK5q2DpU4wF5K 0pwTK+ke/6CMoENwQVT/ib0NvSUpDxJ1JBrvbE1h8orvSUW84S5Nn1lyYy2y44NdwbAX Z0Z4wATZyQCcm4hMdr8Yp7MUKczVEuOaZNjyGK11F3bmWtkmF/G0/JnCarJfvtjh/N3d ly/sBPDtNdPfNwIKBR22NUBq7JmvD/Q08yhuL8Via85STdW/2WCqM/Fd42UI/vgqFFYG /6dn+70jzvduyFBoXKrwrRDFUNol1TdVHC6RdvKpuuYnHHhywPoQDeUB2AhkwEBQjgoN EykA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of tipbot@zytor.com designates 198.137.202.136 as permitted sender) smtp.mailfrom=tipbot@zytor.com Authentication-Results: mx.google.com; spf=pass (google.com: domain of tipbot@zytor.com designates 198.137.202.136 as permitted sender) smtp.mailfrom=tipbot@zytor.com Date: Sat, 17 Feb 2018 02:13:02 -0800 Sender: tip tree robot From: tip-bot for Borislav Petkov Message-ID: Cc: arjan@linux.intel.com, dan.j.williams@intel.com, mingo@kernel.org, luto@kernel.org, bp@alien8.de, gregkh@linuxfoundation.org, hpa@zytor.com, dwmw2@infradead.org, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, ashok.raj@intel.com, dave.hansen@linux.intel.com, bp@suse.de, peterz@infradead.org, jpoimboe@redhat.com, tglx@linutronix.de Reply-To: bp@suse.de, peterz@infradead.org, jpoimboe@redhat.com, tglx@linutronix.de, gregkh@linuxfoundation.org, dwmw2@infradead.org, hpa@zytor.com, torvalds@linux-foundation.org, ashok.raj@intel.com, linux-kernel@vger.kernel.org, dave.hansen@linux.intel.com, mingo@kernel.org, luto@kernel.org, bp@alien8.de, arjan@linux.intel.com, dan.j.williams@intel.com In-Reply-To: <20180216112640.11554-4-bp@alien8.de> References: <20180216112640.11554-4-bp@alien8.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/pti] x86/CPU: Check CPU feature bits after microcode upgrade Git-Commit-ID: 42ca8082e260dcfd8afa2afa6ec1940b9d41724c X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1592643910631502341?= X-GMAIL-MSGID: =?utf-8?q?1592643910631502341?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: Commit-ID: 42ca8082e260dcfd8afa2afa6ec1940b9d41724c Gitweb: https://git.kernel.org/tip/42ca8082e260dcfd8afa2afa6ec1940b9d41724c Author: Borislav Petkov AuthorDate: Fri, 16 Feb 2018 12:26:40 +0100 Committer: Ingo Molnar CommitDate: Sat, 17 Feb 2018 08:43:55 +0100 x86/CPU: Check CPU feature bits after microcode upgrade With some microcode upgrades, new CPUID features can become visible on the CPU. Check what the kernel has mirrored now and issue a warning hinting at possible things the user/admin can do to make use of the newly visible features. Originally-by: Ashok Raj Tested-by: Ashok Raj Signed-off-by: Borislav Petkov Reviewed-by: Ashok Raj Cc: Andy Lutomirski Cc: Arjan van de Ven Cc: Borislav Petkov Cc: Dan Williams Cc: Dave Hansen Cc: David Woodhouse Cc: Greg Kroah-Hartman Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20180216112640.11554-4-bp@alien8.de Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/common.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 84f1cd8..348cf48 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1757,5 +1757,25 @@ core_initcall(init_cpu_syscore); */ void microcode_check(void) { + struct cpuinfo_x86 info; + perf_check_microcode(); + + /* Reload CPUID max function as it might've changed. */ + info.cpuid_level = cpuid_eax(0); + + /* + * Copy all capability leafs to pick up the synthetic ones so that + * memcmp() below doesn't fail on that. The ones coming from CPUID will + * get overwritten in get_cpu_cap(). + */ + memcpy(&info.x86_capability, &boot_cpu_data.x86_capability, sizeof(info.x86_capability)); + + get_cpu_cap(&info); + + if (!memcmp(&info.x86_capability, &boot_cpu_data.x86_capability, sizeof(info.x86_capability))) + return; + + pr_warn("x86/CPU: CPU features have changed after loading microcode, but might not take effect.\n"); + pr_warn("x86/CPU: Please consider either early loading through initrd/built-in or a potential BIOS update.\n"); }