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 29AEB44376; Thu, 15 Aug 2024 14:02:36 +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=1723730556; cv=none; b=gq1CF5cZh/9qnFqWXcRD+JPB8ZJ/CDUvu649l9fL02nuFtpxReaFwnVn5lgfZjyTKVhFugFLwX1HW4iFOB/DeQTypOPM2xWnVUCL8DZW8tmerJqGWgrdiOjb6EQij/8LeKxlOfJG9qRt5qEzEcE/d2fcQbbh65spUDczQaJrlvk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723730556; c=relaxed/simple; bh=e421JMG2QkD386mC1/ilGUF34IyMEVQ4k/Zidb8B8ho=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZjbnUaO+mYnDf837akDX5Fv5BHKFY5BD2jAmytrmkQyh8/W8R/XiJ9kkUbIO56KOwyyNOHi2wo9laVtAKZobQEnGPixQX7W9TzLRH1uWuWW+lXtp5j12DaFZxMBwLJ5ZNpiWu6PVfvWI0VCoVptchEK+lRwwJnnEMb22HdzXEdw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ZgElZeHB; 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="ZgElZeHB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8E0B9C32786; Thu, 15 Aug 2024 14:02:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1723730556; bh=e421JMG2QkD386mC1/ilGUF34IyMEVQ4k/Zidb8B8ho=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZgElZeHBe3s1lTYsol9SCGDLm0iVCHq43Yq47uhI9bPUXLeB6EOfdF4L2iQpha4B/ nfSqf/YQDzT4NPCT6e0+8eRD6ygcwJyNbaCaEEK5fKXxuetIr+HEsNqP9iHfM7t5tx mgyxE25aRJNpcDRzdrYuqyXeQ9fC2hHh/EFdVqQc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Andi Kleen , Thomas Gleixner Subject: [PATCH 5.15 446/484] x86/mtrr: Check if fixed MTRRs exist before saving them Date: Thu, 15 Aug 2024 15:25:04 +0200 Message-ID: <20240815131958.686299944@linuxfoundation.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240815131941.255804951@linuxfoundation.org> References: <20240815131941.255804951@linuxfoundation.org> User-Agent: quilt/0.67 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 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andi Kleen commit 919f18f961c03d6694aa726c514184f2311a4614 upstream. MTRRs have an obsolete fixed variant for fine grained caching control of the 640K-1MB region that uses separate MSRs. This fixed variant has a separate capability bit in the MTRR capability MSR. So far all x86 CPUs which support MTRR have this separate bit set, so it went unnoticed that mtrr_save_state() does not check the capability bit before accessing the fixed MTRR MSRs. Though on a CPU that does not support the fixed MTRR capability this results in a #GP. The #GP itself is harmless because the RDMSR fault is handled gracefully, but results in a WARN_ON(). Add the missing capability check to prevent this. Fixes: 2b1f6278d77c ("[PATCH] x86: Save the MTRRs of the BSP before booting an AP") Signed-off-by: Andi Kleen Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/20240808000244.946864-1-ak@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/mtrr/mtrr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/x86/kernel/cpu/mtrr/mtrr.c +++ b/arch/x86/kernel/cpu/mtrr/mtrr.c @@ -816,7 +816,7 @@ void mtrr_save_state(void) { int first_cpu; - if (!mtrr_enabled()) + if (!mtrr_enabled() || !mtrr_state.have_fixed) return; first_cpu = cpumask_first(cpu_online_mask);