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 6714B18757C; Mon, 12 Aug 2024 16:11:07 +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=1723479067; cv=none; b=Z6FbJ/AUl+1/rEy4IrHzZGhG4ZW1+qaGaIavwXVfUT1fnRVAdMcpMGK+V3S2eAi65wlY0a7FK7B77BsruIz9Pt2YZcr2mrKB0rpiHe3hqfY6uYt1zE6CwlN0iHWuhPIL6MIEl45DNi6SZ6iR5VxNjYwnjWJsUcJ8Hkw7zn0LD+g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723479067; c=relaxed/simple; bh=oS3RXPe04YP1P0Ju+OkG5XRH+GuUatJu2MnuNWgDQb8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=s1t2BiGLkvyoapgKYY6VKmx2pA/60f6h1ur+BJfZ8Dr1VykBKGzNulHvHMKFGtoduVmb/qkV+1+Qo9YrvnEY5Dvg6PMB1xaY6QGKltWt+ey8JFGvNT+1kRLyoO49IWq8PADtXqIp9OCMCAIVL8ZKSm0mUtpokDlcC1CabLIvAh0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=TCK5kjfP; 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="TCK5kjfP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DD395C32782; Mon, 12 Aug 2024 16:11:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1723479067; bh=oS3RXPe04YP1P0Ju+OkG5XRH+GuUatJu2MnuNWgDQb8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TCK5kjfPEo4AdTls6I67ZVz+OAJym2mlJQ7upM53G5PUtbE40vfTjyxbmYis4GLdL RDbH3fK1nmBJFINm25IctL3QUXh521iGuSw4tLivVZrZ8U1P/t7lcwzG6hkuF/F+cf whsgzpID6UjikgDVK1DyVRIitakTrkPOKgiF6L9A= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Andi Kleen , Thomas Gleixner Subject: [PATCH 6.1 121/150] x86/mtrr: Check if fixed MTRRs exist before saving them Date: Mon, 12 Aug 2024 18:03:22 +0200 Message-ID: <20240812160129.834133005@linuxfoundation.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240812160125.139701076@linuxfoundation.org> References: <20240812160125.139701076@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 6.1-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);