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 DCD431AC8BB; Thu, 15 Aug 2024 14:23:31 +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=1723731812; cv=none; b=W3xT6RV1zYzJL+7w3iwRBeOcRtRP5JdYyIRLkkPFv7NEND8w6FntaWMLyZW7KWIBdKQaru1FoA/aybNKYZxOeScB2gXBnr1ThbcNox4TXtDbXazQvIPSnooeGyyzk2o5DRkQ3QkBesBrCYJMVM+vseb1dCHH0EpY2iAhJHj10tg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723731812; c=relaxed/simple; bh=IIpbNEFGmfsTHiYr82QeN0paZJ3quTxS+iJwTdXnqAY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nCMXY2lxWQzw5wKXWT9xyX/hAYK5r+GcquQsZSB1bDc2CGBaQugkkDU1/PfDyhjQ4b4X7GiSqvDP9X2CXl2wsLGxx6jtSyMCosUP83J1jkdw90WR4a7SNllVehkGPsILliamQO1/TA+2AigY8eLWzUkKYCOOFMGsqDZV55vxq5k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=BnP2090y; 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="BnP2090y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C88A6C32786; Thu, 15 Aug 2024 14:23:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1723731811; bh=IIpbNEFGmfsTHiYr82QeN0paZJ3quTxS+iJwTdXnqAY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BnP2090yyAISFvY16RDOEZ4n3GxIoKTeet6inG2l5YgVLRawVGjuao1414W6cHQ0J 91O+XBqrAKlNRAouZrHWh/yQ6PShIxdbC+aniXNAykUr4GPmpbcGsaJwFMd5aHOzDr hYYKLQnm8h8ddDXRMSQySepCavul8w0gkNlyhYX4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Andi Kleen , Thomas Gleixner Subject: [PATCH 5.4 246/259] x86/mtrr: Check if fixed MTRRs exist before saving them Date: Thu, 15 Aug 2024 15:26:19 +0200 Message-ID: <20240815131912.269218001@linuxfoundation.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240815131902.779125794@linuxfoundation.org> References: <20240815131902.779125794@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 5.4-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 @@ -817,7 +817,7 @@ 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);