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 4B4661AAE01; Thu, 15 Aug 2024 14:43:38 +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=1723733018; cv=none; b=CRNiWK8h90bNgip1uyS5DueWcuYp1mcP1jMSwgwWuGGZ9a4KdRSr5YI9ntHGZNXMMaLh/a0zyB+oBMRuz1s4o2bmcF7YUiAjdBFZJt6HBy9PwxtLLIo3tsjm9Tdsno2cVW0pWs/wuRs8VgC83Vzju84pOO+tOcKN7Efbd/HPp44= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723733018; c=relaxed/simple; bh=DIQwabo72AJN272cTtNVi2iOTvWYmkxMuJfmtgfVQHU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=AG3hpC2+4KhrG+tfRzZF31KMuJxLl3H1TIrJ82cAPKpU2hvV8b+A4R609lnJZXcp/8yK7ohryOD8Oi07W5nIRKbbX3+6l9cVk9oxywTPbHndRzZTvGdgPfimaddCvXgHs+DBivBsS7WgP1SRTHWCOdAFl114PvBIIxK/obK9GGY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=uxFRkfxZ; 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="uxFRkfxZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C223EC32786; Thu, 15 Aug 2024 14:43:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1723733018; bh=DIQwabo72AJN272cTtNVi2iOTvWYmkxMuJfmtgfVQHU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uxFRkfxZFnnot+zkhbmsujaT0vMs2XD1vxw1ypJKUk3gI7UoTD4dyxCtt2ii7L8+Z SJzozjOL5pv9vk5klsPPJN2N4mwn0LvRc2kryoloEPgBvN7aBjUO7/yNSfUVZH3jJQ 5ZXtfZACAq/s9LC0Z6iyCXUR+F1CBM/KOQNWuvgA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Andi Kleen , Thomas Gleixner Subject: [PATCH 5.10 325/352] x86/mtrr: Check if fixed MTRRs exist before saving them Date: Thu, 15 Aug 2024 15:26:31 +0200 Message-ID: <20240815131932.014688294@linuxfoundation.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240815131919.196120297@linuxfoundation.org> References: <20240815131919.196120297@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-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);