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 3B98C26E165; Tue, 8 Apr 2025 12:54:11 +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=1744116852; cv=none; b=oyRAD9kE3+XUO8+eVB3BDSLfbcIm+oljDyggSKESYdBhfjUVb+K4v0pBlZy0rosATvhAkQerjlnr94mXsDd4OD0gYBqGJqweIOGx2mKutO4sPf377DbloKjXTPQddAHI1an3T/KUfOwQluQZW+BbDQqmo0BiiyzCZTUowwwoe2g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744116852; c=relaxed/simple; bh=4iUdjLqb0xTmghWfqSb4qm7nq/BHldIq+D8mVyYCV2k=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=c9L+5HnXvBkEv7fjmAu5wztHe98/2foBnriHg3Jj0yw4E+1dWg/jGBTMsPHRS/gEgV3JIpbYFmY34Bjn9lK0ZGZg/9eavXWb1WIgJvyJBgYDNJJZUy+wvtDchmnqaF9xt+kuoSYek6WhSeAj0GPK0rfzc1Xjs7At58EgXy2dZWM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=PnNxSqwR; 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="PnNxSqwR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5A70BC4CEE5; Tue, 8 Apr 2025 12:54:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1744116851; bh=4iUdjLqb0xTmghWfqSb4qm7nq/BHldIq+D8mVyYCV2k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PnNxSqwRhZ63jLj9jzvH44De7L/leNJeIJK1Jep+I40ZRkIODWsY4BYU8t6pF5CV+ QiZ/RrFNSN830WRSwUVmzEeybwdRPlLJ/w37NpJZDPs6lDWZIfwURrhmugBiLvc1bj rnK7rygwn01oPcUeLU3xYTOVEA2C1vDgNeSf+G50= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Vladis Dronov , Ingo Molnar , Kai Huang , Jarkko Sakkinen , Andy Lutomirski , Sean Christopherson , Linus Torvalds , Peter Zijlstra , Sasha Levin Subject: [PATCH 6.12 291/423] x86/sgx: Warn explicitly if X86_FEATURE_SGX_LC is not enabled Date: Tue, 8 Apr 2025 12:50:17 +0200 Message-ID: <20250408104852.560820561@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250408104845.675475678@linuxfoundation.org> References: <20250408104845.675475678@linuxfoundation.org> User-Agent: quilt/0.68 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 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Vladis Dronov [ Upstream commit 65be5c95d08eedda570a6c888a12384c77fe7614 ] The kernel requires X86_FEATURE_SGX_LC to be able to create SGX enclaves, not just X86_FEATURE_SGX. There is quite a number of hardware which has X86_FEATURE_SGX but not X86_FEATURE_SGX_LC. A kernel running on such hardware does not create the /dev/sgx_enclave file and does so silently. Explicitly warn if X86_FEATURE_SGX_LC is not enabled to properly notify users that the kernel disabled the SGX driver. The X86_FEATURE_SGX_LC, a.k.a. SGX Launch Control, is a CPU feature that enables LE (Launch Enclave) hash MSRs to be writable (with additional opt-in required in the 'feature control' MSR) when running enclaves, i.e. using a custom root key rather than the Intel proprietary key for enclave signing. I've hit this issue myself and have spent some time researching where my /dev/sgx_enclave file went on SGX-enabled hardware. Related links: https://github.com/intel/linux-sgx/issues/837 https://patchwork.kernel.org/project/platform-driver-x86/patch/20180827185507.17087-3-jarkko.sakkinen@linux.intel.com/ [ mingo: Made the error message a bit more verbose, and added other cases where the kernel fails to create the /dev/sgx_enclave device node. ] Signed-off-by: Vladis Dronov Signed-off-by: Ingo Molnar Acked-by: Kai Huang Cc: Jarkko Sakkinen Cc: Andy Lutomirski Cc: Sean Christopherson Cc: Linus Torvalds Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20250309172215.21777-2-vdronov@redhat.com Signed-off-by: Sasha Levin --- arch/x86/kernel/cpu/sgx/driver.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/cpu/sgx/driver.c b/arch/x86/kernel/cpu/sgx/driver.c index 22b65a5f5ec6c..7f8d1e11dbee2 100644 --- a/arch/x86/kernel/cpu/sgx/driver.c +++ b/arch/x86/kernel/cpu/sgx/driver.c @@ -150,13 +150,15 @@ int __init sgx_drv_init(void) u64 xfrm_mask; int ret; - if (!cpu_feature_enabled(X86_FEATURE_SGX_LC)) + if (!cpu_feature_enabled(X86_FEATURE_SGX_LC)) { + pr_info("SGX disabled: SGX launch control CPU feature is not available, /dev/sgx_enclave disabled.\n"); return -ENODEV; + } cpuid_count(SGX_CPUID, 0, &eax, &ebx, &ecx, &edx); if (!(eax & 1)) { - pr_err("SGX disabled: SGX1 instruction support not available.\n"); + pr_info("SGX disabled: SGX1 instruction support not available, /dev/sgx_enclave disabled.\n"); return -ENODEV; } @@ -173,8 +175,10 @@ int __init sgx_drv_init(void) } ret = misc_register(&sgx_dev_enclave); - if (ret) + if (ret) { + pr_info("SGX disabled: Unable to register the /dev/sgx_enclave driver (%d).\n", ret); return ret; + } return 0; } -- 2.39.5