From patchwork Tue Dec 14 00:52:03 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Chang S. Bae" X-Patchwork-Id: 524354 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3CC98C433F5 for ; Tue, 14 Dec 2021 00:59:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229672AbhLNA7l (ORCPT ); Mon, 13 Dec 2021 19:59:41 -0500 Received: from mga05.intel.com ([192.55.52.43]:21415 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244546AbhLNA7j (ORCPT ); Mon, 13 Dec 2021 19:59:39 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1639443579; x=1670979579; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=z/ErRUKlY7D4FY0txm0LkQ3s6d6OybLiabjK2vRaL2s=; b=WSM2EVpoJwrq+2tTNHawm8W58Q70/wKv1a6tMfsQCmMngorqJcwwy605 nIkgZH7fbiUQxQ6v+p9eeW6lCPWBL4BmLpPrdWLzA75h01hcV6mLxoWi8 ixcMfF/IeY5miZ91cv5fowJozV8rdFjKAe66xVYflLl3gOZIjV1w2Md0D o1tE1ly8TPWNXbc+6MTAyO1t3QajCwEzz3TUyLIu/Kpf6NcGgYecyiwvs RijsXJAwKGFZuFJZaXwfmk0A4t9zhzVger5WvL60rppqn76qur7WcefSm jxDEi3H4OM6POh/F793sgttuWs/8sha6G5LlEYa0jjf1ZPfMEgaNeqceg A==; X-IronPort-AV: E=McAfee;i="6200,9189,10197"; a="325139619" X-IronPort-AV: E=Sophos;i="5.88,203,1635231600"; d="scan'208";a="325139619" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Dec 2021 16:59:39 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.88,203,1635231600"; d="scan'208";a="505148577" Received: from chang-linux-3.sc.intel.com ([172.25.66.175]) by orsmga007.jf.intel.com with ESMTP; 13 Dec 2021 16:59:38 -0800 From: "Chang S. Bae" To: tglx@linutronix.de, bp@suse.de, dave.hansen@linux.intel.com, mingo@kernel.org, luto@kernel.org, x86@kernel.org, herbert@gondor.apana.org.au Cc: linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, ebiggers@kernel.org, dan.j.williams@intel.com, charishma1.gairuboyina@intel.com, kumar.n.dwarakanath@intel.com, lalithambika.krishnakumar@intel.com, ravi.v.shankar@intel.com, chang.seok.bae@intel.com Subject: [PATCH v4 04/13] x86/asm: Add a wrapper function for the LOADIWKEY instruction Date: Mon, 13 Dec 2021 16:52:03 -0800 Message-Id: <20211214005212.20588-5-chang.seok.bae@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20211214005212.20588-1-chang.seok.bae@intel.com> References: <20211214005212.20588-1-chang.seok.bae@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org Key Locker introduces a CPU-internal wrapping key to encode a user key to a key handle. Then a key handle is referenced instead of the plain text key. The new instruction loads an internal wrapping key in the software-inaccessible CPU state. It operates only in kernel mode. Define struct iwkey to pass the key value. The kernel will use this function to load a new key at boot time when the feature is enabled. Signed-off-by: Chang S. Bae Reviewed-by: Dan Williams Cc: x86@kernel.org Cc: linux-kernel@vger.kernel.org --- Changes from RFC v2: * Separate out the code as a new patch. * Improve the usability with the new struct as an argument. (Dan Williams) Note, Dan wondered if: WARN_ON(!irq_fpu_usable()); would be appropriate in the load_xmm_iwkey() function. --- arch/x86/include/asm/keylocker.h | 25 ++++++++++++++++++++++ arch/x86/include/asm/special_insns.h | 32 ++++++++++++++++++++++++++++ 2 files changed, 57 insertions(+) create mode 100644 arch/x86/include/asm/keylocker.h diff --git a/arch/x86/include/asm/keylocker.h b/arch/x86/include/asm/keylocker.h new file mode 100644 index 000000000000..df84c83228a1 --- /dev/null +++ b/arch/x86/include/asm/keylocker.h @@ -0,0 +1,25 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#ifndef _ASM_KEYLOCKER_H +#define _ASM_KEYLOCKER_H + +#ifndef __ASSEMBLY__ + +#include + +/** + * struct iwkey - A temporary internal wrapping key storage. + * @integrity_key: A 128-bit key to check that key handles have not + * been tampered with. + * @encryption_key: A 256-bit encryption key used in + * wrapping/unwrapping a clear text key. + * + * This storage should be flushed immediately after loaded. + */ +struct iwkey { + struct reg_128_bit integrity_key; + struct reg_128_bit encryption_key[2]; +}; + +#endif /*__ASSEMBLY__ */ +#endif /* _ASM_KEYLOCKER_H */ diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h index 68c257a3de0d..3e50d8396ee1 100644 --- a/arch/x86/include/asm/special_insns.h +++ b/arch/x86/include/asm/special_insns.h @@ -9,6 +9,7 @@ #include #include #include +#include /* * The compiler should not reorder volatile asm statements with respect to each @@ -294,6 +295,37 @@ static inline int enqcmds(void __iomem *dst, const void *src) return 0; } +/** + * load_xmm_iwkey - Load a CPU-internal wrapping key + * @key: A struct iwkey pointer. + * + * Load @key to XMMs then do LOADIWKEY. After this, flush XMM + * registers. Caller is responsible for kernel_cpu_begin(). + */ +static inline void load_xmm_iwkey(struct iwkey *key) +{ + struct reg_128_bit zeros = { 0 }; + + asm volatile ("movdqu %0, %%xmm0; movdqu %1, %%xmm1; movdqu %2, %%xmm2;" + :: "m"(key->integrity_key), "m"(key->encryption_key[0]), + "m"(key->encryption_key[1])); + + /* + * LOADIWKEY %xmm1,%xmm2 + * + * EAX and XMM0 are implicit operands. Load a key value + * from XMM0-2 to a software-invisible CPU state. With zero + * in EAX, CPU does not do hardware randomization and the key + * backup is allowed. + * + * This instruction is supported by binutils >= 2.36. + */ + asm volatile (".byte 0xf3,0x0f,0x38,0xdc,0xd1" :: "a"(0)); + + asm volatile ("movdqu %0, %%xmm0; movdqu %0, %%xmm1; movdqu %0, %%xmm2;" + :: "m"(zeros)); +} + #endif /* __KERNEL__ */ #endif /* _ASM_X86_SPECIAL_INSNS_H */