From mboxrd@z Thu Jan 1 00:00:00 1970 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 77400C433EF for ; Mon, 18 Oct 2021 15:33:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4E632610FC for ; Mon, 18 Oct 2021 15:33:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233375AbhJRPfu (ORCPT ); Mon, 18 Oct 2021 11:35:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36062 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231946AbhJRPfq (ORCPT ); Mon, 18 Oct 2021 11:35:46 -0400 Received: from mail-lf1-x12f.google.com (mail-lf1-x12f.google.com [IPv6:2a00:1450:4864:20::12f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 50B15C061768 for ; Mon, 18 Oct 2021 08:33:35 -0700 (PDT) Received: by mail-lf1-x12f.google.com with SMTP id y15so543304lfk.7 for ; Mon, 18 Oct 2021 08:33:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=shutemov-name.20210112.gappssmtp.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=WPrVir84s/zbJNutNzpoxgVyHO6kagrc6ojPFi/IqQ0=; b=VTisOhP30BHjvkVDUzf+ZIyF2SIBMJFQf76pz8OVD/73fQFB1lCtWD777KHjzaJgx5 Tgvo02RQrNZJYt4uR0Vj+yg/fQ1EHgMJrxRmWTz9RPEa9RWJnBN2kK5rxH5lZDpKmBDi Jo+kTKhYJl25o57m8so/K7lO898Gnqo0AXxIuYY+OUc0ssphsJCwth//6fQn+uqAuRTR rDHNuPWQJhgBMSpG8nrTwNVi1Kw1UMkSz06bmLr5h3adqxjRX+rmCSJ+LzqhVN02mOZn ezVymsUOXmQeHfWaKCUa3w6rdZ/ihsZDWLRguV+6kQ97YTKBLWsNc4lopanVaPwAimj/ XRcQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=WPrVir84s/zbJNutNzpoxgVyHO6kagrc6ojPFi/IqQ0=; b=IGoSSfhCfKotcCtKzPfnlgHuaQTlslYlEC8FyUHiyBb4k+g8RWr3piuSPttClhQslD 7Pij4oKHt8HT618xKGbfDZdRoAZ+ZHrgmv7BWM5ewTUWUqycax9dLE1exnYNAdRURE1h 7jyIgv2H6v3HF3kVmkVZJEn/BdB8bvtSVn6e8Pm5v9H56Lu6hOBuCnw/ztnLGwIyCkko XeFu8tkJDGx7EOR65DuZCDmUzuFwPxq5jlwiEVUZLY4BioVeM9uhfHLbXaepaauHxmSc ik3/fw28P/MBU9Un9PcwlObEF5dqm6RMofwE0dWRfvv7C0gCax7pbw4JaycvIQjRJotB DACQ== X-Gm-Message-State: AOAM531gKhQvtUg6RYeMtYVNKZlQDSdMSYmC7DLqW97IAsBnSiyBfa7S +XOCBBfZzzd2JxCp3+OzBmxDXA== X-Google-Smtp-Source: ABdhPJztAtP4r1nNygR9q8XAfX/3sT7mfInDhZdw7OaDBfjKszIggfXOimryFXjAf2egHk9m+83ZDw== X-Received: by 2002:a05:6512:32c2:: with SMTP id f2mr381723lfg.503.1634571213665; Mon, 18 Oct 2021 08:33:33 -0700 (PDT) Received: from box.localdomain ([86.57.175.117]) by smtp.gmail.com with ESMTPSA id w16sm1431750lfl.189.2021.10.18.08.33.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 18 Oct 2021 08:33:31 -0700 (PDT) From: "Kirill A. Shutemov" X-Google-Original-From: "Kirill A. Shutemov" Received: by box.localdomain (Postfix, from userid 1000) id 19C4D10309C; Mon, 18 Oct 2021 18:33:35 +0300 (+03) To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Tom Lendacky , Joerg Roedel Cc: Kuppuswamy Sathyanarayanan , Andi Kleen , Dave Hansen , Sean Christopherson , x86@kernel.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" , Tony Luck Subject: [PATCH 2/3] x86/insn-eval: Introduce insn_decode_mmio() Date: Mon, 18 Oct 2021 18:33:32 +0300 Message-Id: <20211018153333.8261-3-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20211018153333.8261-1-kirill.shutemov@linux.intel.com> References: <20211018153333.8261-1-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In preparation for sharing MMIO instruction decode between SEV-ES and TDX, factor out the common decode into a new insn_decode_mmio() helper. For regular virtual machine, MMIO is handled by the VMM and KVM emulates instructions that caused MMIO. But, this model doesn't work for a secure VMs (like SEV or TDX) as VMM doesn't have access to the guest memory and register state. So, for TDX or SEV VMM needs assistance in handling MMIO. It induces exception in the guest. Guest has to decode the instruction and handle it on its own. The code is based on the current SEV MMIO implementation. Signed-off-by: Kirill A. Shutemov Reviewed-by: Andi Kleen Reviewed-by: Tony Luck --- arch/x86/include/asm/insn-eval.h | 12 +++++ arch/x86/lib/insn-eval.c | 82 ++++++++++++++++++++++++++++++++ 2 files changed, 94 insertions(+) diff --git a/arch/x86/include/asm/insn-eval.h b/arch/x86/include/asm/insn-eval.h index 041f399153b9..4a4ca7e7be66 100644 --- a/arch/x86/include/asm/insn-eval.h +++ b/arch/x86/include/asm/insn-eval.h @@ -29,4 +29,16 @@ int insn_fetch_from_user_inatomic(struct pt_regs *regs, bool insn_decode_from_regs(struct insn *insn, struct pt_regs *regs, unsigned char buf[MAX_INSN_SIZE], int buf_size); +enum mmio_type { + MMIO_DECODE_FAILED, + MMIO_WRITE, + MMIO_WRITE_IMM, + MMIO_READ, + MMIO_READ_ZERO_EXTEND, + MMIO_READ_SIGN_EXTEND, + MMIO_MOVS, +}; + +enum mmio_type insn_decode_mmio(struct insn *insn, int *bytes); + #endif /* _ASM_X86_INSN_EVAL_H */ diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c index fbaa3fa24bde..2ab29d8d6731 100644 --- a/arch/x86/lib/insn-eval.c +++ b/arch/x86/lib/insn-eval.c @@ -1559,3 +1559,85 @@ bool insn_decode_from_regs(struct insn *insn, struct pt_regs *regs, return true; } + +/** + * insn_decode_mmio() - Decode a MMIO instruction + * @insn: Structure to store decoded instruction + * @bytes: Returns size of memory operand + * + * Decodes instruction that used for Memory-mapped I/O. + * + * Returns: + * + * Type of the instruction. Size of the memory operand is stored in + * @bytes. If decode failed, MMIO_DECODE_FAILED returned. + */ +enum mmio_type insn_decode_mmio(struct insn *insn, int *bytes) +{ + int type = MMIO_DECODE_FAILED; + + *bytes = 0; + + insn_get_opcode(insn); + switch (insn->opcode.bytes[0]) { + case 0x88: /* MOV m8,r8 */ + *bytes = 1; + fallthrough; + case 0x89: /* MOV m16/m32/m64, r16/m32/m64 */ + if (!*bytes) + *bytes = insn->opnd_bytes; + type = MMIO_WRITE; + break; + + case 0xc6: /* MOV m8, imm8 */ + *bytes = 1; + fallthrough; + case 0xc7: /* MOV m16/m32/m64, imm16/imm32/imm64 */ + if (!*bytes) + *bytes = insn->opnd_bytes; + type = MMIO_WRITE_IMM; + break; + + case 0x8a: /* MOV r8, m8 */ + *bytes = 1; + fallthrough; + case 0x8b: /* MOV r16/r32/r64, m16/m32/m64 */ + if (!*bytes) + *bytes = insn->opnd_bytes; + type = MMIO_READ; + break; + + case 0xa4: /* MOVS m8, m8 */ + *bytes = 1; + fallthrough; + case 0xa5: /* MOVS m16/m32/m64, m16/m32/m64 */ + if (!*bytes) + *bytes = insn->opnd_bytes; + type = MMIO_MOVS; + break; + + case 0x0f: /* Two-byte instruction */ + switch (insn->opcode.bytes[1]) { + case 0xb6: /* MOVZX r16/r32/r64, m8 */ + *bytes = 1; + fallthrough; + case 0xb7: /* MOVZX r32/r64, m16 */ + if (!*bytes) + *bytes = 2; + type = MMIO_READ_ZERO_EXTEND; + break; + + case 0xbe: /* MOVSX r16/r32/r64, m8 */ + *bytes = 1; + fallthrough; + case 0xbf: /* MOVSX r32/r64, m16 */ + if (!*bytes) + *bytes = 2; + type = MMIO_READ_SIGN_EXTEND; + break; + } + break; + } + + return type; +} -- 2.32.0