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 X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F02BEC00307 for ; Fri, 6 Sep 2019 13:14:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BE08C214DE for ; Fri, 6 Sep 2019 13:14:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567775657; bh=YxdWojc5fQhCsI3MCFNUb/S38/XJllDgwfcUjCixi7c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=uUb7mCTqNtIv/dyqtts/zJV2vIF0KnXkq9MlB/1QvIUL7F+Qbp2lv/ZTPUR4+70xk lnTbCpp9lSwCsCKfnRSSRoiSisWjP+0+1TByQN0gLwXi6Ie5D+5XuaAhWHkfFgfuyI zfJt8YL4u7VVEDaUOeJPZLi5TBaNmzG0R+fk41mA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393051AbfIFNOR (ORCPT ); Fri, 6 Sep 2019 09:14:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:35558 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388106AbfIFNOQ (ORCPT ); Fri, 6 Sep 2019 09:14:16 -0400 Received: from localhost.localdomain (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4A55A207FC; Fri, 6 Sep 2019 13:14:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567775655; bh=YxdWojc5fQhCsI3MCFNUb/S38/XJllDgwfcUjCixi7c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XkKh5q5Aus2YgqR1dKqCz2etHrZWowX7W3djWGR1gL3U8RvdvMP18XVzrLm0PVhvq //NYVg8iMWghQpO3BWms/dSwsIM70WgaKZlAfM2MP0Ky5XqqK7Fgu+pZ8LCj27jCCE +I0vJVlcHcRe7KlsdYNQ1IBm+oyj6BNlkGQaS2bI= From: Masami Hiramatsu To: Ingo Molnar Cc: Josh Poimboeuf , Andrew Cooper , Peter Zijlstra , Randy Dunlap , Borislav Petkov , Juergen Gross , Boris Ostrovsky , Stefano Stabellini , x86@kernel.org, linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org Subject: [PATCH -tip v4 3/4] x86: xen: insn: Decode Xen and KVM emulate-prefix signature Date: Fri, 6 Sep 2019 22:14:10 +0900 Message-Id: <156777564986.25081.4964537658500952557.stgit@devnote2> X-Mailer: git-send-email 2.20.1 In-Reply-To: <156777561745.25081.1205321122446165328.stgit@devnote2> References: <156777561745.25081.1205321122446165328.stgit@devnote2> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Decode Xen and KVM's emulate-prefix signature by x86 insn decoder. It is called "prefix" but actually not x86 instruction prefix, so this adds insn.emulate_prefix_size field instead of reusing insn.prefixes. If x86 decoder finds a special sequence of instructions of XEN_EMULATE_PREFIX and 'ud2a; .ascii "kvm"', it just counts the length, set insn.emulate_prefix_size and fold it with the next instruction. In other words, the signature and the next instruction is treated as a single instruction. Reported-by: Josh Poimboeuf Signed-off-by: Masami Hiramatsu Acked-by: Josh Poimboeuf --- Changes in v4: - Use asm/emulate_prefix.h instead of xen/prefix.h - Fix to add emulate_prefix.h to the checkist of perf. --- arch/x86/include/asm/insn.h | 6 +++++ arch/x86/lib/insn.c | 34 +++++++++++++++++++++++++++ tools/arch/x86/include/asm/emulate_prefix.h | 14 +++++++++++ tools/arch/x86/include/asm/insn.h | 6 +++++ tools/arch/x86/lib/insn.c | 34 +++++++++++++++++++++++++++ tools/objtool/sync-check.sh | 3 ++ tools/perf/check-headers.sh | 3 ++ 7 files changed, 98 insertions(+), 2 deletions(-) create mode 100644 tools/arch/x86/include/asm/emulate_prefix.h diff --git a/arch/x86/include/asm/insn.h b/arch/x86/include/asm/insn.h index 154f27be8bfc..5c1ae3eff9d4 100644 --- a/arch/x86/include/asm/insn.h +++ b/arch/x86/include/asm/insn.h @@ -45,6 +45,7 @@ struct insn { struct insn_field immediate2; /* for 64bit imm or seg16 */ }; + int emulate_prefix_size; insn_attr_t attr; unsigned char opnd_bytes; unsigned char addr_bytes; @@ -128,6 +129,11 @@ static inline int insn_is_evex(struct insn *insn) return (insn->vex_prefix.nbytes == 4); } +static inline int insn_has_emulate_prefix(struct insn *insn) +{ + return !!insn->emulate_prefix_size; +} + /* Ensure this instruction is decoded completely */ static inline int insn_complete(struct insn *insn) { diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c index 0b5862ba6a75..404279563891 100644 --- a/arch/x86/lib/insn.c +++ b/arch/x86/lib/insn.c @@ -13,6 +13,8 @@ #include #include +#include + /* Verify next sizeof(t) bytes can be on the same instruction */ #define validate_next(t, insn, n) \ ((insn)->next_byte + sizeof(t) + n <= (insn)->end_kaddr) @@ -58,6 +60,36 @@ void insn_init(struct insn *insn, const void *kaddr, int buf_len, int x86_64) insn->addr_bytes = 4; } +static const insn_byte_t xen_prefix[] = { __XEN_EMULATE_PREFIX }; +static const insn_byte_t kvm_prefix[] = { __KVM_EMULATE_PREFIX }; + +static int __insn_get_emulate_prefix(struct insn *insn, + const insn_byte_t *prefix, size_t len) +{ + size_t i; + + for (i = 0; i < len; i++) { + if (peek_nbyte_next(insn_byte_t, insn, i) != prefix[i]) + goto err_out; + } + + insn->emulate_prefix_size = len; + insn->next_byte += len; + + return 1; + +err_out: + return 0; +} + +static void insn_get_emulate_prefix(struct insn *insn) +{ + if (__insn_get_emulate_prefix(insn, xen_prefix, sizeof(xen_prefix))) + return; + + __insn_get_emulate_prefix(insn, kvm_prefix, sizeof(kvm_prefix)); +} + /** * insn_get_prefixes - scan x86 instruction prefix bytes * @insn: &struct insn containing instruction @@ -76,6 +108,8 @@ void insn_get_prefixes(struct insn *insn) if (prefixes->got) return; + insn_get_emulate_prefix(insn); + nb = 0; lb = 0; b = peek_next(insn_byte_t, insn); diff --git a/tools/arch/x86/include/asm/emulate_prefix.h b/tools/arch/x86/include/asm/emulate_prefix.h new file mode 100644 index 000000000000..70f5b98a5286 --- /dev/null +++ b/tools/arch/x86/include/asm/emulate_prefix.h @@ -0,0 +1,14 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_X86_EMULATE_PREFIX_H +#define _ASM_X86_EMULATE_PREFIX_H + +/* + * Virt escape sequences to trigger instruction emulation; + * ideally these would decode to 'whole' instruction and not destroy + * the instruction stream; sadly this is not true for the 'kvm' one :/ + */ + +#define __XEN_EMULATE_PREFIX 0x0f,0x0b,0x78,0x65,0x6e /* ud2 ; .ascii "xen" */ +#define __KVM_EMULATE_PREFIX 0x0f,0x0b,0x6b,0x76,0x6d /* ud2 ; .ascii "kvm" */ + +#endif diff --git a/tools/arch/x86/include/asm/insn.h b/tools/arch/x86/include/asm/insn.h index 37a4c390750b..568854b14d0a 100644 --- a/tools/arch/x86/include/asm/insn.h +++ b/tools/arch/x86/include/asm/insn.h @@ -45,6 +45,7 @@ struct insn { struct insn_field immediate2; /* for 64bit imm or seg16 */ }; + int emulate_prefix_size; insn_attr_t attr; unsigned char opnd_bytes; unsigned char addr_bytes; @@ -128,6 +129,11 @@ static inline int insn_is_evex(struct insn *insn) return (insn->vex_prefix.nbytes == 4); } +static inline int insn_has_emulate_prefix(struct insn *insn) +{ + return !!insn->emulate_prefix_size; +} + /* Ensure this instruction is decoded completely */ static inline int insn_complete(struct insn *insn) { diff --git a/tools/arch/x86/lib/insn.c b/tools/arch/x86/lib/insn.c index 79e048f1d902..0151dfc6da61 100644 --- a/tools/arch/x86/lib/insn.c +++ b/tools/arch/x86/lib/insn.c @@ -13,6 +13,8 @@ #include "../include/asm/inat.h" #include "../include/asm/insn.h" +#include "../include/asm/emulate_prefix.h" + /* Verify next sizeof(t) bytes can be on the same instruction */ #define validate_next(t, insn, n) \ ((insn)->next_byte + sizeof(t) + n <= (insn)->end_kaddr) @@ -58,6 +60,36 @@ void insn_init(struct insn *insn, const void *kaddr, int buf_len, int x86_64) insn->addr_bytes = 4; } +static const insn_byte_t xen_prefix[] = { __XEN_EMULATE_PREFIX }; +static const insn_byte_t kvm_prefix[] = { __KVM_EMULATE_PREFIX }; + +static int __insn_get_emulate_prefix(struct insn *insn, + const insn_byte_t *prefix, size_t len) +{ + size_t i; + + for (i = 0; i < len; i++) { + if (peek_nbyte_next(insn_byte_t, insn, i) != prefix[i]) + goto err_out; + } + + insn->emulate_prefix_size = len; + insn->next_byte += len; + + return 1; + +err_out: + return 0; +} + +static void insn_get_emulate_prefix(struct insn *insn) +{ + if (__insn_get_emulate_prefix(insn, xen_prefix, sizeof(xen_prefix))) + return; + + __insn_get_emulate_prefix(insn, kvm_prefix, sizeof(kvm_prefix)); +} + /** * insn_get_prefixes - scan x86 instruction prefix bytes * @insn: &struct insn containing instruction @@ -76,6 +108,8 @@ void insn_get_prefixes(struct insn *insn) if (prefixes->got) return; + insn_get_emulate_prefix(insn); + nb = 0; lb = 0; b = peek_next(insn_byte_t, insn); diff --git a/tools/objtool/sync-check.sh b/tools/objtool/sync-check.sh index 0a832e265a50..9bd04bbed01e 100755 --- a/tools/objtool/sync-check.sh +++ b/tools/objtool/sync-check.sh @@ -4,6 +4,7 @@ FILES=' arch/x86/include/asm/inat_types.h arch/x86/include/asm/orc_types.h +arch/x86/include/asm/emulate_prefix.h arch/x86/lib/x86-opcode-map.txt arch/x86/tools/gen-insn-attr-x86.awk ' @@ -46,6 +47,6 @@ done check arch/x86/include/asm/inat.h '-I "^#include [\"<]\(asm/\)*inat_types.h[\">]"' check arch/x86/include/asm/insn.h '-I "^#include [\"<]\(asm/\)*inat.h[\">]"' check arch/x86/lib/inat.c '-I "^#include [\"<]\(../include/\)*asm/insn.h[\">]"' -check arch/x86/lib/insn.c '-I "^#include [\"<]\(../include/\)*asm/in\(at\|sn\).h[\">]"' +check arch/x86/lib/insn.c '-I "^#include [\"<]\(../include/\)*asm/in\(at\|sn\).h[\">]" -I "^#include [\"<]\(../include/\)*asm/emulate_prefix.h[\">]"' cd - diff --git a/tools/perf/check-headers.sh b/tools/perf/check-headers.sh index e2e0f06c97d0..988b1879ec98 100755 --- a/tools/perf/check-headers.sh +++ b/tools/perf/check-headers.sh @@ -27,6 +27,7 @@ arch/x86/include/asm/disabled-features.h arch/x86/include/asm/required-features.h arch/x86/include/asm/cpufeatures.h arch/x86/include/asm/inat_types.h +arch/x86/include/asm/emulate_prefix.h arch/x86/include/uapi/asm/prctl.h arch/x86/lib/x86-opcode-map.txt arch/x86/tools/gen-insn-attr-x86.awk @@ -115,7 +116,7 @@ check lib/ctype.c '-I "^EXPORT_SYMBOL" -I "^#include " -B check arch/x86/include/asm/inat.h '-I "^#include [\"<]\(asm/\)*inat_types.h[\">]"' check arch/x86/include/asm/insn.h '-I "^#include [\"<]\(asm/\)*inat.h[\">]"' check arch/x86/lib/inat.c '-I "^#include [\"<]\(../include/\)*asm/insn.h[\">]"' -check arch/x86/lib/insn.c '-I "^#include [\"<]\(../include/\)*asm/in\(at\|sn\).h[\">]"' +check arch/x86/lib/insn.c '-I "^#include [\"<]\(../include/\)*asm/in\(at\|sn\).h[\">]" -I "^#include [\"<]\(../include/\)*asm/emulate_prefix.h[\">]"' # diff non-symmetric files check_2 tools/perf/arch/x86/entry/syscalls/syscall_64.tbl arch/x86/entry/syscalls/syscall_64.tbl