From patchwork Tue May 10 13:30:32 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maximilian Heyne X-Patchwork-Id: 12845058 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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C46C6C4332F for ; Tue, 10 May 2022 13:31:52 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.325621.548272 (Exim 4.92) (envelope-from ) id 1noPxj-0007Qv-In; Tue, 10 May 2022 13:31:39 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 325621.548272; Tue, 10 May 2022 13:31:39 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1noPxj-0007Qo-Ft; Tue, 10 May 2022 13:31:39 +0000 Received: by outflank-mailman (input) for mailman id 325621; Tue, 10 May 2022 13:31:38 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1noPxh-0007QY-FZ for xen-devel@lists.xenproject.org; Tue, 10 May 2022 13:31:38 +0000 Received: from smtp-fw-33001.amazon.com (smtp-fw-33001.amazon.com [207.171.190.10]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id 828044c9-d065-11ec-a406-831a346695d4; Tue, 10 May 2022 15:31:35 +0200 (CEST) Received: from iad12-co-svc-p1-lb1-vlan2.amazon.com (HELO email-inbound-relay-pdx-2a-11a39b7d.us-west-2.amazon.com) ([10.43.8.2]) by smtp-border-fw-33001.sea14.amazon.com with ESMTP; 10 May 2022 13:31:23 +0000 Received: from EX13D08EUC001.ant.amazon.com (pdx1-ws-svc-p6-lb9-vlan3.pdx.amazon.com [10.236.137.198]) by email-inbound-relay-pdx-2a-11a39b7d.us-west-2.amazon.com (Postfix) with ESMTPS id A4BD64191A; Tue, 10 May 2022 13:31:13 +0000 (UTC) Received: from EX13MTAUEE002.ant.amazon.com (10.43.62.24) by EX13D08EUC001.ant.amazon.com (10.43.164.184) with Microsoft SMTP Server (TLS) id 15.0.1497.32; Tue, 10 May 2022 13:31:12 +0000 Received: from dev-dsk-mheyne-1b-c1524648.eu-west-1.amazon.com (10.15.60.66) by mail-relay.amazon.com (10.43.62.224) with Microsoft SMTP Server id 15.0.1497.32 via Frontend Transport; Tue, 10 May 2022 13:31:10 +0000 Received: by dev-dsk-mheyne-1b-c1524648.eu-west-1.amazon.com (Postfix, from userid 5466572) id 0CF9541131; Tue, 10 May 2022 13:31:11 +0000 (UTC) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" X-Inumbo-ID: 828044c9-d065-11ec-a406-831a346695d4 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.de; i=@amazon.de; q=dns/txt; s=amazon201209; t=1652189496; x=1683725496; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=LcBCa7IjI6XtJDgdMuUyaVbxzp9zN8ViQS6A7OjaIjg=; b=XVbCC6R09i0BcE7YycOoM5NfMItVr3FjxqS4fys/6IIvDIVVq7DWuLPq UAyy9jW17iGMlJczcOkjMA15kBd7T7R6ZHqbseqAX+XmUdx4d2yBn+Eb+ e5m8Fq1+sXNqEA7T5M+/ORlv2SU8mhqGkg6k9LVfChjC9VWAm0sWbPFEl 4=; X-IronPort-AV: E=Sophos;i="5.91,214,1647302400"; d="scan'208";a="193949666" From: Maximilian Heyne To: CC: Masami Hiramatsu , Peter Zijlstra , Josh Poimboeuf , Juergen Gross , , Boris Ostrovsky , Ingo Molnar , Stefano Stabellini , Andrew Cooper , Borislav Petkov , , Randy Dunlap , Maximilian Heyne , , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Sasha Levin , , Subject: [PATCH 3/4] x86: xen: insn: Decode Xen and KVM emulate-prefix signature Date: Tue, 10 May 2022 13:30:32 +0000 Message-ID: <20220510133036.46767-4-mheyne@amazon.de> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220510133036.46767-1-mheyne@amazon.de> References: <20220510133036.46767-1-mheyne@amazon.de> MIME-Version: 1.0 Precedence: Bulk From: Masami Hiramatsu commit 4d65adfcd1196818659d3bd9b42dccab291e1751 upstream 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. Signed-off-by: Masami Hiramatsu Signed-off-by: Peter Zijlstra (Intel) Acked-by: Josh Poimboeuf Cc: Juergen Gross Cc: x86@kernel.org Cc: Boris Ostrovsky Cc: Ingo Molnar Cc: Stefano Stabellini Cc: Andrew Cooper Cc: Borislav Petkov Cc: xen-devel@lists.xenproject.org Cc: Randy Dunlap Link: https://lkml.kernel.org/r/156777564986.25081.4964537658500952557.stgit@devnote2 [mheyne: resolved contextual conflict in tools/objtools/sync-check.sh] Signed-off-by: Maximilian Heyne Cc: stable@vger.kernel.org # 5.4.x --- 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 a51ffeea6d87..a8c3d284fa46 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 d7f0ae8f3c44..52c6262e6bfd 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 c3ae1e8ae119..2a1261bfbb62 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 ' @@ -46,4 +47,4 @@ 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[\">]"' diff --git a/tools/perf/check-headers.sh b/tools/perf/check-headers.sh index cea13cb987d0..499235a41162 100755 --- a/tools/perf/check-headers.sh +++ b/tools/perf/check-headers.sh @@ -28,6 +28,7 @@ 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 @@ -116,7 +117,7 @@ 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