From patchwork Fri May 13 14:23:36 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 12848903 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 C9F96C433F5 for ; Fri, 13 May 2022 14:26:45 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.328488.551510 (Exim 4.92) (envelope-from ) id 1npWFR-0004sp-RM; Fri, 13 May 2022 14:26:29 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 328488.551510; Fri, 13 May 2022 14:26:29 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1npWFR-0004si-Og; Fri, 13 May 2022 14:26:29 +0000 Received: by outflank-mailman (input) for mailman id 328488; Fri, 13 May 2022 14:26:29 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1npWFQ-0004sc-UP for xen-devel@lists.xenproject.org; Fri, 13 May 2022 14:26:28 +0000 Received: from dfw.source.kernel.org (dfw.source.kernel.org [2604:1380:4641:c500::1]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id abf708a6-d2c8-11ec-b8b8-f95467ff1ed0; Fri, 13 May 2022 16:26:27 +0200 (CEST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B51AE62154; Fri, 13 May 2022 14:26:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E49D0C34115; Fri, 13 May 2022 14:26:24 +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 Precedence: list Sender: "Xen-devel" X-Inumbo-ID: abf708a6-d2c8-11ec-b8b8-f95467ff1ed0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1652451985; bh=LAW3oRY7WSoDZ6V/paLZpl/L6DCV49O7Hv7830ybxPM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GXyDhOiiJRccrS99PCIsAaKHP9Sfl/W3GtF8OHGZsFeNJgYw2vkdj9lmReCuZSkNW 25YoqfN66gr42evUIl7QNmeNuCH8IypHBLMZpk/+Qzxuxtc4VAsZSMj+3y3daylWvL POShwnNedeIhzgznHSIRDIqrnyaAvDkMlZKy4y9k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Masami Hiramatsu , "Peter Zijlstra (Intel)" , Juergen Gross , x86@kernel.org, Boris Ostrovsky , Ingo Molnar , Stefano Stabellini , Andrew Cooper , Borislav Petkov , xen-devel@lists.xenproject.org, Randy Dunlap , Josh Poimboeuf , Maximilian Heyne Subject: [PATCH 5.4 10/18] x86/asm: Allow to pass macros to __ASM_FORM() Date: Fri, 13 May 2022 16:23:36 +0200 Message-Id: <20220513142229.456082257@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220513142229.153291230@linuxfoundation.org> References: <20220513142229.153291230@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 From: Masami Hiramatsu commit f7919fd943abf0c77aed4441ea9897a323d132f5 upstream. Use __stringify() at __ASM_FORM() so that user can pass code including macros to __ASM_FORM(). Signed-off-by: Masami Hiramatsu Signed-off-by: Peter Zijlstra (Intel) 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 Cc: Josh Poimboeuf Link: https://lkml.kernel.org/r/156777562873.25081.2288083344657460959.stgit@devnote2 Signed-off-by: Maximilian Heyne Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/asm.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/arch/x86/include/asm/asm.h +++ b/arch/x86/include/asm/asm.h @@ -7,9 +7,11 @@ # define __ASM_FORM_RAW(x) x # define __ASM_FORM_COMMA(x) x, #else -# define __ASM_FORM(x) " " #x " " -# define __ASM_FORM_RAW(x) #x -# define __ASM_FORM_COMMA(x) " " #x "," +#include + +# define __ASM_FORM(x) " " __stringify(x) " " +# define __ASM_FORM_RAW(x) __stringify(x) +# define __ASM_FORM_COMMA(x) " " __stringify(x) "," #endif #ifndef __x86_64__ From patchwork Fri May 13 14:23:37 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 12848904 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 E88DAC433FE for ; Fri, 13 May 2022 14:26:45 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.328489.551521 (Exim 4.92) (envelope-from ) id 1npWFU-00058R-56; Fri, 13 May 2022 14:26:32 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 328489.551521; Fri, 13 May 2022 14:26:32 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1npWFU-00058I-17; Fri, 13 May 2022 14:26:32 +0000 Received: by outflank-mailman (input) for mailman id 328489; Fri, 13 May 2022 14:26:31 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1npWFS-0004sc-UI for xen-devel@lists.xenproject.org; Fri, 13 May 2022 14:26:31 +0000 Received: from dfw.source.kernel.org (dfw.source.kernel.org [2604:1380:4641:c500::1]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id adbd4c15-d2c8-11ec-b8b8-f95467ff1ed0; Fri, 13 May 2022 16:26:29 +0200 (CEST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id DF5BB62155; Fri, 13 May 2022 14:26:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0B8DAC36AEC; Fri, 13 May 2022 14:26:28 +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 Precedence: list Sender: "Xen-devel" X-Inumbo-ID: adbd4c15-d2c8-11ec-b8b8-f95467ff1ed0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1652451988; bh=85U1WWVkHeMQrJWMsxOyN59skP9tpj5MeWFM5A12uXE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Z69z3oDXPD21rNW9i5pU2xdBQSPQGAePhxjHL1MhlizvNubIkg2KtoA/5NPLc35nb WRkITwqgnicSG/5sBtZg7Vm2LyEr3KCNf86g+8MC7GZbp5HhpQMlVmZixtDqTet+1D sspSucBEntU5Btet39kQCTflWgfYlUUZ4zmPy+Vg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Peter Zijlstra , Masami Hiramatsu , Juergen Gross , x86@kernel.org, Ingo Molnar , Boris Ostrovsky , Andrew Cooper , Stefano Stabellini , Borislav Petkov , xen-devel@lists.xenproject.org, Randy Dunlap , Josh Poimboeuf , Maximilian Heyne Subject: [PATCH 5.4 11/18] x86: xen: kvm: Gather the definition of emulate prefixes Date: Fri, 13 May 2022 16:23:37 +0200 Message-Id: <20220513142229.483992618@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220513142229.153291230@linuxfoundation.org> References: <20220513142229.153291230@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 From: Masami Hiramatsu commit b3dc0695fa40c3b280230fb6fb7fb7a94ce28bf4 upstream. Gather the emulate prefixes, which forcibly make the following instruction emulated on virtualization, in one place. Suggested-by: Peter Zijlstra Signed-off-by: Masami Hiramatsu Signed-off-by: Peter Zijlstra (Intel) Cc: Juergen Gross Cc: x86@kernel.org Cc: Ingo Molnar Cc: Boris Ostrovsky Cc: Andrew Cooper Cc: Stefano Stabellini Cc: Borislav Petkov Cc: xen-devel@lists.xenproject.org Cc: Randy Dunlap Cc: Josh Poimboeuf Link: https://lkml.kernel.org/r/156777563917.25081.7286628561790289995.stgit@devnote2 Signed-off-by: Maximilian Heyne Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/emulate_prefix.h | 14 ++++++++++++++ arch/x86/include/asm/xen/interface.h | 11 ++++------- arch/x86/kvm/x86.c | 4 +++- 3 files changed, 21 insertions(+), 8 deletions(-) create mode 100644 arch/x86/include/asm/emulate_prefix.h --- /dev/null +++ b/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 --- a/arch/x86/include/asm/xen/interface.h +++ b/arch/x86/include/asm/xen/interface.h @@ -379,12 +379,9 @@ struct xen_pmu_arch { * Prefix forces emulation of some non-trapping instructions. * Currently only CPUID. */ -#ifdef __ASSEMBLY__ -#define XEN_EMULATE_PREFIX .byte 0x0f,0x0b,0x78,0x65,0x6e ; -#define XEN_CPUID XEN_EMULATE_PREFIX cpuid -#else -#define XEN_EMULATE_PREFIX ".byte 0x0f,0x0b,0x78,0x65,0x6e ; " -#define XEN_CPUID XEN_EMULATE_PREFIX "cpuid" -#endif +#include + +#define XEN_EMULATE_PREFIX __ASM_FORM(.byte __XEN_EMULATE_PREFIX ;) +#define XEN_CPUID XEN_EMULATE_PREFIX __ASM_FORM(cpuid) #endif /* _ASM_X86_XEN_INTERFACE_H */ --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -68,6 +68,7 @@ #include #include #include +#include #include #define CREATE_TRACE_POINTS @@ -5583,6 +5584,7 @@ EXPORT_SYMBOL_GPL(kvm_write_guest_virt_s int handle_ud(struct kvm_vcpu *vcpu) { + static const char kvm_emulate_prefix[] = { __KVM_EMULATE_PREFIX }; int emul_type = EMULTYPE_TRAP_UD; char sig[5]; /* ud2; .ascii "kvm" */ struct x86_exception e; @@ -5590,7 +5592,7 @@ int handle_ud(struct kvm_vcpu *vcpu) if (force_emulation_prefix && kvm_read_guest_virt(vcpu, kvm_get_linear_rip(vcpu), sig, sizeof(sig), &e) == 0 && - memcmp(sig, "\xf\xbkvm", sizeof(sig)) == 0) { + memcmp(sig, kvm_emulate_prefix, sizeof(sig)) == 0) { kvm_rip_write(vcpu, kvm_rip_read(vcpu) + sizeof(sig)); emul_type = EMULTYPE_TRAP_UD_FORCED; } From patchwork Fri May 13 14:23:38 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 12848905 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 3B3A3C4332F for ; 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Fri, 13 May 2022 16:26:33 +0200 (CEST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 370F9B83073; Fri, 13 May 2022 14:26:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 51036C34100; Fri, 13 May 2022 14:26:31 +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 Precedence: list Sender: "Xen-devel" X-Inumbo-ID: afef8fa8-d2c8-11ec-aa76-f101dd46aeb6 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1652451991; bh=0C1cmO61Qt6CWllfe71gI5XVVBFSNf2m2kyZRF4iiWw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=q/gOHPrsmHmQ9IgCarEV10qPdGKt3nqPlxqY04cerC2lHLbfz4DTNT6Q9HT1yYIMI DcEQ9LlYAQYhA4E2pu9IKB4z/SeNVOCI1Wt36jtljXQEYmjpy8qdVCQ2q19vrFziyS dnLt1VwR8GS5DFrWi8aC1pgrkZ1tREdTYCk/k1S8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Masami Hiramatsu , "Peter Zijlstra (Intel)" , Josh Poimboeuf , Juergen Gross , x86@kernel.org, Boris Ostrovsky , Ingo Molnar , Stefano Stabellini , Andrew Cooper , Borislav Petkov , xen-devel@lists.xenproject.org, Randy Dunlap , Maximilian Heyne Subject: [PATCH 5.4 12/18] x86: xen: insn: Decode Xen and KVM emulate-prefix signature Date: Fri, 13 May 2022 16:23:38 +0200 Message-Id: <20220513142229.512910493@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220513142229.153291230@linuxfoundation.org> References: <20220513142229.153291230@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 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 Signed-off-by: Greg Kroah-Hartman --- 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 --- 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 in 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) { --- 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 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); --- /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 --- 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 in 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) { --- 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 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); --- 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[\">]"' --- 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_SY 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 From patchwork Fri May 13 14:23:39 2022 Content-Type: text/plain; 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a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1652451994; bh=arJTKN6Rb4CHGdT1xDXtM3SZJ76Ck5SXwxLc4XVG6h0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Lkj2UAFs1vyUgNw/OznDpD3UdBVqNE8K6RAGjcXiZQCZEK2nLckNHvZ2JSX7w9XQR 2zCCsajBmD87WM3JZKnp+P4hwCHqObdQNspqV1ZZhhbcwPjJchztmAo7B1qVwi83FN 5d/y+2eEEMXvBV1OgINjBSgL470b4SpjEs26yluY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Masami Hiramatsu , "Peter Zijlstra (Intel)" , Juergen Gross , x86@kernel.org, Boris Ostrovsky , Ingo Molnar , Stefano Stabellini , Andrew Cooper , Borislav Petkov , xen-devel@lists.xenproject.org, Randy Dunlap , Josh Poimboeuf , Maximilian Heyne Subject: [PATCH 5.4 13/18] x86: kprobes: Prohibit probing on instruction which has emulate prefix Date: Fri, 13 May 2022 16:23:39 +0200 Message-Id: <20220513142229.541060503@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220513142229.153291230@linuxfoundation.org> References: <20220513142229.153291230@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 From: Masami Hiramatsu commit 004e8dce9c5595697951f7cd0e9f66b35c92265e upstream. Prohibit probing on instruction which has XEN_EMULATE_PREFIX or KVM's emulate prefix. Since that prefix is a marker for Xen and KVM, if we modify the marker by kprobe's int3, that doesn't work as expected. Signed-off-by: Masami Hiramatsu Signed-off-by: Peter Zijlstra (Intel) 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 Cc: Josh Poimboeuf Link: https://lkml.kernel.org/r/156777566048.25081.6296162369492175325.stgit@devnote2 Signed-off-by: Maximilian Heyne Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/kprobes/core.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -358,6 +358,10 @@ int __copy_instruction(u8 *dest, u8 *src kernel_insn_init(insn, dest, MAX_INSN_SIZE); insn_get_length(insn); + /* We can not probe force emulate prefixed instruction */ + if (insn_has_emulate_prefix(insn)) + return 0; + /* Another subsystem puts a breakpoint, failed to recover */ if (insn->opcode.bytes[0] == BREAKPOINT_INSTRUCTION) return 0;