[-tip,1/2] x86: xen: insn: Decode XEN_EMULATE_PREFIX correctly

Message ID	156759755900.24473.5182879905681416105.stgit@devnote2 (mailing list archive)
State	New, archived
Headers	show Return-Path: <SRS0=pR42=W7=lists.xenproject.org=xen-devel-bounces@kernel.org> DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EC6EE22CF7 From: Masami Hiramatsu <mhiramat@kernel.org> To: Ingo Molnar <mingo@kernel.org> Date: Wed, 4 Sep 2019 20:45:59 +0900 Message-Id: <156759755900.24473.5182879905681416105.stgit@devnote2> In-Reply-To: <156759754770.24473.11832897710080799131.stgit@devnote2> References: <156759754770.24473.11832897710080799131.stgit@devnote2> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Subject: [Xen-devel] [PATCH -tip 1/2] x86: xen: insn: Decode XEN_EMULATE_PREFIX correctly Precedence: list Cc: Juergen Gross <jgross@suse.com>, Stefano Stabellini <sstabellini@kernel.org>, Peter Zijlstra <peterz@infradead.org>, Randy Dunlap <rdunlap@infradead.org>, x86@kernel.org, linux-kernel@vger.kernel.org, Borislav Petkov <bp@alien8.de>, Josh Poimboeuf <jpoimboe@redhat.com>, xen-devel@lists.xenproject.org, Boris Ostrovsky <boris.ostrovsky@oracle.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" <xen-devel-bounces@lists.xenproject.org>
Series	[-tip,1/2] x86: xen: insn: Decode XEN_EMULATE_PREFIX correctly \| expand [-tip,1/2] x86: xen: insn: Decode XEN_EMULATE_PREFIX correctly

diff --git a/arch/x86/include/asm/insn.h b/arch/x86/include/asm/insn.h index 154f27be8bfc..ac42efd4295a 100644 --- a/arch/x86/include/asm/insn.h +++ b/arch/x86/include/asm/insn.h @@ -128,6 +128,8 @@ static inline int insn_is_evex(struct insn *insn) return (insn->vex_prefix.nbytes == 4); } +extern int insn_has_xen_prefix(struct insn *insn); + /* Ensure this instruction is decoded completely */ static inline int insn_complete(struct insn *insn) { diff --git a/arch/x86/include/asm/xen/interface.h b/arch/x86/include/asm/xen/interface.h index 62ca03ef5c65..fe33a9798708 100644 --- a/arch/x86/include/asm/xen/interface.h +++ b/arch/x86/include/asm/xen/interface.h @@ -379,12 +379,15 @@ struct xen_pmu_arch { * Prefix forces emulation of some non-trapping instructions. * Currently only CPUID. */ +#include <asm/xen/prefix.h> + #ifdef __ASSEMBLY__ -#define XEN_EMULATE_PREFIX .byte 0x0f,0x0b,0x78,0x65,0x6e ; +#define XEN_EMULATE_PREFIX .byte __XEN_EMULATE_PREFIX ; #define XEN_CPUID XEN_EMULATE_PREFIX cpuid #else -#define XEN_EMULATE_PREFIX ".byte 0x0f,0x0b,0x78,0x65,0x6e ; " +#define XEN_EMULATE_PREFIX ".byte " __XEN_EMULATE_PREFIX_STR " ; " #define XEN_CPUID XEN_EMULATE_PREFIX "cpuid" + #endif #endif /* _ASM_X86_XEN_INTERFACE_H */ diff --git a/arch/x86/include/asm/xen/prefix.h b/arch/x86/include/asm/xen/prefix.h new file mode 100644 index 000000000000..f901be0d7a95 --- /dev/null +++ b/arch/x86/include/asm/xen/prefix.h @@ -0,0 +1,10 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _TOOLS_ASM_X86_XEN_PREFIX_H +#define _TOOLS_ASM_X86_XEN_PREFIX_H + +#include <linux/stringify.h> + +#define __XEN_EMULATE_PREFIX 0x0f,0x0b,0x78,0x65,0x6e +#define __XEN_EMULATE_PREFIX_STR __stringify(__XEN_EMULATE_PREFIX) + +#endif diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c index 0b5862ba6a75..310a609ee382 100644 --- a/arch/x86/lib/insn.c +++ b/arch/x86/lib/insn.c @@ -13,6 +13,9 @@ #include <asm/inat.h> #include <asm/insn.h> +/* For special Xen prefix */ +#include <asm/xen/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 +61,42 @@ 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 int insn_xen_prefix(struct insn *insn, insn_byte_t b) +{ + struct insn_field *prefixes = &insn->prefixes; + size_t i; + + for (i = 0; i < sizeof(xen_prefix); i++) { + b = peek_nbyte_next(insn_byte_t, insn, i); + if (b != xen_prefix[i]) + goto err_out; + } + + memcpy(prefixes->bytes, xen_prefix, 3); + prefixes->bytes[3] = xen_prefix[sizeof(xen_prefix) - 1]; + prefixes->nbytes = sizeof(xen_prefix); + insn->next_byte += prefixes->nbytes; + prefixes->got = 1; + + return 1; + +err_out: + return 0; +} + +int insn_has_xen_prefix(struct insn *insn) +{ + if (unlikely(insn->prefixes.nbytes == sizeof(xen_prefix))) { + return !memcmp(insn->prefixes.bytes, xen_prefix, 3) && + insn->prefixes.bytes[3] == + xen_prefix[sizeof(xen_prefix) - 1]; + } + + return 0; +} + /** * insn_get_prefixes - scan x86 instruction prefix bytes * @insn: &struct insn containing instruction @@ -79,6 +118,10 @@ void insn_get_prefixes(struct insn *insn) nb = 0; lb = 0; b = peek_next(insn_byte_t, insn); + + if (insn_xen_prefix(insn, b)) + return; + attr = inat_get_opcode_attribute(b); while (inat_is_legacy_prefix(attr)) { /* Skip if same prefix */ diff --git a/tools/arch/x86/include/asm/insn.h b/tools/arch/x86/include/asm/insn.h index 37a4c390750b..1c723fb5c6ee 100644 --- a/tools/arch/x86/include/asm/insn.h +++ b/tools/arch/x86/include/asm/insn.h @@ -128,6 +128,8 @@ static inline int insn_is_evex(struct insn *insn) return (insn->vex_prefix.nbytes == 4); } +extern int insn_has_xen_prefix(struct insn *insn); + /* Ensure this instruction is decoded completely */ static inline int insn_complete(struct insn *insn) { diff --git a/tools/arch/x86/include/asm/xen/prefix.h b/tools/arch/x86/include/asm/xen/prefix.h new file mode 100644 index 000000000000..f901be0d7a95 --- /dev/null +++ b/tools/arch/x86/include/asm/xen/prefix.h @@ -0,0 +1,10 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _TOOLS_ASM_X86_XEN_PREFIX_H +#define _TOOLS_ASM_X86_XEN_PREFIX_H + +#include <linux/stringify.h> + +#define __XEN_EMULATE_PREFIX 0x0f,0x0b,0x78,0x65,0x6e +#define __XEN_EMULATE_PREFIX_STR __stringify(__XEN_EMULATE_PREFIX) + +#endif diff --git a/tools/arch/x86/lib/insn.c b/tools/arch/x86/lib/insn.c index 79e048f1d902..b34cd1cefb1c 100644 --- a/tools/arch/x86/lib/insn.c +++ b/tools/arch/x86/lib/insn.c @@ -13,6 +13,9 @@ #include "../include/asm/inat.h" #include "../include/asm/insn.h" +/* For special Xen prefix */ +#include "../include/asm/xen/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 +61,42 @@ 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 int insn_xen_prefix(struct insn *insn, insn_byte_t b) +{ + struct insn_field *prefixes = &insn->prefixes; + size_t i; + + for (i = 0; i < sizeof(xen_prefix); i++) { + b = peek_nbyte_next(insn_byte_t, insn, i); + if (b != xen_prefix[i]) + goto err_out; + } + + memcpy(prefixes->bytes, xen_prefix, 3); + prefixes->bytes[3] = xen_prefix[sizeof(xen_prefix) - 1]; + prefixes->nbytes = sizeof(xen_prefix); + insn->next_byte += prefixes->nbytes; + prefixes->got = 1; + + return 1; + +err_out: + return 0; +} + +int insn_has_xen_prefix(struct insn *insn) +{ + if (unlikely(insn->prefixes.nbytes == sizeof(xen_prefix))) { + return !memcmp(insn->prefixes.bytes, xen_prefix, 3) && + insn->prefixes.bytes[3] == + xen_prefix[sizeof(xen_prefix) - 1]; + } + + return 0; +} + /** * insn_get_prefixes - scan x86 instruction prefix bytes * @insn: &struct insn containing instruction @@ -79,6 +118,10 @@ void insn_get_prefixes(struct insn *insn) nb = 0; lb = 0; b = peek_next(insn_byte_t, insn); + + if (insn_xen_prefix(insn, b)) + return; + attr = inat_get_opcode_attribute(b); while (inat_is_legacy_prefix(attr)) { /* Skip if same prefix */ diff --git a/tools/objtool/sync-check.sh b/tools/objtool/sync-check.sh index 0a832e265a50..34143ea3d477 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/xen/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/xen/prefix.h[\">]"' cd -

[-tip,1/2] x86: xen: insn: Decode XEN_EMULATE_PREFIX correctly

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