+++ /dev/null
-From 004e8dce9c5595697951f7cd0e9f66b35c92265e Mon Sep 17 00:00:00 2001
-From: Masami Hiramatsu <mhiramat@kernel.org>
-Date: Fri, 6 Sep 2019 22:14:20 +0900
-Subject: x86: kprobes: Prohibit probing on instruction which has emulate prefix
-
-From: Masami Hiramatsu <mhiramat@kernel.org>
-
-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 <mhiramat@kernel.org>
-Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
-Cc: Juergen Gross <jgross@suse.com>
-Cc: x86@kernel.org
-Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
-Cc: Ingo Molnar <mingo@kernel.org>
-Cc: Stefano Stabellini <sstabellini@kernel.org>
-Cc: Andrew Cooper <andrew.cooper3@citrix.com>
-Cc: Borislav Petkov <bp@alien8.de>
-Cc: xen-devel@lists.xenproject.org
-Cc: Randy Dunlap <rdunlap@infradead.org>
-Cc: Josh Poimboeuf <jpoimboe@redhat.com>
-Link: https://lkml.kernel.org/r/156777566048.25081.6296162369492175325.stgit@devnote2
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-
-diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
-index 43fc13c831af..4f13af7cbcdb 100644
---- a/arch/x86/kernel/kprobes/core.c
-+++ b/arch/x86/kernel/kprobes/core.c
-@@ -351,6 +351,10 @@ int __copy_instruction(u8 *dest, u8 *src, u8 *real, struct insn *insn)
- 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;
+++ /dev/null
-From 4d65adfcd1196818659d3bd9b42dccab291e1751 Mon Sep 17 00:00:00 2001
-From: Masami Hiramatsu <mhiramat@kernel.org>
-Date: Fri, 6 Sep 2019 22:14:10 +0900
-Subject: x86: xen: insn: Decode Xen and KVM emulate-prefix signature
-
-From: Masami Hiramatsu <mhiramat@kernel.org>
-
-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 <mhiramat@kernel.org>
-Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
-Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
-Cc: Juergen Gross <jgross@suse.com>
-Cc: x86@kernel.org
-Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
-Cc: Ingo Molnar <mingo@kernel.org>
-Cc: Stefano Stabellini <sstabellini@kernel.org>
-Cc: Andrew Cooper <andrew.cooper3@citrix.com>
-Cc: Borislav Petkov <bp@alien8.de>
-Cc: xen-devel@lists.xenproject.org
-Cc: Randy Dunlap <rdunlap@infradead.org>
-Link: https://lkml.kernel.org/r/156777564986.25081.4964537658500952557.stgit@devnote2
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-
-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 <asm/inat.h>
- #include <asm/insn.h>
-
-+#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/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 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 <linux/export.h>" -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
+++ /dev/null
-From b3dc0695fa40c3b280230fb6fb7fb7a94ce28bf4 Mon Sep 17 00:00:00 2001
-From: Masami Hiramatsu <mhiramat@kernel.org>
-Date: Fri, 6 Sep 2019 22:13:59 +0900
-Subject: x86: xen: kvm: Gather the definition of emulate prefixes
-
-From: Masami Hiramatsu <mhiramat@kernel.org>
-
-commit b3dc0695fa40c3b280230fb6fb7fb7a94ce28bf4 upstream.
-
-Gather the emulate prefixes, which forcibly make the following
-instruction emulated on virtualization, in one place.
-
-Suggested-by: Peter Zijlstra <peterz@infradead.org>
-Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
-Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
-Cc: Juergen Gross <jgross@suse.com>
-Cc: x86@kernel.org
-Cc: Ingo Molnar <mingo@kernel.org>
-Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
-Cc: Andrew Cooper <andrew.cooper3@citrix.com>
-Cc: Stefano Stabellini <sstabellini@kernel.org>
-Cc: Borislav Petkov <bp@alien8.de>
-Cc: xen-devel@lists.xenproject.org
-Cc: Randy Dunlap <rdunlap@infradead.org>
-Cc: Josh Poimboeuf <jpoimboe@redhat.com>
-Link: https://lkml.kernel.org/r/156777563917.25081.7286628561790289995.stgit@devnote2
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-
-diff --git a/arch/x86/include/asm/emulate_prefix.h b/arch/x86/include/asm/emulate_prefix.h
-new file mode 100644
-index 000000000000..70f5b98a5286
---- /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
-diff --git a/arch/x86/include/asm/xen/interface.h b/arch/x86/include/asm/xen/interface.h
-index 62ca03ef5c65..9139b3e86316 100644
---- 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 <asm/emulate_prefix.h>
-+
-+#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 */
-diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
-index 661e2bf38526..777574f547c0 100644
---- a/arch/x86/kvm/x86.c
-+++ b/arch/x86/kvm/x86.c
-@@ -68,6 +68,7 @@
- #include <asm/mshyperv.h>
- #include <asm/hypervisor.h>
- #include <asm/intel_pt.h>
-+#include <asm/emulate_prefix.h>
- #include <clocksource/hyperv_timer.h>
-
- #define CREATE_TRACE_POINTS
-@@ -5446,6 +5447,7 @@ EXPORT_SYMBOL_GPL(kvm_write_guest_virt_system);
-
- 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;
-@@ -5453,7 +5455,7 @@ 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;
- }
projects / thirdparty / kernel / stable-queue.git / commitdiff
