From: Fenghua Yu <fenghua.yu@intel.com> To: "Thomas Gleixner" <tglx@linutronix.de>, "Ingo Molnar" <mingo@redhat.com>, "Borislav Petkov" <bp@alien8.de>, "Peter Zijlstra" <peterz@infradead.org>, "Andy Lutomirski" <luto@kernel.org>, "Dave Hansen" <dave.hansen@intel.com>, "Tony Luck" <tony.luck@intel.com>, "Lu Baolu" <baolu.lu@linux.intel.com>, "Joerg Roedel" <joro@8bytes.org>, Josh Poimboeuf <jpoimboe@redhat.com>, "Dave Jiang" <dave.jiang@intel.com>, "Jacob Jun Pan" <jacob.jun.pan@intel.com>, "Ashok Raj" <ashok.raj@intel.com>, "Ravi V Shankar" <ravi.v.shankar@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com>, iommu@lists.linux-foundation.org, x86 <x86@kernel.org>, linux-kernel <linux-kernel@vger.kernel.org> Subject: [PATCH 7/8] tools/objtool: Check for use of the ENQCMD instruction in the kernel Date: Mon, 20 Sep 2021 19:23:48 +0000 [thread overview] Message-ID: <20210920192349.2602141-8-fenghua.yu@intel.com> (raw) In-Reply-To: <20210920192349.2602141-1-fenghua.yu@intel.com> The ENQCMD implicitly accesses the PASID_MSR to fill in the pasid field of the descriptor being submitted to an accelerator. But there is no precise (and stable across kernel changes) point at which the PASID_MSR is updated from the value for one task to the next. Kernel code that uses accelerators must always use the ENQCMDS instruction which does not access the PASID_MSR. Check for use of the ENQCMD instruction in the kernel and warn on its usage. Checking the invalid instruction is a relatively new use of objtool and I'm open to feedback about the approach. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Reviewed-by: Tony Luck <tony.luck@intel.com> --- tools/objtool/arch/x86/decode.c | 10 +++++++++- tools/objtool/check.c | 20 ++++++++++++++++++++ tools/objtool/include/objtool/arch.h | 1 + 3 files changed, 30 insertions(+), 1 deletion(-) diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c index bc821056aba9..e63b44ba3bd4 100644 --- a/tools/objtool/arch/x86/decode.c +++ b/tools/objtool/arch/x86/decode.c @@ -110,7 +110,7 @@ int arch_decode_instruction(const struct elf *elf, const struct section *sec, { struct insn insn; int x86_64, ret; - unsigned char op1, op2, + unsigned char op1, op2, op3, rex = 0, rex_b = 0, rex_r = 0, rex_w = 0, rex_x = 0, modrm = 0, modrm_mod = 0, modrm_rm = 0, modrm_reg = 0, sib = 0, /* sib_scale = 0, */ sib_index = 0, sib_base = 0; @@ -137,6 +137,7 @@ int arch_decode_instruction(const struct elf *elf, const struct section *sec, op1 = insn.opcode.bytes[0]; op2 = insn.opcode.bytes[1]; + op3 = insn.opcode.bytes[2]; if (insn.rex_prefix.nbytes) { rex = insn.rex_prefix.bytes[0]; @@ -489,6 +490,13 @@ int arch_decode_instruction(const struct elf *elf, const struct section *sec, /* nopl/nopw */ *type = INSN_NOP; + } else if (op2 == 0x38 && op3 == 0xf8) { + if (insn.prefixes.nbytes == 1 && + insn.prefixes.bytes[0] == 0xf2) { + /* enqcmd */ + *type = INSN_ENQCMD; + } + } else if (op2 == 0xa0 || op2 == 0xa8) { /* push fs/gs */ diff --git a/tools/objtool/check.c b/tools/objtool/check.c index e5947fbb9e7a..91d13521d9d6 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -3133,6 +3133,21 @@ static int validate_reachable_instructions(struct objtool_file *file) return 0; } +static int validate_enqcmd(struct objtool_file *file) +{ + struct instruction *insn; + + for_each_insn(file, insn) { + if (insn->type == INSN_ENQCMD) { + WARN_FUNC("enqcmd instruction", insn->sec, + insn->offset); + return 1; + } + } + + return 0; +} + int check(struct objtool_file *file) { int ret, warnings = 0; @@ -3147,6 +3162,11 @@ int check(struct objtool_file *file) if (list_empty(&file->insn_list)) goto out; + ret = validate_enqcmd(file); + if (ret < 0) + goto out; + warnings += ret; + if (vmlinux && !validate_dup) { ret = validate_vmlinux_functions(file); if (ret < 0) diff --git a/tools/objtool/include/objtool/arch.h b/tools/objtool/include/objtool/arch.h index 062bb6e9b865..5147c0762b49 100644 --- a/tools/objtool/include/objtool/arch.h +++ b/tools/objtool/include/objtool/arch.h @@ -26,6 +26,7 @@ enum insn_type { INSN_CLAC, INSN_STD, INSN_CLD, + INSN_ENQCMD, INSN_OTHER, }; -- 2.33.0 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
WARNING: multiple messages have this Message-ID (diff)
From: Fenghua Yu <fenghua.yu@intel.com> To: "Thomas Gleixner" <tglx@linutronix.de>, "Ingo Molnar" <mingo@redhat.com>, "Borislav Petkov" <bp@alien8.de>, "Peter Zijlstra" <peterz@infradead.org>, "Andy Lutomirski" <luto@kernel.org>, "Dave Hansen" <dave.hansen@intel.com>, "Tony Luck" <tony.luck@intel.com>, "Lu Baolu" <baolu.lu@linux.intel.com>, "Joerg Roedel" <joro@8bytes.org>, Josh Poimboeuf <jpoimboe@redhat.com>, "Dave Jiang" <dave.jiang@intel.com>, "Jacob Jun Pan" <jacob.jun.pan@intel.com>, "Ashok Raj" <ashok.raj@intel.com>, "Ravi V Shankar" <ravi.v.shankar@intel.com> Cc: iommu@lists.linux-foundation.org, "x86" <x86@kernel.org>, "linux-kernel" <linux-kernel@vger.kernel.org>, Fenghua Yu <fenghua.yu@intel.com> Subject: [PATCH 7/8] tools/objtool: Check for use of the ENQCMD instruction in the kernel Date: Mon, 20 Sep 2021 19:23:48 +0000 [thread overview] Message-ID: <20210920192349.2602141-8-fenghua.yu@intel.com> (raw) In-Reply-To: <20210920192349.2602141-1-fenghua.yu@intel.com> The ENQCMD implicitly accesses the PASID_MSR to fill in the pasid field of the descriptor being submitted to an accelerator. But there is no precise (and stable across kernel changes) point at which the PASID_MSR is updated from the value for one task to the next. Kernel code that uses accelerators must always use the ENQCMDS instruction which does not access the PASID_MSR. Check for use of the ENQCMD instruction in the kernel and warn on its usage. Checking the invalid instruction is a relatively new use of objtool and I'm open to feedback about the approach. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Reviewed-by: Tony Luck <tony.luck@intel.com> --- tools/objtool/arch/x86/decode.c | 10 +++++++++- tools/objtool/check.c | 20 ++++++++++++++++++++ tools/objtool/include/objtool/arch.h | 1 + 3 files changed, 30 insertions(+), 1 deletion(-) diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c index bc821056aba9..e63b44ba3bd4 100644 --- a/tools/objtool/arch/x86/decode.c +++ b/tools/objtool/arch/x86/decode.c @@ -110,7 +110,7 @@ int arch_decode_instruction(const struct elf *elf, const struct section *sec, { struct insn insn; int x86_64, ret; - unsigned char op1, op2, + unsigned char op1, op2, op3, rex = 0, rex_b = 0, rex_r = 0, rex_w = 0, rex_x = 0, modrm = 0, modrm_mod = 0, modrm_rm = 0, modrm_reg = 0, sib = 0, /* sib_scale = 0, */ sib_index = 0, sib_base = 0; @@ -137,6 +137,7 @@ int arch_decode_instruction(const struct elf *elf, const struct section *sec, op1 = insn.opcode.bytes[0]; op2 = insn.opcode.bytes[1]; + op3 = insn.opcode.bytes[2]; if (insn.rex_prefix.nbytes) { rex = insn.rex_prefix.bytes[0]; @@ -489,6 +490,13 @@ int arch_decode_instruction(const struct elf *elf, const struct section *sec, /* nopl/nopw */ *type = INSN_NOP; + } else if (op2 == 0x38 && op3 == 0xf8) { + if (insn.prefixes.nbytes == 1 && + insn.prefixes.bytes[0] == 0xf2) { + /* enqcmd */ + *type = INSN_ENQCMD; + } + } else if (op2 == 0xa0 || op2 == 0xa8) { /* push fs/gs */ diff --git a/tools/objtool/check.c b/tools/objtool/check.c index e5947fbb9e7a..91d13521d9d6 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -3133,6 +3133,21 @@ static int validate_reachable_instructions(struct objtool_file *file) return 0; } +static int validate_enqcmd(struct objtool_file *file) +{ + struct instruction *insn; + + for_each_insn(file, insn) { + if (insn->type == INSN_ENQCMD) { + WARN_FUNC("enqcmd instruction", insn->sec, + insn->offset); + return 1; + } + } + + return 0; +} + int check(struct objtool_file *file) { int ret, warnings = 0; @@ -3147,6 +3162,11 @@ int check(struct objtool_file *file) if (list_empty(&file->insn_list)) goto out; + ret = validate_enqcmd(file); + if (ret < 0) + goto out; + warnings += ret; + if (vmlinux && !validate_dup) { ret = validate_vmlinux_functions(file); if (ret < 0) diff --git a/tools/objtool/include/objtool/arch.h b/tools/objtool/include/objtool/arch.h index 062bb6e9b865..5147c0762b49 100644 --- a/tools/objtool/include/objtool/arch.h +++ b/tools/objtool/include/objtool/arch.h @@ -26,6 +26,7 @@ enum insn_type { INSN_CLAC, INSN_STD, INSN_CLD, + INSN_ENQCMD, INSN_OTHER, }; -- 2.33.0
next prev parent reply other threads:[~2021-09-20 20:02 UTC|newest] Thread overview: 154+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-09-20 19:23 [PATCH 0/8] Re-enable ENQCMD and PASID MSR Fenghua Yu 2021-09-20 19:23 ` Fenghua Yu 2021-09-20 19:23 ` [PATCH 1/8] iommu/vt-d: Clean up unused PASID updating functions Fenghua Yu 2021-09-20 19:23 ` Fenghua Yu 2021-09-29 7:34 ` Lu Baolu 2021-09-29 7:34 ` Lu Baolu 2021-09-30 0:40 ` Fenghua Yu 2021-09-30 0:40 ` Fenghua Yu 2021-09-20 19:23 ` [PATCH 2/8] x86/process: Clear PASID state for a newly forked/cloned thread Fenghua Yu 2021-09-20 19:23 ` Fenghua Yu 2021-09-20 19:23 ` [PATCH 3/8] sched: Define and initialize a flag to identify valid PASID in the task Fenghua Yu 2021-09-20 19:23 ` Fenghua Yu 2021-09-20 19:23 ` [PATCH 4/8] x86/traps: Demand-populate PASID MSR via #GP Fenghua Yu 2021-09-20 19:23 ` Fenghua Yu 2021-09-22 21:07 ` Peter Zijlstra 2021-09-22 21:07 ` Peter Zijlstra 2021-09-22 21:11 ` Peter Zijlstra 2021-09-22 21:11 ` Peter Zijlstra 2021-09-22 21:26 ` Luck, Tony 2021-09-22 21:26 ` Luck, Tony 2021-09-23 7:03 ` Peter Zijlstra 2021-09-23 7:03 ` Peter Zijlstra 2021-09-22 21:33 ` Dave Hansen 2021-09-22 21:33 ` Dave Hansen 2021-09-23 7:05 ` Peter Zijlstra 2021-09-23 7:05 ` Peter Zijlstra 2021-09-22 21:36 ` Fenghua Yu 2021-09-22 21:36 ` Fenghua Yu 2021-09-22 23:39 ` Fenghua Yu 2021-09-22 23:39 ` Fenghua Yu 2021-09-23 17:14 ` Luck, Tony 2021-09-23 17:14 ` Luck, Tony 2021-09-24 13:37 ` Peter Zijlstra 2021-09-24 13:37 ` Peter Zijlstra 2021-09-24 15:39 ` Luck, Tony 2021-09-24 15:39 ` Luck, Tony 2021-09-29 9:00 ` Peter Zijlstra 2021-09-29 9:00 ` Peter Zijlstra 2021-09-23 11:31 ` Thomas Gleixner 2021-09-23 11:31 ` Thomas Gleixner 2021-09-23 23:17 ` Andy Lutomirski 2021-09-23 23:17 ` Andy Lutomirski 2021-09-24 2:56 ` Fenghua Yu 2021-09-24 2:56 ` Fenghua Yu 2021-09-24 5:12 ` Andy Lutomirski 2021-09-24 5:12 ` Andy Lutomirski 2021-09-27 21:02 ` Luck, Tony 2021-09-27 21:02 ` Luck, Tony 2021-09-27 23:51 ` Dave Hansen 2021-09-27 23:51 ` Dave Hansen 2021-09-28 18:50 ` Luck, Tony 2021-09-28 18:50 ` Luck, Tony 2021-09-28 19:19 ` Dave Hansen 2021-09-28 19:19 ` Dave Hansen 2021-09-28 20:28 ` Luck, Tony 2021-09-28 20:28 ` Luck, Tony 2021-09-28 20:55 ` Dave Hansen 2021-09-28 20:55 ` Dave Hansen 2021-09-28 23:10 ` Luck, Tony 2021-09-28 23:10 ` Luck, Tony 2021-09-28 23:50 ` Fenghua Yu 2021-09-28 23:50 ` Fenghua Yu 2021-09-29 0:08 ` Luck, Tony 2021-09-29 0:08 ` Luck, Tony 2021-09-29 0:26 ` Yu, Fenghua 2021-09-29 0:26 ` Yu, Fenghua 2021-09-29 1:06 ` Luck, Tony 2021-09-29 1:06 ` Luck, Tony 2021-09-29 1:16 ` Fenghua Yu 2021-09-29 1:16 ` Fenghua Yu 2021-09-29 2:11 ` Luck, Tony 2021-09-29 2:11 ` Luck, Tony 2021-09-29 1:56 ` Yu, Fenghua 2021-09-29 1:56 ` Yu, Fenghua 2021-09-29 2:15 ` Luck, Tony 2021-09-29 2:15 ` Luck, Tony 2021-09-29 16:58 ` Andy Lutomirski 2021-09-29 16:58 ` Andy Lutomirski 2021-09-29 17:07 ` Luck, Tony 2021-09-29 17:07 ` Luck, Tony 2021-09-29 17:48 ` Andy Lutomirski 2021-09-29 17:48 ` Andy Lutomirski 2021-09-20 19:23 ` [PATCH 5/8] x86/mmu: Add mm-based PASID refcounting Fenghua Yu 2021-09-20 19:23 ` Fenghua Yu 2021-09-23 5:43 ` Lu Baolu 2021-09-23 5:43 ` Lu Baolu 2021-09-30 0:44 ` Fenghua Yu 2021-09-30 0:44 ` Fenghua Yu 2021-09-23 14:36 ` Thomas Gleixner 2021-09-23 14:36 ` Thomas Gleixner 2021-09-23 16:40 ` Luck, Tony 2021-09-23 16:40 ` Luck, Tony 2021-09-23 17:48 ` Thomas Gleixner 2021-09-23 17:48 ` Thomas Gleixner 2021-09-24 13:18 ` Thomas Gleixner 2021-09-24 13:18 ` Thomas Gleixner 2021-09-24 16:12 ` Luck, Tony 2021-09-24 16:12 ` Luck, Tony 2021-09-24 23:03 ` Andy Lutomirski 2021-09-24 23:03 ` Andy Lutomirski 2021-09-24 23:11 ` Luck, Tony 2021-09-24 23:11 ` Luck, Tony 2021-09-29 9:54 ` Peter Zijlstra 2021-09-29 9:54 ` Peter Zijlstra 2021-09-29 12:28 ` Thomas Gleixner 2021-09-29 12:28 ` Thomas Gleixner 2021-09-29 16:51 ` Luck, Tony 2021-09-29 16:51 ` Luck, Tony 2021-09-29 17:07 ` Fenghua Yu 2021-09-29 17:07 ` Fenghua Yu 2021-09-29 16:59 ` Andy Lutomirski 2021-09-29 16:59 ` Andy Lutomirski 2021-09-29 17:15 ` Thomas Gleixner 2021-09-29 17:15 ` Thomas Gleixner 2021-09-29 17:41 ` Luck, Tony 2021-09-29 17:41 ` Luck, Tony 2021-09-29 17:46 ` Andy Lutomirski 2021-09-29 17:46 ` Andy Lutomirski 2021-09-29 18:07 ` Fenghua Yu 2021-09-29 18:07 ` Fenghua Yu 2021-09-29 18:31 ` Luck, Tony 2021-09-29 18:31 ` Luck, Tony 2021-09-29 20:07 ` Thomas Gleixner 2021-09-29 20:07 ` Thomas Gleixner 2021-09-24 16:12 ` Fenghua Yu 2021-09-24 16:12 ` Fenghua Yu 2021-09-25 23:13 ` Thomas Gleixner 2021-09-25 23:13 ` Thomas Gleixner 2021-09-28 16:36 ` Fenghua Yu 2021-09-28 16:36 ` Fenghua Yu 2021-09-23 23:09 ` Andy Lutomirski 2021-09-23 23:09 ` Andy Lutomirski 2021-09-23 23:22 ` Luck, Tony 2021-09-23 23:22 ` Luck, Tony 2021-09-24 5:17 ` Andy Lutomirski 2021-09-24 5:17 ` Andy Lutomirski 2021-09-20 19:23 ` [PATCH 6/8] x86/cpufeatures: Re-enable ENQCMD Fenghua Yu 2021-09-20 19:23 ` Fenghua Yu 2021-09-20 19:23 ` Fenghua Yu [this message] 2021-09-20 19:23 ` [PATCH 7/8] tools/objtool: Check for use of the ENQCMD instruction in the kernel Fenghua Yu 2021-09-22 21:03 ` Peter Zijlstra 2021-09-22 21:03 ` Peter Zijlstra 2021-09-22 23:44 ` Fenghua Yu 2021-09-22 23:44 ` Fenghua Yu 2021-09-23 7:17 ` Peter Zijlstra 2021-09-23 7:17 ` Peter Zijlstra 2021-09-23 15:26 ` Fenghua Yu 2021-09-23 15:26 ` Fenghua Yu 2021-09-24 0:55 ` Josh Poimboeuf 2021-09-24 0:55 ` Josh Poimboeuf 2021-09-24 0:57 ` Fenghua Yu 2021-09-24 0:57 ` Fenghua Yu 2021-09-20 19:23 ` [PATCH 8/8] docs: x86: Change documentation for SVA (Shared Virtual Addressing) Fenghua Yu 2021-09-20 19:23 ` Fenghua Yu
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