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Patch "x86/speculation: Update Speculation Control microcode blacklist" has been added to the 4.15-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled x86/speculation: Update Speculation Control microcode blacklist to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: x86-speculation-update-speculation-control-microcode-blacklist.patch and it can be found in the queue-4.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From 1751342095f0d2b36fa8114d8e12c5688c455ac4 Mon Sep 17 00:00:00 2001 From: David Woodhouse <dwmw(a)amazon.co.uk> Date: Sat, 10 Feb 2018 23:39:22 +0000 Subject: x86/speculation: Update Speculation Control microcode blacklist From: David Woodhouse <dwmw(a)amazon.co.uk> commit 1751342095f0d2b36fa8114d8e12c5688c455ac4 upstream. Intel have retroactively blessed the 0xc2 microcode on Skylake mobile and desktop parts, and the Gemini Lake 0x22 microcode is apparently fine too. We blacklisted the latter purely because it was present with all the other problematic ones in the 2018-01-08 release, but now it's explicitly listed as OK. We still list 0x84 for the various Kaby Lake / Coffee Lake parts, as that appeared in one version of the blacklist and then reverted to 0x80 again. We can change it if 0x84 is actually announced to be safe. Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Arjan van de Ven <arjan(a)linux.intel.com> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Dan Williams <dan.j.williams(a)intel.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Woodhouse <dwmw2(a)infradead.org> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: arjan.van.de.ven(a)intel.com Cc: jmattson(a)google.com Cc: karahmed(a)amazon.de Cc: kvm(a)vger.kernel.org Cc: pbonzini(a)redhat.com Cc: rkrcmar(a)redhat.com Cc: sironi(a)amazon.de Link: http://lkml.kernel.org/r/1518305967-31356-2-git-send-email-dwmw@amazon.co.uk Signed-off-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/kernel/cpu/intel.c | 4 ---- 1 file changed, 4 deletions(-) --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -123,8 +123,6 @@ static const struct sku_microcode spectr { INTEL_FAM6_KABYLAKE_MOBILE, 0x09, 0x84 }, { INTEL_FAM6_SKYLAKE_X, 0x03, 0x0100013e }, { INTEL_FAM6_SKYLAKE_X, 0x04, 0x0200003c }, - { INTEL_FAM6_SKYLAKE_MOBILE, 0x03, 0xc2 }, - { INTEL_FAM6_SKYLAKE_DESKTOP, 0x03, 0xc2 }, { INTEL_FAM6_BROADWELL_CORE, 0x04, 0x28 }, { INTEL_FAM6_BROADWELL_GT3E, 0x01, 0x1b }, { INTEL_FAM6_BROADWELL_XEON_D, 0x02, 0x14 }, @@ -136,8 +134,6 @@ static const struct sku_microcode spectr { INTEL_FAM6_HASWELL_X, 0x02, 0x3b }, { INTEL_FAM6_HASWELL_X, 0x04, 0x10 }, { INTEL_FAM6_IVYBRIDGE_X, 0x04, 0x42a }, - /* Updated in the 20180108 release; blacklist until we know otherwise */ - { INTEL_FAM6_ATOM_GEMINI_LAKE, 0x01, 0x22 }, /* Observed in the wild */ { INTEL_FAM6_SANDYBRIDGE_X, 0x06, 0x61b }, { INTEL_FAM6_SANDYBRIDGE_X, 0x07, 0x712 }, Patches currently in stable-queue which might be from dwmw(a)amazon.co.uk are queue-4.15/kvm-nvmx-set-the-cpu_based_use_msr_bitmaps-if-we-have-a-valid-l02-msr-bitmap.patch queue-4.15/x86-nvmx-properly-set-spec_ctrl-and-pred_cmd-before-merging-msrs.patch queue-4.15/x86-speculation-update-speculation-control-microcode-blacklist.patch queue-4.15/x86-speculation-correct-speculation-control-microcode-blacklist-again.patch queue-4.15/kvm-x86-reduce-retpoline-performance-impact-in-slot_handle_level_range-by-always-inlining-iterator-helper-methods.patch queue-4.15/x86-speculation-clean-up-various-spectre-related-details.patch queue-4.15/revert-x86-speculation-simplify-indirect_branch_prediction_barrier.patch

7 years, 4 months

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Patch "x86/speculation: Correct Speculation Control microcode blacklist again" has been added to the 4.15-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled x86/speculation: Correct Speculation Control microcode blacklist again to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: x86-speculation-correct-speculation-control-microcode-blacklist-again.patch and it can be found in the queue-4.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From d37fc6d360a404b208547ba112e7dabb6533c7fc Mon Sep 17 00:00:00 2001 From: David Woodhouse <dwmw(a)amazon.co.uk> Date: Mon, 12 Feb 2018 15:27:34 +0000 Subject: x86/speculation: Correct Speculation Control microcode blacklist again From: David Woodhouse <dwmw(a)amazon.co.uk> commit d37fc6d360a404b208547ba112e7dabb6533c7fc upstream. Arjan points out that the Intel document only clears the 0xc2 microcode on *some* parts with CPUID 506E3 (INTEL_FAM6_SKYLAKE_DESKTOP stepping 3). For the Skylake H/S platform it's OK but for Skylake E3 which has the same CPUID it isn't (yet) cleared. So removing it from the blacklist was premature. Put it back for now. Also, Arjan assures me that the 0x84 microcode for Kaby Lake which was featured in one of the early revisions of the Intel document was never released to the public, and won't be until/unless it is also validated as safe. So those can change to 0x80 which is what all *other* versions of the doc have identified. Once the retrospective testing of existing public microcodes is done, we should be back into a mode where new microcodes are only released in batches and we shouldn't even need to update the blacklist for those anyway, so this tweaking of the list isn't expected to be a thing which keeps happening. Requested-by: Arjan van de Ven <arjan.van.de.ven(a)intel.com> Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Arjan van de Ven <arjan(a)linux.intel.com> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Dan Williams <dan.j.williams(a)intel.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Woodhouse <dwmw2(a)infradead.org> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: arjan.van.de.ven(a)intel.com Cc: dave.hansen(a)intel.com Cc: kvm(a)vger.kernel.org Cc: pbonzini(a)redhat.com Link: http://lkml.kernel.org/r/1518449255-2182-1-git-send-email-dwmw@amazon.co.uk Signed-off-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/kernel/cpu/intel.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -116,13 +116,14 @@ struct sku_microcode { u32 microcode; }; static const struct sku_microcode spectre_bad_microcodes[] = { - { INTEL_FAM6_KABYLAKE_DESKTOP, 0x0B, 0x84 }, - { INTEL_FAM6_KABYLAKE_DESKTOP, 0x0A, 0x84 }, - { INTEL_FAM6_KABYLAKE_DESKTOP, 0x09, 0x84 }, - { INTEL_FAM6_KABYLAKE_MOBILE, 0x0A, 0x84 }, - { INTEL_FAM6_KABYLAKE_MOBILE, 0x09, 0x84 }, + { INTEL_FAM6_KABYLAKE_DESKTOP, 0x0B, 0x80 }, + { INTEL_FAM6_KABYLAKE_DESKTOP, 0x0A, 0x80 }, + { INTEL_FAM6_KABYLAKE_DESKTOP, 0x09, 0x80 }, + { INTEL_FAM6_KABYLAKE_MOBILE, 0x0A, 0x80 }, + { INTEL_FAM6_KABYLAKE_MOBILE, 0x09, 0x80 }, { INTEL_FAM6_SKYLAKE_X, 0x03, 0x0100013e }, { INTEL_FAM6_SKYLAKE_X, 0x04, 0x0200003c }, + { INTEL_FAM6_SKYLAKE_DESKTOP, 0x03, 0xc2 }, { INTEL_FAM6_BROADWELL_CORE, 0x04, 0x28 }, { INTEL_FAM6_BROADWELL_GT3E, 0x01, 0x1b }, { INTEL_FAM6_BROADWELL_XEON_D, 0x02, 0x14 }, Patches currently in stable-queue which might be from dwmw(a)amazon.co.uk are queue-4.15/kvm-nvmx-set-the-cpu_based_use_msr_bitmaps-if-we-have-a-valid-l02-msr-bitmap.patch queue-4.15/x86-nvmx-properly-set-spec_ctrl-and-pred_cmd-before-merging-msrs.patch queue-4.15/x86-speculation-update-speculation-control-microcode-blacklist.patch queue-4.15/x86-speculation-correct-speculation-control-microcode-blacklist-again.patch queue-4.15/kvm-x86-reduce-retpoline-performance-impact-in-slot_handle_level_range-by-always-inlining-iterator-helper-methods.patch queue-4.15/x86-speculation-clean-up-various-spectre-related-details.patch queue-4.15/revert-x86-speculation-simplify-indirect_branch_prediction_barrier.patch

7 years, 4 months

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Patch "x86/speculation: Clean up various Spectre related details" has been added to the 4.15-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled x86/speculation: Clean up various Spectre related details to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: x86-speculation-clean-up-various-spectre-related-details.patch and it can be found in the queue-4.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From 21e433bdb95bdf3aa48226fd3d33af608437f293 Mon Sep 17 00:00:00 2001 From: Ingo Molnar <mingo(a)kernel.org> Date: Tue, 13 Feb 2018 09:03:08 +0100 Subject: x86/speculation: Clean up various Spectre related details From: Ingo Molnar <mingo(a)kernel.org> commit 21e433bdb95bdf3aa48226fd3d33af608437f293 upstream. Harmonize all the Spectre messages so that a: dmesg | grep -i spectre ... gives us most Spectre related kernel boot messages. Also fix a few other details: - clarify a comment about firmware speculation control - s/KPTI/PTI - remove various line-breaks that made the code uglier Acked-by: David Woodhouse <dwmw(a)amazon.co.uk> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Arjan van de Ven <arjan(a)linux.intel.com> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Dan Williams <dan.j.williams(a)intel.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Woodhouse <dwmw2(a)infradead.org> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: linux-kernel(a)vger.kernel.org Signed-off-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/kernel/cpu/bugs.c | 28 +++++++++++----------------- 1 file changed, 11 insertions(+), 17 deletions(-) --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -162,8 +162,7 @@ static enum spectre_v2_mitigation_cmd __ if (cmdline_find_option_bool(boot_command_line, "nospectre_v2")) return SPECTRE_V2_CMD_NONE; else { - ret = cmdline_find_option(boot_command_line, "spectre_v2", arg, - sizeof(arg)); + ret = cmdline_find_option(boot_command_line, "spectre_v2", arg, sizeof(arg)); if (ret < 0) return SPECTRE_V2_CMD_AUTO; @@ -175,8 +174,7 @@ static enum spectre_v2_mitigation_cmd __ } if (i >= ARRAY_SIZE(mitigation_options)) { - pr_err("unknown option (%s). Switching to AUTO select\n", - mitigation_options[i].option); + pr_err("unknown option (%s). Switching to AUTO select\n", mitigation_options[i].option); return SPECTRE_V2_CMD_AUTO; } } @@ -185,8 +183,7 @@ static enum spectre_v2_mitigation_cmd __ cmd == SPECTRE_V2_CMD_RETPOLINE_AMD || cmd == SPECTRE_V2_CMD_RETPOLINE_GENERIC) && !IS_ENABLED(CONFIG_RETPOLINE)) { - pr_err("%s selected but not compiled in. Switching to AUTO select\n", - mitigation_options[i].option); + pr_err("%s selected but not compiled in. Switching to AUTO select\n", mitigation_options[i].option); return SPECTRE_V2_CMD_AUTO; } @@ -256,14 +253,14 @@ static void __init spectre_v2_select_mit goto retpoline_auto; break; } - pr_err("kernel not compiled with retpoline; no mitigation available!"); + pr_err("Spectre mitigation: kernel not compiled with retpoline; no mitigation available!"); return; retpoline_auto: if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) { retpoline_amd: if (!boot_cpu_has(X86_FEATURE_LFENCE_RDTSC)) { - pr_err("LFENCE not serializing. Switching to generic retpoline\n"); + pr_err("Spectre mitigation: LFENCE not serializing, switching to generic retpoline\n"); goto retpoline_generic; } mode = retp_compiler() ? SPECTRE_V2_RETPOLINE_AMD : @@ -281,7 +278,7 @@ retpoline_auto: pr_info("%s\n", spectre_v2_strings[mode]); /* - * If neither SMEP or KPTI are available, there is a risk of + * If neither SMEP nor PTI are available, there is a risk of * hitting userspace addresses in the RSB after a context switch * from a shallow call stack to a deeper one. To prevent this fill * the entire RSB, even when using IBRS. @@ -295,21 +292,20 @@ retpoline_auto: if ((!boot_cpu_has(X86_FEATURE_PTI) && !boot_cpu_has(X86_FEATURE_SMEP)) || is_skylake_era()) { setup_force_cpu_cap(X86_FEATURE_RSB_CTXSW); - pr_info("Filling RSB on context switch\n"); + pr_info("Spectre v2 mitigation: Filling RSB on context switch\n"); } /* Initialize Indirect Branch Prediction Barrier if supported */ if (boot_cpu_has(X86_FEATURE_IBPB)) { setup_force_cpu_cap(X86_FEATURE_USE_IBPB); - pr_info("Enabling Indirect Branch Prediction Barrier\n"); + pr_info("Spectre v2 mitigation: Enabling Indirect Branch Prediction Barrier\n"); } } #undef pr_fmt #ifdef CONFIG_SYSFS -ssize_t cpu_show_meltdown(struct device *dev, - struct device_attribute *attr, char *buf) +ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf) { if (!boot_cpu_has_bug(X86_BUG_CPU_MELTDOWN)) return sprintf(buf, "Not affected\n"); @@ -318,16 +314,14 @@ ssize_t cpu_show_meltdown(struct device return sprintf(buf, "Vulnerable\n"); } -ssize_t cpu_show_spectre_v1(struct device *dev, - struct device_attribute *attr, char *buf) +ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr, char *buf) { if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V1)) return sprintf(buf, "Not affected\n"); return sprintf(buf, "Mitigation: __user pointer sanitization\n"); } -ssize_t cpu_show_spectre_v2(struct device *dev, - struct device_attribute *attr, char *buf) +ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, char *buf) { if (!boot_cpu_has_bug(X86_BUG_SPECTRE_V2)) return sprintf(buf, "Not affected\n"); Patches currently in stable-queue which might be from mingo(a)kernel.org are queue-4.15/x86-gpu-add-cfl-to-early-quirks.patch queue-4.15/kvm-nvmx-set-the-cpu_based_use_msr_bitmaps-if-we-have-a-valid-l02-msr-bitmap.patch queue-4.15/x86-nvmx-properly-set-spec_ctrl-and-pred_cmd-before-merging-msrs.patch queue-4.15/x86-speculation-update-speculation-control-microcode-blacklist.patch queue-4.15/x86-speculation-correct-speculation-control-microcode-blacklist-again.patch queue-4.15/x86-entry-64-clear-extra-registers-beyond-syscall-arguments-to-reduce-speculation-attack-surface.patch queue-4.15/kvm-x86-reduce-retpoline-performance-impact-in-slot_handle_level_range-by-always-inlining-iterator-helper-methods.patch queue-4.15/x86-mm-pti-fix-pti-comment-in-entry_syscall_64.patch queue-4.15/x86-speculation-clean-up-various-spectre-related-details.patch queue-4.15/x86-kexec-make-kexec-mostly-work-in-5-level-paging-mode.patch queue-4.15/revert-x86-speculation-simplify-indirect_branch_prediction_barrier.patch queue-4.15/x86-entry-64-compat-clear-registers-for-compat-syscalls-to-reduce-speculation-attack-surface.patch

7 years, 4 months

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Patch "X86/nVMX: Properly set spec_ctrl and pred_cmd before merging MSRs" has been added to the 4.15-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled X86/nVMX: Properly set spec_ctrl and pred_cmd before merging MSRs to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: x86-nvmx-properly-set-spec_ctrl-and-pred_cmd-before-merging-msrs.patch and it can be found in the queue-4.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From 206587a9fb764d71f035dc7f6d3b6488f5d5b304 Mon Sep 17 00:00:00 2001 From: KarimAllah Ahmed <karahmed(a)amazon.de> Date: Sat, 10 Feb 2018 23:39:25 +0000 Subject: X86/nVMX: Properly set spec_ctrl and pred_cmd before merging MSRs MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: KarimAllah Ahmed <karahmed(a)amazon.de> commit 206587a9fb764d71f035dc7f6d3b6488f5d5b304 upstream. These two variables should check whether SPEC_CTRL and PRED_CMD are supposed to be passed through to L2 guests or not. While msr_write_intercepted_l01 would return 'true' if it is not passed through. So just invert the result of msr_write_intercepted_l01 to implement the correct semantics. Signed-off-by: KarimAllah Ahmed <karahmed(a)amazon.de> Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk> Reviewed-by: Jim Mattson <jmattson(a)google.com> Acked-by: Paolo Bonzini <pbonzini(a)redhat.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Arjan van de Ven <arjan(a)linux.intel.com> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Dan Williams <dan.j.williams(a)intel.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Woodhouse <dwmw2(a)infradead.org> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Radim Krčmář <rkrcmar(a)redhat.com> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: arjan.van.de.ven(a)intel.com Cc: dave.hansen(a)intel.com Cc: kvm(a)vger.kernel.org Cc: sironi(a)amazon.de Fixes: 086e7d4118cc ("KVM: VMX: Allow direct access to MSR_IA32_SPEC_CTRL") Link: http://lkml.kernel.org/r/1518305967-31356-5-git-send-email-dwmw@amazon.co.uk Signed-off-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/kvm/vmx.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -10220,8 +10220,8 @@ static inline bool nested_vmx_merge_msr_ * updated to reflect this when L1 (or its L2s) actually write to * the MSR. */ - bool pred_cmd = msr_write_intercepted_l01(vcpu, MSR_IA32_PRED_CMD); - bool spec_ctrl = msr_write_intercepted_l01(vcpu, MSR_IA32_SPEC_CTRL); + bool pred_cmd = !msr_write_intercepted_l01(vcpu, MSR_IA32_PRED_CMD); + bool spec_ctrl = !msr_write_intercepted_l01(vcpu, MSR_IA32_SPEC_CTRL); if (!nested_cpu_has_virt_x2apic_mode(vmcs12) && !pred_cmd && !spec_ctrl) Patches currently in stable-queue which might be from karahmed(a)amazon.de are queue-4.15/kvm-nvmx-set-the-cpu_based_use_msr_bitmaps-if-we-have-a-valid-l02-msr-bitmap.patch queue-4.15/x86-nvmx-properly-set-spec_ctrl-and-pred_cmd-before-merging-msrs.patch queue-4.15/x86-speculation-update-speculation-control-microcode-blacklist.patch queue-4.15/kvm-x86-reduce-retpoline-performance-impact-in-slot_handle_level_range-by-always-inlining-iterator-helper-methods.patch queue-4.15/revert-x86-speculation-simplify-indirect_branch_prediction_barrier.patch

7 years, 4 months

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Patch "x86/mm/pti: Fix PTI comment in entry_SYSCALL_64()" has been added to the 4.15-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled x86/mm/pti: Fix PTI comment in entry_SYSCALL_64() to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: x86-mm-pti-fix-pti-comment-in-entry_syscall_64.patch and it can be found in the queue-4.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From 14b1fcc62043729d12e8ae00f8297ab2ffe9fa91 Mon Sep 17 00:00:00 2001 From: Nadav Amit <namit(a)vmware.com> Date: Fri, 9 Feb 2018 09:06:38 -0800 Subject: x86/mm/pti: Fix PTI comment in entry_SYSCALL_64() From: Nadav Amit <namit(a)vmware.com> commit 14b1fcc62043729d12e8ae00f8297ab2ffe9fa91 upstream. The comment is confusing since the path is taken when CONFIG_PAGE_TABLE_ISOLATION=y is disabled (while the comment says it is not taken). Signed-off-by: Nadav Amit <namit(a)vmware.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Arjan van de Ven <arjan(a)linux.intel.com> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Dan Williams <dan.j.williams(a)intel.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Woodhouse <dwmw2(a)infradead.org> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: nadav.amit(a)gmail.com Link: http://lkml.kernel.org/r/20180209170638.15161-1-namit@vmware.com Signed-off-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/entry/entry_64.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -213,7 +213,7 @@ ENTRY(entry_SYSCALL_64) swapgs /* - * This path is not taken when PAGE_TABLE_ISOLATION is disabled so it + * This path is only taken when PAGE_TABLE_ISOLATION is disabled so it * is not required to switch CR3. */ movq %rsp, PER_CPU_VAR(rsp_scratch) Patches currently in stable-queue which might be from namit(a)vmware.com are queue-4.15/x86-mm-pti-fix-pti-comment-in-entry_syscall_64.patch

7 years, 4 months

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Patch "x86/entry/64/compat: Clear registers for compat syscalls, to reduce speculation attack surface" has been added to the 4.15-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled x86/entry/64/compat: Clear registers for compat syscalls, to reduce speculation attack surface to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: x86-entry-64-compat-clear-registers-for-compat-syscalls-to-reduce-speculation-attack-surface.patch and it can be found in the queue-4.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From 6b8cf5cc9965673951f1ab3f0e3cf23d06e3e2ee Mon Sep 17 00:00:00 2001 From: Dan Williams <dan.j.williams(a)intel.com> Date: Mon, 5 Feb 2018 17:18:17 -0800 Subject: x86/entry/64/compat: Clear registers for compat syscalls, to reduce speculation attack surface From: Dan Williams <dan.j.williams(a)intel.com> commit 6b8cf5cc9965673951f1ab3f0e3cf23d06e3e2ee upstream. At entry userspace may have populated registers with values that could otherwise be useful in a speculative execution attack. Clear them to minimize the kernel's attack surface. Originally-From: Andi Kleen <ak(a)linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams(a)intel.com> Cc: <stable(a)vger.kernel.org> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Brian Gerst <brgerst(a)gmail.com> Cc: Denys Vlasenko <dvlasenk(a)redhat.com> Cc: H. Peter Anvin <hpa(a)zytor.com> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Thomas Gleixner <tglx(a)linutronix.de> Link: http://lkml.kernel.org/r/151787989697.7847.4083702787288600552.stgit@dwilli… [ Made small improvements to the changelog. ] Signed-off-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/entry/entry_64_compat.S | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -85,15 +85,25 @@ ENTRY(entry_SYSENTER_compat) pushq %rcx /* pt_regs->cx */ pushq $-ENOSYS /* pt_regs->ax */ pushq $0 /* pt_regs->r8 = 0 */ + xorq %r8, %r8 /* nospec r8 */ pushq $0 /* pt_regs->r9 = 0 */ + xorq %r9, %r9 /* nospec r9 */ pushq $0 /* pt_regs->r10 = 0 */ + xorq %r10, %r10 /* nospec r10 */ pushq $0 /* pt_regs->r11 = 0 */ + xorq %r11, %r11 /* nospec r11 */ pushq %rbx /* pt_regs->rbx */ + xorl %ebx, %ebx /* nospec rbx */ pushq %rbp /* pt_regs->rbp (will be overwritten) */ + xorl %ebp, %ebp /* nospec rbp */ pushq $0 /* pt_regs->r12 = 0 */ + xorq %r12, %r12 /* nospec r12 */ pushq $0 /* pt_regs->r13 = 0 */ + xorq %r13, %r13 /* nospec r13 */ pushq $0 /* pt_regs->r14 = 0 */ + xorq %r14, %r14 /* nospec r14 */ pushq $0 /* pt_regs->r15 = 0 */ + xorq %r15, %r15 /* nospec r15 */ cld /* @@ -214,15 +224,25 @@ GLOBAL(entry_SYSCALL_compat_after_hwfram pushq %rbp /* pt_regs->cx (stashed in bp) */ pushq $-ENOSYS /* pt_regs->ax */ pushq $0 /* pt_regs->r8 = 0 */ + xorq %r8, %r8 /* nospec r8 */ pushq $0 /* pt_regs->r9 = 0 */ + xorq %r9, %r9 /* nospec r9 */ pushq $0 /* pt_regs->r10 = 0 */ + xorq %r10, %r10 /* nospec r10 */ pushq $0 /* pt_regs->r11 = 0 */ + xorq %r11, %r11 /* nospec r11 */ pushq %rbx /* pt_regs->rbx */ + xorl %ebx, %ebx /* nospec rbx */ pushq %rbp /* pt_regs->rbp (will be overwritten) */ + xorl %ebp, %ebp /* nospec rbp */ pushq $0 /* pt_regs->r12 = 0 */ + xorq %r12, %r12 /* nospec r12 */ pushq $0 /* pt_regs->r13 = 0 */ + xorq %r13, %r13 /* nospec r13 */ pushq $0 /* pt_regs->r14 = 0 */ + xorq %r14, %r14 /* nospec r14 */ pushq $0 /* pt_regs->r15 = 0 */ + xorq %r15, %r15 /* nospec r15 */ /* * User mode is traced as though IRQs are on, and SYSENTER @@ -338,15 +358,25 @@ ENTRY(entry_INT80_compat) pushq %rcx /* pt_regs->cx */ pushq $-ENOSYS /* pt_regs->ax */ pushq $0 /* pt_regs->r8 = 0 */ + xorq %r8, %r8 /* nospec r8 */ pushq $0 /* pt_regs->r9 = 0 */ + xorq %r9, %r9 /* nospec r9 */ pushq $0 /* pt_regs->r10 = 0 */ + xorq %r10, %r10 /* nospec r10 */ pushq $0 /* pt_regs->r11 = 0 */ + xorq %r11, %r11 /* nospec r11 */ pushq %rbx /* pt_regs->rbx */ + xorl %ebx, %ebx /* nospec rbx */ pushq %rbp /* pt_regs->rbp */ + xorl %ebp, %ebp /* nospec rbp */ pushq %r12 /* pt_regs->r12 */ + xorq %r12, %r12 /* nospec r12 */ pushq %r13 /* pt_regs->r13 */ + xorq %r13, %r13 /* nospec r13 */ pushq %r14 /* pt_regs->r14 */ + xorq %r14, %r14 /* nospec r14 */ pushq %r15 /* pt_regs->r15 */ + xorq %r15, %r15 /* nospec r15 */ cld /* Patches currently in stable-queue which might be from dan.j.williams(a)intel.com are queue-4.15/kvm-nvmx-set-the-cpu_based_use_msr_bitmaps-if-we-have-a-valid-l02-msr-bitmap.patch queue-4.15/x86-nvmx-properly-set-spec_ctrl-and-pred_cmd-before-merging-msrs.patch queue-4.15/x86-speculation-update-speculation-control-microcode-blacklist.patch queue-4.15/x86-speculation-correct-speculation-control-microcode-blacklist-again.patch queue-4.15/x86-entry-64-clear-extra-registers-beyond-syscall-arguments-to-reduce-speculation-attack-surface.patch queue-4.15/kvm-x86-reduce-retpoline-performance-impact-in-slot_handle_level_range-by-always-inlining-iterator-helper-methods.patch queue-4.15/x86-mm-pti-fix-pti-comment-in-entry_syscall_64.patch queue-4.15/x86-speculation-clean-up-various-spectre-related-details.patch queue-4.15/revert-x86-speculation-simplify-indirect_branch_prediction_barrier.patch queue-4.15/x86-entry-64-compat-clear-registers-for-compat-syscalls-to-reduce-speculation-attack-surface.patch

7 years, 4 months

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Patch "x86/entry/64: Clear extra registers beyond syscall arguments, to reduce speculation attack surface" has been added to the 4.15-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled x86/entry/64: Clear extra registers beyond syscall arguments, to reduce speculation attack surface to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: x86-entry-64-clear-extra-registers-beyond-syscall-arguments-to-reduce-speculation-attack-surface.patch and it can be found in the queue-4.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From 8e1eb3fa009aa7c0b944b3c8b26b07de0efb3200 Mon Sep 17 00:00:00 2001 From: Dan Williams <dan.j.williams(a)intel.com> Date: Mon, 5 Feb 2018 17:18:05 -0800 Subject: x86/entry/64: Clear extra registers beyond syscall arguments, to reduce speculation attack surface From: Dan Williams <dan.j.williams(a)intel.com> commit 8e1eb3fa009aa7c0b944b3c8b26b07de0efb3200 upstream. At entry userspace may have (maliciously) populated the extra registers outside the syscall calling convention with arbitrary values that could be useful in a speculative execution (Spectre style) attack. Clear these registers to minimize the kernel's attack surface. Note, this only clears the extra registers and not the unused registers for syscalls less than 6 arguments, since those registers are likely to be clobbered well before their values could be put to use under speculation. Note, Linus found that the XOR instructions can be executed with minimized cost if interleaved with the PUSH instructions, and Ingo's analysis found that R10 and R11 should be included in the register clearing beyond the typical 'extra' syscall calling convention registers. Suggested-by: Linus Torvalds <torvalds(a)linux-foundation.org> Reported-by: Andi Kleen <ak(a)linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams(a)intel.com> Cc: <stable(a)vger.kernel.org> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Brian Gerst <brgerst(a)gmail.com> Cc: Denys Vlasenko <dvlasenk(a)redhat.com> Cc: H. Peter Anvin <hpa(a)zytor.com> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Thomas Gleixner <tglx(a)linutronix.de> Link: http://lkml.kernel.org/r/151787988577.7847.16733592218894189003.stgit@dwill… [ Made small improvements to the changelog and the code comments. ] Signed-off-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/entry/entry_64.S | 13 +++++++++++++ 1 file changed, 13 insertions(+) --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -235,13 +235,26 @@ GLOBAL(entry_SYSCALL_64_after_hwframe) pushq %r8 /* pt_regs->r8 */ pushq %r9 /* pt_regs->r9 */ pushq %r10 /* pt_regs->r10 */ + /* + * Clear extra registers that a speculation attack might + * otherwise want to exploit. Interleave XOR with PUSH + * for better uop scheduling: + */ + xorq %r10, %r10 /* nospec r10 */ pushq %r11 /* pt_regs->r11 */ + xorq %r11, %r11 /* nospec r11 */ pushq %rbx /* pt_regs->rbx */ + xorl %ebx, %ebx /* nospec rbx */ pushq %rbp /* pt_regs->rbp */ + xorl %ebp, %ebp /* nospec rbp */ pushq %r12 /* pt_regs->r12 */ + xorq %r12, %r12 /* nospec r12 */ pushq %r13 /* pt_regs->r13 */ + xorq %r13, %r13 /* nospec r13 */ pushq %r14 /* pt_regs->r14 */ + xorq %r14, %r14 /* nospec r14 */ pushq %r15 /* pt_regs->r15 */ + xorq %r15, %r15 /* nospec r15 */ UNWIND_HINT_REGS TRACE_IRQS_OFF Patches currently in stable-queue which might be from dan.j.williams(a)intel.com are queue-4.15/kvm-nvmx-set-the-cpu_based_use_msr_bitmaps-if-we-have-a-valid-l02-msr-bitmap.patch queue-4.15/x86-nvmx-properly-set-spec_ctrl-and-pred_cmd-before-merging-msrs.patch queue-4.15/x86-speculation-update-speculation-control-microcode-blacklist.patch queue-4.15/x86-speculation-correct-speculation-control-microcode-blacklist-again.patch queue-4.15/x86-entry-64-clear-extra-registers-beyond-syscall-arguments-to-reduce-speculation-attack-surface.patch queue-4.15/kvm-x86-reduce-retpoline-performance-impact-in-slot_handle_level_range-by-always-inlining-iterator-helper-methods.patch queue-4.15/x86-mm-pti-fix-pti-comment-in-entry_syscall_64.patch queue-4.15/x86-speculation-clean-up-various-spectre-related-details.patch queue-4.15/revert-x86-speculation-simplify-indirect_branch_prediction_barrier.patch queue-4.15/x86-entry-64-compat-clear-registers-for-compat-syscalls-to-reduce-speculation-attack-surface.patch

7 years, 4 months

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Patch "Revert "x86/speculation: Simplify indirect_branch_prediction_barrier()"" has been added to the 4.15-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled Revert "x86/speculation: Simplify indirect_branch_prediction_barrier()" to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: revert-x86-speculation-simplify-indirect_branch_prediction_barrier.patch and it can be found in the queue-4.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From f208820a321f9b23d77d7eed89945d862d62a3ed Mon Sep 17 00:00:00 2001 From: David Woodhouse <dwmw(a)amazon.co.uk> Date: Sat, 10 Feb 2018 23:39:23 +0000 Subject: Revert "x86/speculation: Simplify indirect_branch_prediction_barrier()" From: David Woodhouse <dwmw(a)amazon.co.uk> commit f208820a321f9b23d77d7eed89945d862d62a3ed upstream. This reverts commit 64e16720ea0879f8ab4547e3b9758936d483909b. We cannot call C functions like that, without marking all the call-clobbered registers as, well, clobbered. We might have got away with it for now because the __ibp_barrier() function was *fairly* unlikely to actually use any other registers. But no. Just no. Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Arjan van de Ven <arjan(a)linux.intel.com> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Dan Williams <dan.j.williams(a)intel.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Woodhouse <dwmw2(a)infradead.org> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: arjan.van.de.ven(a)intel.com Cc: dave.hansen(a)intel.com Cc: jmattson(a)google.com Cc: karahmed(a)amazon.de Cc: kvm(a)vger.kernel.org Cc: pbonzini(a)redhat.com Cc: rkrcmar(a)redhat.com Cc: sironi(a)amazon.de Link: http://lkml.kernel.org/r/1518305967-31356-3-git-send-email-dwmw@amazon.co.uk Signed-off-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/include/asm/nospec-branch.h | 13 +++++++++---- arch/x86/include/asm/processor.h | 3 --- arch/x86/kernel/cpu/bugs.c | 6 ------ 3 files changed, 9 insertions(+), 13 deletions(-) --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -164,10 +164,15 @@ static inline void vmexit_fill_RSB(void) static inline void indirect_branch_prediction_barrier(void) { - alternative_input("", - "call __ibp_barrier", - X86_FEATURE_USE_IBPB, - ASM_NO_INPUT_CLOBBER("eax", "ecx", "edx", "memory")); + asm volatile(ALTERNATIVE("", + "movl %[msr], %%ecx\n\t" + "movl %[val], %%eax\n\t" + "movl $0, %%edx\n\t" + "wrmsr", + X86_FEATURE_USE_IBPB) + : : [msr] "i" (MSR_IA32_PRED_CMD), + [val] "i" (PRED_CMD_IBPB) + : "eax", "ecx", "edx", "memory"); } #endif /* __ASSEMBLY__ */ --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -969,7 +969,4 @@ bool xen_set_default_idle(void); void stop_this_cpu(void *dummy); void df_debug(struct pt_regs *regs, long error_code); - -void __ibp_barrier(void); - #endif /* _ASM_X86_PROCESSOR_H */ --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -337,9 +337,3 @@ ssize_t cpu_show_spectre_v2(struct devic spectre_v2_module_string()); } #endif - -void __ibp_barrier(void) -{ - __wrmsr(MSR_IA32_PRED_CMD, PRED_CMD_IBPB, 0); -} -EXPORT_SYMBOL_GPL(__ibp_barrier); Patches currently in stable-queue which might be from dwmw(a)amazon.co.uk are queue-4.15/kvm-nvmx-set-the-cpu_based_use_msr_bitmaps-if-we-have-a-valid-l02-msr-bitmap.patch queue-4.15/x86-nvmx-properly-set-spec_ctrl-and-pred_cmd-before-merging-msrs.patch queue-4.15/x86-speculation-update-speculation-control-microcode-blacklist.patch queue-4.15/x86-speculation-correct-speculation-control-microcode-blacklist-again.patch queue-4.15/kvm-x86-reduce-retpoline-performance-impact-in-slot_handle_level_range-by-always-inlining-iterator-helper-methods.patch queue-4.15/x86-speculation-clean-up-various-spectre-related-details.patch queue-4.15/revert-x86-speculation-simplify-indirect_branch_prediction_barrier.patch

7 years, 4 months

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Patch "powerpc/mm/radix: Split linear mapping on hot-unplug" has been added to the 4.15-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled powerpc/mm/radix: Split linear mapping on hot-unplug to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: powerpc-mm-radix-split-linear-mapping-on-hot-unplug.patch and it can be found in the queue-4.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From 4dd5f8a99e791a8c6500e3592f3ce81ae7edcde1 Mon Sep 17 00:00:00 2001 From: Balbir Singh <bsingharora(a)gmail.com> Date: Wed, 7 Feb 2018 17:35:51 +1100 Subject: powerpc/mm/radix: Split linear mapping on hot-unplug From: Balbir Singh <bsingharora(a)gmail.com> commit 4dd5f8a99e791a8c6500e3592f3ce81ae7edcde1 upstream. This patch splits the linear mapping if the hot-unplug range is smaller than the mapping size. The code detects if the mapping needs to be split into a smaller size and if so, uses the stop machine infrastructure to clear the existing mapping and then remap the remaining range using a smaller page size. The code will skip any region of the mapping that overlaps with kernel text and warn about it once. We don't want to remove a mapping where the kernel text and the LMB we intend to remove overlap in the same TLB mapping as it may affect the currently executing code. I've tested these changes under a kvm guest with 2 vcpus, from a split mapping point of view, some of the caveats mentioned above applied to the testing I did. Fixes: 4b5d62ca17a1 ("powerpc/mm: add radix__remove_section_mapping()") Signed-off-by: Balbir Singh <bsingharora(a)gmail.com> [mpe: Tweak change log to match updated behaviour] Signed-off-by: Michael Ellerman <mpe(a)ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/powerpc/mm/pgtable-radix.c | 95 +++++++++++++++++++++++++++++++--------- 1 file changed, 74 insertions(+), 21 deletions(-) --- a/arch/powerpc/mm/pgtable-radix.c +++ b/arch/powerpc/mm/pgtable-radix.c @@ -17,6 +17,7 @@ #include <linux/of_fdt.h> #include <linux/mm.h> #include <linux/string_helpers.h> +#include <linux/stop_machine.h> #include <asm/pgtable.h> #include <asm/pgalloc.h> @@ -671,6 +672,30 @@ static void free_pmd_table(pmd_t *pmd_st pud_clear(pud); } +struct change_mapping_params { + pte_t *pte; + unsigned long start; + unsigned long end; + unsigned long aligned_start; + unsigned long aligned_end; +}; + +static int stop_machine_change_mapping(void *data) +{ + struct change_mapping_params *params = + (struct change_mapping_params *)data; + + if (!data) + return -1; + + spin_unlock(&init_mm.page_table_lock); + pte_clear(&init_mm, params->aligned_start, params->pte); + create_physical_mapping(params->aligned_start, params->start); + create_physical_mapping(params->end, params->aligned_end); + spin_lock(&init_mm.page_table_lock); + return 0; +} + static void remove_pte_table(pte_t *pte_start, unsigned long addr, unsigned long end) { @@ -699,6 +724,52 @@ static void remove_pte_table(pte_t *pte_ } } +/* + * clear the pte and potentially split the mapping helper + */ +static void split_kernel_mapping(unsigned long addr, unsigned long end, + unsigned long size, pte_t *pte) +{ + unsigned long mask = ~(size - 1); + unsigned long aligned_start = addr & mask; + unsigned long aligned_end = addr + size; + struct change_mapping_params params; + bool split_region = false; + + if ((end - addr) < size) { + /* + * We're going to clear the PTE, but not flushed + * the mapping, time to remap and flush. The + * effects if visible outside the processor or + * if we are running in code close to the + * mapping we cleared, we are in trouble. + */ + if (overlaps_kernel_text(aligned_start, addr) || + overlaps_kernel_text(end, aligned_end)) { + /* + * Hack, just return, don't pte_clear + */ + WARN_ONCE(1, "Linear mapping %lx->%lx overlaps kernel " + "text, not splitting\n", addr, end); + return; + } + split_region = true; + } + + if (split_region) { + params.pte = pte; + params.start = addr; + params.end = end; + params.aligned_start = addr & ~(size - 1); + params.aligned_end = min_t(unsigned long, aligned_end, + (unsigned long)__va(memblock_end_of_DRAM())); + stop_machine(stop_machine_change_mapping, &params, NULL); + return; + } + + pte_clear(&init_mm, addr, pte); +} + static void remove_pmd_table(pmd_t *pmd_start, unsigned long addr, unsigned long end) { @@ -714,13 +785,7 @@ static void remove_pmd_table(pmd_t *pmd_ continue; if (pmd_huge(*pmd)) { - if (!IS_ALIGNED(addr, PMD_SIZE) || - !IS_ALIGNED(next, PMD_SIZE)) { - WARN_ONCE(1, "%s: unaligned range\n", __func__); - continue; - } - - pte_clear(&init_mm, addr, (pte_t *)pmd); + split_kernel_mapping(addr, end, PMD_SIZE, (pte_t *)pmd); continue; } @@ -745,13 +810,7 @@ static void remove_pud_table(pud_t *pud_ continue; if (pud_huge(*pud)) { - if (!IS_ALIGNED(addr, PUD_SIZE) || - !IS_ALIGNED(next, PUD_SIZE)) { - WARN_ONCE(1, "%s: unaligned range\n", __func__); - continue; - } - - pte_clear(&init_mm, addr, (pte_t *)pud); + split_kernel_mapping(addr, end, PUD_SIZE, (pte_t *)pud); continue; } @@ -777,13 +836,7 @@ static void remove_pagetable(unsigned lo continue; if (pgd_huge(*pgd)) { - if (!IS_ALIGNED(addr, PGDIR_SIZE) || - !IS_ALIGNED(next, PGDIR_SIZE)) { - WARN_ONCE(1, "%s: unaligned range\n", __func__); - continue; - } - - pte_clear(&init_mm, addr, (pte_t *)pgd); + split_kernel_mapping(addr, end, PGDIR_SIZE, (pte_t *)pgd); continue; } Patches currently in stable-queue which might be from bsingharora(a)gmail.com are queue-4.15/powerpc-radix-remove-trace_tlbie-call-from-radix__flush_tlb_all.patch queue-4.15/powerpc-mm-radix-split-linear-mapping-on-hot-unplug.patch

7 years, 4 months

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Patch "KVM/x86: Reduce retpoline performance impact in slot_handle_level_range(), by always inlining iterator helper methods" has been added to the 4.15-stable tree

by gregkh＠linuxfoundation.org

This is a note to let you know that I've just added the patch titled KVM/x86: Reduce retpoline performance impact in slot_handle_level_range(), by always inlining iterator helper methods to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=sum… The filename of the patch is: kvm-x86-reduce-retpoline-performance-impact-in-slot_handle_level_range-by-always-inlining-iterator-helper-methods.patch and it can be found in the queue-4.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org> know about it. >From 928a4c39484281f8ca366f53a1db79330d058401 Mon Sep 17 00:00:00 2001 From: David Woodhouse <dwmw(a)amazon.co.uk> Date: Sat, 10 Feb 2018 23:39:24 +0000 Subject: KVM/x86: Reduce retpoline performance impact in slot_handle_level_range(), by always inlining iterator helper methods MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: David Woodhouse <dwmw(a)amazon.co.uk> commit 928a4c39484281f8ca366f53a1db79330d058401 upstream. With retpoline, tight loops of "call this function for every XXX" are very much pessimised by taking a prediction miss *every* time. This one is by far the biggest contributor to the guest launch time with retpoline. By marking the iterator slot_handle_…() functions always_inline, we can ensure that the indirect function call can be optimised away into a direct call and it actually generates slightly smaller code because some of the other conditionals can get optimised away too. Performance is now pretty close to what we see with nospectre_v2 on the command line. Suggested-by: Linus Torvalds <torvalds(a)linux-foundation.org> Tested-by: Filippo Sironi <sironi(a)amazon.de> Signed-off-by: David Woodhouse <dwmw(a)amazon.co.uk> Reviewed-by: Filippo Sironi <sironi(a)amazon.de> Acked-by: Paolo Bonzini <pbonzini(a)redhat.com> Cc: Andy Lutomirski <luto(a)kernel.org> Cc: Arjan van de Ven <arjan(a)linux.intel.com> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Dan Williams <dan.j.williams(a)intel.com> Cc: Dave Hansen <dave.hansen(a)linux.intel.com> Cc: David Woodhouse <dwmw2(a)infradead.org> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Josh Poimboeuf <jpoimboe(a)redhat.com> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: arjan.van.de.ven(a)intel.com Cc: dave.hansen(a)intel.com Cc: jmattson(a)google.com Cc: karahmed(a)amazon.de Cc: kvm(a)vger.kernel.org Cc: rkrcmar(a)redhat.com Link: http://lkml.kernel.org/r/1518305967-31356-4-git-send-email-dwmw@amazon.co.uk Signed-off-by: Ingo Molnar <mingo(a)kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- arch/x86/kvm/mmu.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -5058,7 +5058,7 @@ void kvm_mmu_uninit_vm(struct kvm *kvm) typedef bool (*slot_level_handler) (struct kvm *kvm, struct kvm_rmap_head *rmap_head); /* The caller should hold mmu-lock before calling this function. */ -static bool +static __always_inline bool slot_handle_level_range(struct kvm *kvm, struct kvm_memory_slot *memslot, slot_level_handler fn, int start_level, int end_level, gfn_t start_gfn, gfn_t end_gfn, bool lock_flush_tlb) @@ -5088,7 +5088,7 @@ slot_handle_level_range(struct kvm *kvm, return flush; } -static bool +static __always_inline bool slot_handle_level(struct kvm *kvm, struct kvm_memory_slot *memslot, slot_level_handler fn, int start_level, int end_level, bool lock_flush_tlb) @@ -5099,7 +5099,7 @@ slot_handle_level(struct kvm *kvm, struc lock_flush_tlb); } -static bool +static __always_inline bool slot_handle_all_level(struct kvm *kvm, struct kvm_memory_slot *memslot, slot_level_handler fn, bool lock_flush_tlb) { @@ -5107,7 +5107,7 @@ slot_handle_all_level(struct kvm *kvm, s PT_MAX_HUGEPAGE_LEVEL, lock_flush_tlb); } -static bool +static __always_inline bool slot_handle_large_level(struct kvm *kvm, struct kvm_memory_slot *memslot, slot_level_handler fn, bool lock_flush_tlb) { @@ -5115,7 +5115,7 @@ slot_handle_large_level(struct kvm *kvm, PT_MAX_HUGEPAGE_LEVEL, lock_flush_tlb); } -static bool +static __always_inline bool slot_handle_leaf(struct kvm *kvm, struct kvm_memory_slot *memslot, slot_level_handler fn, bool lock_flush_tlb) { Patches currently in stable-queue which might be from dwmw(a)amazon.co.uk are queue-4.15/kvm-nvmx-set-the-cpu_based_use_msr_bitmaps-if-we-have-a-valid-l02-msr-bitmap.patch queue-4.15/x86-nvmx-properly-set-spec_ctrl-and-pred_cmd-before-merging-msrs.patch queue-4.15/x86-speculation-update-speculation-control-microcode-blacklist.patch queue-4.15/x86-speculation-correct-speculation-control-microcode-blacklist-again.patch queue-4.15/kvm-x86-reduce-retpoline-performance-impact-in-slot_handle_level_range-by-always-inlining-iterator-helper-methods.patch queue-4.15/x86-speculation-clean-up-various-spectre-related-details.patch queue-4.15/revert-x86-speculation-simplify-indirect_branch_prediction_barrier.patch

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