This is a note to let you know that I've just added the patch titled
x86/cpufeature: Add facility to check for min microcode revisions
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-cpufeature-add-facility-to-check-for-min-microcode-revisions.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Mon Oct 31 07:55:50 AM CET 2022
From: Suraj Jitindar Singh <surajjs@xxxxxxxxxx>
Date: Thu, 27 Oct 2022 13:54:28 -0700
Subject: x86/cpufeature: Add facility to check for min microcode revisions
To: <stable@xxxxxxxxxxxxxxx>
Cc: <surajjs@xxxxxxxxxx>, <sjitindarsingh@xxxxxxxxx>, <cascardo@xxxxxxxxxxxxx>, <kvm@xxxxxxxxxxxxxxx>, <pbonzini@xxxxxxxxxx>, <jpoimboe@xxxxxxxxxx>, <peterz@xxxxxxxxxxxxx>, <x86@xxxxxxxxxx>
Message-ID: <20221027205430.17122-2-surajjs@xxxxxxxxxx>
From: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
commit 0f42b790c9ba5ec2f25b7da8b0b6d361082d67b0 upstream
For bug workarounds or checks, it is useful to check for specific
microcode revisions.
Add a new generic function to match the CPU with stepping.
Add the other function to check the min microcode revisions for
the matched CPU.
A new table format is introduced to facilitate the quirk to
fill the related information.
This does not change the existing x86_cpu_id because it's an ABI
shared with modules, and also has quite different requirements,
as in no wildcards, but everything has to be matched exactly.
Originally-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Suggested-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Acked-by: Borislav Petkov <bp@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: eranian@xxxxxxxxxx
Link: https://lkml.kernel.org/r/1549319013-4522-1-git-send-email-kan.liang@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/cpu_device_id.h | 28 ++++++++++++++++++++++++++++
arch/x86/kernel/cpu/match.c | 31 +++++++++++++++++++++++++++++++
2 files changed, 59 insertions(+)
--- a/arch/x86/include/asm/cpu_device_id.h
+++ b/arch/x86/include/asm/cpu_device_id.h
@@ -11,4 +11,32 @@
extern const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match);
+/*
+ * Match specific microcode revisions.
+ *
+ * vendor/family/model/stepping must be all set.
+ *
+ * Only checks against the boot CPU. When mixed-stepping configs are
+ * valid for a CPU model, add a quirk for every valid stepping and
+ * do the fine-tuning in the quirk handler.
+ */
+
+struct x86_cpu_desc {
+ __u8 x86_family;
+ __u8 x86_vendor;
+ __u8 x86_model;
+ __u8 x86_stepping;
+ __u32 x86_microcode_rev;
+};
+
+#define INTEL_CPU_DESC(mod, step, rev) { \
+ .x86_family = 6, \
+ .x86_vendor = X86_VENDOR_INTEL, \
+ .x86_model = mod, \
+ .x86_stepping = step, \
+ .x86_microcode_rev = rev, \
+}
+
+extern bool x86_cpu_has_min_microcode_rev(const struct x86_cpu_desc *table);
+
#endif
--- a/arch/x86/kernel/cpu/match.c
+++ b/arch/x86/kernel/cpu/match.c
@@ -48,3 +48,34 @@ const struct x86_cpu_id *x86_match_cpu(c
return NULL;
}
EXPORT_SYMBOL(x86_match_cpu);
+
+static const struct x86_cpu_desc *
+x86_match_cpu_with_stepping(const struct x86_cpu_desc *match)
+{
+ struct cpuinfo_x86 *c = &boot_cpu_data;
+ const struct x86_cpu_desc *m;
+
+ for (m = match; m->x86_family | m->x86_model; m++) {
+ if (c->x86_vendor != m->x86_vendor)
+ continue;
+ if (c->x86 != m->x86_family)
+ continue;
+ if (c->x86_model != m->x86_model)
+ continue;
+ if (c->x86_stepping != m->x86_stepping)
+ continue;
+ return m;
+ }
+ return NULL;
+}
+
+bool x86_cpu_has_min_microcode_rev(const struct x86_cpu_desc *table)
+{
+ const struct x86_cpu_desc *res = x86_match_cpu_with_stepping(table);
+
+ if (!res || res->x86_microcode_rev > boot_cpu_data.microcode)
+ return false;
+
+ return true;
+}
+EXPORT_SYMBOL_GPL(x86_cpu_has_min_microcode_rev);
Patches currently in stable-queue which might be from surajjs@xxxxxxxxxx are
queue-4.14/x86-speculation-disable-rrsba-behavior.patch
queue-4.14/x86-bugs-report-intel-retbleed-vulnerability.patch
queue-4.14/x86-entry-add-kernel-ibrs-implementation.patch
queue-4.14/x86-bugs-warn-when-ibrs-mitigation-is-selected-on-enhanced-ibrs-parts.patch
queue-4.14/x86-cpu-add-a-steppings-field-to-struct-x86_cpu_id.patch
queue-4.14/x86-speculation-fix-spec_ctrl-write-on-smt-state-change.patch
queue-4.14/entel_idle-disable-ibrs-during-long-idle.patch
queue-4.14/x86-speculation-use-cached-host-spec_ctrl-value-for-guest-entry-exit.patch
queue-4.14/x86-speculation-change-fill_return_buffer-to-work-with-objtool.patch
queue-4.14/x86-speculation-add-lfence-to-rsb-fill-sequence.patch
queue-4.14/x86-bugs-report-amd-retbleed-vulnerability.patch
queue-4.14/x86-speculation-add-spectre_v2-ibrs-option-to-support-kernel-ibrs.patch
queue-4.14/x86-bugs-keep-a-per-cpu-ia32_spec_ctrl-value.patch
queue-4.14/x86-speculation-fill-rsb-on-vmexit-for-ibrs.patch
queue-4.14/x86-speculation-fix-rsb-filling-with-config_retpoline-n.patch
queue-4.14/x86-speculation-add-rsb-vm-exit-protections.patch
queue-4.14/x86-bugs-optimize-spec_ctrl-msr-writes.patch
queue-4.14/kvm-vmx-fix-ibrs-handling-after-vmexit.patch
queue-4.14/kvm-vmx-prevent-guest-rsb-poisoning-attacks-with-eibrs.patch
queue-4.14/x86-speculation-fix-firmware-entry-spec_ctrl-handling.patch
queue-4.14/x86-bugs-add-amd-retbleed-boot-parameter.patch
queue-4.14/x86-cpu-add-consistent-cpu-match-macros.patch
queue-4.14/x86-speculation-remove-x86_spec_ctrl_mask.patch
queue-4.14/x86-speculation-use-declare_per_cpu-for-x86_spec_ctrl_current.patch
queue-4.14/x86-cpufeature-fix-various-quality-problems-in-the-asm-cpu_device_hd.h-header.patch
queue-4.14/x86-entry-remove-skip_r11rcx.patch
queue-4.14/revert-x86-cpu-add-a-steppings-field-to-struct-x86_cpu_id.patch
queue-4.14/x86-common-stamp-out-the-stepping-madness.patch
queue-4.14/x86-cpu-amd-enumerate-btc_no.patch
queue-4.14/x86-bugs-add-cannon-lake-to-retbleed-affected-cpu-list.patch
queue-4.14/x86-devicetable-move-x86-specific-macro-out-of-generic-code.patch
queue-4.14/x86-bugs-split-spectre_v2_select_mitigation-and-spectre_v2_user_select_mitigation.patch
queue-4.14/x86-cpufeatures-move-retpoline-flags-to-word-11.patch
queue-4.14/x86-cpufeature-add-facility-to-check-for-min-microcode-revisions.patch
