From 42ca8082e260dcfd8afa2afa6ec1940b9d41724c Mon Sep 17 00:00:00 2001 | |
From: Borislav Petkov <bp@suse.de> | |
Date: Fri, 16 Feb 2018 12:26:40 +0100 | |
Subject: x86/CPU: Check CPU feature bits after microcode upgrade | |
With some microcode upgrades, new CPUID features can become visible on | |
the CPU. Check what the kernel has mirrored now and issue a warning | |
hinting at possible things the user/admin can do to make use of the | |
newly visible features. | |
Originally-by: Ashok Raj <ashok.raj@intel.com> | |
Tested-by: Ashok Raj <ashok.raj@intel.com> | |
Signed-off-by: Borislav Petkov <bp@suse.de> | |
Reviewed-by: Ashok Raj <ashok.raj@intel.com> | |
Cc: Andy Lutomirski <luto@kernel.org> | |
Cc: Arjan van de Ven <arjan@linux.intel.com> | |
Cc: Borislav Petkov <bp@alien8.de> | |
Cc: Dan Williams <dan.j.williams@intel.com> | |
Cc: Dave Hansen <dave.hansen@linux.intel.com> | |
Cc: David Woodhouse <dwmw2@infradead.org> | |
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
Cc: Josh Poimboeuf <jpoimboe@redhat.com> | |
Cc: Linus Torvalds <torvalds@linux-foundation.org> | |
Cc: Peter Zijlstra <peterz@infradead.org> | |
Cc: Thomas Gleixner <tglx@linutronix.de> | |
Link: http://lkml.kernel.org/r/20180216112640.11554-4-bp@alien8.de | |
Signed-off-by: Ingo Molnar <mingo@kernel.org> | |
--- | |
arch/x86/kernel/cpu/common.c | 20 ++++++++++++++++++++ | |
1 file changed, 20 insertions(+) | |
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c | |
index 84f1cd8..348cf48 100644 | |
--- a/arch/x86/kernel/cpu/common.c | |
+++ b/arch/x86/kernel/cpu/common.c | |
@@ -1757,5 +1757,25 @@ core_initcall(init_cpu_syscore); | |
*/ | |
void microcode_check(void) | |
{ | |
+ struct cpuinfo_x86 info; | |
+ | |
perf_check_microcode(); | |
+ | |
+ /* Reload CPUID max function as it might've changed. */ | |
+ info.cpuid_level = cpuid_eax(0); | |
+ | |
+ /* | |
+ * Copy all capability leafs to pick up the synthetic ones so that | |
+ * memcmp() below doesn't fail on that. The ones coming from CPUID will | |
+ * get overwritten in get_cpu_cap(). | |
+ */ | |
+ memcpy(&info.x86_capability, &boot_cpu_data.x86_capability, sizeof(info.x86_capability)); | |
+ | |
+ get_cpu_cap(&info); | |
+ | |
+ if (!memcmp(&info.x86_capability, &boot_cpu_data.x86_capability, sizeof(info.x86_capability))) | |
+ return; | |
+ | |
+ pr_warn("x86/CPU: CPU features have changed after loading microcode, but might not take effect.\n"); | |
+ pr_warn("x86/CPU: Please consider either early loading through initrd/built-in or a potential BIOS update.\n"); | |
} | |
-- | |
cgit v1.1 | |