Messages in this thread Patch in this message | | | From | Ashok Raj <> | Subject | [PATCH v4 1/6] x86/microcode: Add a parameter to microcode_check() to store CPU capabilities | Date | Mon, 9 Jan 2023 07:35:50 -0800 |
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Add a parameter to store CPU capabilities before performing a microcode update so that the code later can compare CPU capabilities before and after performing the update.
Signed-off-by: Ashok Raj <ashok.raj@intel.com> Cc: LKML <linux-kernel@vger.kernel.org> Cc: x86 <x86@kernel.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Alison Schofield <alison.schofield@intel.com> Cc: Reinette Chatre <reinette.chatre@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Ingo Molnar <mingo@kernel.org> --- Changes since V3
Boris: - Fix commit log to drop "next patch". - Add documentation to new parameter to microcode_check() --- arch/x86/include/asm/processor.h | 2 +- arch/x86/kernel/cpu/common.c | 21 +++++++++++++-------- arch/x86/kernel/cpu/microcode/core.c | 3 ++- 3 files changed, 16 insertions(+), 10 deletions(-)
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 4e35c66edeb7..f256a4ddd25d 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -697,7 +697,7 @@ bool xen_set_default_idle(void); #endif void __noreturn stop_this_cpu(void *dummy); -void microcode_check(void); +void microcode_check(struct cpuinfo_x86 *prev_info); enum l1tf_mitigations { L1TF_MITIGATION_OFF, diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 9cfca3d7d0e2..0f5a173d0871 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -2297,30 +2297,35 @@ void cpu_init_secondary(void) #endif #ifdef CONFIG_MICROCODE_LATE_LOADING -/* +/** + * microcode_check() - Check if any CPU capabilities changed after an update. + * @prev_info: CPU capabilities stored before an update. + * * The microcode loader calls this upon late microcode load to recheck features, * only when microcode has been updated. Caller holds microcode_mutex and CPU * hotplug lock. + * + * Return: None */ -void microcode_check(void) +void microcode_check(struct cpuinfo_x86 *prev_info) { - struct cpuinfo_x86 info; - perf_check_microcode(); /* Reload CPUID max function as it might've changed. */ - info.cpuid_level = cpuid_eax(0); + prev_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)); + memcpy(&prev_info->x86_capability, &boot_cpu_data.x86_capability, + sizeof(prev_info->x86_capability)); - get_cpu_cap(&info); + get_cpu_cap(prev_info); - if (!memcmp(&info.x86_capability, &boot_cpu_data.x86_capability, sizeof(info.x86_capability))) + if (!memcmp(&prev_info->x86_capability, &boot_cpu_data.x86_capability, + sizeof(prev_info->x86_capability))) return; pr_warn("x86/CPU: CPU features have changed after loading microcode, but might not take effect.\n"); diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index c4cd7328177b..e39d83be794b 100644 --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -439,6 +439,7 @@ static int __reload_late(void *info) static int microcode_reload_late(void) { int old = boot_cpu_data.microcode, ret; + struct cpuinfo_x86 prev_info; pr_err("Attempting late microcode loading - it is dangerous and taints the kernel.\n"); pr_err("You should switch to early loading, if possible.\n"); @@ -448,7 +449,7 @@ static int microcode_reload_late(void) ret = stop_machine_cpuslocked(__reload_late, NULL, cpu_online_mask); if (ret == 0) - microcode_check(); + microcode_check(&prev_info); pr_info("Reload completed, microcode revision: 0x%x -> 0x%x\n", old, boot_cpu_data.microcode); -- 2.34.1
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