From: Ashok Raj <ashok.raj@intel.com>
To: Borislav Petkov <bp@alien8.de>, Thomas Gleixner <tglx@linutronix.de>
Cc: X86-kernel <x86@kernel.org>,
LKML Mailing List <linux-kernel@vger.kernel.org>,
Ashok Raj <ashok.raj@intel.com>,
Dave Hansen <dave.hansen@intel.com>,
Tony Luck <tony.luck@intel.com>, Ingo Molnar <mingo@kernel.org>,
alison.schofield@intel.com, reinette.chatre@intel.com,
Tom Lendacky <thomas.lendacky@amd.com>
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 [thread overview]
Message-ID: <20230109153555.4986-2-ashok.raj@intel.com> (raw)
In-Reply-To: <20230109153555.4986-1-ashok.raj@intel.com>
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
next prev parent reply other threads:[~2023-01-09 15:40 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-09 15:35 [PATCH v4 0/6] Some fixes and cleanups for microcode Ashok Raj
2023-01-09 15:35 ` Ashok Raj [this message]
2023-01-21 14:54 ` [tip: x86/microcode] x86/microcode: Add a parameter to microcode_check() to store CPU capabilities tip-bot2 for Ashok Raj
2023-01-09 15:35 ` [PATCH v4 2/6] x86/microcode/core: Take a snapshot before and after applying microcode Ashok Raj
2023-01-21 14:54 ` [tip: x86/microcode] x86/microcode: Check CPU capabilities after late microcode update correctly tip-bot2 for Ashok Raj
2023-01-09 15:35 ` [PATCH v4 3/6] x86/microcode: Display revisions only when update is successful Ashok Raj
2023-01-09 15:35 ` [PATCH v4 4/6] x86/microcode/intel: Use a plain revision argument for print_ucode_rev() Ashok Raj
2023-01-15 19:25 ` Borislav Petkov
2023-01-15 19:39 ` Borislav Petkov
2023-01-17 16:05 ` Ashok Raj
2023-01-17 18:16 ` Borislav Petkov
2023-01-09 15:35 ` [PATCH v4 5/6] x86/microcode/intel: Print old and new rev during early boot Ashok Raj
2023-01-09 15:35 ` [PATCH v4 6/6] x86/microcode/intel: Print when early microcode loading fails Ashok Raj
2023-01-15 19:05 ` Borislav Petkov
2023-01-17 16:12 ` Ashok Raj
2023-01-17 16:29 ` Dave Hansen
2023-01-17 18:21 ` Borislav Petkov
2023-01-17 18:32 ` Dave Hansen
2023-01-17 18:40 ` Borislav Petkov
2023-01-17 20:40 ` Ashok Raj
2023-01-17 20:58 ` Luck, Tony
2023-01-19 17:59 ` Ashok Raj
2023-01-20 12:03 ` Borislav Petkov
2023-01-20 16:52 ` Ashok Raj
2023-01-17 21:00 ` Dave Hansen
2023-01-17 21:06 ` Borislav Petkov
2023-01-17 21:34 ` Ashok Raj
2023-01-17 19:10 ` Ashok Raj
2023-01-17 16:35 ` Dave Hansen
2023-01-17 17:59 ` Ashok Raj
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