This is a note to let you know that I've just added the patch titled
x86/microcode: Add a parameter to microcode_check() to store CPU capabilities
to the 5.10-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-microcode-add-a-parameter-to-microcode_check-to-.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 619a2fe99a192cca4928022fd8cb3a6855b4ab02
Author: Ashok Raj <ashok.raj@xxxxxxxxx>
Date: Mon Jan 9 07:35:50 2023 -0800
x86/microcode: Add a parameter to microcode_check() to store CPU capabilities
[ Upstream commit ab31c74455c64e69342ddab21fd9426fcbfefde7 ]
Add a parameter to store CPU capabilities before performing a microcode
update so that CPU capabilities can be compared before and after update.
[ bp: Massage. ]
Signed-off-by: Ashok Raj <ashok.raj@xxxxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Link: https://lore.kernel.org/r/20230109153555.4986-2-ashok.raj@xxxxxxxxx
Stable-dep-of: c0dd9245aa9e ("x86/microcode: Check CPU capabilities after late microcode update correctly")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 01bcbf8a25b29..6d40c409ebc16 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -840,7 +840,7 @@ 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 95f52540db378..f724002adbfc3 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -2130,30 +2130,35 @@ 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 707a385943b41..2c70f3cfae68e 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -509,13 +509,14 @@ static int __reload_late(void *info)
static int microcode_reload_late(void)
{
int old = boot_cpu_data.microcode, ret;
+ struct cpuinfo_x86 prev_info;
atomic_set(&late_cpus_in, 0);
atomic_set(&late_cpus_out, 0);
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);
