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 <[email protected]>
Cc: LKML <[email protected]>
Cc: x86 <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Alison Schofield <[email protected]>
Cc: Reinette Chatre <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Tom Lendacky <[email protected]>
Cc: Ingo Molnar <[email protected]>
---
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
The following commit has been merged into the x86/microcode branch of tip:
Commit-ID: ab31c74455c64e69342ddab21fd9426fcbfefde7
Gitweb: https://git.kernel.org/tip/ab31c74455c64e69342ddab21fd9426fcbfefde7
Author: Ashok Raj <[email protected]>
AuthorDate: Mon, 09 Jan 2023 07:35:50 -08:00
Committer: Borislav Petkov (AMD) <[email protected]>
CommitterDate: Fri, 20 Jan 2023 21:45:13 +01:00
x86/microcode: Add a parameter to microcode_check() to store CPU capabilities
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 <[email protected]>
Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
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 4e35c66..f256a4d 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 9cfca3d..0f5a173 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 99abb31..dc5dfba 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -438,6 +438,7 @@ wait_for_siblings:
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");
@@ -447,7 +448,7 @@ 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);