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x86/microcode: Add a parameter to microcode_check() to store CPU capabilities

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[ 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@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230109153555.4986-2-ashok.raj@intel.com
Stable-dep-of: c0dd9245aa9e ("x86/microcode: Check CPU capabilities after late microcode update correctly")
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Ashok Raj
2023-01-09 07:35:50 -08:00
committed by Greg Kroah-Hartman
parent f5e78fa916
commit 89e848bb4a
3 changed files with 16 additions and 10 deletions
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2
arch/x86/include/asm/processor.h
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@@ -840,7 +840,7 @@ bool xen_set_default_idle(void);
#endif #endif
void __noreturn stop_this_cpu(void *dummy); void __noreturn stop_this_cpu(void *dummy);
void microcode_check(void); void microcode_check(struct cpuinfo_x86 *prev_info);
enum l1tf_mitigations { enum l1tf_mitigations {
L1TF_MITIGATION_OFF, L1TF_MITIGATION_OFF,

21
arch/x86/kernel/cpu/common.c
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@@ -2130,30 +2130,35 @@ void cpu_init_secondary(void)
#endif #endif
#ifdef CONFIG_MICROCODE_LATE_LOADING #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, * The microcode loader calls this upon late microcode load to recheck features,
* only when microcode has been updated. Caller holds microcode_mutex and CPU * only when microcode has been updated. Caller holds microcode_mutex and CPU
* hotplug lock. * hotplug lock.
*
* Return: None
*/ */
void microcode_check(void) void microcode_check(struct cpuinfo_x86 *prev_info)
{ {
struct cpuinfo_x86 info;
perf_check_microcode(); perf_check_microcode();
/* Reload CPUID max function as it might've changed. */ /* 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 * 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 * memcmp() below doesn't fail on that. The ones coming from CPUID will
* get overwritten in get_cpu_cap(). * 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; return;
pr_warn("x86/CPU: CPU features have changed after loading microcode, but might not take effect.\n"); pr_warn("x86/CPU: CPU features have changed after loading microcode, but might not take effect.\n");

3
arch/x86/kernel/cpu/microcode/core.c
View File

@@ -509,13 +509,14 @@ wait_for_siblings:
static int microcode_reload_late(void) static int microcode_reload_late(void)
{ {
int old = boot_cpu_data.microcode, ret; int old = boot_cpu_data.microcode, ret;
struct cpuinfo_x86 prev_info;
atomic_set(&late_cpus_in, 0); atomic_set(&late_cpus_in, 0);
atomic_set(&late_cpus_out, 0); atomic_set(&late_cpus_out, 0);
ret = stop_machine_cpuslocked(__reload_late, NULL, cpu_online_mask); ret = stop_machine_cpuslocked(__reload_late, NULL, cpu_online_mask);
if (ret == 0) if (ret == 0)
microcode_check(); microcode_check(&prev_info);
pr_info("Reload completed, microcode revision: 0x%x -> 0x%x\n", pr_info("Reload completed, microcode revision: 0x%x -> 0x%x\n",
old, boot_cpu_data.microcode); old, boot_cpu_data.microcode);