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x86/cpu: Load microcode during restore_processor_state() 

When resuming from system sleep state, restore_processor_state()
restores the boot CPU MSRs. These MSRs could be emulated by microcode.
If microcode is not loaded yet, writing to emulated MSRs leads to
unchecked MSR access error:

  ...
  PM: Calling lapic_suspend+0x0/0x210
  unchecked MSR access error: WRMSR to 0x10f (tried to write 0x0...0) at rIP: ... (native_write_msr)
  Call Trace:
    <TASK>
    ? restore_processor_state
    x86_acpi_suspend_lowlevel
    acpi_suspend_enter
    suspend_devices_and_enter
    pm_suspend.cold
    state_store
    kobj_attr_store
    sysfs_kf_write
    kernfs_fop_write_iter
    new_sync_write
    vfs_write
    ksys_write
    __x64_sys_write
    do_syscall_64
    entry_SYSCALL_64_after_hwframe
   RIP: 0033:0x7fda13c260a7

To ensure microcode emulated MSRs are available for restoration, load
the microcode on the boot CPU before restoring these MSRs.

  [ Pawan: write commit message and productize it. ]

Fixes: e2a1256b17 ("x86/speculation: Restore speculation related MSRs during S3 resume")
Reported-by: Kyle D. Pelton <kyle.d.pelton@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Tested-by: Kyle D. Pelton <kyle.d.pelton@intel.com>
Cc: stable@vger.kernel.org
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215841
Link: https://lore.kernel.org/r/4350dfbf785cd482d3fafa72b2b49c83102df3ce.1650386317.git.pawan.kumar.gupta@linux.intel.com
This commit is contained in:
Borislav Petkov 2022-04-19 09:52:41 -07:00
parent 3ccce93403
commit f9e14dbbd4
3 changed files with 14 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/include/asm/microcode.h
View File

@ -131,10 +131,12 @@ extern void __init load_ucode_bsp(void);
extern void load_ucode_ap(void);
void reload_early_microcode(void);
extern bool initrd_gone;
void microcode_bsp_resume(void);
#else
static inline void __init load_ucode_bsp(void) { }
static inline void load_ucode_ap(void) { }
static inline void reload_early_microcode(void) { }
static inline void microcode_bsp_resume(void) { }
#endif
#endif /* _ASM_X86_MICROCODE_H */

6
arch/x86/kernel/cpu/microcode/core.c
View File

@ -758,9 +758,9 @@ static struct subsys_interface mc_cpu_interface = {
};
/**
* mc_bp_resume - Update boot CPU microcode during resume.
* microcode_bsp_resume - Update boot CPU microcode during resume.
*/
static void mc_bp_resume(void)
void microcode_bsp_resume(void)
{
int cpu = smp_processor_id();
struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
@ -772,7 +772,7 @@ static void mc_bp_resume(void)
}
static struct syscore_ops mc_syscore_ops = {
.resume = mc_bp_resume,
.resume = microcode_bsp_resume,
};
static int mc_cpu_starting(unsigned int cpu)

10
arch/x86/power/cpu.c
View File

@ -25,6 +25,7 @@
#include <asm/cpu.h>
#include <asm/mmu_context.h>
#include <asm/cpu_device_id.h>
#include <asm/microcode.h>
#ifdef CONFIG_X86_32
__visible unsigned long saved_context_ebx;
@ -262,11 +263,18 @@ static void notrace __restore_processor_state(struct saved_context *ctxt)
x86_platform.restore_sched_clock_state();
mtrr_bp_restore();
perf_restore_debug_store();
msr_restore_context(ctxt);
c = &cpu_data(smp_processor_id());
if (cpu_has(c, X86_FEATURE_MSR_IA32_FEAT_CTL))
init_ia32_feat_ctl(c);
microcode_bsp_resume();
/*
* This needs to happen after the microcode has been updated upon resume
* because some of the MSRs are "emulated" in microcode.
*/
msr_restore_context(ctxt);
}
/* Needed by apm.c */