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authorBorislav Petkov <bp@suse.de>2022-04-19 09:52:41 -0700
committerBorislav Petkov <bp@suse.de>2022-04-19 19:37:05 +0200
commitf9e14dbbd454581061c736bf70bf5cbb15ac927c (patch)
tree9920906a27b7dce55aeb504bdc69856eba8e65c7 /arch
parent3ccce9340326df40ba4462d4d2a1692b6387a68e (diff)
downloadlinux-f9e14dbbd454581061c736bf70bf5cbb15ac927c.tar.bz2
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: e2a1256b17b1 ("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
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/include/asm/microcode.h2
-rw-r--r--arch/x86/kernel/cpu/microcode/core.c6
-rw-r--r--arch/x86/power/cpu.c10
3 files changed, 14 insertions, 4 deletions
diff --git a/arch/x86/include/asm/microcode.h b/arch/x86/include/asm/microcode.h
index d6bfdfb0f0af..0c3d3440fe27 100644
--- a/arch/x86/include/asm/microcode.h
+++ b/arch/x86/include/asm/microcode.h
@@ -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 */
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c
index f955d25076ba..239ff5fcec6a 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -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)
diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
index 3822666fb73d..bb176c72891c 100644
--- a/arch/x86/power/cpu.c
+++ b/arch/x86/power/cpu.c
@@ -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 */