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kernel/SOURCES/1016-x86-cpu-Load-microcode-during-restore_processor_stat.patch

130 lines
4.4 KiB
Diff

From be1cba911af4925ef0f42bdfee9682b01c94dfcb Mon Sep 17 00:00:00 2001
From: Borislav Petkov <bp@suse.de>
Date: Tue, 19 Apr 2022 09:52:41 -0700
Subject: [PATCH 02/36] 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
(cherry picked from commit f9e14dbbd454581061c736bf70bf5cbb15ac927c)
Signed-off-by: Mridula Shastry <mridula.c.shastry@oracle.com>
Reviewed-by: Todd Vierling <todd.vierling@oracle.com>
---
arch/x86/include/asm/microcode.h | 2 ++
arch/x86/kernel/cpu/microcode/core.c | 6 +++---
arch/x86/power/cpu.c | 8 ++++++++
3 files changed, 13 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/microcode.h b/arch/x86/include/asm/microcode.h
index 2b7cc5397f80..a930a63d1260 100644
--- a/arch/x86/include/asm/microcode.h
+++ b/arch/x86/include/asm/microcode.h
@@ -133,6 +133,7 @@ extern void load_ucode_ap(void);
void reload_early_microcode(void);
extern bool get_builtin_firmware(struct cpio_data *cd, const char *name);
extern bool initrd_gone;
+void microcode_bsp_resume(void);
#else
static inline int __init microcode_init(void) { return 0; };
static inline void __init load_ucode_bsp(void) { }
@@ -140,6 +141,7 @@ static inline void load_ucode_ap(void) { }
static inline void reload_early_microcode(void) { }
static inline bool
get_builtin_firmware(struct cpio_data *cd, const char *name) { return false; }
+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 e263da7247af..f0946658f885 100644
--- a/arch/x86/kernel/cpu/microcode/core.c
+++ b/arch/x86/kernel/cpu/microcode/core.c
@@ -778,9 +778,9 @@ 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;
@@ -792,7 +792,7 @@ 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 f48756c903d4..dd5a29553697 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 <linux/dmi.h>
+#include <asm/microcode.h>
#ifdef CONFIG_X86_32
__visible unsigned long saved_context_ebx;
@@ -266,6 +267,13 @@ static void notrace __restore_processor_state(struct saved_context *ctxt)
x86_platform.restore_sched_clock_state();
mtrr_bp_restore();
perf_restore_debug_store();
+
+ 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);
}
--
2.39.3