x86: correct ordering of operations during S3 resume

Microcode loading needs to happen before re-enabling interrupts, in case
only updated microcode allows the use of e.g. the SPEC_{CTRL,CMD} MSRs.
Otoh it doesn't need to happen at all when we didn't suspend in the
first place. It needs to happen before spin_debug_enable() though, as it
acquires a lock and hence would otherwise make
common/spinlock.c:check_lock() unhappy. As micrcode loading can be
pretty verbose, also make sure it only runs after console_end_sync().

cpufreq_add_cpu() doesn't need calling on the only "goto enable_cpu"
path, which sits ahead of cpufreq_del_cpu().

Reported-by: Simon Gaiser <simon@invisiblethingslab.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
master commit: cb2a4a449dfd50af309a333aa805835015fbc8c8
master date: 2018-04-16 14:08:30 +0200

(cherry picked from commit 9cba9aeb4d9b8edad91db30ccfab451244e67a9d)

Gbp-Pq: Name x86-correct-ordering-of-operations-durin.patch

diff --git a/xen/arch/x86/acpi/power.c b/xen/arch/x86/acpi/power.c
index 2cb3d13347091382e1aa73787898d0d527430169..9abca61cd6a4e2f47a92297b1575b52b25756955 100644 (file)
--- a/xen/arch/x86/acpi/power.c
+++ b/xen/arch/x86/acpi/power.c
@@ -204,6 +204,7 @@ static int enter_state(u32 state)
         printk(XENLOG_ERR "Some devices failed to power down.");
         system_state = SYS_STATE_resume;
         device_power_up(error);
+        console_end_sync();
         error = -EIO;
         goto done;
     }
@@ -244,17 +245,19 @@ static int enter_state(u32 state)
     if ( (state == ACPI_STATE_S3) && error )
         tboot_s3_error(error);
 
+    console_end_sync();
+
+    microcode_resume_cpu(0);
+
  done:
     spin_debug_enable();
     local_irq_restore(flags);
-    console_end_sync();
     acpi_sleep_post(state);
     if ( hvm_cpu_up() )
         BUG();
+    cpufreq_add_cpu(0);
 
  enable_cpu:
-    cpufreq_add_cpu(0);
-    microcode_resume_cpu(0);
     rcu_barrier();
     mtrr_aps_sync_begin();
     enable_nonboot_cpus();