[PATCH 3.12 15/63] arm: kvm: implement CPU PM notifier

[Jiri Slaby]

From: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit 1fcf7ce0c60213994269fb59569ec161eb6e08d6 upstream.

Upon CPU shutdown and consequent warm-reboot, the hypervisor CPU state
must be re-initialized. This patch implements a CPU PM notifier that
upon warm-boot calls a KVM hook to reinitialize properly the hypervisor
state so that the CPU can be safely resumed.

Acked-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Acked-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
 arch/arm/kvm/arm.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index 78ee10bed798..64ec98b786ae 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -17,6 +17,7 @@
  */
 
 #include <linux/cpu.h>
+#include <linux/cpu_pm.h>
 #include <linux/errno.h>
 #include <linux/err.h>
 #include <linux/kvm_host.h>
@@ -857,6 +858,33 @@ static struct notifier_block hyp_init_cpu_nb = {
 	.notifier_call = hyp_init_cpu_notify,
 };
 
+#ifdef CONFIG_CPU_PM
+static int hyp_init_cpu_pm_notifier(struct notifier_block *self,
+				    unsigned long cmd,
+				    void *v)
+{
+	if (cmd == CPU_PM_EXIT) {
+		cpu_init_hyp_mode(NULL);
+		return NOTIFY_OK;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block hyp_init_cpu_pm_nb = {
+	.notifier_call = hyp_init_cpu_pm_notifier,
+};
+
+static void __init hyp_cpu_pm_init(void)
+{
+	cpu_pm_register_notifier(&hyp_init_cpu_pm_nb);
+}
+#else
+static inline void hyp_cpu_pm_init(void)
+{
+}
+#endif
+
 /**
  * Inits Hyp-mode on all online CPUs
  */
@@ -1017,6 +1045,8 @@ int kvm_arch_init(void *opaque)
 		goto out_err;
 	}
 
+	hyp_cpu_pm_init();
+
 	kvm_coproc_table_init();
 	return 0;
 out_err:
-- 
2.3.5

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