[RFC][PATCH] kvm: add suspend pm-notifier

[Sergey Senozhatsky <senozhatsky@chromium.org>]

Add KVM suspend/hibernate PM-notifier which lets architectures
to implement arch-specific VM suspend code. For instance, on x86
this sets PVCLOCK_GUEST_STOPPED on all the VCPUs.

Our case is that user puts the host system into sleep multiple
times a day (e.g. closes the laptop's lid) so we need a reliable
way to suspend VMs properly.

Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
---
 arch/arm64/kvm/arm.c       |  4 ++++
 arch/mips/kvm/mips.c       |  4 ++++
 arch/powerpc/kvm/powerpc.c |  4 ++++
 arch/s390/kvm/kvm-s390.c   |  4 ++++
 arch/x86/kvm/x86.c         | 21 ++++++++++++++++++++
 include/linux/kvm_host.h   |  8 ++++++++
 virt/kvm/kvm_main.c        | 40 ++++++++++++++++++++++++++++++++++++++
 7 files changed, 85 insertions(+)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 1126eae27400..547dbe44d039 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1311,6 +1311,10 @@ static int kvm_vm_ioctl_set_device_addr(struct kvm *kvm,
 	}
 }
 
+void kvm_arch_pm_notifier(struct kvm *kvm)
+{
+}
+
 long kvm_arch_vm_ioctl(struct file *filp,
 		       unsigned int ioctl, unsigned long arg)
 {
diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
index 4d4af97dcc88..d4408acd2be6 100644
--- a/arch/mips/kvm/mips.c
+++ b/arch/mips/kvm/mips.c
@@ -980,6 +980,10 @@ void kvm_arch_flush_remote_tlbs_memslot(struct kvm *kvm,
 	kvm_flush_remote_tlbs(kvm);
 }
 
+void kvm_arch_pm_notifier(struct kvm *kvm)
+{
+}
+
 long kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
 {
 	long r;
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index a2a68a958fa0..96e8a7b6fcf0 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -2334,6 +2334,10 @@ static int kvmppc_get_cpu_char(struct kvm_ppc_cpu_char *cp)
 }
 #endif
 
+void kvm_arch_pm_notifier(struct kvm *kvm)
+{
+}
+
 long kvm_arch_vm_ioctl(struct file *filp,
                        unsigned int ioctl, unsigned long arg)
 {
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 1296fc10f80c..c5f86fc1e497 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2367,6 +2367,10 @@ static int kvm_s390_handle_pv(struct kvm *kvm, struct kvm_pv_cmd *cmd)
 	return r;
 }
 
+void kvm_arch_pm_notifier(struct kvm *kvm)
+{
+}
+
 long kvm_arch_vm_ioctl(struct file *filp,
 		       unsigned int ioctl, unsigned long arg)
 {
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index bbc4e04e67ad..3f3d6497593f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5613,6 +5613,27 @@ static int kvm_vm_ioctl_set_msr_filter(struct kvm *kvm, void __user *argp)
 	return 0;
 }
 
+void kvm_arch_pm_notifier(struct kvm *kvm)
+{
+#ifdef CONFIG_PM
+	int c;
+
+	mutex_lock(&kvm->lock);
+	for (c = 0; c < kvm->created_vcpus; c++) {
+		struct kvm_vcpu *vcpu = kvm->vcpus[c];
+		int r;
+
+		if (!vcpu)
+			continue;
+		r = kvm_set_guest_paused(vcpu);
+		if (!r)
+			continue;
+		pr_err("Failed to suspend VCPU-%d: %d\n", vcpu->vcpu_id,  r);
+	}
+	mutex_unlock(&kvm->lock);
+#endif
+}
+
 long kvm_arch_vm_ioctl(struct file *filp,
 		       unsigned int ioctl, unsigned long arg)
 {
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 2f34487e21f2..86695320a6b7 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -37,6 +37,8 @@
 #include <asm/kvm_host.h>
 #include <linux/kvm_dirty_ring.h>
 
+#include <linux/notifier.h>
+
 #ifndef KVM_MAX_VCPU_ID
 #define KVM_MAX_VCPU_ID KVM_MAX_VCPUS
 #endif
@@ -579,6 +581,10 @@ struct kvm {
 	pid_t userspace_pid;
 	unsigned int max_halt_poll_ns;
 	u32 dirty_ring_size;
+
+#ifdef CONFIG_PM
+	struct notifier_block pm_notifier;
+#endif
 };
 
 #define kvm_err(fmt, ...) \
@@ -992,6 +998,8 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu);
 void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu);
 void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu);
 
+void kvm_arch_pm_notifier(struct kvm *kvm);
+
 #ifdef __KVM_HAVE_ARCH_VCPU_DEBUGFS
 void kvm_arch_create_vcpu_debugfs(struct kvm_vcpu *vcpu, struct dentry *debugfs_dentry);
 #endif
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 6b4feb92dc79..86925ab7d162 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -51,6 +51,7 @@
 #include <linux/io.h>
 #include <linux/lockdep.h>
 #include <linux/kthread.h>
+#include <linux/suspend.h>
 
 #include <asm/processor.h>
 #include <asm/ioctl.h>
@@ -779,6 +780,43 @@ static int kvm_init_mmu_notifier(struct kvm *kvm)
 
 #endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */
 
+#ifdef CONFIG_PM
+static int kvm_pm_notifier_call(struct notifier_block *bl,
+				unsigned long state,
+				void *unused)
+{
+	struct kvm *kvm = container_of(bl, struct kvm, pm_notifier);
+
+	switch (state) {
+	case PM_HIBERNATION_PREPARE:
+	case PM_SUSPEND_PREPARE:
+		kvm_arch_pm_notifier(kvm);
+		break;
+	}
+	return NOTIFY_DONE;
+}
+
+static void kvm_init_pm_notifier(struct kvm *kvm)
+{
+	kvm->pm_notifier.notifier_call = kvm_pm_notifier_call;
+	kvm->pm_notifier.priority = INT_MAX;
+	register_pm_notifier(&kvm->pm_notifier);
+}
+
+static void kvm_destroy_pm_notifier(struct kvm *kvm)
+{
+	unregister_pm_notifier(&kvm->pm_notifier);
+}
+#else
+static void kvm_init_pm_notifier(struct kvm *kvm)
+{
+}
+
+static void kvm_destroy_pm_notifier(struct kvm *kvm)
+{
+}
+#endif /* CONFIG_PM */
+
 static struct kvm_memslots *kvm_alloc_memslots(void)
 {
 	int i;
@@ -962,6 +1000,7 @@ static struct kvm *kvm_create_vm(unsigned long type)
 	mutex_unlock(&kvm_lock);
 
 	preempt_notifier_inc();
+	kvm_init_pm_notifier(kvm);
 
 	return kvm;
 
@@ -1009,6 +1048,7 @@ static void kvm_destroy_vm(struct kvm *kvm)
 	int i;
 	struct mm_struct *mm = kvm->mm;
 
+	kvm_destroy_pm_notifier(kvm);
 	kvm_uevent_notify_change(KVM_EVENT_DESTROY_VM, kvm);
 	kvm_destroy_vm_debugfs(kvm);
 	kvm_arch_sync_events(kvm);
-- 
2.32.0.rc0.204.g9fa02ecfa5-goog


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