[PATCH 2/3] KVM: Add kvm_arch_sync_events to sync with asynchronize events

[Sheng Yang <sheng@linux.intel.com>]

kvm_arch_sync_events is introduced to quiet down all other events may happen
contemporary with VM destroy process, like IRQ handler and work struct for
assigned device.

For kvm_arch_sync_events is called at the very beginning of kvm_destroy_vm(), so
the state of KVM here is legal and can provide a environment to quiet down other
events.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
---
 arch/ia64/kvm/kvm-ia64.c   |    4 ++++
 arch/powerpc/kvm/powerpc.c |    4 ++++
 arch/s390/kvm/kvm-s390.c   |    4 ++++
 arch/x86/kvm/x86.c         |    4 ++++
 include/linux/kvm_host.h   |    1 +
 virt/kvm/kvm_main.c        |    1 +
 6 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index c2bf538..8e0af13 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -1336,6 +1336,10 @@ static void kvm_release_vm_pages(struct kvm *kvm)
 	}
 }
 
+void kvm_arch_sync_events(struct kvm *kvm)
+{
+}
+
 void kvm_arch_destroy_vm(struct kvm *kvm)
 {
 	kvm_iommu_unmap_guest(kvm);
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 74b576a..26b1ae6 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -124,6 +124,10 @@ static void kvmppc_free_vcpus(struct kvm *kvm)
 	}
 }
 
+void kvm_arch_sync_events(struct kvm *kvm)
+{
+}
+
 void kvm_arch_destroy_vm(struct kvm *kvm)
 {
 	kvmppc_free_vcpus(kvm);
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 54b6534..cbfe91e 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -212,6 +212,10 @@ static void kvm_free_vcpus(struct kvm *kvm)
 	}
 }
 
+void kvm_arch_sync_events(struct kvm *kvm)
+{
+}
+
 void kvm_arch_destroy_vm(struct kvm *kvm)
 {
 	kvm_free_vcpus(kvm);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8ea3c7b..0a045fc 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4192,6 +4192,10 @@ static void kvm_free_vcpus(struct kvm *kvm)
 
 }
 
+void kvm_arch_sync_events(struct kvm *kvm)
+{
+}
+
 void kvm_arch_destroy_vm(struct kvm *kvm)
 {
 	kvm_free_all_assigned_devices(kvm);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 76cc371..04a2a47 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -284,6 +284,7 @@ void kvm_free_physmem(struct kvm *kvm);
 struct  kvm *kvm_arch_create_vm(void);
 void kvm_arch_destroy_vm(struct kvm *kvm);
 void kvm_free_all_assigned_devices(struct kvm *kvm);
+void kvm_arch_sync_events(struct kvm *kvm);
 
 int kvm_cpu_get_interrupt(struct kvm_vcpu *v);
 int kvm_cpu_has_interrupt(struct kvm_vcpu *v);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index ffd261d..d348788 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -848,6 +848,7 @@ static void kvm_destroy_vm(struct kvm *kvm)
 {
 	struct mm_struct *mm = kvm->mm;
 
+	kvm_arch_sync_events(kvm);
 	spin_lock(&kvm_lock);
 	list_del(&kvm->vm_list);
 	spin_unlock(&kvm_lock);
-- 
1.5.4.5