live migration support for initial write protect of VM

index 1e739f9..9f827c8 100644
@@ -67,6 +67,12 @@ struct kvm_arch {
 
 	/* Interrupt controller */
 	struct vgic_dist	vgic;
+
+	/* Marks start of migration, used to handle 2nd stage page faults
+	 * during migration, prevent installing huge pages and split huge pages
+	 * to small pages.
+	 */
+	int migration_in_progress;
 };
 
 #define KVM_NR_MEM_OBJS     40

@@ -230,4 +236,6 @@ int kvm_arm_timer_set_reg(struct kvm_vcpu *, u64 regid, u64 value);
 
 void kvm_tlb_flush_vmid(struct kvm *kvm);
 
+int kvm_mmu_slot_remove_write_access(struct kvm *kvm, int slot);
+
 #endif /* __ARM_KVM_HOST_H__ */

index a91c863..342ae81 100644
@@ -111,6 +111,17 @@ static inline void kvm_set_s2pte_writable(pte_t *pte)
 	pte_val(*pte) |= L_PTE_S2_RDWR;
 }
 
+static inline void kvm_set_s2pte_readonly(pte_t *pte)
+{
+	pte_val(*pte) &= ~(L_PTE_S2_RDONLY ^ L_PTE_S2_RDWR);
+}
+
+static inline bool kvm_s2pte_readonly(pte_t *pte)
+{
+	return (pte_val(*pte) & L_PTE_S2_RDWR) == L_PTE_S2_RDONLY;
+}
+
+
 static inline void kvm_set_s2pmd_writable(pmd_t *pmd)
 {
 	pmd_val(*pmd) |= L_PMD_S2_RDWR;

index 9a4bc10..b916478 100644
@@ -233,6 +233,9 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 				   struct kvm_userspace_memory_region *mem,
 				   enum kvm_mr_change change)
 {
+	/* Request for migration issued by user, write protect memory slot */
+	if ((change != KVM_MR_DELETE) && (mem->flags & KVM_MEM_LOG_DIRTY_PAGES))
+		return kvm_mmu_slot_remove_write_access(kvm, mem->slot);
 	return 0;
 }
 

227 lines not on this page · raw message

index 03a0381..1d11912 100644
@@ -184,7 +184,10 @@ static bool make_all_cpus_request(struct kvm *kvm, unsigned int req)
 	return called;
 }
 
-void kvm_flush_remote_tlbs(struct kvm *kvm)
+/* Architectures like >= ARMv7 hardware broadcast TLB invalidations and don't
+ * use IPIs.
+ */
+void __weak kvm_flush_remote_tlbs(struct kvm *kvm)
 {
 	long dirty_count = kvm->tlbs_dirty;