@@ -6702,6 +6702,21 @@ MAP_SHARED mmap will result in an -EINVAL return.
When enabled the VMM may make use of the ``KVM_ARM_MTE_COPY_TAGS`` ioctl to
perform a bulk copy of tags to/from the guest.
+7.29 KVM_CAP_VM_MIGRATE_PROTECTED_VM_FROM
+-------------------------------------
+
+Architectures: x86 SEV enabled
+Type: vm
+Parameters: args[0] is the fd of the source vm
+Returns: 0 on success
+
+This capability enables userspace to migrate the encryption context from the VM
+indicated by the fd to the VM this is called on.
+
+This is intended to support intra-host migration of VMs between userspace VMMs.
+in-guest workloads scheduled by the host. This allows for upgrading the VMM
+process without interrupting the guest.
+
8. Other capabilities.
======================
@@ -1456,6 +1456,7 @@ struct kvm_x86_ops {
int (*mem_enc_reg_region)(struct kvm *kvm, struct kvm_enc_region *argp);
int (*mem_enc_unreg_region)(struct kvm *kvm, struct kvm_enc_region *argp);
int (*vm_copy_enc_context_from)(struct kvm *kvm, unsigned int source_fd);
+ int (*vm_migrate_protected_vm_from)(struct kvm *kvm, unsigned int source_fd);
int (*get_msr_feature)(struct kvm_msr_entry *entry);
@@ -1501,6 +1501,142 @@ static int sev_receive_finish(struct kvm *kvm, struct kvm_sev_cmd *argp)
return sev_issue_cmd(kvm, SEV_CMD_RECEIVE_FINISH, &data, &argp->error);
}
+static int sev_lock_for_migration(struct kvm *kvm)
+{
+ struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+
+ /*
+ * Bail if this VM is already involved in a migration to avoid deadlock
+ * between two VMs trying to migrate to/from each other.
+ */
+ if (atomic_cmpxchg_acquire(&sev->migration_in_progress, 0, 1))
+ return -EBUSY;
+
+ mutex_lock(&kvm->lock);
+
+ return 0;
+}
+
+static void sev_unlock_after_migration(struct kvm *kvm)
+{
+ struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
+
+ mutex_unlock(&kvm->lock);
+ atomic_set_release(&sev->migration_in_progress, 0);
+}
+
+
+static int sev_lock_vcpus_for_migration(struct kvm *kvm)
+{
+ struct kvm_vcpu *vcpu;
+ int i, j;
+
+ kvm_for_each_vcpu(i, vcpu, kvm) {
+ if (mutex_lock_killable(&vcpu->mutex))
+ goto out_unlock;
+ }
+
+ return 0;
+
+out_unlock:
+ kvm_for_each_vcpu(j, vcpu, kvm) {
+ mutex_unlock(&vcpu->mutex);
+ if (i == j)
+ break;
+ }
+ return -EINTR;
+}
+
+static void sev_unlock_vcpus_for_migration(struct kvm *kvm)
+{
+ struct kvm_vcpu *vcpu;
+ int i;
+
+ kvm_for_each_vcpu(i, vcpu, kvm) {
+ mutex_unlock(&vcpu->mutex);
+ }
+}
+
+static void sev_migrate_from(struct kvm_sev_info *dst,
+ struct kvm_sev_info *src)
+{
+ dst->active = true;
+ dst->asid = src->asid;
+ dst->misc_cg = src->misc_cg;
+ dst->handle = src->handle;
+ dst->pages_locked = src->pages_locked;
+
+ src->asid = 0;
+ src->active = false;
+ src->handle = 0;
+ src->pages_locked = 0;
+ src->misc_cg = NULL;
+
+ INIT_LIST_HEAD(&dst->regions_list);
+ list_replace_init(&src->regions_list, &dst->regions_list);
+}
+
+int svm_vm_migrate_from(struct kvm *kvm, unsigned int source_fd)
+{
+ struct kvm_sev_info *dst_sev = &to_kvm_svm(kvm)->sev_info;
+ struct file *source_kvm_file;
+ struct kvm *source_kvm;
+ struct kvm_vcpu *vcpu;
+ int i, ret;
+
+ ret = sev_lock_for_migration(kvm);
+ if (ret)
+ return ret;
+
+ if (sev_guest(kvm)) {
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+
+ source_kvm_file = fget(source_fd);
+ if (!file_is_kvm(source_kvm_file)) {
+ ret = -EBADF;
+ goto out_fput;
+ }
+
+ source_kvm = source_kvm_file->private_data;
+ ret = sev_lock_for_migration(source_kvm);
+ if (ret)
+ goto out_fput;
+
+ if (!sev_guest(source_kvm) || sev_es_guest(source_kvm)) {
+ ret = -EINVAL;
+ goto out_source;
+ }
+ ret = sev_lock_vcpus_for_migration(kvm);
+ if (ret)
+ goto out_dst_vcpu;
+ ret = sev_lock_vcpus_for_migration(source_kvm);
+ if (ret)
+ goto out_source_vcpu;
+
+ sev_migrate_from(dst_sev, &to_kvm_svm(source_kvm)->sev_info);
+ kvm_for_each_vcpu(i, vcpu, source_kvm) {
+ kvm_vcpu_reset(vcpu, /* init_event= */ false);
+ }
+ ret = 0;
+
+out_source_vcpu:
+ sev_unlock_vcpus_for_migration(source_kvm);
+
+out_dst_vcpu:
+ sev_unlock_vcpus_for_migration(kvm);
+
+out_source:
+ sev_unlock_after_migration(source_kvm);
+out_fput:
+ if (source_kvm_file)
+ fput(source_kvm_file);
+out_unlock:
+ sev_unlock_after_migration(kvm);
+ return ret;
+}
+
int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
{
struct kvm_sev_cmd sev_cmd;
@@ -4625,6 +4625,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = {
.mem_enc_unreg_region = svm_unregister_enc_region,
.vm_copy_enc_context_from = svm_vm_copy_asid_from,
+ .vm_migrate_protected_vm_from = svm_vm_migrate_from,
.can_emulate_instruction = svm_can_emulate_instruction,
@@ -80,6 +80,7 @@ struct kvm_sev_info {
u64 ap_jump_table; /* SEV-ES AP Jump Table address */
struct kvm *enc_context_owner; /* Owner of copied encryption context */
struct misc_cg *misc_cg; /* For misc cgroup accounting */
+ atomic_t migration_in_progress;
};
struct kvm_svm {
@@ -552,6 +553,7 @@ int svm_register_enc_region(struct kvm *kvm,
int svm_unregister_enc_region(struct kvm *kvm,
struct kvm_enc_region *range);
int svm_vm_copy_asid_from(struct kvm *kvm, unsigned int source_fd);
+int svm_vm_migrate_from(struct kvm *kvm, unsigned int source_fd);
void pre_sev_run(struct vcpu_svm *svm, int cpu);
void __init sev_set_cpu_caps(void);
void __init sev_hardware_setup(void);
@@ -5654,6 +5654,12 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
if (kvm_x86_ops.vm_copy_enc_context_from)
r = kvm_x86_ops.vm_copy_enc_context_from(kvm, cap->args[0]);
return r;
+ case KVM_CAP_VM_MIGRATE_PROTECTED_VM_FROM:
+ r = -EINVAL;
+ if (kvm_x86_ops.vm_migrate_protected_vm_from)
+ r = kvm_x86_ops.vm_migrate_protected_vm_from(
+ kvm, cap->args[0]);
+ return r;
case KVM_CAP_EXIT_HYPERCALL:
if (cap->args[0] & ~KVM_EXIT_HYPERCALL_VALID_MASK) {
r = -EINVAL;
@@ -1112,6 +1112,7 @@ struct kvm_ppc_resize_hpt {
#define KVM_CAP_BINARY_STATS_FD 203
#define KVM_CAP_EXIT_ON_EMULATION_FAILURE 204
#define KVM_CAP_ARM_MTE 205
+#define KVM_CAP_VM_MIGRATE_PROTECTED_VM_FROM 206
#ifdef KVM_CAP_IRQ_ROUTING