[RFC PATCH v2 09/13] KVM: x86: Refactor common migration preparation code out of sev_vm_move_enc_context_from

[Ryan Afranji <afranji@google.com>]

From: Ackerley Tng <ackerleytng@google.com>

Co-developed-by: Sagi Shahar <sagis@google.com>
Signed-off-by: Sagi Shahar <sagis@google.com>
Co-developed-by: Vishal Annapurve <vannapurve@google.com>
Signed-off-by: Vishal Annapurve <vannapurve@google.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
Signed-off-by: Ryan Afranji <afranji@google.com>
---
 arch/x86/include/asm/kvm_host.h |  2 +-
 arch/x86/kvm/svm/sev.c          | 29 +++---------------------
 arch/x86/kvm/svm/svm.h          |  2 +-
 arch/x86/kvm/x86.c              | 39 ++++++++++++++++++++++++++++++++-
 4 files changed, 43 insertions(+), 29 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 6c06f3d6e081..179618300270 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1871,7 +1871,7 @@ struct kvm_x86_ops {
 	int (*mem_enc_register_region)(struct kvm *kvm, struct kvm_enc_region *argp);
 	int (*mem_enc_unregister_region)(struct kvm *kvm, struct kvm_enc_region *argp);
 	int (*vm_copy_enc_context_from)(struct kvm *kvm, unsigned int source_fd);
-	int (*vm_move_enc_context_from)(struct kvm *kvm, unsigned int source_fd);
+	int (*vm_move_enc_context_from)(struct kvm *kvm, struct kvm *source_kvm);
 	void (*guest_memory_reclaimed)(struct kvm *kvm);
 
 	int (*get_feature_msr)(u32 msr, u64 *data);
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index b3048ec411e2..689521d9e26f 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -2000,34 +2000,15 @@ static int sev_check_source_vcpus(struct kvm *dst, struct kvm *src)
 	return 0;
 }
 
-int sev_vm_move_enc_context_from(struct kvm *kvm, unsigned int source_fd)
+int sev_vm_move_enc_context_from(struct kvm *kvm, struct kvm *source_kvm)
 {
 	struct kvm_sev_info *dst_sev = to_kvm_sev_info(kvm);
 	struct kvm_sev_info *src_sev, *cg_cleanup_sev;
-	CLASS(fd, f)(source_fd);
-	struct kvm *source_kvm;
 	bool charged = false;
 	int ret;
 
-	if (fd_empty(f))
-		return -EBADF;
-
-	if (!file_is_kvm(fd_file(f)))
-		return -EBADF;
-
-	source_kvm = fd_file(f)->private_data;
-	ret = kvm_mark_migration_in_progress(kvm, source_kvm);
-	if (ret)
-		return ret;
-	ret = kvm_lock_two_vms(kvm, source_kvm);
-	if (ret)
-		goto out_mark_migration_done;
-
-	if (kvm->arch.vm_type != source_kvm->arch.vm_type ||
-	    sev_guest(kvm) || !sev_guest(source_kvm)) {
-		ret = -EINVAL;
-		goto out_unlock;
-	}
+	if (sev_guest(kvm) || !sev_guest(source_kvm))
+		return -EINVAL;
 
 	src_sev = to_kvm_sev_info(source_kvm);
 
@@ -2066,10 +2047,6 @@ int sev_vm_move_enc_context_from(struct kvm *kvm, unsigned int source_fd)
 		sev_misc_cg_uncharge(cg_cleanup_sev);
 	put_misc_cg(cg_cleanup_sev->misc_cg);
 	cg_cleanup_sev->misc_cg = NULL;
-out_unlock:
-	kvm_unlock_two_vms(kvm, source_kvm);
-out_mark_migration_done:
-	kvm_mark_migration_done(kvm, source_kvm);
 	return ret;
 }
 
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 35df8be621c5..7bd31c0b135a 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -757,7 +757,7 @@ int sev_mem_enc_register_region(struct kvm *kvm,
 int sev_mem_enc_unregister_region(struct kvm *kvm,
 				  struct kvm_enc_region *range);
 int sev_vm_copy_enc_context_from(struct kvm *kvm, unsigned int source_fd);
-int sev_vm_move_enc_context_from(struct kvm *kvm, unsigned int source_fd);
+int sev_vm_move_enc_context_from(struct kvm *kvm, struct kvm *source_kvm);
 void sev_guest_memory_reclaimed(struct kvm *kvm);
 int sev_handle_vmgexit(struct kvm_vcpu *vcpu);
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 422c66a033d2..637540309456 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6597,6 +6597,43 @@ int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_event,
 	return 0;
 }
 
+static int kvm_vm_move_enc_context_from(struct kvm *kvm, unsigned int source_fd)
+{
+	int r;
+	struct kvm *source_kvm;
+	struct fd f = fdget(source_fd);
+	struct file *file = fd_file(f);
+
+	r = -EBADF;
+	if (!file)
+		return r;
+
+	if (!file_is_kvm(file))
+		goto out_fdput;
+
+	r = -EINVAL;
+	source_kvm = file->private_data;
+	if (kvm->arch.vm_type != source_kvm->arch.vm_type)
+		goto out_fdput;
+
+	r = kvm_mark_migration_in_progress(kvm, source_kvm);
+	if (r)
+		goto out_fdput;
+
+	r = kvm_lock_two_vms(kvm, source_kvm);
+	if (r)
+		goto out_mark_migration_done;
+
+	r = kvm_x86_call(vm_move_enc_context_from)(kvm, source_kvm);
+
+	kvm_unlock_two_vms(kvm, source_kvm);
+out_mark_migration_done:
+	kvm_mark_migration_done(kvm, source_kvm);
+out_fdput:
+	fdput(f);
+	return r;
+}
+
 int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
 			    struct kvm_enable_cap *cap)
 {
@@ -6738,7 +6775,7 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
 		if (!kvm_x86_ops.vm_move_enc_context_from)
 			break;
 
-		r = kvm_x86_call(vm_move_enc_context_from)(kvm, cap->args[0]);
+		r = kvm_vm_move_enc_context_from(kvm, cap->args[0]);
 		break;
 	case KVM_CAP_EXIT_HYPERCALL:
 		if (cap->args[0] & ~KVM_EXIT_HYPERCALL_VALID_MASK) {
-- 
2.49.0.1101.gccaa498523-goog