[RFC Part2 PATCH v3 10/26] KVM: Introduce KVM_MEMORY_ENCRYPT_REGISTER/UNREGISTER_RAM ioctl

[Brijesh Singh]

If hardware support memory encryption then KVM_MEMORY_REGISTER_RAM and
KVM_MEMORY_UNREGISTER_RAM ioctl's can be used by userspace to register/
unregister the guest memory regions which may contains the encrypted
data (e.g guest RAM, PCI BAR, SMRAM etc).

Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
---
 arch/x86/include/asm/kvm_host.h |  4 ++++
 arch/x86/kvm/x86.c              | 36 ++++++++++++++++++++++++++++++++++++
 include/uapi/linux/kvm.h        |  9 +++++++++
 3 files changed, 49 insertions(+)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 99a0e11..4295f82 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1059,6 +1059,10 @@ struct kvm_x86_ops {
 	void (*setup_mce)(struct kvm_vcpu *vcpu);
 
 	int (*memory_encryption_op)(struct kvm *kvm, void __user *argp);
+	int (*memory_encryption_register_ram)(struct kvm *kvm,
+					struct kvm_memory_encrypt_ram *ram);
+	int (*memory_encryption_unregister_ram)(struct kvm *kvm,
+					struct kvm_memory_encrypt_ram *ram);
 };
 
 struct kvm_arch_async_pf {
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c9d3ff5..8febdb5 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3982,6 +3982,24 @@ static int kvm_vm_ioctl_memory_encryption_op(struct kvm *kvm, void __user *argp)
 	return -ENOTTY;
 }
 
+static int kvm_vm_ioctl_mem_encrypt_register_ram(struct kvm *kvm,
+					struct kvm_memory_encrypt_ram *ram)
+{
+	if (kvm_x86_ops->memory_encryption_register_ram)
+		return kvm_x86_ops->memory_encryption_register_ram(kvm, ram);
+
+	return -ENOTTY;
+}
+
+static int kvm_vm_ioctl_mem_encrypt_unregister_ram(struct kvm *kvm,
+					struct kvm_memory_encrypt_ram *ram)
+{
+	if (kvm_x86_ops->memory_encryption_unregister_ram)
+		return kvm_x86_ops->memory_encryption_unregister_ram(kvm, ram);
+
+	return -ENOTTY;
+}
+
 long kvm_arch_vm_ioctl(struct file *filp,
 		       unsigned int ioctl, unsigned long arg)
 {
@@ -4246,6 +4264,24 @@ long kvm_arch_vm_ioctl(struct file *filp,
 		r = kvm_vm_ioctl_memory_encryption_op(kvm, argp);
 		break;
 	}
+	case KVM_MEMORY_ENCRYPT_REGISTER_RAM: {
+		struct kvm_memory_encrypt_ram ram;
+
+		r = -EFAULT;
+		if (copy_from_user(&ram, argp, sizeof(ram)))
+			goto out;
+		r = kvm_vm_ioctl_mem_encrypt_register_ram(kvm, &ram);
+		break;
+	}
+	case KVM_MEMORY_ENCRYPT_UNREGISTER_RAM: {
+		struct kvm_memory_encrypt_ram ram;
+
+		r = -EFAULT;
+		if (copy_from_user(&ram, argp, sizeof(ram)))
+			goto out;
+		r = kvm_vm_ioctl_mem_encrypt_unregister_ram(kvm, &ram);
+		break;
+	}
 	default:
 		r = -ENOTTY;
 	}
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index ab3b711..6074065 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1357,6 +1357,15 @@ struct kvm_s390_ucas_mapping {
 #define KVM_S390_SET_CMMA_BITS      _IOW(KVMIO, 0xb9, struct kvm_s390_cmma_log)
 /* Memory Encryption Commands */
 #define KVM_MEMORY_ENCRYPT_OP	  _IOWR(KVMIO, 0xba, unsigned long)
+#define KVM_MEMORY_ENCRYPT_REGISTER_RAM	   _IOR(KVMIO, 0xbb, \
+						struct kvm_memory_encrypt_ram)
+#define KVM_MEMORY_ENCRYPT_UNREGISTER_RAM  _IOR(KVMIO, 0xbc, \
+						struct kvm_memory_encrypt_ram)
+
+struct kvm_memory_encrypt_ram {
+	__u64 address;
+	__u64 size;
+};
 
 #define KVM_DEV_ASSIGN_ENABLE_IOMMU	(1 << 0)
 #define KVM_DEV_ASSIGN_PCI_2_3		(1 << 1)
-- 
2.9.4