[Part2 PATCH v4 11/29] KVM: Introduce KVM_MEMORY_ENCRYPT_OP ioctl

[Brijesh Singh <brijesh.singh@amd.com>]

If hardware supports memory encryption then KVM_MEMORY_ENCRYPT_OP ioctl can
be used by qemu to issue a platform specific memory encryption commands.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: x86@kernel.org
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 Documentation/virtual/kvm/api.txt | 15 +++++++++++++++
 arch/x86/include/asm/kvm_host.h   |  2 ++
 arch/x86/kvm/x86.c                | 12 ++++++++++++
 include/uapi/linux/kvm.h          |  2 ++
 4 files changed, 31 insertions(+)

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index e63a35fafef0..3f0dc33d8a8b 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -3390,6 +3390,21 @@ invalid, if invalid pages are written to (e.g. after the end of memory)
 or if no page table is present for the addresses (e.g. when using
 hugepages).
 
+4.109 KVM_MEMORY_ENCRYPTION_OP
+
+Capability: basic
+Architectures: x86
+Type: system
+Parameters: a opaque platform specific structure (in/out)
+Returns: 0 on success; -1 on error
+
+If platform supports creating encrypted VMs then this ioctl can be used for
+issuing a platform specific memory encryption commands to manage the encrypted
+VMs.
+
+Currently, this ioctl is used for issuing Secure Encrypted Virtualization (SEV)
+commands on AMD Processors.
+
 5. The kvm_run structure
 ------------------------
 
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index c73e493adf07..48001ca48c14 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1061,6 +1061,8 @@ struct kvm_x86_ops {
 	void (*cancel_hv_timer)(struct kvm_vcpu *vcpu);
 
 	void (*setup_mce)(struct kvm_vcpu *vcpu);
+
+	int (*mem_enc_op)(struct kvm *kvm, void __user *argp);
 };
 
 struct kvm_arch_async_pf {
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index cd17b7d9a107..ec9f634b75f0 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4010,6 +4010,14 @@ static int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
 	return r;
 }
 
+static int kvm_vm_ioctl_mem_enc_op(struct kvm *kvm, void __user *argp)
+{
+	if (kvm_x86_ops->mem_enc_op)
+		return kvm_x86_ops->mem_enc_op(kvm, argp);
+
+	return -ENOTTY;
+}
+
 long kvm_arch_vm_ioctl(struct file *filp,
 		       unsigned int ioctl, unsigned long arg)
 {
@@ -4270,6 +4278,10 @@ long kvm_arch_vm_ioctl(struct file *filp,
 		r = kvm_vm_ioctl_enable_cap(kvm, &cap);
 		break;
 	}
+	case KVM_MEMORY_ENCRYPTION_OP: {
+		r = kvm_vm_ioctl_mem_enc_op(kvm, argp);
+		break;
+	}
 	default:
 		r = -ENOTTY;
 	}
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 838887587411..23028a78f12f 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1356,6 +1356,8 @@ struct kvm_s390_ucas_mapping {
 /* Available with KVM_CAP_S390_CMMA_MIGRATION */
 #define KVM_S390_GET_CMMA_BITS      _IOWR(KVMIO, 0xb8, struct kvm_s390_cmma_log)
 #define KVM_S390_SET_CMMA_BITS      _IOW(KVMIO, 0xb9, struct kvm_s390_cmma_log)
+/* Memory Encryption Commands */
+#define KVM_MEMORY_ENCRYPTION_OP  _IOWR(KVMIO, 0xba, unsigned long)
 
 #define KVM_DEV_ASSIGN_ENABLE_IOMMU	(1 << 0)
 #define KVM_DEV_ASSIGN_PCI_2_3		(1 << 1)
-- 
2.9.5