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KVM: Introduce KVM_MEMORY_ENCRYPT_{UN,}REG_REGION ioctl

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

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
Improvements-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
This commit is contained in:
Brijesh Singh 2017-12-04 10:57:26 -06:00
parent 5acc5c0631
commit 69eaedee41
4 changed files with 68 additions and 0 deletions
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34
Documentation/virtual/kvm/api.txt
View File

@ -3410,6 +3410,40 @@ Currently, this ioctl is used for issuing Secure Encrypted Virtualization
(SEV) commands on AMD Processors. The SEV commands are defined in
Documentation/virtual/kvm/amd-memory-encryption.txt.
4.110 KVM_MEMORY_ENCRYPT_REG_REGION
Capability: basic
Architectures: x86
Type: system
Parameters: struct kvm_enc_region (in)
Returns: 0 on success; -1 on error
This ioctl can be used to register a guest memory region which may
contain encrypted data (e.g. guest RAM, SMRAM etc).
It is used in the SEV-enabled guest. When encryption is enabled, a guest
memory region may contain encrypted data. The SEV memory encryption
engine uses a tweak such that two identical plaintext pages, each at
different locations will have differing ciphertexts. So swapping or
moving ciphertext of those pages will not result in plaintext being
swapped. So relocating (or migrating) physical backing pages for the SEV
guest will require some additional steps.
Note: The current SEV key management spec does not provide commands to
swap or migrate (move) ciphertext pages. Hence, for now we pin the guest
memory region registered with the ioctl.
4.111 KVM_MEMORY_ENCRYPT_UNREG_REGION
Capability: basic
Architectures: x86
Type: system
Parameters: struct kvm_enc_region (in)
Returns: 0 on success; -1 on error
This ioctl can be used to unregister the guest memory region registered
with KVM_MEMORY_ENCRYPT_REG_REGION ioctl above.
5. The kvm_run structure
------------------------

2
arch/x86/include/asm/kvm_host.h
View File

@ -1068,6 +1068,8 @@ struct kvm_x86_ops {
int (*enable_smi_window)(struct kvm_vcpu *vcpu);
int (*mem_enc_op)(struct kvm *kvm, void __user *argp);
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);
};
struct kvm_arch_async_pf {

24
arch/x86/kvm/x86.c
View File

@ -4287,6 +4287,30 @@ set_identity_unlock:
r = kvm_x86_ops->mem_enc_op(kvm, argp);
break;
}
case KVM_MEMORY_ENCRYPT_REG_REGION: {
struct kvm_enc_region region;
r = -EFAULT;
if (copy_from_user(&region, argp, sizeof(region)))
goto out;
r = -ENOTTY;
if (kvm_x86_ops->mem_enc_reg_region)
r = kvm_x86_ops->mem_enc_reg_region(kvm, &region);
break;
}
case KVM_MEMORY_ENCRYPT_UNREG_REGION: {
struct kvm_enc_region region;
r = -EFAULT;
if (copy_from_user(&region, argp, sizeof(region)))
goto out;
r = -ENOTTY;
if (kvm_x86_ops->mem_enc_unreg_region)
r = kvm_x86_ops->mem_enc_unreg_region(kvm, &region);
break;
}
default:
r = -ENOTTY;
}

8
include/uapi/linux/kvm.h
View File

@ -1361,6 +1361,14 @@ struct kvm_s390_ucas_mapping {
/* Memory Encryption Commands */
#define KVM_MEMORY_ENCRYPT_OP _IOWR(KVMIO, 0xba, unsigned long)
struct kvm_enc_region {
__u64 addr;
__u64 size;
};
#define KVM_MEMORY_ENCRYPT_REG_REGION _IOR(KVMIO, 0xbb, struct kvm_enc_region)
#define KVM_MEMORY_ENCRYPT_UNREG_REGION _IOR(KVMIO, 0xbc, struct kvm_enc_region)
#define KVM_DEV_ASSIGN_ENABLE_IOMMU (1 << 0)
#define KVM_DEV_ASSIGN_PCI_2_3 (1 << 1)
#define KVM_DEV_ASSIGN_MASK_INTX (1 << 2)