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SubjectRe: [RFC Part2 PATCH v3 10/26] KVM: Introduce KVM_MEMORY_ENCRYPT_REGISTER/UNREGISTER_RAM ioctl
On Mon, Jul 24, 2017 at 03:02:47PM -0500, Brijesh Singh wrote:
> If hardware support memory encryption then KVM_MEMORY_REGISTER_RAM and

supports

> KVM_MEMORY_UNREGISTER_RAM ioctl's can be used by userspace to register/
> unregister the guest memory regions which may contains the encrypted

"... which may contain encrypted data ... "

> data (e.g guest RAM, PCI BAR, SMRAM etc).
>
> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> ---
> 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);
> };

You can shorten those prefixes to "mem_enc" or so and struct
kvm_memory_encrypt_ram to struct enc_region - which is exactly what it
is - an encrypted memory region descriptor - and then fit each function
on a single line.

>
> 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)))

As earlier, those ioctl functions need to check the user-supplied values.

> 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)

As with KVM_MEMORY_ENCRYPT_OP, those two need to be in the KVM API document.

--
Regards/Gruss,
Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--

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