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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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