On Sun, 12 Mar 2023 10:55:41 -0700
isaku.yamahata@xxxxxxxxx wrote:
> From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
>
> Add a place holder function for TDX specific VM-scoped ioctl as mem_enc_op.
> TDX specific sub-commands will be added to retrieve/pass TDX specific
> parameters. Make mem_enc_ioctl non-optional as it's not optional now.
^ it is optional now.
>
> KVM_MEMORY_ENCRYPT_OP was introduced for VM-scoped operations specific for
> guest state-protected VM. It defined subcommands for technology-specific
> operations under KVM_MEMORY_ENCRYPT_OP. Despite its name, the subcommands
> are not limited to memory encryption, but various technology-specific
> operations are defined. It's natural to repurpose KVM_MEMORY_ENCRYPT_OP
> for TDX specific operations and define subcommands.
>
> TDX requires VM-scoped TDX-specific operations for device model, for
> example, qemu. Getting system-wide parameters, TDX-specific VM
> initialization.
^ Above two paragraphs are the "background" paragraphs, they should be in
the beginning of the patch comments.
>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> ---
> arch/x86/include/asm/kvm-x86-ops.h | 2 +-
> arch/x86/kvm/vmx/main.c | 9 +++++++++
> arch/x86/kvm/vmx/tdx.c | 26 ++++++++++++++++++++++++++
> arch/x86/kvm/vmx/x86_ops.h | 4 ++++
> arch/x86/kvm/x86.c | 4 ----
> 5 files changed, 40 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
> index b46dcac078b2..58fbaa05fc8c 100644
> --- a/arch/x86/include/asm/kvm-x86-ops.h
> +++ b/arch/x86/include/asm/kvm-x86-ops.h
> @@ -117,7 +117,7 @@ KVM_X86_OP(enter_smm)
> KVM_X86_OP(leave_smm)
> KVM_X86_OP(enable_smi_window)
> #endif
> -KVM_X86_OP_OPTIONAL(dev_mem_enc_ioctl)
> +KVM_X86_OP(dev_mem_enc_ioctl)
I guess it should be KVM_X86_OP(mem_enc_ioctl) here.
> KVM_X86_OP_OPTIONAL(mem_enc_ioctl)
> KVM_X86_OP_OPTIONAL(mem_enc_register_region)
> KVM_X86_OP_OPTIONAL(mem_enc_unregister_region)
> diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
> index 6a5d0c7a2950..8ddd263eeabc 100644
> --- a/arch/x86/kvm/vmx/main.c
> +++ b/arch/x86/kvm/vmx/main.c
> @@ -50,6 +50,14 @@ static int vt_vm_init(struct kvm *kvm)
> return vmx_vm_init(kvm);
> }
>
> +static int vt_mem_enc_ioctl(struct kvm *kvm, void __user *argp)
> +{
> + if (!is_td(kvm))
> + return -ENOTTY;
> +
> + return tdx_vm_ioctl(kvm, argp);
> +}
> +
> #define VMX_REQUIRED_APICV_INHIBITS \
> ( \
> BIT(APICV_INHIBIT_REASON_DISABLE)| \
> @@ -203,6 +211,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
> .vcpu_deliver_sipi_vector = kvm_vcpu_deliver_sipi_vector,
>
> .dev_mem_enc_ioctl = tdx_dev_ioctl,
> + .mem_enc_ioctl = vt_mem_enc_ioctl,
> };
>
> struct kvm_x86_init_ops vt_init_ops __initdata = {
> diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
> index b59d3081d061..d759028a698e 100644
> --- a/arch/x86/kvm/vmx/tdx.c
> +++ b/arch/x86/kvm/vmx/tdx.c
> @@ -72,6 +72,32 @@ int tdx_dev_ioctl(void __user *argp)
> return 0;
> }
>
> +int tdx_vm_ioctl(struct kvm *kvm, void __user *argp)
> +{
> + struct kvm_tdx_cmd tdx_cmd;
> + int r;
> +
> + if (copy_from_user(&tdx_cmd, argp, sizeof(struct kvm_tdx_cmd)))
> + return -EFAULT;
> + if (tdx_cmd.error || tdx_cmd.unused)
> + return -EINVAL;
> +
> + mutex_lock(&kvm->lock);
> +
> + switch (tdx_cmd.id) {
> + default:
> + r = -EINVAL;
> + goto out;
> + }
> +
> + if (copy_to_user(argp, &tdx_cmd, sizeof(struct kvm_tdx_cmd)))
> + r = -EFAULT;
> +
> +out:
> + mutex_unlock(&kvm->lock);
> + return r;
> +}
> +
> static int __init tdx_module_setup(void)
> {
> const struct tdsysinfo_struct *tdsysinfo;
> diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
> index 78c5537e23a1..c70749114e9e 100644
> --- a/arch/x86/kvm/vmx/x86_ops.h
> +++ b/arch/x86/kvm/vmx/x86_ops.h
> @@ -142,11 +142,15 @@ int __init tdx_hardware_setup(struct kvm_x86_ops *x86_ops);
> int tdx_hardware_enable(void);
> bool tdx_is_vm_type_supported(unsigned long type);
> int tdx_dev_ioctl(void __user *argp);
> +
> +int tdx_vm_ioctl(struct kvm *kvm, void __user *argp);
> #else
> static inline int tdx_hardware_setup(struct kvm_x86_ops *x86_ops) { return -ENOSYS; }
> static inline int tdx_hardware_enable(void) { return -EOPNOTSUPP; }
> static inline bool tdx_is_vm_type_supported(unsigned long type) { return false; }
> static inline int tdx_dev_ioctl(void __user *argp) { return -EOPNOTSUPP; };
> +
> +static inline int tdx_vm_ioctl(struct kvm *kvm, void __user *argp) { return -EOPNOTSUPP; }
> #endif
>
> #endif /* __KVM_X86_VMX_X86_OPS_H */
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index a3dc32e33aca..8687623929c3 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -6978,10 +6978,6 @@ long kvm_arch_vm_ioctl(struct file *filp,
> goto out;
> }
> case KVM_MEMORY_ENCRYPT_OP: {
> - r = -ENOTTY;
> - if (!kvm_x86_ops.mem_enc_ioctl)
> - goto out;
> -
> r = static_call(kvm_x86_mem_enc_ioctl)(kvm, argp);
> break;
> }
