Re: [PATCH v7 030/102] KVM: TDX: Do TDX specific vcpu initialization

[Yuan Yao <yuan.yao@linux.intel.com>]

On Mon, Jun 27, 2022 at 02:53:22PM -0700, isaku.yamahata@intel.com wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
>
> TD guest vcpu need to be configured before ready to run which requests
> addtional information from Device model (e.g. qemu), one 64bit value is
> passed to vcpu's RCX as an initial value.  Repurpose KVM_MEMORY_ENCRYPT_OP
> to vcpu-scope and add new sub-commands KVM_TDX_INIT_VCPU under it for such
> additional vcpu configuration.
>
> Add callback for kvm vCPU-scoped operations of KVM_MEMORY_ENCRYPT_OP and
> add a new subcommand, KVM_TDX_INIT_VCPU, for further vcpu initialization.
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> ---
>  arch/x86/include/asm/kvm-x86-ops.h    |  1 +
>  arch/x86/include/asm/kvm_host.h       |  1 +
>  arch/x86/include/uapi/asm/kvm.h       |  1 +
>  arch/x86/kvm/vmx/main.c               |  9 +++++++
>  arch/x86/kvm/vmx/tdx.c                | 36 +++++++++++++++++++++++++++
>  arch/x86/kvm/vmx/tdx.h                |  4 +++
>  arch/x86/kvm/vmx/x86_ops.h            |  2 ++
>  arch/x86/kvm/x86.c                    |  6 +++++
>  tools/arch/x86/include/uapi/asm/kvm.h |  1 +
>  9 files changed, 61 insertions(+)
>
> diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
> index 3677a5015a4f..32a6df784ea6 100644
> --- a/arch/x86/include/asm/kvm-x86-ops.h
> +++ b/arch/x86/include/asm/kvm-x86-ops.h
> @@ -119,6 +119,7 @@ KVM_X86_OP(leave_smm)
>  KVM_X86_OP(enable_smi_window)
>  KVM_X86_OP_OPTIONAL(dev_mem_enc_ioctl)
>  KVM_X86_OP_OPTIONAL(mem_enc_ioctl)
> +KVM_X86_OP_OPTIONAL(vcpu_mem_enc_ioctl)
>  KVM_X86_OP_OPTIONAL(mem_enc_register_region)
>  KVM_X86_OP_OPTIONAL(mem_enc_unregister_region)
>  KVM_X86_OP_OPTIONAL(vm_copy_enc_context_from)
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 81638987cdb9..e5d4e5b60fdc 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1595,6 +1595,7 @@ struct kvm_x86_ops {
>
>  	int (*dev_mem_enc_ioctl)(void __user *argp);
>  	int (*mem_enc_ioctl)(struct kvm *kvm, void __user *argp);
> +	int (*vcpu_mem_enc_ioctl)(struct kvm_vcpu *vcpu, void __user *argp);
>  	int (*mem_enc_register_region)(struct kvm *kvm, struct kvm_enc_region *argp);
>  	int (*mem_enc_unregister_region)(struct kvm *kvm, struct kvm_enc_region *argp);
>  	int (*vm_copy_enc_context_from)(struct kvm *kvm, unsigned int source_fd);
> diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h
> index f89774ccd4ae..399c28b2f4f5 100644
> --- a/arch/x86/include/uapi/asm/kvm.h
> +++ b/arch/x86/include/uapi/asm/kvm.h
> @@ -538,6 +538,7 @@ struct kvm_pmu_event_filter {
>  enum kvm_tdx_cmd_id {
>  	KVM_TDX_CAPABILITIES = 0,
>  	KVM_TDX_INIT_VM,
> +	KVM_TDX_INIT_VCPU,
>
>  	KVM_TDX_CMD_NR_MAX,
>  };
> diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
> index 4f4ed4ad65a7..ce12cc8276ef 100644
> --- a/arch/x86/kvm/vmx/main.c
> +++ b/arch/x86/kvm/vmx/main.c
> @@ -113,6 +113,14 @@ static int vt_mem_enc_ioctl(struct kvm *kvm, void __user *argp)
>  	return tdx_vm_ioctl(kvm, argp);
>  }
>
> +static int vt_vcpu_mem_enc_ioctl(struct kvm_vcpu *vcpu, void __user *argp)
> +{
> +	if (!is_td_vcpu(vcpu))
> +		return -EINVAL;
> +
> +	return tdx_vcpu_ioctl(vcpu, argp);
> +}
> +
>  struct kvm_x86_ops vt_x86_ops __initdata = {
>  	.name = "kvm_intel",
>
> @@ -255,6 +263,7 @@ struct kvm_x86_ops vt_x86_ops __initdata = {
>
>  	.dev_mem_enc_ioctl = tdx_dev_ioctl,
>  	.mem_enc_ioctl = vt_mem_enc_ioctl,
> +	.vcpu_mem_enc_ioctl = vt_vcpu_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 d9fe3f6463c3..2772775457b0 100644
> --- a/arch/x86/kvm/vmx/tdx.c
> +++ b/arch/x86/kvm/vmx/tdx.c
> @@ -83,6 +83,11 @@ static inline bool is_hkid_assigned(struct kvm_tdx *kvm_tdx)
>  	return kvm_tdx->hkid > 0;
>  }
>
> +static inline bool is_td_finalized(struct kvm_tdx *kvm_tdx)
> +{
> +	return kvm_tdx->finalized;
> +}
> +
>  static void tdx_clear_page(unsigned long page)
>  {
>  	const void *zero_page = (const void *) __va(page_to_phys(ZERO_PAGE(0)));
> @@ -805,6 +810,37 @@ int tdx_vm_ioctl(struct kvm *kvm, void __user *argp)
>  	return r;
>  }
>
> +int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp)
> +{
> +	struct kvm_tdx *kvm_tdx = to_kvm_tdx(vcpu->kvm);
> +	struct vcpu_tdx *tdx = to_tdx(vcpu);
> +	struct kvm_tdx_cmd cmd;
> +	u64 err;
> +
> +	if (tdx->initialized)

Minor: How about "tdx_vcpu->initialized" ? there's
"is_td_initialized()" below, the "tdx" here may lead guys to treat it
as whole td vm until they confirmed it's type again.

> +		return -EINVAL;
> +
> +	if (!is_td_initialized(vcpu->kvm) || is_td_finalized(kvm_tdx))
> +		return -EINVAL;
> +
> +	if (copy_from_user(&cmd, argp, sizeof(cmd)))
> +		return -EFAULT;
> +
> +	if (cmd.error || cmd.unused)
> +		return -EINVAL;
> +	if (cmd.flags || cmd.id != KVM_TDX_INIT_VCPU)
> +		return -EINVAL;
> +
> +	err = tdh_vp_init(tdx->tdvpr.pa, cmd.data);
> +	if (WARN_ON_ONCE(err)) {
> +		pr_tdx_error(TDH_VP_INIT, err, NULL);
> +		return -EIO;
> +	}
> +
> +	tdx->initialized = true;
> +	return 0;
> +}
> +
>  int __init tdx_module_setup(void)
>  {
>  	const struct tdsysinfo_struct *tdsysinfo;
> diff --git a/arch/x86/kvm/vmx/tdx.h b/arch/x86/kvm/vmx/tdx.h
> index 892e7dc96e99..337c3adb4fcf 100644
> --- a/arch/x86/kvm/vmx/tdx.h
> +++ b/arch/x86/kvm/vmx/tdx.h
> @@ -25,6 +25,8 @@ struct kvm_tdx {
>  	u64 xfam;
>  	int hkid;
>
> +	bool finalized;
> +
>  	u64 tsc_offset;
>  	unsigned long tsc_khz;
>  };
> @@ -35,6 +37,8 @@ struct vcpu_tdx {
>  	struct tdx_td_page tdvpr;
>  	struct tdx_td_page *tdvpx;
>
> +	bool initialized;
> +
>  	/*
>  	 * Dummy to make pmu_intel not corrupt memory.
>  	 * TODO: Support PMU for TDX.  Future work.
> diff --git a/arch/x86/kvm/vmx/x86_ops.h b/arch/x86/kvm/vmx/x86_ops.h
> index 42b634971544..7e38c7b756d4 100644
> --- a/arch/x86/kvm/vmx/x86_ops.h
> +++ b/arch/x86/kvm/vmx/x86_ops.h
> @@ -143,6 +143,7 @@ void tdx_vcpu_free(struct kvm_vcpu *vcpu);
>  void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event);
>
>  int tdx_vm_ioctl(struct kvm *kvm, void __user *argp);
> +int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, void __user *argp);
>  #else
>  static inline int tdx_hardware_setup(struct kvm_x86_ops *x86_ops) { return 0; }
>  static inline bool tdx_is_vm_type_supported(unsigned long type) { return false; }
> @@ -159,6 +160,7 @@ static inline void tdx_vcpu_free(struct kvm_vcpu *vcpu) {}
>  static inline void tdx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) {}
>
>  static inline int tdx_vm_ioctl(struct kvm *kvm, void __user *argp) { return -EOPNOTSUPP; }
> +static inline int tdx_vcpu_ioctl(struct kvm_vcpu *vcpu, 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 6037ce93bcb7..4309ef0ade21 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -5778,6 +5778,12 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
>  	case KVM_SET_DEVICE_ATTR:
>  		r = kvm_vcpu_ioctl_device_attr(vcpu, ioctl, argp);
>  		break;
> +	case KVM_MEMORY_ENCRYPT_OP:
> +		r = -ENOTTY;
> +		if (!kvm_x86_ops.vcpu_mem_enc_ioctl)
> +			goto out;
> +		r = kvm_x86_ops.vcpu_mem_enc_ioctl(vcpu, argp);
> +		break;
>  	default:
>  		r = -EINVAL;
>  	}
> diff --git a/tools/arch/x86/include/uapi/asm/kvm.h b/tools/arch/x86/include/uapi/asm/kvm.h
> index 779dfd683d66..60a79f9ef174 100644
> --- a/tools/arch/x86/include/uapi/asm/kvm.h
> +++ b/tools/arch/x86/include/uapi/asm/kvm.h
> @@ -532,6 +532,7 @@ struct kvm_pmu_event_filter {
>  enum kvm_tdx_cmd_id {
>  	KVM_TDX_CAPABILITIES = 0,
>  	KVM_TDX_INIT_VM,
> +	KVM_TDX_INIT_VCPU,
>
>  	KVM_TDX_CMD_NR_MAX,
>  };
> --
> 2.25.1
>