[v11] KVM TDX basic feature support

[PATCH v11 016/113] KVM: TDX: Add place holder for TDX VM specific mem_enc_op ioctl

Posted by isaku.yamahata@intel.com 2 years, 8 months ago

From: Isaku Yamahata <isaku.yamahata@intel.com>

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.

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.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
---
 arch/x86/kvm/vmx/main.c    |  9 +++++++++
 arch/x86/kvm/vmx/tdx.c     | 26 ++++++++++++++++++++++++++
 arch/x86/kvm/vmx/x86_ops.h |  4 ++++
 3 files changed, 39 insertions(+)

diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index 16053ec3e0ae..781fbc896120 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -37,6 +37,14 @@ 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);
+}
+
 struct kvm_x86_ops vt_x86_ops __initdata = {
 	.name = KBUILD_MODNAME,
 
@@ -179,6 +187,7 @@ 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 f46579102a44..2bd1cc37abab 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -78,6 +78,32 @@ 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 f0803cc15151..bb4090dbae37 100644
--- a/arch/x86/kvm/vmx/x86_ops.h
+++ b/arch/x86/kvm/vmx/x86_ops.h
@@ -141,10 +141,14 @@ void vmx_setup_mce(struct kvm_vcpu *vcpu);
 int __init tdx_hardware_setup(struct kvm_x86_ops *x86_ops);
 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 0; }
 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 */
-- 
2.25.1

Re: [PATCH v11 016/113] KVM: TDX: Add place holder for TDX VM specific mem_enc_op ioctl

Posted by Huang, Kai 2 years, 7 months ago

On Thu, 2023-01-12 at 08:31 -0800, isaku.yamahata@intel.com wrote:
> From: Isaku Yamahata <isaku.yamahata@intel.com>
> 
> 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.
> 
> 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.

There's grammar issue in the last paragraph.  Please use grammar check.

> 
> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> ---
>  arch/x86/kvm/vmx/main.c    |  9 +++++++++
>  arch/x86/kvm/vmx/tdx.c     | 26 ++++++++++++++++++++++++++
>  arch/x86/kvm/vmx/x86_ops.h |  4 ++++
>  3 files changed, 39 insertions(+)
> 
> diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
> index 16053ec3e0ae..781fbc896120 100644
> --- a/arch/x86/kvm/vmx/main.c
> +++ b/arch/x86/kvm/vmx/main.c
> @@ -37,6 +37,14 @@ 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);
> +}
> +
>  struct kvm_x86_ops vt_x86_ops __initdata = {
>  	.name = KBUILD_MODNAME,
>  
> @@ -179,6 +187,7 @@ 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,
>  };

IIUC, now both AMD and Intel have mem_enc_ioctl() callback implemented, so the
KVM_X86_OP_OPTIONAL() of it can be changed to KVM_X86_OP(), and the function
pointer check can be removed in the IOCTL:

diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-
ops.h
index 8dc345cc6318..a59852fb5e2a 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -116,7 +116,7 @@ KVM_X86_OP(enter_smm)
 KVM_X86_OP(leave_smm)
 KVM_X86_OP(enable_smi_window)
 #endif
-KVM_X86_OP_OPTIONAL(mem_enc_ioctl)
+KVM_X86_OP(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/kvm/x86.c b/arch/x86/kvm/x86.c
index c936f8d28a53..dfa279e35478 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6937,10 +6937,6 @@ 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;
        }

[snip]

Re: [PATCH v11 016/113] KVM: TDX: Add place holder for TDX VM specific mem_enc_op ioctl

Posted by Isaku Yamahata 2 years, 6 months ago

On Thu, Jan 19, 2023 at 02:40:17AM +0000,
"Huang, Kai" <kai.huang@intel.com> wrote:

> > diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
> > index 16053ec3e0ae..781fbc896120 100644
> > --- a/arch/x86/kvm/vmx/main.c
> > +++ b/arch/x86/kvm/vmx/main.c
> > @@ -37,6 +37,14 @@ 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);
> > +}
> > +
> >  struct kvm_x86_ops vt_x86_ops __initdata = {
> >  	.name = KBUILD_MODNAME,
> >  
> > @@ -179,6 +187,7 @@ 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,
> >  };
> 
> IIUC, now both AMD and Intel have mem_enc_ioctl() callback implemented, so the
> KVM_X86_OP_OPTIONAL() of it can be changed to KVM_X86_OP(), and the function
> pointer check can be removed in the IOCTL:

Makes sense. Merged the following patch into the patch. Thanks for it.


> 
> diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-
> ops.h
> index 8dc345cc6318..a59852fb5e2a 100644
> --- a/arch/x86/include/asm/kvm-x86-ops.h
> +++ b/arch/x86/include/asm/kvm-x86-ops.h
> @@ -116,7 +116,7 @@ KVM_X86_OP(enter_smm)
>  KVM_X86_OP(leave_smm)
>  KVM_X86_OP(enable_smi_window)
>  #endif
> -KVM_X86_OP_OPTIONAL(mem_enc_ioctl)
> +KVM_X86_OP(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/kvm/x86.c b/arch/x86/kvm/x86.c
> index c936f8d28a53..dfa279e35478 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -6937,10 +6937,6 @@ 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;
>         }
> 
> [snip]
> 

-- 
Isaku Yamahata <isaku.yamahata@gmail.com>