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

Add placeholders TDX VM/vcpu structure that overlays with VMX VM/vcpu
structures.  Initialize VM structure size and vcpu size/align so that x86
KVM common code knows those size irrespective of VMX or TDX.  Those
structures will be populated as guest creation logic develops.

Add helper functions to check if the VM is guest TD and add conversion
functions between KVM VM/VCPU and TDX VM/VCPU.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
---
 arch/x86/kvm/vmx/main.c |  9 ++++++++
 arch/x86/kvm/vmx/tdx.c  |  1 +
 arch/x86/kvm/vmx/tdx.h  | 50 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 60 insertions(+)
 create mode 100644 arch/x86/kvm/vmx/tdx.h

diff --git a/arch/x86/kvm/vmx/main.c b/arch/x86/kvm/vmx/main.c
index d1c9c7f55050..5bc31c41bea9 100644
--- a/arch/x86/kvm/vmx/main.c
+++ b/arch/x86/kvm/vmx/main.c
@@ -5,6 +5,7 @@
 #include "vmx.h"
 #include "nested.h"
 #include "pmu.h"
+#include "tdx.h"
 
 static bool enable_tdx __ro_after_init;
 module_param_named(tdx, enable_tdx, bool, 0444);
@@ -224,6 +225,14 @@ static int __init vt_init(void)
 	vt_x86_ops.vm_size = sizeof(struct kvm_vmx);
 	vcpu_size = sizeof(struct vcpu_vmx);
 	vcpu_align = __alignof__(struct vcpu_vmx);
+	if (enable_tdx) {
+		vt_x86_ops.vm_size = max_t(unsigned int, vt_x86_ops.vm_size,
+					   sizeof(struct kvm_tdx));
+		vcpu_size = max_t(unsigned int, vcpu_size,
+				  sizeof(struct vcpu_tdx));
+		vcpu_align = max_t(unsigned int, vcpu_align,
+				   __alignof__(struct vcpu_tdx));
+	}
 	r = kvm_init(vcpu_size, vcpu_align, THIS_MODULE);
 	if (r)
 		goto err_kvm_init;
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index e51314bbb439..2f9eaefee249 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -6,6 +6,7 @@
 #include "capabilities.h"
 #include "x86_ops.h"
 #include "x86.h"
+#include "tdx.h"
 
 #undef pr_fmt
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
diff --git a/arch/x86/kvm/vmx/tdx.h b/arch/x86/kvm/vmx/tdx.h
new file mode 100644
index 000000000000..2210c8c1e893
--- /dev/null
+++ b/arch/x86/kvm/vmx/tdx.h
@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __KVM_X86_TDX_H
+#define __KVM_X86_TDX_H
+
+#ifdef CONFIG_INTEL_TDX_HOST
+struct kvm_tdx {
+	struct kvm kvm;
+	/* TDX specific members follow. */
+};
+
+struct vcpu_tdx {
+	struct kvm_vcpu	vcpu;
+	/* TDX specific members follow. */
+};
+
+static inline bool is_td(struct kvm *kvm)
+{
+	return kvm->arch.vm_type == KVM_X86_PROTECTED_VM;
+}
+
+static inline bool is_td_vcpu(struct kvm_vcpu *vcpu)
+{
+	return is_td(vcpu->kvm);
+}
+
+static inline struct kvm_tdx *to_kvm_tdx(struct kvm *kvm)
+{
+	return container_of(kvm, struct kvm_tdx, kvm);
+}
+
+static inline struct vcpu_tdx *to_tdx(struct kvm_vcpu *vcpu)
+{
+	return container_of(vcpu, struct vcpu_tdx, vcpu);
+}
+#else
+struct kvm_tdx {
+	struct kvm kvm;
+};
+
+struct vcpu_tdx {
+	struct kvm_vcpu	vcpu;
+};
+
+static inline bool is_td(struct kvm *kvm) { return false; }
+static inline bool is_td_vcpu(struct kvm_vcpu *vcpu) { return false; }
+static inline struct kvm_tdx *to_kvm_tdx(struct kvm *kvm) { return NULL; }
+static inline struct vcpu_tdx *to_tdx(struct kvm_vcpu *vcpu) { return NULL; }
+#endif /* CONFIG_INTEL_TDX_HOST */
+
+#endif /* __KVM_X86_TDX_H */
-- 
2.25.1

On Sun, 2023-03-12 at 10:55 -0700, isaku.yamahata@intel.com wrote:
> +
> +static inline bool is_td(struct kvm *kvm)
> +{
> +	return kvm->arch.vm_type == KVM_X86_PROTECTED_VM;
> +}
> +

KVM_X86_PROTECTED_VM is defined in the next patch, which means this patch cannot
compile.

Also, why KVM_X86_PROTECTED_VM == TDX VM?

On Wed, Mar 15, 2023 at 10:42:09AM +0000,
"Huang, Kai" <kai.huang@intel.com> wrote:

> On Sun, 2023-03-12 at 10:55 -0700, isaku.yamahata@intel.com wrote:
> > +
> > +static inline bool is_td(struct kvm *kvm)
> > +{
> > +	return kvm->arch.vm_type == KVM_X86_PROTECTED_VM;
> > +}
> > +
> 
> KVM_X86_PROTECTED_VM is defined in the next patch, which means this patch cannot
> compile.
> 
> Also, why KVM_X86_PROTECTED_VM == TDX VM?

This part needs to be resolved.
Use KVM_X86_PROTECTED_VM as TDX VM or new type KVM_X86_TDX_VM or other way
to specify VM type.
Given pKVM is coming, dedicated VM type seems better.  I'll switch it to
KVM_X86_TDX_VM next respin.
-- 
Isaku Yamahata <isaku.yamahata@gmail.com>

On Thu, 2023-03-16 at 08:41 -0700, Isaku Yamahata wrote:
> On Wed, Mar 15, 2023 at 10:42:09AM +0000,
> "Huang, Kai" <kai.huang@intel.com> wrote:
> 
> > On Sun, 2023-03-12 at 10:55 -0700, isaku.yamahata@intel.com wrote:
> > > +
> > > +static inline bool is_td(struct kvm *kvm)
> > > +{
> > > +	return kvm->arch.vm_type == KVM_X86_PROTECTED_VM;
> > > +}
> > > +
> > 
> > KVM_X86_PROTECTED_VM is defined in the next patch, which means this patch cannot
> > compile.

Oh I see your patch only added this type to tools/.../asm/kvm.h

--- a/tools/arch/x86/include/uapi/asm/kvm.h
+++ b/tools/arch/x86/include/uapi/asm/kvm.h
@@ -559,4 +559,7 @@ struct kvm_pmu_event_filter {
 #define KVM_VCPU_TSC_CTRL 0 /* control group for the timestamp counter (TSC) */
 #define   KVM_VCPU_TSC_OFFSET 0 /* attribute for the TSC offset */
 
+#define KVM_X86_DEFAULT_VM	0
+#define KVM_X86_PROTECTED_VM	1
+

So this one has already been in UPM series.

But I thought Sean had a comment saying we should not add such definition to
header file under tools/:

Even it needs to be added, it should be in the relevant patch in UPM series, but
not here.

> > 
> > Also, why KVM_X86_PROTECTED_VM == TDX VM?
> 
> This part needs to be resolved.
> Use KVM_X86_PROTECTED_VM as TDX VM or new type KVM_X86_TDX_VM or other way
> to specify VM type.
> Given pKVM is coming, dedicated VM type seems better.  I'll switch it to
> KVM_X86_TDX_VM next respin.
> -- 
> Isaku Yamahata <isaku.yamahata@gmail.com>

I'll leave to Sean and Paolo.