KVM: TDX: Report supported optional TDVMCALLs in TDX capabilities

Allow userspace to advertise TDG.VP.VMCALL subfunctions that the
kernel also supports.  For each output register of GetTdVmCallInfo's
leaf 1, add two fields to KVM_TDX_CAPABILITIES: one for kernel-supported
TDVMCALLs (userspace can set those blindly) and one for user-supported
TDVMCALLs (userspace can set those if it knows how to handle them).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 14 insertions, 1 deletions

diff --git a/Documentation/virt/kvm/x86/intel-tdx.rst b/Documentation/virt/kvm/x86/intel-tdx.rst
index 76bdd95334d6..5efac62c92c7 100644
--- a/Documentation/virt/kvm/x86/intel-tdx.rst
+++ b/Documentation/virt/kvm/x86/intel-tdx.rst
@@ -79,7 +79,20 @@ to be configured to the TDX guest.
   struct kvm_tdx_capabilities {
         __u64 supported_attrs;
         __u64 supported_xfam;
-        __u64 reserved[254];
+
+        /* TDG.VP.VMCALL hypercalls executed in kernel and forwarded to
+         * userspace, respectively
+         */
+        __u64 kernel_tdvmcallinfo_1_r11;
+        __u64 user_tdvmcallinfo_1_r11;
+
+        /* TDG.VP.VMCALL instruction executions subfunctions executed in kernel
+         * and forwarded to userspace, respectively
+         */
+        __u64 kernel_tdvmcallinfo_1_r12;
+        __u64 user_tdvmcallinfo_1_r12;
+
+        __u64 reserved[250];
 
         /* Configurable CPUID bits for userspace */
         struct kvm_cpuid2 cpuid;