i386/tdx: Introduce is_tdx_vm() helper and cache tdx_guest object

It will need special handling for TDX VMs all around the QEMU.
Introduce is_tdx_vm() helper to query if it's a TDX VM.

Cache tdx_guest object thus no need to cast from ms->cgs every time.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20250508150002.689633-7-xiaoyao.li@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c
index f8ec4fa217e1bb4b80a2d62527cffddb58039cf9..3750889453d8705044cd399a5b98373532403677 100644 (file)
--- a/target/i386/kvm/tdx.c
+++ b/target/i386/kvm/tdx.c
@@ -18,8 +18,16 @@
 #include "kvm_i386.h"
 #include "tdx.h"
 
+static TdxGuest *tdx_guest;
+
 static struct kvm_tdx_capabilities *tdx_caps;
 
+/* Valid after kvm_arch_init()->confidential_guest_kvm_init()->tdx_kvm_init() */
+bool is_tdx_vm(void)
+{
+    return !!tdx_guest;
+}
+
 enum tdx_ioctl_level {
     TDX_VM_IOCTL,
     TDX_VCPU_IOCTL,
@@ -117,15 +125,20 @@ static int get_tdx_capabilities(Error **errp)
 
 static int tdx_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
 {
+    TdxGuest *tdx = TDX_GUEST(cgs);
     int r = 0;
 
     kvm_mark_guest_state_protected();
 
     if (!tdx_caps) {
         r = get_tdx_capabilities(errp);
+        if (r) {
+            return r;
+        }
     }
 
-    return r;
+    tdx_guest = tdx;
+    return 0;
 }
 
 static int tdx_kvm_type(X86ConfidentialGuest *cg)

diff --git a/target/i386/kvm/tdx.h b/target/i386/kvm/tdx.h
index f3b72533616130c347e782910e388bf2eb9fd15d..de8ae9196163f30c1c36730c426ed26944066140 100644 (file)
--- a/target/i386/kvm/tdx.h
+++ b/target/i386/kvm/tdx.h
@@ -3,6 +3,10 @@
 #ifndef QEMU_I386_TDX_H
 #define QEMU_I386_TDX_H
 
+#ifndef CONFIG_USER_ONLY
+#include CONFIG_DEVICES /* CONFIG_TDX */
+#endif
+
 #include "confidential-guest.h"
 
 #define TYPE_TDX_GUEST "tdx-guest"
@@ -18,4 +22,10 @@ typedef struct TdxGuest {
     uint64_t attributes;    /* TD attributes */
 } TdxGuest;
 
+#ifdef CONFIG_TDX
+bool is_tdx_vm(void);
+#else
+#define is_tdx_vm() 0
+#endif /* CONFIG_TDX */
+
 #endif /* QEMU_I386_TDX_H */