i386/cgs: Introduce x86_confidential_guest_check_features()

To do cgs specific feature checking. Note the feature checking in
x86_cpu_filter_features() is valid for non-cgs VMs. For cgs VMs like
TDX, what features can be supported has more restrictions.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20250508150002.689633-51-xiaoyao.li@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/target/i386/confidential-guest.h b/target/i386/confidential-guest.h
index 777d43cc9688f3d743960185537084e204a27e13..48b88dbd3130d3aad54408a84c62fc37f8a8acd0 100644 (file)
--- a/target/i386/confidential-guest.h
+++ b/target/i386/confidential-guest.h
@@ -42,6 +42,7 @@ struct X86ConfidentialGuestClass {
     void (*cpu_instance_init)(X86ConfidentialGuest *cg, CPUState *cpu);
     uint32_t (*adjust_cpuid_features)(X86ConfidentialGuest *cg, uint32_t feature,
                                       uint32_t index, int reg, uint32_t value);
+    int (*check_features)(X86ConfidentialGuest *cg, CPUState *cs);
 };
 
 /**
@@ -91,4 +92,16 @@ static inline int x86_confidential_guest_adjust_cpuid_features(X86ConfidentialGu
     }
 }
 
+static inline int x86_confidential_guest_check_features(X86ConfidentialGuest *cg,
+                                                        CPUState *cs)
+{
+    X86ConfidentialGuestClass *klass = X86_CONFIDENTIAL_GUEST_GET_CLASS(cg);
+
+    if (klass->check_features) {
+        return klass->check_features(cg, cs);
+    }
+
+    return 0;
+}
+
 #endif

diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index cd87f5502a31117e7c4d94e6d27f88c4c108798d..a6bc089d020d663a3e479b32113fcaff76aecf55 100644 (file)
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -2093,6 +2093,14 @@ int kvm_arch_init_vcpu(CPUState *cs)
     int r;
     Error *local_err = NULL;
 
+    if (current_machine->cgs) {
+        r = x86_confidential_guest_check_features(
+                X86_CONFIDENTIAL_GUEST(current_machine->cgs), cs);
+        if (r < 0) {
+            return r;
+        }
+    }
+
     memset(&cpuid_data, 0, sizeof(cpuid_data));
 
     cpuid_i = 0;