KVM: x86: Do not use kvm_rip_read() unconditionally for KVM_PROFILING

Not all VMs allow access to RIP.  Check guest_state_protected before
calling kvm_rip_read().

This avoids, for example, hitting WARN_ON_ONCE in vt_cache_reg() for
TDX VMs.

Fixes: 81bf912b2c15 ("KVM: TDX: Implement TDX vcpu enter/exit path")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Message-ID: <20250415104821.247234-3-adrian.hunter@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/x86.c

@@ -11098,7 +11098,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 	/*
 	 * Profile KVM exit RIPs:
 	 */
-	if (unlikely(prof_on == KVM_PROFILING)) {
+	if (unlikely(prof_on == KVM_PROFILING &&
+		     !vcpu->arch.guest_state_protected)) {
 		unsigned long rip = kvm_rip_read(vcpu);
 		profile_hit(KVM_PROFILING, (void *)rip);
 	}