KVM: x86/mmu: Do not enable page track for TD guest

Fail kvm_page_track_write_tracking_enabled() if VM type is TDX to make the
external page track user fail in kvm_page_track_register_notifier() since
TDX does not support write protection and hence page track.

No need to fail KVM internal users of page track (i.e. for shadow page),
because TDX is always with EPT enabled and currently TDX module does not
emulate and send VMLAUNCH/VMRESUME VMExits to VMM.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com>
Cc: Yuan Yao <yuan.yao@linux.intel.com>
Message-ID: <20241112073515.22028-1-yan.y.zhao@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/mmu/page_track.c b/arch/x86/kvm/mmu/page_track.c
index 561c331fd6ecc728d7b6ac85cde9743d0eb2f8a5..1b17b12393a8cb2d8624d39a7b419433debe9516 100644 (file)
--- a/arch/x86/kvm/mmu/page_track.c
+++ b/arch/x86/kvm/mmu/page_track.c
@@ -172,6 +172,9 @@ static int kvm_enable_external_write_tracking(struct kvm *kvm)
        struct kvm_memory_slot *slot;
        int r = 0, i, bkt;
 
+       if (kvm->arch.vm_type == KVM_X86_TDX_VM)
+               return -EOPNOTSUPP;
+
        mutex_lock(&kvm->slots_arch_lock);
 
        /*