[PATCH v2 24/27] KVM: x86/mmu: Bug the VM if write-tracking is used but not enabled

[Sean Christopherson]

Bug the VM if something attempts to write-track a gfn, but write-tracking
isn't enabled.  The VM is doomed (and KVM has an egregious bug) if KVM or
KVMGT wants to shadow guest page tables but can't because write-tracking
isn't enabled.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
 arch/x86/kvm/mmu/page_track.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/mmu/page_track.c b/arch/x86/kvm/mmu/page_track.c
index ffcd7ac66f9e..327e73be62d6 100644
--- a/arch/x86/kvm/mmu/page_track.c
+++ b/arch/x86/kvm/mmu/page_track.c
@@ -90,7 +90,7 @@ void kvm_write_track_add_gfn(struct kvm *kvm, struct kvm_memory_slot *slot,
 	lockdep_assert_once(lockdep_is_held(&kvm->slots_lock) ||
 			    srcu_read_lock_held(&kvm->srcu));
 
-	if (WARN_ON(!kvm_page_track_write_tracking_enabled(kvm)))
+	if (KVM_BUG_ON(!kvm_page_track_write_tracking_enabled(kvm), kvm))
 		return;
 
 	update_gfn_write_track(slot, gfn, 1);
@@ -122,7 +122,7 @@ void kvm_write_track_remove_gfn(struct kvm *kvm,
 	lockdep_assert_once(lockdep_is_held(&kvm->slots_lock) ||
 			    srcu_read_lock_held(&kvm->srcu));
 
-	if (WARN_ON(!kvm_page_track_write_tracking_enabled(kvm)))
+	if (KVM_BUG_ON(!kvm_page_track_write_tracking_enabled(kvm), kvm))
 		return;
 
 	update_gfn_write_track(slot, gfn, -1);
-- 
2.40.0.rc1.284.g88254d51c5-goog