Commit 427c76ae authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: x86/mmu: Bug the VM if write-tracking is used but not enabled 



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.

Tested-by: default avatarYongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-27-seanjc@google.com


Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent e18c5429

arch/x86/kvm/mmu/page_track.c

+2 −2
Original line number Diff line number Diff line
@@ -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_ONCE(!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_ONCE(!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);