Commit fcb93eb6 authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

kvm: x86/mmu: Flush TLB before zap_gfn_range releases RCU 



Since "KVM: x86/mmu: Zap only TDP MMU leafs in kvm_zap_gfn_range()"
is going to be reverted, it's not going to be true anymore that
the zap-page flow does not free any 'struct kvm_mmu_page'.  Introduce
an early flush before tdp_mmu_zap_leafs() returns, to preserve
bisectability.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 714797c9

arch/x86/kvm/mmu/tdp_mmu.c

+9 −5
Original line number Diff line number Diff line
@@ -941,13 +941,17 @@ static bool tdp_mmu_zap_leafs(struct kvm *kvm, struct kvm_mmu_page *root, 
		flush = true;

	}



	rcu_read_unlock();



	/*

	 * Because this flow zaps _only_ leaf SPTEs, the caller doesn't need

	 * to provide RCU protection as no 'struct kvm_mmu_page' will be freed.

	 * Need to flush before releasing RCU.  TODO: do it only if intermediate

	 * page tables were zapped; there is no need to flush under RCU protection

	 * if no 'struct kvm_mmu_page' is freed.

	 */

	return flush;

	if (flush)

		kvm_flush_remote_tlbs_with_address(kvm, start, end - start);



	rcu_read_unlock();



	return false;

}



/*