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Commit 5cf2360b authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm 

Pull KVM fix from Radim Krčmář:
 "Fix PPC HV host crash that can occur as a result of resizing the guest
  hashed page table"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: PPC: Book3S HV: Fix exclusion between HPT resizing and other HPT updates
parents a579e949 d850a255

arch/powerpc/kvm/book3s_64_mmu_hv.c

+10 −0
Original line number Diff line number Diff line
@@ -646,6 +646,16 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, 
		hnow_v = hpte_new_to_old_v(hnow_v, hnow_r);

		hnow_r = hpte_new_to_old_r(hnow_r);

	}



	/*

	 * If the HPT is being resized, don't update the HPTE,

	 * instead let the guest retry after the resize operation is complete.

	 * The synchronization for hpte_setup_done test vs. set is provided

	 * by the HPTE lock.

	 */

	if (!kvm->arch.hpte_setup_done)

		goto out_unlock;



	if ((hnow_v & ~HPTE_V_HVLOCK) != hpte[0] || hnow_r != hpte[1] ||

	    rev->guest_rpte != hpte[2])

		/* HPTE has been changed under us; let the guest retry */

arch/powerpc/kvm/book3s_hv.c

+19 −10
Original line number Diff line number Diff line
@@ -2705,11 +2705,14 @@ static noinline void kvmppc_run_core(struct kvmppc_vcore *vc) 
	 * Hard-disable interrupts, and check resched flag and signals.

	 * If we need to reschedule or deliver a signal, clean up

	 * and return without going into the guest(s).

	 * If the hpte_setup_done flag has been cleared, don't go into the

	 * guest because that means a HPT resize operation is in progress.

	 */

	local_irq_disable();

	hard_irq_disable();

	if (lazy_irq_pending() || need_resched() ||

	    recheck_signals(&core_info)) {

	    recheck_signals(&core_info) ||

	    (!kvm_is_radix(vc->kvm) && !vc->kvm->arch.hpte_setup_done)) {

		local_irq_enable();

		vc->vcore_state = VCORE_INACTIVE;

		/* Unlock all except the primary vcore */
@@ -3078,7 +3081,7 @@ static void kvmppc_vcore_blocked(struct kvmppc_vcore *vc) 


static int kvmppc_run_vcpu(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)

{

	int n_ceded, i;

	int n_ceded, i, r;

	struct kvmppc_vcore *vc;

	struct kvm_vcpu *v;
@@ -3132,6 +3135,20 @@ static int kvmppc_run_vcpu(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu) 


	while (vcpu->arch.state == KVMPPC_VCPU_RUNNABLE &&

	       !signal_pending(current)) {

		/* See if the HPT and VRMA are ready to go */

		if (!kvm_is_radix(vcpu->kvm) &&

		    !vcpu->kvm->arch.hpte_setup_done) {

			spin_unlock(&vc->lock);

			r = kvmppc_hv_setup_htab_rma(vcpu);

			spin_lock(&vc->lock);

			if (r) {

				kvm_run->exit_reason = KVM_EXIT_FAIL_ENTRY;

				kvm_run->fail_entry.hardware_entry_failure_reason = 0;

				vcpu->arch.ret = r;

				break;

			}

		}



		if (vc->vcore_state == VCORE_PREEMPT && vc->runner == NULL)

			kvmppc_vcore_end_preempt(vc);
@@ -3249,13 +3266,6 @@ static int kvmppc_vcpu_run_hv(struct kvm_run *run, struct kvm_vcpu *vcpu) 
	/* Order vcpus_running vs. hpte_setup_done, see kvmppc_alloc_reset_hpt */

	smp_mb();



	/* On the first time here, set up HTAB and VRMA */

	if (!kvm_is_radix(vcpu->kvm) && !vcpu->kvm->arch.hpte_setup_done) {

		r = kvmppc_hv_setup_htab_rma(vcpu);

		if (r)

			goto out;

	}



	flush_all_to_thread(current);



	/* Save userspace EBB and other register values */
@@ -3303,7 +3313,6 @@ static int kvmppc_vcpu_run_hv(struct kvm_run *run, struct kvm_vcpu *vcpu) 
	}

	mtspr(SPRN_VRSAVE, user_vrsave);



 out:

	vcpu->arch.state = KVMPPC_VCPU_NOTREADY;

	atomic_dec(&vcpu->kvm->arch.vcpus_running);

	return r;