Commit 3ed0dc03 authored by Oliver Upton's avatar Oliver Upton
Browse files

Merge branch 'kvm-arm64/misc' into kvmarm/next 



* kvm-arm64/misc:
  : Miscellaneous fixes/cleanups for KVM/arm64
  :
  :  - Avoid GICv4 vLPI configuration when confronted with user error
  :
  :  - Only attempt vLPI configuration when the target routing is an MSI
  :
  :  - Document ordering requirements to avoid aforementioned user error
  KVM: arm64: Tear down vGIC on failed vCPU creation
  KVM: arm64: Document ordering requirements for irqbypass
  KVM: arm64: vgic-v4: Fall back to software irqbypass if LPI not found
  KVM: arm64: vgic-v4: Only WARN for HW IRQ mismatch when unmapping vLPI
  KVM: arm64: vgic-v4: Only attempt vLPI mapping for actual MSIs

Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
parents 80e54e84 250f2536

Documentation/virt/kvm/devices/arm-vgic-its.rst

+4 −1
Original line number Diff line number Diff line
@@ -126,7 +126,8 @@ KVM_DEV_ARM_VGIC_GRP_ITS_REGS 
ITS Restore Sequence:

---------------------



The following ordering must be followed when restoring the GIC and the ITS:

The following ordering must be followed when restoring the GIC, ITS, and

KVM_IRQFD assignments:



a) restore all guest memory and create vcpus

b) restore all redistributors
@@ -139,6 +140,8 @@ d) restore the ITS in the following order: 
     3. Load the ITS table data (KVM_DEV_ARM_ITS_RESTORE_TABLES)

     4. Restore GITS_CTLR



e) restore KVM_IRQFD assignments for MSIs



Then vcpus can be started.



ITS Table ABI REV0:

arch/arm64/kvm/arm.c

+17 −1
Original line number Diff line number Diff line
@@ -466,7 +466,11 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) 
	if (err)

		return err;



	return kvm_share_hyp(vcpu, vcpu + 1);

	err = kvm_share_hyp(vcpu, vcpu + 1);

	if (err)

		kvm_vgic_vcpu_destroy(vcpu);



	return err;

}



void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
@@ -2714,6 +2718,14 @@ int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *cons, 
{

	struct kvm_kernel_irqfd *irqfd =

		container_of(cons, struct kvm_kernel_irqfd, consumer);

	struct kvm_kernel_irq_routing_entry *irq_entry = &irqfd->irq_entry;



	/*

	 * The only thing we have a chance of directly-injecting is LPIs. Maybe

	 * one day...

	 */

	if (irq_entry->type != KVM_IRQ_ROUTING_MSI)

		return 0;



	return kvm_vgic_v4_set_forwarding(irqfd->kvm, prod->irq,

					  &irqfd->irq_entry);
@@ -2723,6 +2735,10 @@ void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *cons, 
{

	struct kvm_kernel_irqfd *irqfd =

		container_of(cons, struct kvm_kernel_irqfd, consumer);

	struct kvm_kernel_irq_routing_entry *irq_entry = &irqfd->irq_entry;



	if (irq_entry->type != KVM_IRQ_ROUTING_MSI)

		return;



	kvm_vgic_v4_unset_forwarding(irqfd->kvm, prod->irq,

				     &irqfd->irq_entry);

arch/arm64/kvm/vgic/vgic-v4.c

+11 −6
Original line number Diff line number Diff line
@@ -415,7 +415,7 @@ int kvm_vgic_v4_set_forwarding(struct kvm *kvm, int virq, 
	struct vgic_irq *irq;

	struct its_vlpi_map map;

	unsigned long flags;

	int ret;

	int ret = 0;



	if (!vgic_supports_direct_msis(kvm))

		return 0;
@@ -430,10 +430,15 @@ int kvm_vgic_v4_set_forwarding(struct kvm *kvm, int virq, 


	mutex_lock(&its->its_lock);



	/* Perform the actual DevID/EventID -> LPI translation. */

	ret = vgic_its_resolve_lpi(kvm, its, irq_entry->msi.devid,

				   irq_entry->msi.data, &irq);

	if (ret)

	/*

	 * Perform the actual DevID/EventID -> LPI translation.

	 *

	 * Silently exit if translation fails as the guest (or userspace!) has

	 * managed to do something stupid. Emulated LPI injection will still

	 * work if the guest figures itself out at a later time.

	 */

	if (vgic_its_resolve_lpi(kvm, its, irq_entry->msi.devid,

				 irq_entry->msi.data, &irq))

		goto out;



	/* Silently exit if the vLPI is already mapped */
@@ -512,7 +517,7 @@ int kvm_vgic_v4_unset_forwarding(struct kvm *kvm, int virq, 
	if (ret)

		goto out;



	WARN_ON(!(irq->hw && irq->host_irq == virq));

	WARN_ON(irq->hw && irq->host_irq != virq);

	if (irq->hw) {

		atomic_dec(&irq->target_vcpu->arch.vgic_cpu.vgic_v3.its_vpe.vlpi_count);

		irq->hw = false;