KVM: arm64: Resolve vLPI by host IRQ in vgic_v4_unset_forwarding()

The virtual mapping and "GSI" routing of a particular vLPI is subject to
change in response to the guest / userspace. This can be pretty annoying
to deal with when KVM needs to track the physical state that's managed
for vLPI direct injection.

Make vgic_v4_unset_forwarding() resilient by using the host IRQ to
resolve the vgic IRQ. Since this uses the LPI xarray directly, finding
the ITS by doorbell address + grabbing it's its_lock is no longer
necessary. Note that matching the right ITS / ITE is already handled in
vgic_v4_set_forwarding(), and unless there's a bug in KVM's VGIC ITS
emulation the virtual mapping that should remain stable for the lifetime
of the vLPI mapping.

Tested-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20250523194722.4066715-4-oliver.upton@linux.dev
Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Oliver Upton
2025-05-23 12:47:20 -07:00
committed by Marc Zyngier
parent fc4dafe87b
commit 05b9405f2f
3 changed files with 27 additions and 24 deletions

View File

@@ -434,8 +434,7 @@ struct kvm_kernel_irq_routing_entry;
int kvm_vgic_v4_set_forwarding(struct kvm *kvm, int irq,
struct kvm_kernel_irq_routing_entry *irq_entry);
int kvm_vgic_v4_unset_forwarding(struct kvm *kvm, int irq,
struct kvm_kernel_irq_routing_entry *irq_entry);
int kvm_vgic_v4_unset_forwarding(struct kvm *kvm, int host_irq);
int vgic_v4_load(struct kvm_vcpu *vcpu);
void vgic_v4_commit(struct kvm_vcpu *vcpu);