Commit 286054a7 authored by Andre Przywara's avatar Andre Przywara Committed by Christoffer Dall
Browse files

KVM: arm64: ITS: avoid re-mapping LPIs 



When a guest wants to map a device-ID/event-ID combination that is
already mapped, we may end up in a situation where an LPI is never
"put", thus never being freed.
Since the GICv3 spec says that mapping an already mapped LPI is
UNPREDICTABLE, lets just bail out early in this situation to avoid
any potential leaks.

Signed-off-by: default avatarAndre Przywara <andre.przywara@arm.com>
Reviewed-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: default avatarChristoffer Dall <christoffer.dall@linaro.org>
parent 505a19ee

virt/kvm/arm/vgic/vgic-its.c

+13 −14
Original line number Diff line number Diff line
@@ -731,7 +731,7 @@ static int vgic_its_cmd_handle_mapi(struct kvm *kvm, struct vgic_its *its, 
	u32 device_id = its_cmd_get_deviceid(its_cmd);

	u32 event_id = its_cmd_get_id(its_cmd);

	u32 coll_id = its_cmd_get_collection(its_cmd);

	struct its_itte *itte, *new_itte = NULL;

	struct its_itte *itte;

	struct its_device *device;

	struct its_collection *collection, *new_coll = NULL;

	int lpi_nr;
@@ -749,6 +749,10 @@ static int vgic_its_cmd_handle_mapi(struct kvm *kvm, struct vgic_its *its, 
	    lpi_nr >= max_lpis_propbaser(kvm->arch.vgic.propbaser))

		return E_ITS_MAPTI_PHYSICALID_OOR;



	/* If there is an existing mapping, behavior is UNPREDICTABLE. */

	if (find_itte(its, device_id, event_id))

		return 0;



	collection = find_collection(its, coll_id);

	if (!collection) {

		int ret = vgic_its_alloc_collection(its, &collection, coll_id);
@@ -757,8 +761,6 @@ static int vgic_its_cmd_handle_mapi(struct kvm *kvm, struct vgic_its *its, 
		new_coll = collection;

	}



	itte = find_itte(its, device_id, event_id);

	if (!itte) {

	itte = kzalloc(sizeof(struct its_itte), GFP_KERNEL);

	if (!itte) {

		if (new_coll)
@@ -766,10 +768,8 @@ static int vgic_its_cmd_handle_mapi(struct kvm *kvm, struct vgic_its *its, 
		return -ENOMEM;

	}



		new_itte = itte;

	itte->event_id	= event_id;

	list_add_tail(&itte->itte_list, &device->itt_head);

	}



	itte->collection = collection;

	itte->lpi = lpi_nr;
@@ -778,8 +778,7 @@ static int vgic_its_cmd_handle_mapi(struct kvm *kvm, struct vgic_its *its, 
	if (IS_ERR(irq)) {

		if (new_coll)

			vgic_its_free_collection(its, coll_id);

		if (new_itte)

			its_free_itte(kvm, new_itte);

		its_free_itte(kvm, itte);

		return PTR_ERR(irq);

	}

	itte->irq = irq;

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