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: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 9533080..4660a7d 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -731,7 +731,7 @@
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 @@
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);
@@ -757,20 +761,16 @@
new_coll = collection;
}
- itte = find_itte(its, device_id, event_id);
+ itte = kzalloc(sizeof(struct its_itte), GFP_KERNEL);
if (!itte) {
- itte = kzalloc(sizeof(struct its_itte), GFP_KERNEL);
- if (!itte) {
- if (new_coll)
- vgic_its_free_collection(its, coll_id);
- return -ENOMEM;
- }
-
- new_itte = itte;
- itte->event_id = event_id;
- list_add_tail(&itte->itte_list, &device->itt_head);
+ if (new_coll)
+ vgic_its_free_collection(its, coll_id);
+ return -ENOMEM;
}
+ 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 @@
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;