Commit a1ccfd6f authored by Ricardo Koller's avatar Ricardo Koller Committed by Marc Zyngier
Browse files

KVM: arm64: vgic: Do not ignore vgic_its_restore_cte failures 



Restoring a corrupted collection entry (like an out of range ID) is
being ignored and treated as success. More specifically, a
vgic_its_restore_cte failure is treated as success by
vgic_its_restore_collection_table.  vgic_its_restore_cte uses positive
and negative numbers to return error, and +1 to return success.  The
caller then uses "ret > 0" to check for success.

Fix this by having vgic_its_restore_cte only return negative numbers on
error.  Do this by changing alloc_collection return codes to only return
negative numbers on error.

Signed-off-by: default avatarRicardo Koller <ricarkol@google.com>
Reviewed-by: default avatarOliver Upton <oupton@google.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220510001633.552496-4-ricarkol@google.com
parent 243b1f6c

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

+23 −4
Original line number Diff line number Diff line
@@ -999,15 +999,16 @@ static bool vgic_its_check_event_id(struct vgic_its *its, struct its_device *dev 
	return __is_visible_gfn_locked(its, gpa);

}



/*

 * Add a new collection into the ITS collection table.

 * Returns 0 on success, and a negative error value for generic errors.

 */

static int vgic_its_alloc_collection(struct vgic_its *its,

				     struct its_collection **colp,

				     u32 coll_id)

{

	struct its_collection *collection;



	if (!vgic_its_check_id(its, its->baser_coll_table, coll_id, NULL))

		return E_ITS_MAPC_COLLECTION_OOR;



	collection = kzalloc(sizeof(*collection), GFP_KERNEL_ACCOUNT);

	if (!collection)

		return -ENOMEM;
@@ -1101,7 +1102,12 @@ static int vgic_its_cmd_handle_mapi(struct kvm *kvm, struct vgic_its *its, 


	collection = find_collection(its, coll_id);

	if (!collection) {

		int ret = vgic_its_alloc_collection(its, &collection, coll_id);

		int ret;



		if (!vgic_its_check_id(its, its->baser_coll_table, coll_id, NULL))

			return E_ITS_MAPC_COLLECTION_OOR;



		ret = vgic_its_alloc_collection(its, &collection, coll_id);

		if (ret)

			return ret;

		new_coll = collection;
@@ -1256,6 +1262,10 @@ static int vgic_its_cmd_handle_mapc(struct kvm *kvm, struct vgic_its *its, 
		if (!collection) {

			int ret;



			if (!vgic_its_check_id(its, its->baser_coll_table,

						coll_id, NULL))

				return E_ITS_MAPC_COLLECTION_OOR;



			ret = vgic_its_alloc_collection(its, &collection,

							coll_id);

			if (ret)
@@ -2491,6 +2501,11 @@ static int vgic_its_save_cte(struct vgic_its *its, 
	return kvm_write_guest_lock(its->dev->kvm, gpa, &val, esz);

}



/*

 * Restore a collection entry into the ITS collection table.

 * Return +1 on success, 0 if the entry was invalid (which should be

 * interpreted as end-of-table), and a negative error value for generic errors.

 */

static int vgic_its_restore_cte(struct vgic_its *its, gpa_t gpa, int esz)

{

	struct its_collection *collection;
@@ -2517,6 +2532,10 @@ static int vgic_its_restore_cte(struct vgic_its *its, gpa_t gpa, int esz) 
	collection = find_collection(its, coll_id);

	if (collection)

		return -EEXIST;



	if (!vgic_its_check_id(its, its->baser_coll_table, coll_id, NULL))

		return -EINVAL;



	ret = vgic_its_alloc_collection(its, &collection, coll_id);

	if (ret)

		return ret;