From: Robin Murphy robin.murphy@arm.com
[ Upstream commit c919739ce4721ecf7b96b99253b032df30fcf19b ]
Currently we rely on registering all our instances before initially allowing any .probe_device calls via bus_set_iommu(). In preparation for phasing out the latter, make sure we won't inadvertently return success for a device associated with a known but not yet registered instance, otherwise we'll run straight into iommu_group_get_for_dev() trying to use NULL ops.
That also highlights an issue with intel_iommu_get_resv_regions() taking dmar_global_lock from within a section where intel_iommu_init() already holds it, which already exists via probe_acpi_namespace_devices() when an ANDD device is probed, but gets more obvious with the upcoming change to iommu_device_register(). Since they are both read locks it manages not to deadlock in practice, and a more in-depth rework of this locking is underway, so no attempt is made to address it here.
Reviewed-by: Kevin Tian kevin.tian@intel.com Signed-off-by: Robin Murphy robin.murphy@arm.com Link: https://lore.kernel.org/r/579f2692291bcbfc3ac64f7456fcff0d629af131.166057278... Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/iommu/intel/iommu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 31bc50e538a3..ed63386b9b60 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -4457,7 +4457,7 @@ static struct iommu_device *intel_iommu_probe_device(struct device *dev) u8 bus, devfn;
iommu = device_to_iommu(dev, &bus, &devfn); - if (!iommu) + if (!iommu || !iommu->iommu.ops) return ERR_PTR(-ENODEV);
info = kzalloc(sizeof(*info), GFP_KERNEL);