Re: [PATCH 3/8] iommufd: Support attach/replace hwpt per pasid

On Sun, Nov 26, 2023 at 10:34:23PM -0800, Yi Liu wrote:

@@ -534,7 +537,17 @@ iommufd_device_do_replace(struct iommufd_device *idev, static struct iommufd_hw_pagetable *do_attach(struct iommufd_device *idev, struct iommufd_hw_pagetable *hwpt, struct attach_data *data) {

• return data->attach_fn(idev, hwpt);

• if (data->pasid == IOMMU_PASID_INVALID) {

• BUG_ON((data->attach_fn != iommufd_device_do_attach) &&
  

•        (data->attach_fn != iommufd_device_do_replace));
  

• return data->attach_fn(idev, hwpt);
  

• } else {

• BUG_ON((data->pasid_attach_fn !=
  

• 	iommufd_device_pasid_do_attach) &&
  

•        (data->pasid_attach_fn !=
  

• 	iommufd_device_pasid_do_replace));
  

• return data->pasid_attach_fn(idev, data->pasid, hwpt);
  

• }

Seems like the BUG_ON's are pointless

+/**

• • iommufd_device_pasid_detach - Disconnect a {device, pasid} to an iommu_domain
• • @idev: device to detach
• • @pasid: pasid to detach
• • Undo iommufd_device_pasid_attach(). This disconnects the idev/pasid from
• • the previously attached pt_id.
• */

+void iommufd_device_pasid_detach(struct iommufd_device *idev, u32 pasid) +{

• struct iommufd_hw_pagetable *hwpt;
• hwpt = xa_load(&idev->pasid_hwpts, pasid);
• if (!hwpt)

• return;
  

• xa_erase(&idev->pasid_hwpts, pasid);
• iommu_detach_device_pasid(hwpt->domain, idev->dev, pasid);
• iommufd_hw_pagetable_put(idev->ictx, hwpt);

+}

None of this xarray stuff looks locked properly

Jason