iommufd_fault_iopf_enable has limitation to PRI on PCI/SRIOV VFs
because the PRI might be a shared resource and current iommu
subsystem is not ready to support enabling/disabling PRI on a VF
without any impact on others.

However, we have devices that appear as PCI but are actually on the
AMBA bus. These fake PCI devices have PASID capability, support
stall as well as SRIOV, so remove the limitation for these devices.

Co-developed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/iommufd/fault.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/iommufd/fault.c b/drivers/iommu/iommufd/fault.c
index 80efef1c127d..c5b0aa719948 100644
--- a/drivers/iommu/iommufd/fault.c
+++ b/drivers/iommu/iommufd/fault.c
@@ -10,6 +10,7 @@
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/pci.h>
+#include <linux/pci-ats.h>
 #include <linux/poll.h>
 #include <uapi/linux/iommufd.h>
 
@@ -27,8 +28,12 @@ static int iommufd_fault_iopf_enable(struct iommufd_device *idev)
 	 * resource between PF and VFs. There is no coordination for this
 	 * shared capability. This waits for a vPRI reset to recover.
 	 */
-	if (dev_is_pci(dev) && to_pci_dev(dev)->is_virtfn)
-		return -EINVAL;
+	if (dev_is_pci(dev)) {
+		struct pci_dev *pdev = to_pci_dev(dev);
+
+		if (pdev->is_virtfn && pci_pri_supported(pdev))
+			return -EINVAL;
+	}
 
 	mutex_lock(&idev->iopf_lock);
 	/* Device iopf has already been on. */
-- 
2.25.1

On Thu, Nov 07, 2024 at 04:37:11AM +0000, Zhangfei Gao wrote:
> iommufd_fault_iopf_enable has limitation to PRI on PCI/SRIOV VFs
> because the PRI might be a shared resource and current iommu
> subsystem is not ready to support enabling/disabling PRI on a VF
> without any impact on others.
> 
> However, we have devices that appear as PCI but are actually on the
> AMBA bus. These fake PCI devices have PASID capability, support
> stall as well as SRIOV, so remove the limitation for these devices.
> 
> Co-developed-by: Lu Baolu <baolu.lu@linux.intel.com>
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org>
> Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
> ---
>  drivers/iommu/iommufd/fault.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)

Applied to iommufd thanks

Jason