On 2023/12/7 16:47, Tian, Kevin wrote:
From: Liu, Yi L <yi.l.liu@xxxxxxxxx>
Sent: Monday, November 27, 2023 2:39 PM
+static int vfio_pci_core_feature_pasid(struct vfio_device *device, u32 flags,
+ struct vfio_device_feature_pasid __user
*arg,
+ size_t argsz)
+{
+ struct vfio_pci_core_device *vdev =
+ container_of(device, struct vfio_pci_core_device, vdev);
+ struct vfio_device_feature_pasid pasid = { 0 };
+ struct pci_dev *pdev = vdev->pdev;
+ u32 capabilities = 0;
+ int ret;
+
+ /* We do not support SET of the PASID capability */
this line alone is meaningless. Please explain the reason e.g. due to
no PASID capability per VF...
sure. I think the major reason is we don't allow userspace to change the
PASID configuration. is it?
+ ret = vfio_check_feature(flags, argsz, VFIO_DEVICE_FEATURE_GET,
+ sizeof(pasid));
+ if (ret != 1)
+ return ret;
+
+ /*
+ * Needs go to PF if the device is VF as VF shares its PF's
+ * PASID Capability.
+ */
/* VF shares the PASID capability of its PF */
got it.
+ if (pdev->is_virtfn)
+ pdev = pci_physfn(pdev);
+
+ if (!pdev->pasid_enabled)
+ goto out;
+
+#ifdef CONFIG_PCI_PASID
+ pci_read_config_dword(pdev, pdev->pasid_cap + PCI_PASID_CAP,
+ &capabilities);
+#endif
#ifdef is unnecessary. If CONFIG_PCI_PASID is false pdev->pasid_enabled
won't be set anyway.
it's sad that the pdev->pasid_cap is defined under #if CONFIG_PCI_PASID.
Perhaps we can have a wrapper for it.
and it should read from PCI_PASID_CTRL which indicates whether a
capability is actually enabled.
yes, for the EXEC and PRIV capability, needs to check if it's enabled or
not before reporting.
+/**
+ * Upon VFIO_DEVICE_FEATURE_GET, return the PASID capability for the
device.
+ * Zero width means no support for PASID.
also mention the encoding of this field according to PCIe spec.
yes.
or turn it to a plain number field.
It is not exact the same as the spec since bit0 is reserved. But
here bit0 is used as well.
+ */
+struct vfio_device_feature_pasid {
+ __u16 capabilities;
+#define VFIO_DEVICE_PASID_CAP_EXEC (1 << 0)
+#define VFIO_DEVICE_PASID_CAP_PRIV (1 << 1)
+ __u8 width;
+ __u8 __reserved;
+};
+#define VFIO_DEVICE_FEATURE_PASID 11
+
/* -------- API for Type1 VFIO IOMMU -------- */
/**
--
2.34.1
--
Regards,
Yi Liu
