On Tue, Jun 15, 2021 at 08:59:25AM +0000, Tian, Kevin wrote:

Hi, Jason,

quoted

From: Jason Gunthorpe
Sent: Thursday, June 3, 2021 9:05 PM

On Thu, Jun 03, 2021 at 06:39:30AM +0000, Tian, Kevin wrote:

quoted

quoted

quoted

Two helper functions are provided to support VFIO_ATTACH_IOASID:

	struct attach_info {
		u32	ioasid;
		// If valid, the PASID to be used physically
		u32	pasid;
	};
	int ioasid_device_attach(struct ioasid_dev *dev,
		struct attach_info info);
	int ioasid_device_detach(struct ioasid_dev *dev, u32 ioasid);

Honestly, I still prefer this to be highly explicit as this is where
all device driver authors get invovled:

ioasid_pci_device_attach(struct pci_device *pdev, struct ioasid_dev *dev,
u32 ioasid);
ioasid_pci_device_pasid_attach(struct pci_device *pdev, u32

*physical_pasid,

quoted

quoted

struct ioasid_dev *dev, u32 ioasid);

Then better naming it as pci_device_attach_ioasid since the 1st parameter
is struct pci_device?

No, the leading tag indicates the API's primary subystem, in this case
it is iommu (and if you prefer list the iommu related arguments first)

I have a question on this suggestion when working on v2.

Within IOMMU fd it uses only the generic struct device pointer, which
is already saved in struct ioasid_dev at device bind time:

	struct ioasid_dev *ioasid_register_device(struct ioasid_ctx *ctx,
		struct device *device, u64 device_label);

What does this additional struct pci_device bring when it's specified in
the attach call? If we save it in attach_data, at which point will it be
used or checked? 

The above was for attaching to an ioasid not the register path

You should call 'device_label' 'device_cookie' if it is a user
provided u64

Jason