On Mon, Nov 20, 2023 at 08:34:58AM +0000, Tian, Kevin wrote:
From: Liu, Yi L yi.l.liu@intel.com Sent: Monday, November 20, 2023 4:30 PM
On 2023/11/20 16:09, Tian, Kevin wrote:
From: Liu, Yi L yi.l.liu@intel.com Sent: Friday, November 17, 2023 9:07 PM
- @req_len: Length (in bytes) of a request entry in the request array
- @req_num: Input the number of cache invalidation requests in the
array.
Output the number of requests successfully handled by kernel.
- @out_driver_error_code: Report a driver speicifc error code upon
failure.
It's optional, driver has a choice to fill it or
not.Being optional how does the user tell whether the code is filled or not?
Well, naming it "error_code" indicates zero means no error while non-zero means something? An error return from this ioctl could also tell the user space to look up for this driver error code, if it ever cares.
seems like we need a flag for it. otherwise, a reserved special value is required. or is it enough to just document it that this field is available or not per the iommu_hw_info_type?
No guarantee that a reserved special value applies to all vendors.
I'll just remove the optional part. the viommu driver knows what a valid code is, if the driver fills it.
Hmm, remove out_driver_error_code? Do you mean by reusing ioctl error code to tell the user space what driver error code it gets?
Nicolin