On Thu, Aug 05, 2021 at 09:14:50PM +0800, Dongdong Liu wrote: > On 2021/8/4 23:51, Logan Gunthorpe wrote: > > > > > > > > On 2021-08-04 7:47 a.m., Dongdong Liu wrote: > > > PCIe spec 5.0 r1.0 section 2.2.6.2 says that if an Endpoint supports > > > sending Requests to other Endpoints (as opposed to host memory), the > > > Endpoint must not send 10-Bit Tag Requests to another given Endpoint > > > unless an implementation-specific mechanism determines that the Endpoint > > > supports 10-Bit Tag Completer capability. Add a 10bit_tag sysfs file, > > > write 0 to disable 10-Bit Tag Requester when the driver does not bind > > > the device if the peer device does not support the 10-Bit Tag Completer. > > > This will make P2P traffic safe. the 10bit_tag file content indicate > > > current 10-Bit Tag Requester Enable status. > > > > Can we not have both the sysfs file and the command line parameter? If > > the user wants to disable it always for a specific device this sysfs > > parameter is fairly awkward. A script at boot to unbind the driver, set > > the sysfs file and rebind the driver is not trivial and the command line > > parameter offers additional options for users. > Does the command line parameter as "[PATCH V6 7/8] PCI: Add > "pci=disable_10bit_tag=" parameter for peer-to-peer support" does? > > Do we also need such command line if we already had sysfs file? > I think we may not need. I think the same. > > Thanks, > Dongdong > > > > Logan > > . > >
