[+cc Amey (working on PCI resets), linux-pci] On Fri, Aug 13, 2021 at 05:01:32PM +0000, Vikram Sethi wrote: > Hi Dan, > > > -----Original Message----- > > From: Dan Williams <dan.j.williams@xxxxxxxxx> > > > > On Wed, Aug 11, 2021 at 9:42 AM Chris Browy <cbrowy@xxxxxxxxxxxxxxxx> > > wrote: > > > > /sys/bus/pci/devices/$device/reset is a method to trigger PCI > > device reset, but I do not expect that will ever gain CXL specific > > knowledge. > > > CXL reset may need some thought, specially for devices that don't > expose FLR but do expose CXL reset (while former does not affect > CXL.cache/mem, the latter wipes out CXL.cache/mem state in the > device and there is discoverability as to whether or not memory > contents can be cleared as part of CXL reset). We may need a way of > triggering CXL reset from userspace, and if the existing > /sys/bus/pci/devices/$device/reset won't have knowledge of CXL > reset, there still should be a prioritized order in the kernel in > which CXL reset is attempted before more drastic resets like SBR. > IIRC CXL reset can also impact all functions that use CXL.cache/mem, > but not legacy PCIe functions on the device which do not use > CXL.cache/mem (there is discoverability as to which functions are > not impacted by CXL reset). > > Thanks, > Vikram
