On Mon, Jul 23, 2018 at 04:24:31PM -0600, Alex Williamson wrote: > Take advantage of NVMe devices using a standard interface to quiesce > the controller prior to reset, including device specific delays before > and after that reset. This resolves several NVMe device assignment > scenarios with two different vendors. The Intel DC P3700 controller > has been shown to only work as a VM boot device on the initial VM > startup, failing after reset or reboot, and also fails to initialize > after hot-plug into a VM. Adding a delay after FLR resolves these > cases. The Samsung SM961/PM961 (960 EVO) sometimes fails to return > from FLR with the PCI config space reading back as -1. A reproducible > instance of this behavior is resolved by clearing the enable bit in > the configuration register and waiting for the ready status to clear > (disabling the NVMe controller) prior to FLR. > > As all NVMe devices make use of this standard interface and the NVMe > specification also requires PCIe FLR support, we can apply this quirk > to all devices with matching class code. Shouldn't this go in the nvme driver's reset_prepare/reset_done callbacks?
