On Wed, 22 May 2024 13:52:21 -0300 Jason Gunthorpe <jgg@xxxxxxxxxx> wrote: > On Wed, May 22, 2024 at 08:43:18AM -0600, Alex Williamson wrote: > > > But I think this also means that regardless of virtualizing > > PCI_EXP_DEVCTL_NOSNOOP_EN, there will be momentary gaps around device > > resets where a device could legitimately perform no-snoop > > transactions. > > Isn't memory enable turned off after FLR? If not do we have to make it > off before doing FLR? > > I'm not sure how a no-snoop could leak out around FLR? Good point, modulo s/memory/bus master/. Yes, we'd likely need to make sure we enter pci_reset_function() with BM disabled so that we don't have an ordering issue between restoring the PCIe capability and the command register. Likewise no-snoop handling would need to avoid gaps around backdoor resets like we try to do when we're masking INTx support on the device (vfio_bar_restore). Thanks, Alex
