On Thursday 22 October 2015 15:26:55 Eric Auger wrote: > >> @@ -181,6 +182,8 @@ static int vfio_platform_open(void *device_data) > >> if (ret) > >> goto err_irq; > >> > >> + vfio_platform_get_reset(vdev); > >> + > >> if (vdev->reset) > >> vdev->reset(vdev); > >> > > > > This needs some error handling to ensure that the open() fails > > if there is no reset handler. > > Is that really what we want? The code was meant to allow the use case > where the VFIO platform driver would be used without such reset module. > > I think the imperious need for a reset module depends on the device and > more importantly depends on the IOMMU mapping. With QEMU VFIO > integration this is needed because the whole VM memory is IOMMU mapped > but in a simpler user-space driver context, we might live without. > > Any thought? I would think we need a reset driver for any device that can start DMA, otherwise things can go wrong as soon as you attach it to a different domain while there is ongoing DMA. Maybe we could just allow devices to be attached without a reset handler, but then disallow DMA on them? Arnd -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
