Messages in this thread | | | Date | Tue, 2 Jan 2024 12:28:22 -0700 | From | Alex Williamson <> | Subject | Re: [Question] Is it must for vfio-mdev parent driver to implement a pci-compliant configuration r/w interface |
| |
On Tue, 26 Dec 2023 10:30:04 +0800 Wu Zongyong <wuzongyong@linux.alibaba.com> wrote:
> Hi, > > For vfio, I know there are two method to get region size: > 1. VFIO_DEVICE_GET_REGION_INFO ioctl > 2. write a value of all 1's to the bar register of vfio-device fd > and then read the value back which is described in pci spec > > Now I am curious about is it a must for a vfio-mdev parent driver to > implement the method 2? Or it is just a optional interface.
If there's not a working, compliant config space, the device shouldn't claim to implement a vfio-pci interface. There's vfio-platform available for non-PCI devices. While the BAR size may be found via either REGION_INFO or config space itself, the BAR address space is only found via config space, ie. memory or IO, 32 or 64-bit, prefetchable or not. Thanks,
Alex
| |