On 7/19/2022 7:09 AM, Tian, Kevin wrote:
From: Alex Williamson <alex.williamson@xxxxxxxxxx>
Sent: Tuesday, July 19, 2022 6:30 AM
On Thu, 14 Jul 2022 11:12:43 +0300
Yishai Hadas <yishaih@xxxxxxxxxx> wrote:
DMA logging allows a device to internally record what DMAs the device is
initiating and report them back to userspace. It is part of the VFIO
migration infrastructure that allows implementing dirty page tracking
during the pre copy phase of live migration. Only DMA WRITEs are logged,
and this API is not connected to
VFIO_DEVICE_FEATURE_MIG_DEVICE_STATE.
This patch introduces the DMA logging involved uAPIs.
It uses the FEATURE ioctl with its GET/SET/PROBE options as of below.
It exposes a PROBE option to detect if the device supports DMA logging.
It exposes a SET option to start device DMA logging in given IOVAs
ranges.
It exposes a SET option to stop device DMA logging that was previously
started.
It exposes a GET option to read back and clear the device DMA log.
Extra details exist as part of vfio.h per a specific option.
Kevin, Kirti, others, any comments on this uAPI proposal? Are there
potentially other devices that might make use of this or is everyone
else waiting for IOMMU based dirty tracking?
I had briefly screened through it, I'm taking a closer look of it.
NVIDIA vGPU might use this API.
Thanks,
Kirti
