On Wed, 25 Mar 2020 02:38:58 +0530 Kirti Wankhede <kwankh...@nvidia.com> wrote:
> Hi, > > This Patch set adds migration support for VFIO devices in QEMU. Hi Kirti, Do you have any migration data you can share to show that this solution is viable and useful? I was chatting with Dave Gilbert and there still seems to be a concern that we actually have a real-world practical solution. We know this is inefficient with QEMU today, vendor pinned memory will get copied multiple times if we're lucky. If we're not lucky we may be copying all of guest RAM repeatedly. There are known inefficiencies with vIOMMU, etc. QEMU could learn new heuristics to account for some of this and we could potentially report different bitmaps in different phases through vfio, but let's make sure that there are useful cases enabled by this first implementation. With a reasonably sized VM, running a reasonable graphics demo or workload, can we achieve reasonably live migration? What kind of downtime do we achieve and what is the working set size of the pinned memory? Intel folks, if you've been able to port to this or similar code base, please report your results as well, open source consumers are arguably even more important. Thanks, Alex
