On 6/15/2021 3:14 PM, Dr. David Alan Gilbert wrote: > * Steven Sistare (steven.sist...@oracle.com) wrote: >> On 5/20/2021 9:00 AM, Dr. David Alan Gilbert wrote: >>> Hi Steven, >>> I'd like to split the discussion into reboot and restart, >>> so I can make sure I understand them individually. >>> >>> So reboot mode; >>> Can you explain which parts of this series are needed for reboot mode; >>> I've managed to do a kexec based reboot on qemu with the current qemu - >>> albeit with no vfio devices, my current understanding is that for doing >>> reboot with vfio we just need some way of getting migrate to send the >>> metadata associated with vfio devices if the guest is in S3. >>> >>> Is there something I'm missing and which you have in this series? >> >> You are correct, this series has little special code for reboot mode, but it >> does allow >> reboot and restart to be handled similarly, which simplifies the management >> layer because >> the same calls are performed for each mode. >> >> For vfio in reboot mode, prior to sending cprload, the manager sends the >> guest-suspend-ram >> command to the qemu guest agent. This flushes requests and brings the guest >> device to a >> reset state, so there is no vfio metadata to save. Reboot mode does not >> call vfio_cprsave. >> >> There are a few unique patches to support reboot mode. One is >> qemu_ram_volatile, which >> is a sanity check that the writable ram blocks are backed by some form of >> shared memory. >> Plus there are a few fragments in the "cpr" patch that handle the suspended >> state that >> is induced by guest-suspend-ram. See qemu_system_start_on_wake_request() >> and instances >> of RUN_STATE_SUSPENDED in migration/cpr.c > > Could you split the 'reboot' part of separately, then we can review > that and perhaps get it in first? It should be a relatively small patch > set - it'll get things moving in the right direction. > > The guest-suspend-ram stuff seems reasonable as an idea; lets just try > and avoid doing it all via environment variables though; make it proper > command line options.
How about I delete reboot mode and the mode argument instead. Having two modes is causing no end of confusion, and my primary business need is for restart mode. - Steve
