Re: [PATCH v2 2/4] Support live migration between file-backed memory and anonymous memory.

Hi, On 8/6/24 07:38, Martin Kletzander wrote: > On Wed, Jun 05, 2024 at 04:37:36PM -0400, mgalaxy(a)akamai.com wrote: >> From: Michael Galaxy <mgalaxy(a)akamai.com&gt; >> >> >>     if (src->mem.source != dst->mem.source) { >> -        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, >> -                       _("Target memoryBacking source '%1$s' doesn't >> match source memoryBacking source'%2$s'"), >> - virDomainMemorySourceTypeToString(dst->mem.source), >> - virDomainMemorySourceTypeToString(src->mem.source)); >> -        return false; >> +        /* >> +         * The current use case for this is the live migration of >> live-update >> +         * capable CPR guests mounted on PMEM devices at the host > > Does libvirt need more adjustments to support cpr-reboots?  I don't > think we have any support for them yet. > Ummmm, no, not really, no. Which is a good question. CPR has two different modes. "reboots" and "execs". The former is when you want to do a full kexec (which blows away libvirt because you're  rebooting), and the latter does not do a kexec at all. We are only  currently using the reboot mode. And it works just fine. There are a number of QMP commands that CPR uses, but we are feeding those commands through libvirt with just the normal qmp command support that it already provides rather than doing any "built-in" changes to libvirt to support those features, currently. So, no, we don't have a need (currently) to further modify libvirt to support CPR.

- Michael