* Dr. David Alan Gilbert (dgilb...@redhat.com) wrote: > * Peng Tao (tao.p...@linux.alibaba.com) wrote: > > By removing the share ram check, qemu is able to migrate > > to private destination ram when x-ignore-shared capability > > is on. Then we can create multiple destination VMs based > > on the same source VM. > > > > This changes the x-ignore-shared migration capability to > > work similar to Lai's original bypass-shared-memory > > work(https://lists.gnu.org/archive/html/qemu-devel/2018-04/msg00003.html) > > which enables kata containers (https://katacontainers.io) > > to implement the VM templating feature. > > > > An example usage in kata containers(https://katacontainers.io): > > 1. Start the source VM: > > qemu-system-x86 -m 2G \ > > -object > > memory-backend-file,id=mem0,size=2G,share=on,mem-path=/tmpfs/template-memory > > \ > > -numa node,memdev=mem0 > > 2. Stop the template VM, set migration x-ignore-shared capability, > > migrate "exec:cat>/tmpfs/state", quit it > > 3. Start target VM: > > qemu-system-x86 -m 2G \ > > -object > > memory-backend-file,id=mem0,size=2G,share=off,mem-path=/tmpfs/template-memory > > \ > > -numa node,memdev=mem0 \ > > -incoming defer > > 4. connect to target VM qmp, set migration x-ignore-shared capability, > > migrate_incoming "exec:cat /tmpfs/state" > > 5. create more target VMs repeating 3 and 4 > > > > Cc: Dr. David Alan Gilbert <dgilb...@redhat.com> > > Cc: Yury Kotov <yury-ko...@yandex-team.ru> > > Cc: Jiangshan Lai <la...@hyper.sh> > > Cc: Xu Wang <x...@hyper.sh> > > Signed-off-by: Peng Tao <tao.p...@linux.alibaba.com> > > I think this is OK, but please post this to qemu-devel.
Oh you did :-) That's double fine then! > Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com> > > > --- > > migration/ram.c | 7 ------- > > 1 file changed, 7 deletions(-) > > > > diff --git a/migration/ram.c b/migration/ram.c > > index 1ca9ba7..cdb82a3 100644 > > --- a/migration/ram.c > > +++ b/migration/ram.c > > @@ -3373,7 +3373,6 @@ static int ram_save_setup(QEMUFile *f, void *opaque) > > } > > if (migrate_ignore_shared()) { > > qemu_put_be64(f, block->mr->addr); > > - qemu_put_byte(f, ramblock_is_ignored(block) ? 1 : 0); > > } > > } > > > > @@ -4340,12 +4339,6 @@ static int ram_load(QEMUFile *f, void *opaque, int > > version_id) > > } > > if (migrate_ignore_shared()) { > > hwaddr addr = qemu_get_be64(f); > > - bool ignored = qemu_get_byte(f); > > - if (ignored != ramblock_is_ignored(block)) { > > - error_report("RAM block %s should %s be > > migrated", > > - id, ignored ? "" : "not"); > > - ret = -EINVAL; > > - } > > if (ramblock_is_ignored(block) && > > block->mr->addr != addr) { > > error_report("Mismatched GPAs for block %s " > > -- > > 1.8.3.1 > > > -- > Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK