Re: [Qemu-devel] [PATCH] migration: allow private destination ram with x-ignore-shared

2019-06-17 Thread Dr. David Alan Gilbert 
* 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/msg3.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 
> > Cc: Yury Kotov 
> > Cc: Jiangshan Lai 
> > Cc: Xu Wang 
> > Signed-off-by: Peng Tao 
> 
> 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 
> 
> > ---
> >  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

Re: [Qemu-devel] [PATCH] migration: allow private destination ram with x-ignore-shared

2019-06-17 Thread Dr. David Alan Gilbert 
* 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/msg3.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 
> Cc: Yury Kotov 
> Cc: Jiangshan Lai 
> Cc: Xu Wang 
> Signed-off-by: Peng Tao 

I think this is OK, but please post this to qemu-devel.

Reviewed-by: Dr. David Alan Gilbert 

> ---
>  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

Re: [Qemu-devel] [PATCH] migration: allow private destination ram with x-ignore-shared

2019-06-13 Thread Peng Tao 




On 2019/6/14 14:35, Peng Tao 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/msg3.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

FYI, corresponding kata pull request is posted at 
https://github.com/kata-containers/runtime/pull/1799


Cheers,
Tao
--
Into something rich and strange.

[Qemu-devel] [PATCH] migration: allow private destination ram with x-ignore-shared

2019-06-13 Thread Peng Tao 
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/msg3.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 
Cc: Yury Kotov 
Cc: Jiangshan Lai 
Cc: Xu Wang 
Signed-off-by: Peng Tao 
---
 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