Re: [Qemu-devel] [PATCH] migrate: Migration aborts abruptly for machine "none"

[Daniel P. Berrange]

On Thu, Jan 26, 2017 at 02:46:52PM +0530, Ashijeet Acharya wrote:
> Migration of a "none" machine with no RAM crashes abruptly as
> bitmap_new() fails and thus aborts. Instead, place a check for
> last_ram_offset() being '0' at the start of ram_save_setup() and
> error out with a meaningful error message.
> 
> Signed-off-by: Ashijeet Acharya <address@hidden>
> ---
>  migration/ram.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/migration/ram.c b/migration/ram.c
> index ef8fadf..bf05d69 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -1947,6 +1947,11 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
>  {
>      RAMBlock *block;
>  
> +    if (last_ram_offset() == 0) {
> +        error_report("Failed to migrate: No RAM available!");
> +        return -1;
> +    }
> +

If we're merely going to block migration, as opposed to making it work,
then IMHO we should use migration blockers registered at machine setup
for this task.

We have a new cli arg added to QEMU to tell it to abort startup if the
machine configuration is not migratable. That only works if using
migration blockers - this check you've added is too late to be detected
at startup.


Regards,
Daniel
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