Re: [Qemu-devel] [RFC] exec: eliminate ram naming issue as migration

[Paolo Bonzini]

On 05/02/2018 15:58, Jianfeng Tan wrote:
> Here are some options to fix this:
> 
> 1. When we do ram name comparison, we truncate the prefix as this patch shows.
> It cannot cover the corner case: the source VM could have two ram blocks
> with name of "pc.ram" and "/object/pc.ram".

That shouldn't happen ("pc.ram" exists even in the "-numa
node,memdev=..." case, but it has no RAM block).

>      RAMBLOCK_FOREACH(block) {
> -        if (!strcmp(name, block->idstr)) {
> +        name2 = strdup(block->idstr);
> +     id2 = basename(name2);
> +        if (!strcmp(id1, id2)) {
> +            free(name1);
> +         free(name2);
>              return block;
>          }
> +     free(name2);

Instead of this, perhaps just skip "/object/" in both id1 and
block->idstr?  This also removes the need for strdup/free.

However, note that

  -m xG -numa node,memdev=pc.ram \
  -object memory-backend-file,id=pc.ram,...

works for both vhost-kernel and vhost-user, so I'd rather consider this
a configuration problem and not do anything.

Thanks,

Paolo

>      }
>  
> +    free(name1);
>      return NULL;
>  }
>  
>