On Mon, 5 Feb 2018 14:58:55 +0000
Jianfeng Tan <jianfeng....@intel.com> wrote:
> Existing VMs with virtio devices and vhost-kernel as the backend
> are always started with mem config:
>
> "-m xG"
> (with a ram block named "pc.ram")
>
> while new VMs with virtio devices and vhost-user as the backend
> are always started with mem config:
>
> "-m xG -numa node,memdev=pc.ram -object memory-backend-file,id=pc.ram,..."
> (with a ram block named "/object/pc.ram")
could you elaborate more on what src command line migrating to what dst command
line?
> As we migrate from vhost-kernel to vhost-user, it failes as:
>
> Unknown ramblock "pc.ram", cannot accept migration
> error while loading state for instance 0x0 of device 'ram'
> load of migration failed: Invalid argument
>
> 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".
>
> 2. We add an alias name to RAMBlock; when we do name comparison, not only
> idstr is compared, but also compared to the alias. But this will add more
> complexity to upper layer stack OpenStack/libvirt.
>
> Any thoughts?
>
> Cc: Jason Wang <jasow...@redhat.com>
> Cc: Michael S. Tsirkin <m...@redhat.com>
> Cc: Maxime Coquelin <maxime.coque...@redhat.com>
> Cc: Paolo Bonzini <pbonz...@redhat.com>
> Suggested-by: Michael S. Tsirkin <m...@redhat.com>
> Signed-off-by: Jianfeng Tan <jianfeng....@intel.com>
> ---
> exec.c | 13 ++++++++++++-
> 1 file changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/exec.c b/exec.c
> index 4722e52..d294e5c 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -2334,13 +2334,24 @@ found:
> RAMBlock *qemu_ram_block_by_name(const char *name)
> {
> RAMBlock *block;
> + char *name1, *id1;
> + char *name2, *id2;
> +
> + name1 = strdup(name);
> + id1 = basename(name1);
>
> 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);
> }
>
> + free(name1);
> return NULL;
> }
>
