Anthony Liguori wrote:
> Izik Eidus wrote:
>> Anthony Liguori wrote:
>>>
>>> I think it's just a matter of calling do_mmap() with the appropriate 
>>> parameters.  It looks likes there's some drivers call do_mmap() 
>>> directly.
>>>
>> yea, i think you right, this is excellent idea!, when we will merge 
>> the swapping to kvm, we will add swapping support to older userspace.
>
> Here's a patch against your series.  The memset in kvmctl ends up 
> making the guest use all physical memory to start off with but I did 
> confirm that once the system is under memory pressure, the guest's 
> memory becomes swappable.  Of course, it's quite painful :-)
>
> A nice thing though is that a lot of the code becomes a bit cleaner 
> and we can eliminate the phys_mem array entirely.

>      /* Allocate if a slot is being created */
> -    if (npages && !new.phys_mem) {
> -        new.phys_mem = vmalloc(npages * sizeof(struct page *));
> -
> -        if (!new.phys_mem)
> -            goto out_unlock;
> -
> +    if (npages) {

This is wrong apparently.  We needed to have new.phys_mem to indicate 
whether the slot has been created yet or not.  The new attached patch 
uses new.rmap instead of new.phys_mem to accomplish the same goal.

I no longer see the BUG() that I was seeing.

> Regards,
>
> Anthony Liguori
>
>