tools: any user of xc_dom_image->allocate?

tools: any user of xc_dom_image->allocate?

[Juergen Gross]

While testing xen tools patches to start a pv-domU >512GB I stumbled
over a problem in the domain builder: it is keeping track of the last
allocated virtual address in the memory image it is creating. For
very huge domains (>1TB) this virtual address will wrap around as it is
starting at -2GB and the p2m for such a domain is >2GB.

With a modern pvops kernel (4.3) this would be no problem, as it is
supporting mapping the p2m to an arbitrary address.

In the domain builder, however, I can't currently just ignore the wrap,
as after each memory allocation for the domain image dom->allocate() is
being called with the last allocated virtual address as an argument.
dom->allocate() is allowed to be NULL (in which case it isn't called).

I have found no user of dom->allocate(), deleting it from the struct
xc_dom_image and removing the call sites in xc_dom_core.c didn't break
the build.

Are there any objections to remove the allocate() function in struct
xc_dom_image?


Juergen

Re: tools: any user of xc_dom_image->allocate?

[Andrew Cooper]

On 11/09/15 08:25, Juergen Gross wrote:
> While testing xen tools patches to start a pv-domU >512GB I stumbled
> over a problem in the domain builder: it is keeping track of the last
> allocated virtual address in the memory image it is creating. For
> very huge domains (>1TB) this virtual address will wrap around as it is
> starting at -2GB and the p2m for such a domain is >2GB.
>
> With a modern pvops kernel (4.3) this would be no problem, as it is
> supporting mapping the p2m to an arbitrary address.
>
> In the domain builder, however, I can't currently just ignore the wrap,
> as after each memory allocation for the domain image dom->allocate() is
> being called with the last allocated virtual address as an argument.
> dom->allocate() is allowed to be NULL (in which case it isn't called).
>
> I have found no user of dom->allocate(), deleting it from the struct
> xc_dom_image and removing the call sites in xc_dom_core.c didn't break
> the build.
>
> Are there any objections to remove the allocate() function in struct
> xc_dom_image?

If there are no in-tree users, and no known out-of-tree users, good 
riddance to it.

~Andrew