Re: [Xen-devel] [PATCH v2 07/16] x86: put XEN_DOMCTL_{set, get}_address_size under CONFIG_PV

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Fri, Oct 19, 2018 at 04:18:21PM +0100, Andrew Cooper wrote:
> On 19/10/18 15:28, Wei Liu wrote:
> > They are useful to PV only.
> >
> > Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
> 
> How easy is this to turn into a domaincreate flag?  It is yet another
> singleton operation which complicated Xen's init/cleanup path having to
> cope with it being enabled after the fact.
> 
> (This is a slightly loaded question.  I have a suspicion that the answer
> is "rather complicated to make the associated libxl changes", as you
> need to know the bitness of the PV kernel before calling domaincreate.

It appears that by the time the set hypercall is called toolstack should
have already known the bitness of the kernel, so it is possible to turn
the set hypercall into a flag (but still non-trivial). Getting rid of
the get hypercall is more complicated because the bitness is not
recorded anywhere in userspace. Parsing the kernel again is not an
option.

Wei.

> 
> ~Andrew

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel