Re: [Xen-devel] [PATCH v10 5/6] x86/ioreq server: Asynchronously reset outstanding p2m_ioreq_server entries.

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 02.04.17 at 14:24, <yu.c.zhang@xxxxxxxxxxxxxxx> wrote:
> --- a/xen/arch/x86/mm/p2m.c
> +++ b/xen/arch/x86/mm/p2m.c
> @@ -317,6 +317,15 @@ int p2m_set_ioreq_server(struct domain *d,
>          if ( p2m->ioreq.server != NULL )
>              goto out;
>  
> +        /*
> +         * It is possible that an ioreq server has just been unmapped,
> +         * released the spin lock, with some p2m_ioreq_server entries
> +         * in p2m table remained. We shall refuse another ioreq server
> +         * mapping request in such case.
> +         */
> +        if ( read_atomic(&p2m->ioreq.entry_count) )
> +            goto out;

So this produces the same -EINVAL as the earlier check in context
above. I think it would be nice if neither did - -EINUSE for the first
(which we don't have, so -EOPNOTSUPP would seem the second
bets option there) and -EBUSY for the second would seem more
appropriate. If you agree, respective adjustments could be done
while committing, if no other reason for a v11 arises.

Jan


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel