Messages in this thread | | | Date | Fri, 16 Mar 2007 09:54:51 +0100 | From | Ingo Molnar <> | Subject | Re: [patch 21/26] Xen-paravirt_ops: Use the hvc console infrastructure for Xen console |
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* Jeremy Fitzhardinge <jeremy@goop.org> wrote:
> Implement a Xen back-end for hvc console.
> + cons = intf->out_cons; > + prod = intf->out_prod; > + mb(); > + BUG_ON((prod - cons) > sizeof(intf->out)); > + > + while ((sent < len) && ((prod - cons) < sizeof(intf->out))) > + intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++]; > + > + wmb(); > + intf->out_prod = prod;
> + prod = intf->in_prod; > + mb(); > + BUG_ON((prod - cons) > sizeof(intf->in));
such mb()'s are typically a sign of "i have no clear idea what SMP serialization rules apply here, but something is needed because otherwise it breaks" ?
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