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xen-devel
[Xen-devel] Re: [patch 21/26] Xen-paravirt_ops: Use the hvc console infr
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To: |
Jeremy Fitzhardinge <jeremy@xxxxxxxx> |
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Subject: |
[Xen-devel] Re: [patch 21/26] Xen-paravirt_ops: Use the hvc console infrastructure for Xen console |
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From: |
Ingo Molnar <mingo@xxxxxxx> |
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Date: |
Fri, 16 Mar 2007 09:54:51 +0100 |
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Cc: |
Zachary Amsden <zach@xxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx, virtualization@xxxxxxxxxxxxxx, Rusty Russell <rusty@xxxxxxxxxxxxxxx>, linux-kernel@xxxxxxxxxxxxxxx, Chris Wright <chrisw@xxxxxxxxxxxx>, Andi Kleen <ak@xxxxxx>, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> |
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Fri, 16 Mar 2007 01:54:38 -0700 |
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* Jeremy Fitzhardinge <jeremy@xxxxxxxx> 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" ?
Ingo
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