Xen devel - Feb 2006 - RE: [Xen-ia64-devel] [PATCH]Make VTIdomain boot again

Williamson,

This patch is just a workaround, the essential cause is, the soft_IRQ should be
done at the path of ia64_leave_kernel which aligned with native linux and
XEN/X86, instead of being invoking in irq_exit function.

What''s your opinion?

Thanks,
-Anthony 
>-----Original Message-----
>From: Alex Williamson [mailto:alex.williamson@hp.com]
>Sent: 2006年2月9日 11:32
>To: Xu, Anthony
>Cc: xen-devel@lists.xensource.com; xen-ia64-devel@lists.xensource.com
>Subject: Re: [Xen-ia64-devel] [Xen-devel] [PATCH]Make VTIdomain boot again
>
>On Thu, 2006-02-09 at 10:31 +0800, Xu, Anthony wrote:
>> Keir,
>>
>> This patch is intended to make VTIdomain boot again, and will not
impact
>> domU. Actually VTIdomain and domU can boot simultaneously after
applying
>> this patch, Could you please check this patch into xen-unstable.hg?
This
>> is a must in 3.0.1.
>
>Hi Anthony,
>
>   Xen 3.0.1 went out on Feb. 1st.  A couple comments
>
>--- a/xen/arch/ia64/linux-xen/irq_ia64.c        Thu Jan 26 10:31:28 2006
>+++ b/xen/arch/ia64/linux-xen/irq_ia64.c        Wed Feb  8 16:28:11 2006
>@@ -169,7 +169,7 @@
>         * handler needs to be able to wait for further keyboard
>interrupts, which can''t
>         * come through until ia64_eoi() has been done.
>         */
>-       irq_exit();
>+       xen_irq_exit(regs);
> }
>
>>>> This needs to be in an #ifdef XEN.
>
>-void irq_exit(void)
>+void xen_irq_exit(struct pt_regs *regs)
> {
>        //account_system_vtime(current);
>        sub_preempt_count(IRQ_EXIT_OFFSET);
>-       if (!in_interrupt() && local_softirq_pending()) {
>+    if((((char *)regs) -(char *) current)
!>(IA64_STK_OFFSET-IA64_PT_REGS_SIZE))
>+        return;
>+
>+       if (!in_interrupt()&&local_softirq_pending()) {
>
>>>> Formatting here is inconsistent with the rest of the file and
>itself.  Could we be setting some flag and adding the test to the
>existing in_interrupt/local_softirq_pending check?  This looks rather
>precarious.  Thanks,
>
>	Alex
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On Thu, 2006-02-09 at 15:14 +0800, Xu, Anthony wrote:
> Williamson,
> 
> This patch is just a workaround, the essential cause is, the soft_IRQ
> should be done at the path of ia64_leave_kernel which aligned with
> native linux and XEN/X86, instead of being invoking in irq_exit
> function.
> 
> What''s your opinion?
   I''m afraid workarounds always last longer than expected, so we
should
still try to do this cleanly.  Xen 3.0.1 is already out so the time
pressure to get this fixed is lessened.  Being ia64 specific Xen code, I
think we should try to do it right, get it into xen-ia64-unstable, then
push it to xen-unstable.  Thanks,

	Alex

-- 
Alex Williamson                             HP Linux & Open Source Lab


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