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Commit 052c0bff authored by Yinghai Lu's avatar Yinghai Lu Committed by Ingo Molnar
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x86: fix probe_nr_irqs for xen 



otherwise Xen is _completely_ unusable with 5 or more VCPUs.
(when !CONFIG_HAVE_SPARSE_IRQ).

based on Alex Nixon's patch.

also add +1 offset after redir_entries

Signed-off-by: default avatarYinghai Lu <yhlu.kernel@gmail.com>
Acked-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: default avatarAlex Nixon <alex.nixon@citrix.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent a2d332fa

arch/x86/kernel/io_apic.c

+8 −3
Original line number Diff line number Diff line
@@ -3625,16 +3625,21 @@ int __init probe_nr_irqs(void) 
{

	int idx;

	int nr = 0;

#ifndef CONFIG_XEN

	int nr_min = 32;

#else

	int nr_min = NR_IRQS;

#endif



	for (idx = 0; idx < nr_ioapics; idx++)

		nr += io_apic_get_redir_entries(idx);

		nr += io_apic_get_redir_entries(idx) + 1;



	/* double it for hotplug and msi and nmi */

	nr <<= 1;



	/* something wrong ? */

	if (nr < 32)

		nr = 32;

	if (nr < nr_min)

		nr = nr_min;



	return nr;

}