From: Stefano Stabellini <sstabellini@kernel.org>
Date: Wed, 20 Apr 2016 13:15:01 +0000 (+0100)
Subject: xen/x86: actually allocate legacy interrupts on PV guests
X-Git-Tag: firefly_0821_release~176^2~4^2~43^2~25
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=3bf7d0328640474509d6345f9c3356e08bebf585;p=firefly-linux-kernel-4.4.55.git

xen/x86: actually allocate legacy interrupts on PV guests

commit 702f926067d2a4b28c10a3c41a1172dd62d9e735 upstream.

b4ff8389ed14 is incomplete: relies on nr_legacy_irqs() to get the number
of legacy interrupts when actually nr_legacy_irqs() returns 0 after
probe_8259A(). Use NR_IRQS_LEGACY instead.

Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index ff31ab464213..c6d6efed392a 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -488,8 +488,11 @@ int __init pci_xen_initial_domain(void)
 #endif
 	__acpi_register_gsi = acpi_register_gsi_xen;
 	__acpi_unregister_gsi = NULL;
-	/* Pre-allocate legacy irqs */
-	for (irq = 0; irq < nr_legacy_irqs(); irq++) {
+	/*
+	 * Pre-allocate the legacy IRQs.  Use NR_LEGACY_IRQS here
+	 * because we don't have a PIC and thus nr_legacy_irqs() is zero.
+	 */
+	for (irq = 0; irq < NR_IRQS_LEGACY; irq++) {
 		int trigger, polarity;
 
 		if (acpi_get_override_irq(irq, &trigger, &polarity) == -1)