xen/x86: actually allocate legacy interrupts on PV guests

[ Upstream commit 702f926067d2a4b28c10a3c41a1172dd62d9e735 ]

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>
CC: stable@vger.kernel.org
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index 3c41716ea8ba9e5134f1863e6120dbb82ac68b4a..41c15dc4241cff6fbaf30b77dc7d6806fc061a88 100644 (file)
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -466,8 +466,11 @@ 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)