[PATCH] xen/events: Always allocate legacy interrupts on PV guests

From: Boris Ostrovsky
Date: Tue Nov 17 2015 - 10:36:30 EST


After commit 8c058b0b9c34 ("x86/irq: Probe for PIC presence before
allocating descs for legacy IRQs") early_irq_init() will no longer
preallocate descriptors for legacy interrupts if PIT does not
exist.

Therefore we need to allocate those descriptors for PV guests
ourselves.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Suggested-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
drivers/xen/events/events_base.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 849500e..a2bb333 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -419,8 +419,8 @@ static int __must_check xen_allocate_irq_gsi(unsigned gsi)
if (xen_pv_domain() && !xen_initial_domain())
return xen_allocate_irq_dynamic();

- /* Legacy IRQ descriptors are already allocated by the arch. */
- if (gsi < NR_IRQS_LEGACY)
+ /* On HVM legacy IRQ descriptors are already allocated by the arch. */
+ if (xen_hvm_domain() && gsi < NR_IRQS_LEGACY)
irq = gsi;
else
irq = irq_alloc_desc_at(gsi, -1);
@@ -445,8 +445,8 @@ static void xen_free_irq(unsigned irq)

kfree(info);

- /* Legacy IRQ descriptors are managed by the arch. */
- if (irq < NR_IRQS_LEGACY)
+ /* On HVM legacy IRQ descriptors are managed by the arch. */
+ if (xen_hvm_domain() && irq < NR_IRQS_LEGACY)
return;

irq_free_desc(irq);
--
1.9.3

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