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

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

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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