This is a note to let you know that I've just added the patch titled

    xen/events: Always allocate legacy interrupts on PV guests

to the 4.3-stable tree which can be found at:
    
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     xen-events-always-allocate-legacy-interrupts-on-pv-guests.patch
and it can be found in the queue-4.3 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From b4ff8389ed14b849354b59ce9b360bdefcdbf99c Mon Sep 17 00:00:00 2001
From: Boris Ostrovsky <[email protected]>
Date: Fri, 20 Nov 2015 11:25:04 -0500
Subject: xen/events: Always allocate legacy interrupts on PV guests

From: Boris Ostrovsky <[email protected]>

commit b4ff8389ed14b849354b59ce9b360bdefcdbf99c upstream.

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 PIC does not
exist, which is the case for Xen PV guests.

Therefore we may need to allocate those descriptors ourselves.

Signed-off-by: Boris Ostrovsky <[email protected]>
Suggested-by: Thomas Gleixner <[email protected]>
Signed-off-by: David Vrabel <[email protected]>
Cc: Vitaly Kuznetsov <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 arch/arm/include/asm/irq.h       |    5 +++++
 arch/arm64/include/asm/irq.h     |    5 +++++
 drivers/xen/events/events_base.c |    5 +++--
 3 files changed, 13 insertions(+), 2 deletions(-)

--- a/arch/arm/include/asm/irq.h
+++ b/arch/arm/include/asm/irq.h
@@ -40,6 +40,11 @@ extern void arch_trigger_all_cpu_backtra
 #define arch_trigger_all_cpu_backtrace(x) arch_trigger_all_cpu_backtrace(x)
 #endif
 
+static inline int nr_legacy_irqs(void)
+{
+       return NR_IRQS_LEGACY;
+}
+
 #endif
 
 #endif
--- a/arch/arm64/include/asm/irq.h
+++ b/arch/arm64/include/asm/irq.h
@@ -21,4 +21,9 @@ static inline void acpi_irq_init(void)
 }
 #define acpi_irq_init acpi_irq_init
 
+static inline int nr_legacy_irqs(void)
+{
+       return 0;
+}
+
 #endif
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -39,6 +39,7 @@
 #include <asm/irq.h>
 #include <asm/idle.h>
 #include <asm/io_apic.h>
+#include <asm/i8259.h>
 #include <asm/xen/pci.h>
 #include <xen/page.h>
 #endif
@@ -420,7 +421,7 @@ static int __must_check xen_allocate_irq
                return xen_allocate_irq_dynamic();
 
        /* Legacy IRQ descriptors are already allocated by the arch. */
-       if (gsi < NR_IRQS_LEGACY)
+       if (gsi < nr_legacy_irqs())
                irq = gsi;
        else
                irq = irq_alloc_desc_at(gsi, -1);
@@ -446,7 +447,7 @@ static void xen_free_irq(unsigned irq)
        kfree(info);
 
        /* Legacy IRQ descriptors are managed by the arch. */
-       if (irq < NR_IRQS_LEGACY)
+       if (irq < nr_legacy_irqs())
                return;
 
        irq_free_desc(irq);


Patches currently in stable-queue which might be from 
[email protected] are

queue-4.3/xen-events-always-allocate-legacy-interrupts-on-pv-guests.patch
queue-4.3/x86-cpu-fix-smap-check-in-pvops-environments.patch
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