From d1b758ebc2a82d738092cb42e742470f9d0ea53e Mon Sep 17 00:00:00 2001
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Date: Thu, 9 Dec 2010 14:53:29 -0500
Subject: [PATCH 1/4] xen/irq: Cleanup the find_unbound_irq

The "find_unbound_irq" is a bit unusual - it allocates
virtual IRQ (event channels) in reverse order. This means
starting at the "top" of the available IRQs (nr_irqs) down
to the GSI/MSI IRQs (nr_irqs_gsi). Lets document this and
also make the variables easier to understand.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/events.c |   18 ++++++++++++------
 1 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 31af0ac..4d4a23d 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -405,15 +405,21 @@ static int find_unbound_irq(void)
 {
 	struct irq_data *data;
 	int irq, res;
-	int start = get_nr_hw_irqs();
+	int bottom = get_nr_hw_irqs();
+	int top = nr_irqs-1;
 
-	if (start == nr_irqs)
+	if (bottom == nr_irqs)
 		goto no_irqs;
 
-	/* nr_irqs is a magic value. Must not use it.*/
-	for (irq = nr_irqs-1; irq > start; irq--) {
+	/* This loop starts from the top of IRQ space and goes down.
+	 * We need this b/c if we have a PCI device in a Xen PV guest
+	 * we do not have an IO-APIC (though the backend might have them)
+	 * mapped in. To not have a collision of physical IRQs with the Xen
+	 * event channels start at the top of the IRQ space for virtual IRQs.
+	 */
+	for (irq = top; irq > bottom; irq--) {
 		data = irq_get_irq_data(irq);
-		/* only 0->15 have init'd desc; handle irq > 16 */
+		/* only 15->0 have init'd desc; handle irq > 16 */
 		if (!data)
 			break;
 		if (data->chip == &no_irq_chip)
@@ -424,7 +430,7 @@ static int find_unbound_irq(void)
 			return irq;
 	}
 
-	if (irq == start)
+	if (irq == bottom)
 		goto no_irqs;
 
 	res = irq_alloc_desc_at(irq, -1);
-- 
1.7.3.4


From 67b0ea2bdcd781c17bb2d7949b42059c13c8bfb1 Mon Sep 17 00:00:00 2001
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Date: Thu, 9 Dec 2010 15:01:11 -0500
Subject: [PATCH 2/4] xen/irq: Don't fall over when nr_irqs_gsi > nr_irqs.

This scenario where the nr_irq_gsi is greater than nr_irqs
is rather strange but lets still try to survive. Make sure
to print a warning so the user wouldn't be surprised in case
things don't work.

Solves a bootup-crash when booting Xen and Linux under QEMU.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/events.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 4d4a23d..98b7220 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -411,6 +411,7 @@ static int find_unbound_irq(void)
 	if (bottom == nr_irqs)
 		goto no_irqs;
 
+retry:
 	/* This loop starts from the top of IRQ space and goes down.
 	 * We need this b/c if we have a PCI device in a Xen PV guest
 	 * we do not have an IO-APIC (though the backend might have them)
@@ -434,6 +435,14 @@ static int find_unbound_irq(void)
 		goto no_irqs;
 
 	res = irq_alloc_desc_at(irq, -1);
+	if (res == -EEXIST) {
+		top--;
+		if (bottom > top)
+			printk(KERN_ERR "Eating in GSI/MSI space (%d)!" \
+				" Your PCI device might not work!\n", top);
+		if (top > NR_IRQS_LEGACY)
+			goto retry;
+	}
 
 	if (WARN_ON(res != irq))
 		return -1;
-- 
1.7.3.4


From 2e9876d91d05d8d76c260b9e525d88ce6216dedd Mon Sep 17 00:00:00 2001
From: Kenji Wakamiya <wkenji@jp.fujitsu.com>
Date: Tue, 14 Dec 2010 14:31:36 +0900
Subject: [PATCH 3/4] xen/manage: fix "xm save -c" issue

When using 'xm save -c' (which checkpoints the guest) on PV
guests, the dpms_resume_end() should be surpressed. It is OK
to make this call when doing 'xm save'.

Signed-off-by: Kenji Wakamiya <wkenji@jp.fujitsu.com>
Signed-off-by: Kazuhiro Suzuki <kaz@jp.fujitsu.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 drivers/xen/manage.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
index db8c4c4..e32b9c0 100644
--- a/drivers/xen/manage.c
+++ b/drivers/xen/manage.c
@@ -145,11 +145,10 @@ out_resume:
 	if (!cancelled) {
 		xen_arch_resume();
 		xs_resume();
+		dpm_resume_end(PMSG_RESUME);
 	} else
 		xs_suspend_cancel();
 
-	dpm_resume_end(PMSG_RESUME);
-
 	/* Make sure timer events get retriggered on all CPUs */
 	clock_was_set();
 
-- 
1.7.3.4


From f4ae15846ee57116dcddfd71094e211e5cdefecf Mon Sep 17 00:00:00 2001
From: Sheng Yang <sheng@linux.intel.com>
Date: Tue, 21 Dec 2010 14:18:48 +0800
Subject: [PATCH 4/4] apic: Move hypervisor detection of x2apic to hypervisor.h

Then we can reuse it for Xen later.

Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: Avi Kivity <avi@redhat.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 arch/x86/include/asm/hypervisor.h |    9 +++++++++
 arch/x86/kernel/apic/apic.c       |    5 +++--
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/hypervisor.h b/arch/x86/include/asm/hypervisor.h
index ff2546c..0c6f7af 100644
--- a/arch/x86/include/asm/hypervisor.h
+++ b/arch/x86/include/asm/hypervisor.h
@@ -20,6 +20,8 @@
 #ifndef _ASM_X86_HYPERVISOR_H
 #define _ASM_X86_HYPERVISOR_H
 
+#include <asm/kvm_para.h>
+
 extern void init_hypervisor(struct cpuinfo_x86 *c);
 extern void init_hypervisor_platform(void);
 
@@ -47,4 +49,11 @@ extern const struct hypervisor_x86 x86_hyper_vmware;
 extern const struct hypervisor_x86 x86_hyper_ms_hyperv;
 extern const struct hypervisor_x86 x86_hyper_xen_hvm;
 
+static inline bool hypervisor_x2apic_available(void)
+{
+	if (kvm_para_available())
+		return true;
+	return false;
+}
+
 #endif
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 3f838d5..8408f2d 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -50,8 +50,8 @@
 #include <asm/mtrr.h>
 #include <asm/smp.h>
 #include <asm/mce.h>
-#include <asm/kvm_para.h>
 #include <asm/tsc.h>
+#include <asm/hypervisor.h>
 
 unsigned int num_processors;
 
@@ -1476,7 +1476,8 @@ void __init enable_IR_x2apic(void)
 		/* IR is required if there is APIC ID > 255 even when running
 		 * under KVM
 		 */
-		if (max_physical_apicid > 255 || !kvm_para_available())
+		if (max_physical_apicid > 255 ||
+		    !hypervisor_x2apic_available())
 			goto nox2apic;
 		/*
 		 * without IR all CPUs can be addressed by IOAPIC/MSI
-- 
1.7.3.4