From 6c79718e811fdecff9f7b1271df7395357054fc2 Mon Sep 17 00:00:00 2001
From: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Date: Mon, 18 Oct 2010 13:30:25 +0100
Subject: [PATCH 1/2] Revert "xen/events: use PHYSDEVOP_pirq_eoi_gmfn to get pirq need-EOI info"

This reverts commit 2390c371ecd32d9f06e22871636185382bf70ab7.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
---
 drivers/xen/events.c            |   45 ++++++--------------------------------
 include/xen/interface/physdev.h |   13 -----------
 2 files changed, 7 insertions(+), 51 deletions(-)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 175e931..5db8e98 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -103,12 +103,9 @@ struct irq_info
 		} pirq;
 	} u;
 };
+#define PIRQ_NEEDS_EOI	(1 << 0)
 #define PIRQ_SHAREABLE	(1 << 1)
 
-/* Bitmap indicating which PIRQs require Xen to be notified on unmask. */
-static bool pirq_eoi_does_unmask;
-static unsigned long *pirq_needs_eoi_bits;
-
 static struct irq_info *irq_info;
 
 static int *evtchn_to_irq;
@@ -251,7 +248,7 @@ static bool pirq_needs_eoi(unsigned irq)
 
 	BUG_ON(info->type != IRQT_PIRQ);
 
-	return test_bit(info->u.pirq.gsi, pirq_needs_eoi_bits);
+	return info->u.pirq.flags & PIRQ_NEEDS_EOI;
 }
 
 static inline unsigned long active_evtchns(unsigned int cpu,
@@ -438,19 +435,13 @@ static bool identity_mapped_irq(unsigned irq)
 
 static void pirq_eoi(unsigned int irq)
 {
-	struct irq_info *info = info_for_irq(irq);
-	struct physdev_eoi eoi = { .irq = info->u.pirq.gsi };
-	bool need_eoi;
-
-	need_eoi = pirq_needs_eoi(irq);
+	struct physdev_eoi eoi = { .irq = irq };
 
-	if (!need_eoi || !pirq_eoi_does_unmask)
-		unmask_evtchn(info->evtchn);
-
-	if (need_eoi) {
+	if (pirq_needs_eoi(irq)) {
 		int rc = HYPERVISOR_physdev_op(PHYSDEVOP_eoi, &eoi);
 		WARN_ON(rc);
 	}
+	unmask_irq(irq);
 }
 
 static void pirq_query_unmask(int irq)
@@ -458,18 +449,15 @@ static void pirq_query_unmask(int irq)
 	struct physdev_irq_status_query irq_status;
 	struct irq_info *info = info_for_irq(irq);
 
-	if (pirq_eoi_does_unmask)
-		return;
-
 	BUG_ON(info->type != IRQT_PIRQ);
 
 	irq_status.irq = info->u.pirq.gsi;
 	if (HYPERVISOR_physdev_op(PHYSDEVOP_irq_status_query, &irq_status))
 		irq_status.flags = 0;
 
-	clear_bit(info->u.pirq.gsi, pirq_needs_eoi_bits);
+	info->u.pirq.flags &= ~PIRQ_NEEDS_EOI;
 	if (irq_status.flags & XENIRQSTAT_needs_eoi)
-		set_bit(info->u.pirq.gsi, pirq_needs_eoi_bits);
+		info->u.pirq.flags |= PIRQ_NEEDS_EOI;
 }
 
 static bool probing_irq(int irq)
@@ -1369,16 +1357,6 @@ void xen_irq_resume(void)
 		restore_cpu_virqs(cpu);
 		restore_cpu_ipis(cpu);
 	}
-
-	if (pirq_eoi_does_unmask) {
-		struct physdev_pirq_eoi_gmfn eoi_gmfn;
-		
-		eoi_gmfn.gmfn = virt_to_mfn(pirq_needs_eoi_bits);
-		if (HYPERVISOR_physdev_op(PHYSDEVOP_pirq_eoi_gmfn, &eoi_gmfn) != 0) {
-			/* Could recover by reverting to old method...? */
-			BUG();
-		}
-	}
 }
 
 static struct irq_chip xen_dynamic_chip __read_mostly = {
@@ -1462,8 +1440,6 @@ void xen_callback_vector(void) {}
 void __init xen_init_IRQ(void)
 {
 	int i;
-	struct physdev_pirq_eoi_gmfn eoi_gmfn;
-	int nr_pirqs = NR_IRQS;
 
 	cpu_evtchn_mask_p = kcalloc(nr_cpu_ids, sizeof(struct cpu_evtchn_s),
 				    GFP_KERNEL);
@@ -1474,13 +1450,6 @@ void __init xen_init_IRQ(void)
 	for(i = 0; i < NR_EVENT_CHANNELS; i++)
 		evtchn_to_irq[i] = -1;
 
-	i = get_order(sizeof(unsigned long) * BITS_TO_LONGS(nr_pirqs));
-	pirq_needs_eoi_bits = (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, i);
-
- 	eoi_gmfn.gmfn = virt_to_mfn(pirq_needs_eoi_bits);
-	if (HYPERVISOR_physdev_op(PHYSDEVOP_pirq_eoi_gmfn, &eoi_gmfn) == 0)
-		pirq_eoi_does_unmask = true;
-
 	init_evtchn_cpu_bindings();
 
 	/* No event channels are 'live' right now. */
diff --git a/include/xen/interface/physdev.h b/include/xen/interface/physdev.h
index 0703ef6..66122aa 100644
--- a/include/xen/interface/physdev.h
+++ b/include/xen/interface/physdev.h
@@ -39,19 +39,6 @@ struct physdev_eoi {
 };
 
 /*
- * Register a shared page for the hypervisor to indicate whether the guest
- * must issue PHYSDEVOP_eoi. The semantics of PHYSDEVOP_eoi change slightly
- * once the guest used this function in that the associated event channel
- * will automatically get unmasked. The page registered is used as a bit
- * array indexed by Xen's PIRQ value.
- */
-#define PHYSDEVOP_pirq_eoi_gmfn         17
-struct physdev_pirq_eoi_gmfn {
-    /* IN */
-    unsigned long gmfn;
-};
-
-/*
  * Query the status of an IRQ line.
  * @arg == pointer to physdev_irq_status_query structure.
  */
-- 
1.5.6.5