--- a/drivers/xen/xen-pciback/pci_stub.c
+++ b/drivers/xen/xen-pciback/pci_stub.c
@@ -733,10 +733,17 @@ static pci_ers_result_t common_process(s
 	wmb();
 	notify_remote_via_irq(pdev->evtchn_irq);
 
+	/* Enable IRQ to signal "request done". */
+	xen_pcibk_lateeoi(pdev, 0);
+
 	ret = wait_event_timeout(xen_pcibk_aer_wait_queue,
 				 !(test_bit(_XEN_PCIB_active, (unsigned long *)
 				 &sh_info->flags)), 300*HZ);
 
+	/* Enable IRQ for pcifront request if not already active. */
+	if (!test_bit(_PDEVF_op_active, &pdev->flags))
+		xen_pcibk_lateeoi(pdev, 0);
+
 	if (!ret) {
 		if (test_bit(_XEN_PCIB_active,
 			(unsigned long *)&sh_info->flags)) {
@@ -750,13 +757,6 @@ static pci_ers_result_t common_process(s
 	}
 	clear_bit(_PCIB_op_pending, (unsigned long *)&pdev->flags);
 
-	if (test_bit(_XEN_PCIF_active,
-		(unsigned long *)&sh_info->flags)) {
-		dev_dbg(&psdev->dev->dev,
-			"schedule pci_conf service in " DRV_NAME "\n");
-		xen_pcibk_test_and_schedule_op(psdev->pdev);
-	}
-
 	res = (pci_ers_result_t)aer_op->err;
 	return res;
 }
--- a/drivers/xen/xen-pciback/pciback.h
+++ b/drivers/xen/xen-pciback/pciback.h
@@ -14,6 +14,7 @@
 #include <linux/spinlock.h>
 #include <linux/workqueue.h>
 #include <linux/atomic.h>
+#include <xen/events.h>
 #include <xen/interface/io/pciif.h>
 
 #define DRV_NAME	"xen-pciback"
@@ -27,6 +28,8 @@ struct pci_dev_entry {
 #define PDEVF_op_active		(1<<(_PDEVF_op_active))
 #define _PCIB_op_pending	(1)
 #define PCIB_op_pending		(1<<(_PCIB_op_pending))
+#define _EOI_pending		(2)
+#define EOI_pending		(1<<(_EOI_pending))
 
 struct xen_pcibk_device {
 	void *pci_dev_data;
@@ -182,12 +185,17 @@ static inline void xen_pcibk_release_dev
 irqreturn_t xen_pcibk_handle_event(int irq, void *dev_id);
 void xen_pcibk_do_op(struct work_struct *data);
 
+static inline void xen_pcibk_lateeoi(struct xen_pcibk_device *pdev,
+				     unsigned int eoi_flag)
+{
+	if (test_and_clear_bit(_EOI_pending, &pdev->flags))
+		xen_irq_lateeoi(pdev->evtchn_irq, eoi_flag);
+}
+
 int xen_pcibk_xenbus_register(void);
 void xen_pcibk_xenbus_unregister(void);
 
 extern int verbose_request;
-
-void xen_pcibk_test_and_schedule_op(struct xen_pcibk_device *pdev);
 #endif
 
 /* Handles shared IRQs that can to device domain and control domain. */
--- a/drivers/xen/xen-pciback/pciback_ops.c
+++ b/drivers/xen/xen-pciback/pciback_ops.c
@@ -297,26 +297,41 @@ int xen_pcibk_disable_msix(struct xen_pc
 	return 0;
 }
 #endif
+
+static inline bool xen_pcibk_test_op_pending(struct xen_pcibk_device *pdev)
+{
+	return test_bit(_XEN_PCIF_active,
+			(unsigned long *)&pdev->sh_info->flags) &&
+	       !test_and_set_bit(_PDEVF_op_active, &pdev->flags);
+}
+
 /*
 * Now the same evtchn is used for both pcifront conf_read_write request
 * as well as pcie aer front end ack. We use a new work_queue to schedule
 * xen_pcibk conf_read_write service for avoiding confict with aer_core
 * do_recovery job which also use the system default work_queue
 */
-void xen_pcibk_test_and_schedule_op(struct xen_pcibk_device *pdev)
+static void xen_pcibk_test_and_schedule_op(struct xen_pcibk_device *pdev)
 {
+	bool eoi = true;
+
 	/* Check that frontend is requesting an operation and that we are not
 	 * already processing a request */
-	if (test_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags)
-	    && !test_and_set_bit(_PDEVF_op_active, &pdev->flags)) {
+	if (xen_pcibk_test_op_pending(pdev)) {
 		schedule_work(&pdev->op_work);
+		eoi = false;
 	}
 	/*_XEN_PCIB_active should have been cleared by pcifront. And also make
 	sure xen_pcibk is waiting for ack by checking _PCIB_op_pending*/
 	if (!test_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags)
 	    && test_bit(_PCIB_op_pending, &pdev->flags)) {
 		wake_up(&xen_pcibk_aer_wait_queue);
+		eoi = false;
 	}
+
+	/* EOI if there was nothing to do. */
+	if (eoi)
+		xen_pcibk_lateeoi(pdev, XEN_EOI_FLAG_SPURIOUS);
 }
 
 /* Performing the configuration space reads/writes must not be done in atomic
@@ -324,10 +339,8 @@ void xen_pcibk_test_and_schedule_op(stru
  * use of semaphores). This function is intended to be called from a work
  * queue in process context taking a struct xen_pcibk_device as a parameter */
 
-void xen_pcibk_do_op(struct work_struct *data)
+static void xen_pcibk_do_one_op(struct xen_pcibk_device *pdev)
 {
-	struct xen_pcibk_device *pdev =
-		container_of(data, struct xen_pcibk_device, op_work);
 	struct pci_dev *dev;
 	struct xen_pcibk_dev_data *dev_data = NULL;
 	struct xen_pci_op *op = &pdev->op;
@@ -400,16 +413,31 @@ void xen_pcibk_do_op(struct work_struct
 	smp_mb__before_atomic(); /* /after/ clearing PCIF_active */
 	clear_bit(_PDEVF_op_active, &pdev->flags);
 	smp_mb__after_atomic(); /* /before/ final check for work */
+}
 
-	/* Check to see if the driver domain tried to start another request in
-	 * between clearing _XEN_PCIF_active and clearing _PDEVF_op_active.
-	*/
-	xen_pcibk_test_and_schedule_op(pdev);
+void xen_pcibk_do_op(struct work_struct *data)
+{
+	struct xen_pcibk_device *pdev =
+		container_of(data, struct xen_pcibk_device, op_work);
+
+	do {
+		xen_pcibk_do_one_op(pdev);
+	} while (xen_pcibk_test_op_pending(pdev));
+
+	xen_pcibk_lateeoi(pdev, 0);
 }
 
 irqreturn_t xen_pcibk_handle_event(int irq, void *dev_id)
 {
 	struct xen_pcibk_device *pdev = dev_id;
+	bool eoi;
+
+	/* IRQs might come in before pdev->evtchn_irq is written. */
+	if (unlikely(pdev->evtchn_irq != irq))
+		pdev->evtchn_irq = irq;
+
+	eoi = test_and_set_bit(_EOI_pending, &pdev->flags);
+	WARN(eoi, "IRQ while EOI pending\n");
 
 	xen_pcibk_test_and_schedule_op(pdev);
 
--- a/drivers/xen/xen-pciback/xenbus.c
+++ b/drivers/xen/xen-pciback/xenbus.c
@@ -123,7 +123,7 @@ static int xen_pcibk_do_attach(struct xe
 
 	pdev->sh_info = vaddr;
 
-	err = bind_interdomain_evtchn_to_irqhandler(
+	err = bind_interdomain_evtchn_to_irqhandler_lateeoi(
 		pdev->xdev->otherend_id, remote_evtchn, xen_pcibk_handle_event,
 		0, DRV_NAME, pdev);
 	if (err < 0) {
