hw/vfio/platform: do not set resamplefd for edge-sensitive IRQS

In irqfd mode, current code attempts to set a resamplefd whatever
the type of the IRQ. For an edge-sensitive IRQ this attempt fails
and as a consequence, the whole irqfd setup fails and we fall back
to the slow mode. This patch bypasses the resamplefd setting for
non level-sentive IRQs.
Signed-off-by: NEric Auger <eric.auger@linaro.org>
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>

hw/vfio/platform.c

@@ -32,6 +32,11 @@
  * Functions used whatever the injection method
  */
 
+static inline bool vfio_irq_is_automasked(VFIOINTp *intp)
+{
+    return intp->flags & VFIO_IRQ_INFO_AUTOMASKED;
+}
+
 /**
  * vfio_init_intp - allocate, initialize the IRQ struct pointer
  * and add it into the list of IRQs
@@ -65,15 +70,17 @@ static VFIOINTp *vfio_init_intp(VFIODevice *vbasedev,
         error_report("vfio: Error: trigger event_notifier_init failed ");
         return NULL;
     }
-    /* Get an eventfd for resample/unmask */
-    intp->unmask = g_malloc0(sizeof(EventNotifier));
-    ret = event_notifier_init(intp->unmask, 0);
-    if (ret) {
-        g_free(intp->interrupt);
-        g_free(intp->unmask);
-        g_free(intp);
-        error_report("vfio: Error: resamplefd event_notifier_init failed");
-        return NULL;
+    if (vfio_irq_is_automasked(intp)) {
+        /* Get an eventfd for resample/unmask */
+        intp->unmask = g_malloc0(sizeof(EventNotifier));
+        ret = event_notifier_init(intp->unmask, 0);
+        if (ret) {
+            g_free(intp->interrupt);
+            g_free(intp->unmask);
+            g_free(intp);
+            error_report("vfio: Error: resamplefd event_notifier_init failed");
+            return NULL;
+        }
     }
 
     QLIST_INSERT_HEAD(&vdev->intp_list, intp, next);
@@ -294,7 +301,7 @@ static void vfio_platform_eoi(VFIODevice *vbasedev)
             /* deassert the virtual IRQ */
             qemu_set_irq(intp->qemuirq, 0);
 
-            if (intp->flags & VFIO_IRQ_INFO_AUTOMASKED) {
+            if (vfio_irq_is_automasked(intp)) {
                 /* unmasks the physical level-sensitive IRQ */
                 vfio_unmask_single_irqindex(vbasedev, intp->pin);
             }
@@ -409,15 +416,20 @@ static void vfio_start_irqfd_injection(SysBusDevice *sbdev, qemu_irq irq)
     if (vfio_set_trigger_eventfd(intp, NULL) < 0) {
         goto fail_vfio;
     }
-    if (vfio_set_resample_eventfd(intp) < 0) {
-        goto fail_vfio;
+    if (vfio_irq_is_automasked(intp)) {
+        if (vfio_set_resample_eventfd(intp) < 0) {
+            goto fail_vfio;
+        }
+        trace_vfio_platform_start_level_irqfd_injection(intp->pin,
+                                    event_notifier_get_fd(intp->interrupt),
+                                    event_notifier_get_fd(intp->unmask));
+    } else {
+        trace_vfio_platform_start_edge_irqfd_injection(intp->pin,
+                                    event_notifier_get_fd(intp->interrupt));
     }
 
     intp->kvm_accel = true;
 
-    trace_vfio_platform_start_irqfd_injection(intp->pin,
-                                     event_notifier_get_fd(intp->interrupt),
-                                     event_notifier_get_fd(intp->unmask));
     return;
 fail_vfio:
     kvm_irqchip_remove_irqfd_notifier(kvm_state, intp->interrupt, irq);

trace-events

@@ -1624,7 +1624,9 @@ vfio_platform_intp_interrupt(int pin, int fd) "Inject IRQ #%d (fd = %d)"
 vfio_platform_intp_inject_pending_lockheld(int pin, int fd) "Inject pending IRQ #%d (fd = %d)"
 vfio_platform_populate_interrupts(int pin, int count, int flags) "- IRQ index %d: count %d, flags=0x%x"
 vfio_intp_interrupt_set_pending(int index) "irq %d is set PENDING"
-vfio_platform_start_irqfd_injection(int index, int fd, int resamplefd) "IRQ index=%d, fd = %d, resamplefd = %d"
+vfio_platform_start_level_irqfd_injection(int index, int fd, int resamplefd) "IRQ index=%d, fd = %d, resamplefd = %d"
+vfio_platform_start_edge_irqfd_injection(int index, int fd) "IRQ index=%d, fd = %d"
+
 
 #hw/acpi/memory_hotplug.c
 mhp_acpi_invalid_slot_selected(uint32_t slot) "0x%"PRIx32