[RFC PATCH v2 7/7] vfio-ccw: Add support for the CRW irq

[Eric Farman <farman@linux.ibm.com>]

From: Farhan Ali <alifm@linux.ibm.com>

The CRW irq will be used by vfio-ccw to notify the userspace
about any CRWs the userspace needs to handle. Let's add support
for it.

Signed-off-by: Farhan Ali <alifm@linux.ibm.com>
Signed-off-by: Eric Farman <farman@linux.ibm.com>
---

Notes:
    v1->v2:
     - Add a loop to continually read region while data is
       present, queueing CRWs as found [CH]
    v0->v1: [EF]
     - Check vcdev->crw_region before registering the irq,
       in case host kernel does not have matching support
     - Split the refactoring changes to an earlier (new) patch
       (and don't remove the "num_irqs" check in the register
       routine, but adjust it to the check the input variable)
     - Don't revert the cool vfio_set_irq_signaling() stuff
     - Unregister CRW IRQ before IO IRQ in unrealize
     - s/crw1/crw0/

 hw/vfio/ccw.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c
index 044441a277..5e3d446213 100644
--- a/hw/vfio/ccw.c
+++ b/hw/vfio/ccw.c
@@ -48,6 +48,7 @@ struct VFIOCCWDevice {
     uint64_t crw_region_offset;
     struct ccw_crw_region *crw_region;
     EventNotifier io_notifier;
+    EventNotifier crw_notifier;
     bool force_orb_pfch;
     bool warned_orb_pfch;
 };
@@ -265,6 +266,40 @@ static void vfio_ccw_reset(DeviceState *dev)
     ioctl(vcdev->vdev.fd, VFIO_DEVICE_RESET);
 }
 
+static void vfio_ccw_crw_notifier_handler(void *opaque)
+{
+    VFIOCCWDevice *vcdev = opaque;
+    struct ccw_crw_region *region = vcdev->crw_region;
+    CRW crw;
+    int size;
+    uint8_t rsc, erc;
+
+    if (!event_notifier_test_and_clear(&vcdev->crw_notifier)) {
+        return;
+    }
+
+    do {
+        memset(region, 0, sizeof(*region));
+        size = pread(vcdev->vdev.fd, region, vcdev->crw_region_size,
+                     vcdev->crw_region_offset);
+
+        if (size == -1) {
+            error_report("vfio-ccw: Read crw region failed with errno=%d", errno);
+            break;
+        }
+
+        if (size == 0 || region->crw0 == 0) {
+            /* No more CRWs to queue */
+            break;
+        }
+
+        memcpy(&crw, &region->crw0, sizeof(CRW));
+        rsc = (crw.flags & 0x0f00) >> 8;
+        erc = crw.flags & 0x003f;
+        css_queue_crw(rsc, erc, 0, 0, crw.rsid);
+    } while (1);
+}
+
 static void vfio_ccw_io_notifier_handler(void *opaque)
 {
     VFIOCCWDevice *vcdev = opaque;
@@ -351,6 +386,10 @@ static void vfio_ccw_register_irq_notifier(VFIOCCWDevice *vcdev,
         notifier = &vcdev->io_notifier;
         fd_read = vfio_ccw_io_notifier_handler;
         break;
+    case VFIO_CCW_CRW_IRQ_INDEX:
+        notifier = &vcdev->crw_notifier;
+        fd_read = vfio_ccw_crw_notifier_handler;
+        break;
     default:
         error_setg(errp, "vfio: Unsupported device irq(%d)", irq);
         return;
@@ -401,6 +440,9 @@ static void vfio_ccw_unregister_irq_notifier(VFIOCCWDevice *vcdev,
     case VFIO_CCW_IO_IRQ_INDEX:
         notifier = &vcdev->io_notifier;
         break;
+    case VFIO_CCW_CRW_IRQ_INDEX:
+        notifier = &vcdev->crw_notifier;
+        break;
     default:
         error_report("vfio: Unsupported device irq(%d)", irq);
         return;
@@ -621,6 +663,14 @@ static void vfio_ccw_realize(DeviceState *dev, Error **errp)
         goto out_notifier_err;
     }
 
+    if (vcdev->crw_region) {
+        vfio_ccw_register_irq_notifier(vcdev, VFIO_CCW_CRW_IRQ_INDEX, &err);
+        if (err) {
+            vfio_ccw_unregister_irq_notifier(vcdev, VFIO_CCW_IO_IRQ_INDEX);
+            goto out_notifier_err;
+        }
+    }
+
     return;
 
 out_notifier_err:
@@ -645,6 +695,7 @@ static void vfio_ccw_unrealize(DeviceState *dev, Error **errp)
     S390CCWDeviceClass *cdc = S390_CCW_DEVICE_GET_CLASS(cdev);
     VFIOGroup *group = vcdev->vdev.group;
 
+    vfio_ccw_unregister_irq_notifier(vcdev, VFIO_CCW_CRW_IRQ_INDEX);
     vfio_ccw_unregister_irq_notifier(vcdev, VFIO_CCW_IO_IRQ_INDEX);
     vfio_ccw_put_region(vcdev);
     vfio_ccw_put_device(vcdev);
-- 
2.17.1