[Qemu-devel] [PATCH RFC 3/8] vfio: ccw: basic implementation for vfio_ccw driver

[Dong Jia Shi]

Add a basic vfio_ccw driver, which depends on the VFIO No-IOMMU
support.

Add a new config option:
  Device Drivers
  --> VFIO Non-Privileged userspace driver framework
    --> VFIO No-IOMMU support
      --> VFIO support for ccw devices

Signed-off-by: Dong Jia Shi <address@hidden>
Reviewed-by: Pierre Morel <address@hidden>
---
 arch/s390/include/asm/irq.h |   1 +
 arch/s390/kernel/irq.c      |   1 +
 drivers/vfio/Kconfig        |   1 +
 drivers/vfio/Makefile       |   1 +
 drivers/vfio/ccw/Kconfig    |   7 ++
 drivers/vfio/ccw/Makefile   |   2 +
 drivers/vfio/ccw/vfio_ccw.c | 160 ++++++++++++++++++++++++++++++++++++++++++++
 7 files changed, 173 insertions(+)
 create mode 100644 drivers/vfio/ccw/Kconfig
 create mode 100644 drivers/vfio/ccw/Makefile
 create mode 100644 drivers/vfio/ccw/vfio_ccw.c

diff --git a/arch/s390/include/asm/irq.h b/arch/s390/include/asm/irq.h
index f97b055..5ec272a 100644
--- a/arch/s390/include/asm/irq.h
+++ b/arch/s390/include/asm/irq.h
@@ -66,6 +66,7 @@ enum interruption_class {
        IRQIO_VAI,
        NMI_NMI,
        CPU_RST,
+       IRQIO_VFC,
        NR_ARCH_IRQS
 };
 
diff --git a/arch/s390/kernel/irq.c b/arch/s390/kernel/irq.c
index c373a1d..706002a 100644
--- a/arch/s390/kernel/irq.c
+++ b/arch/s390/kernel/irq.c
@@ -88,6 +88,7 @@ static const struct irq_class irqclass_sub_desc[] = {
        {.irq = IRQIO_VAI,  .name = "VAI", .desc = "[I/O] Virtual I/O Devices 
AI"},
        {.irq = NMI_NMI,    .name = "NMI", .desc = "[NMI] Machine Check"},
        {.irq = CPU_RST,    .name = "RST", .desc = "[CPU] CPU Restart"},
+       {.irq = IRQIO_VFC,  .name = "VFC", .desc = "[I/O] VFIO CCW Devices"},
 };
 
 void __init init_IRQ(void)
diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig
index da6e2ce..f1d414c 100644
--- a/drivers/vfio/Kconfig
+++ b/drivers/vfio/Kconfig
@@ -46,6 +46,7 @@ menuconfig VFIO_NOIOMMU
 
          If you don't know what to do here, say N.
 
+source "drivers/vfio/ccw/Kconfig"
 source "drivers/vfio/pci/Kconfig"
 source "drivers/vfio/platform/Kconfig"
 source "virt/lib/Kconfig"
diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
index 7b8a31f..2b39593 100644
--- a/drivers/vfio/Makefile
+++ b/drivers/vfio/Makefile
@@ -7,3 +7,4 @@ obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o
 obj-$(CONFIG_VFIO_SPAPR_EEH) += vfio_spapr_eeh.o
 obj-$(CONFIG_VFIO_PCI) += pci/
 obj-$(CONFIG_VFIO_PLATFORM) += platform/
+obj-$(CONFIG_VFIO_CCW) += ccw/
diff --git a/drivers/vfio/ccw/Kconfig b/drivers/vfio/ccw/Kconfig
new file mode 100644
index 0000000..6281152
--- /dev/null
+++ b/drivers/vfio/ccw/Kconfig
@@ -0,0 +1,7 @@
+config VFIO_CCW
+       tristate "VFIO support for CCW devices"
+       depends on VFIO_NOIOMMU && CCW
+       help
+         VFIO support for CCW bus driver. Note that this is just
+         the base driver; you'll also need a userspace program
+         to provide a device configuration and channel programs.
diff --git a/drivers/vfio/ccw/Makefile b/drivers/vfio/ccw/Makefile
new file mode 100644
index 0000000..ea14ca9
--- /dev/null
+++ b/drivers/vfio/ccw/Makefile
@@ -0,0 +1,2 @@
+vfio-ccw-y := vfio_ccw.o
+obj-$(CONFIG_VFIO_CCW) += vfio-ccw.o
diff --git a/drivers/vfio/ccw/vfio_ccw.c b/drivers/vfio/ccw/vfio_ccw.c
new file mode 100644
index 0000000..8b0acae
--- /dev/null
+++ b/drivers/vfio/ccw/vfio_ccw.c
@@ -0,0 +1,160 @@
+/*
+ * vfio based ccw device driver
+ *
+ * Copyright IBM Corp. 2016
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (version 2 only)
+ * as published by the Free Software Foundation.
+ *
+ * Author(s): Dong Jia Shi <address@hidden>
+ *            Xiao Feng Ren <address@hidden>
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/iommu.h>
+#include <linux/vfio.h>
+#include <asm/ccwdev.h>
+#include <asm/cio.h>
+
+/**
+ * struct vfio_ccw_device
+ * @cdev: ccw device
+ * @going_away: if an offline procedure was already ongoing
+ */
+struct vfio_ccw_device {
+       struct ccw_device       *cdev;
+       bool                    going_away;
+};
+
+enum vfio_ccw_device_type {
+       vfio_dasd_eckd,
+};
+
+struct ccw_device_id vfio_ccw_ids[] = {
+       { CCW_DEVICE_DEVTYPE(0x3990, 0, 0x3390, 0),
+         .driver_info = vfio_dasd_eckd},
+       { /* End of list. */ },
+};
+MODULE_DEVICE_TABLE(ccw, vfio_ccw_ids);
+
+/*
+ * vfio callbacks
+ */
+static int vfio_ccw_open(void *device_data)
+{
+       if (!try_module_get(THIS_MODULE))
+               return -ENODEV;
+
+       return 0;
+}
+
+static void vfio_ccw_release(void *device_data)
+{
+       module_put(THIS_MODULE);
+}
+
+static long vfio_ccw_ioctl(void *device_data, unsigned int cmd,
+                          unsigned long arg)
+{
+       return -ENOTTY;
+}
+
+static const struct vfio_device_ops vfio_ccw_ops = {
+       .name           = "vfio_ccw",
+       .open           = vfio_ccw_open,
+       .release        = vfio_ccw_release,
+       .ioctl          = vfio_ccw_ioctl,
+};
+
+static int vfio_ccw_probe(struct ccw_device *cdev)
+{
+       struct iommu_group *group = vfio_iommu_group_get(&cdev->dev);
+
+       if (!group)
+               return -EINVAL;
+
+       return 0;
+}
+
+static int vfio_ccw_set_offline(struct ccw_device *cdev)
+{
+       struct vfio_device *device = vfio_device_get_from_dev(&cdev->dev);
+       struct vfio_ccw_device *vdev;
+
+       if (!device)
+               return 0;
+
+       vdev = vfio_device_data(device);
+       vfio_device_put(device);
+       if (!vdev || vdev->going_away)
+               return 0;
+
+       vdev->going_away = true;
+       vfio_del_group_dev(&cdev->dev);
+       kfree(vdev);
+
+       return 0;
+}
+
+void vfio_ccw_remove(struct ccw_device *cdev)
+{
+       if (cdev && cdev->online)
+               vfio_ccw_set_offline(cdev);
+
+       vfio_iommu_group_put(cdev->dev.iommu_group, &cdev->dev);
+}
+
+static int vfio_ccw_set_online(struct ccw_device *cdev)
+{
+       struct vfio_ccw_device *vdev;
+       int ret;
+
+       vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
+       if (!vdev)
+               return -ENOMEM;
+
+       vdev->cdev = cdev;
+
+       ret = vfio_add_group_dev(&cdev->dev, &vfio_ccw_ops, vdev);
+       if (ret)
+               kfree(vdev);
+
+       return ret;
+}
+
+static int vfio_ccw_notify(struct ccw_device *cdev, int event)
+{
+       /* LATER: We probably need to handle device/path state changes. */
+       return 0;
+}
+
+static struct ccw_driver vfio_ccw_driver = {
+       .driver = {
+               .name   = "vfio_ccw",
+               .owner  = THIS_MODULE,
+       },
+       .ids         = vfio_ccw_ids,
+       .probe       = vfio_ccw_probe,
+       .remove      = vfio_ccw_remove,
+       .set_offline = vfio_ccw_set_offline,
+       .set_online  = vfio_ccw_set_online,
+       .notify      = vfio_ccw_notify,
+       .int_class   = IRQIO_VFC,
+};
+
+static int __init vfio_ccw_init(void)
+{
+       return ccw_driver_register(&vfio_ccw_driver);
+}
+
+static void __exit vfio_ccw_cleanup(void)
+{
+       ccw_driver_unregister(&vfio_ccw_driver);
+}
+
+module_init(vfio_ccw_init);
+module_exit(vfio_ccw_cleanup);
+
+MODULE_LICENSE("GPL v2");
-- 
2.6.6