vfio-cdx: add bus mastering device feature support

Support Bus master enable and disable on VFIO-CDX devices using
VFIO_DEVICE_FEATURE_BUS_MASTER flag over VFIO_DEVICE_FEATURE IOCTL.

Co-developed-by: Shubham Rohila <shubham.rohila@amd.com>
Signed-off-by: Shubham Rohila <shubham.rohila@amd.com>
Signed-off-by: Nipun Gupta <nipun.gupta@amd.com>
Link: https://lore.kernel.org/r/20230915045423.31630-3-nipun.gupta@amd.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/vfio/cdx/main.c b/drivers/vfio/cdx/main.c
index de56686581ae4f7314aeb2aee5cc1a6af982fe01..a437630be3546970cbb695935deaabad9fe6fd9d 100644 (file)
--- a/drivers/vfio/cdx/main.c
+++ b/drivers/vfio/cdx/main.c
@@ -14,7 +14,7 @@ static int vfio_cdx_open_device(struct vfio_device *core_vdev)
                container_of(core_vdev, struct vfio_cdx_device, vdev);
        struct cdx_device *cdx_dev = to_cdx_device(core_vdev->dev);
        int count = cdx_dev->res_count;
-       int i;
+       int i, ret;
 
        vdev->regions = kcalloc(count, sizeof(struct vfio_cdx_region),
                                GFP_KERNEL_ACCOUNT);
@@ -39,6 +39,17 @@ static int vfio_cdx_open_device(struct vfio_device *core_vdev)
                if (!(cdx_dev->res[i].flags & IORESOURCE_READONLY))
                        vdev->regions[i].flags |= VFIO_REGION_INFO_FLAG_WRITE;
        }
+       ret = cdx_dev_reset(core_vdev->dev);
+       if (ret) {
+               kfree(vdev->regions);
+               vdev->regions = NULL;
+               return ret;
+       }
+       ret = cdx_clear_master(cdx_dev);
+       if (ret)
+               vdev->flags &= ~BME_SUPPORT;
+       else
+               vdev->flags |= BME_SUPPORT;
 
        return 0;
 }
@@ -52,6 +63,49 @@ static void vfio_cdx_close_device(struct vfio_device *core_vdev)
        cdx_dev_reset(core_vdev->dev);
 }
 
+static int vfio_cdx_bm_ctrl(struct vfio_device *core_vdev, u32 flags,
+                           void __user *arg, size_t argsz)
+{
+       size_t minsz =
+               offsetofend(struct vfio_device_feature_bus_master, op);
+       struct vfio_cdx_device *vdev =
+               container_of(core_vdev, struct vfio_cdx_device, vdev);
+       struct cdx_device *cdx_dev = to_cdx_device(core_vdev->dev);
+       struct vfio_device_feature_bus_master ops;
+       int ret;
+
+       if (!vdev->flags & BME_SUPPORT)
+               return -ENOTTY;
+
+       ret = vfio_check_feature(flags, argsz, VFIO_DEVICE_FEATURE_SET,
+                                sizeof(ops));
+       if (ret != 1)
+               return ret;
+
+       if (copy_from_user(&ops, arg, minsz))
+               return -EFAULT;
+
+       switch (ops.op) {
+       case VFIO_DEVICE_FEATURE_CLEAR_MASTER:
+               return cdx_clear_master(cdx_dev);
+       case VFIO_DEVICE_FEATURE_SET_MASTER:
+               return cdx_set_master(cdx_dev);
+       default:
+               return -EINVAL;
+       }
+}
+
+static int vfio_cdx_ioctl_feature(struct vfio_device *device, u32 flags,
+                                 void __user *arg, size_t argsz)
+{
+       switch (flags & VFIO_DEVICE_FEATURE_MASK) {
+       case VFIO_DEVICE_FEATURE_BUS_MASTER:
+               return vfio_cdx_bm_ctrl(device, flags, arg, argsz);
+       default:
+               return -ENOTTY;
+       }
+}
+
 static int vfio_cdx_ioctl_get_info(struct vfio_cdx_device *vdev,
                                   struct vfio_device_info __user *arg)
 {
@@ -169,6 +223,7 @@ static const struct vfio_device_ops vfio_cdx_ops = {
        .open_device    = vfio_cdx_open_device,
        .close_device   = vfio_cdx_close_device,
        .ioctl          = vfio_cdx_ioctl,
+       .device_feature = vfio_cdx_ioctl_feature,
        .mmap           = vfio_cdx_mmap,
        .bind_iommufd   = vfio_iommufd_physical_bind,
        .unbind_iommufd = vfio_iommufd_physical_unbind,

diff --git a/drivers/vfio/cdx/private.h b/drivers/vfio/cdx/private.h
index 8bdc117ea88edd6d181aea65c082004d521e405e..8e9d25913728286d54ba094db852ad7b943486d5 100644 (file)
--- a/drivers/vfio/cdx/private.h
+++ b/drivers/vfio/cdx/private.h
@@ -23,6 +23,8 @@ struct vfio_cdx_region {
 struct vfio_cdx_device {
        struct vfio_device      vdev;
        struct vfio_cdx_region  *regions;
+       u32                     flags;
+#define BME_SUPPORT BIT(0)
 };
 
 #endif /* VFIO_CDX_PRIVATE_H */