From f59a7b6af012619199c55f587a6c4ed681639b32 Mon Sep 17 00:00:00 2001 From: Nipun Gupta Date: Fri, 15 Sep 2023 10:24:22 +0530 Subject: vfio: add bus master feature to device feature ioctl add bus mastering control to VFIO_DEVICE_FEATURE IOCTL. The VFIO user can use this feature to enable or disable the Bus Mastering of a device bound to VFIO. Co-developed-by: Shubham Rohila Signed-off-by: Shubham Rohila Signed-off-by: Nipun Gupta Link: https://lore.kernel.org/r/20230915045423.31630-2-nipun.gupta@amd.com Signed-off-by: Alex Williamson --- include/uapi/linux/vfio.h | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index afc1369216d9..b177424149f4 100644 --- a/include/uapi/linux/vfio.h +++ b/include/uapi/linux/vfio.h @@ -1434,6 +1434,27 @@ struct vfio_device_feature_mig_data_size { #define VFIO_DEVICE_FEATURE_MIG_DATA_SIZE 9 +/** + * Upon VFIO_DEVICE_FEATURE_SET, set or clear the BUS mastering for the device + * based on the operation specified in op flag. + * + * The functionality is incorporated for devices that needs bus master control, + * but the in-band device interface lacks the support. Consequently, it is not + * applicable to PCI devices, as bus master control for PCI devices is managed + * in-band through the configuration space. At present, this feature is supported + * only for CDX devices. + * When the device's BUS MASTER setting is configured as CLEAR, it will result in + * blocking all incoming DMA requests from the device. On the other hand, configuring + * the device's BUS MASTER setting as SET (enable) will grant the device the + * capability to perform DMA to the host memory. + */ +struct vfio_device_feature_bus_master { + __u32 op; +#define VFIO_DEVICE_FEATURE_CLEAR_MASTER 0 /* Clear Bus Master */ +#define VFIO_DEVICE_FEATURE_SET_MASTER 1 /* Set Bus Master */ +}; +#define VFIO_DEVICE_FEATURE_BUS_MASTER 10 + /* -------- API for Type1 VFIO IOMMU -------- */ /** -- cgit v1.2.3