From a9e3760b0838299649c0d57cca44daaf40ba3c33 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 14 Sep 2026 22:12:34 -1000 Subject: sched_ext: Maintain an online cid mask in the scheduler arena Schedulers on the default cid mapping treat [0, nr_online_cids) as the online set and restart on hotplug. Schedulers that install their own mapping with scx_bpf_cid_override() have no way to learn which cids are online: the count no longer identifies members and the CPU-form cpumask is unusable from cid programs. This is an obvious hole in the cid API. Add scx_bpf_online_cmask(), a kernel-maintained cmask in the scheduler's arena, allocated alongside the per-CPU scratch masks and populated after the cid mapping is finalized and before ops.init(), for child schedulers too. The pointer stays valid through ops.exit() with no reference to take. It is the arena offset as a void pointer, the same form struct_ops arena arguments arrive in. The verifier types the void return as a scalar for the program's arena cast. The mask follows the SCX hotplug notifications: seeded from cpu_active_mask and updated before ops.cid_online/offline() runs, so it lags cpu_online_mask only inside a hotplug transition. Updates walk the scheduler list under the lock that also serializes unlinking. Reads are live, not atomic snapshots. Root initialization excludes hotplug. v2: Reworded the getter kerneldoc (Andrea Righi). Signed-off-by: Tejun Heo Reviewed-by: Andrea Righi --- samples/vfio-mdev/mdpy.c | 743 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 743 insertions(+) create mode 100644 samples/vfio-mdev/mdpy.c (limited to 'samples/vfio-mdev/mdpy.c') diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c new file mode 100644 index 000000000..0759bd68e --- /dev/null +++ b/samples/vfio-mdev/mdpy.c @@ -0,0 +1,743 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Mediated virtual PCI display host device driver + * + * See mdpy-defs.h for device specs + * + * (c) Gerd Hoffmann + * + * based on mtty driver which is: + * Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved. + * Author: Neo Jia + * Kirti Wankhede + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "mdpy-defs.h" + +#define MDPY_NAME "mdpy" +#define MDPY_CLASS_NAME "mdpy" + +#define MDPY_CONFIG_SPACE_SIZE 0xff +#define MDPY_MEMORY_BAR_OFFSET PAGE_SIZE +#define MDPY_DISPLAY_REGION 16 + +#define STORE_LE16(addr, val) (*(u16 *)addr = val) +#define STORE_LE32(addr, val) (*(u32 *)addr = val) + + +MODULE_DESCRIPTION("Mediated virtual PCI display host device driver"); +MODULE_LICENSE("GPL v2"); + +#define MDPY_TYPE_1 "vga" +#define MDPY_TYPE_2 "xga" +#define MDPY_TYPE_3 "hd" + +static struct mdpy_type { + struct mdev_type type; + u32 format; + u32 bytepp; + u32 width; + u32 height; +} mdpy_types[] = { + { + .type.sysfs_name = MDPY_TYPE_1, + .type.pretty_name = MDPY_CLASS_NAME "-" MDPY_TYPE_1, + .format = DRM_FORMAT_XRGB8888, + .bytepp = 4, + .width = 640, + .height = 480, + }, { + .type.sysfs_name = MDPY_TYPE_2, + .type.pretty_name = MDPY_CLASS_NAME "-" MDPY_TYPE_2, + .format = DRM_FORMAT_XRGB8888, + .bytepp = 4, + .width = 1024, + .height = 768, + }, { + .type.sysfs_name = MDPY_TYPE_3, + .type.pretty_name = MDPY_CLASS_NAME "-" MDPY_TYPE_3, + .format = DRM_FORMAT_XRGB8888, + .bytepp = 4, + .width = 1920, + .height = 1080, + }, +}; + +static struct mdev_type *mdpy_mdev_types[] = { + &mdpy_types[0].type, + &mdpy_types[1].type, + &mdpy_types[2].type, +}; + +static dev_t mdpy_devt; +static const struct class mdpy_class = { + .name = MDPY_CLASS_NAME, +}; +static struct cdev mdpy_cdev; +static struct device mdpy_dev; +static struct mdev_parent mdpy_parent; +static const struct vfio_device_ops mdpy_dev_ops; + +/* State of each mdev device */ +struct mdev_state { + struct vfio_device vdev; + u8 *vconfig; + u32 bar_mask; + struct mutex ops_lock; + struct mdev_device *mdev; + struct vfio_device_info dev_info; + + const struct mdpy_type *type; + u32 memsize; + void *memblk; +}; + +static void mdpy_create_config_space(struct mdev_state *mdev_state) +{ + STORE_LE16((u16 *) &mdev_state->vconfig[PCI_VENDOR_ID], + MDPY_PCI_VENDOR_ID); + STORE_LE16((u16 *) &mdev_state->vconfig[PCI_DEVICE_ID], + MDPY_PCI_DEVICE_ID); + STORE_LE16((u16 *) &mdev_state->vconfig[PCI_SUBSYSTEM_VENDOR_ID], + MDPY_PCI_SUBVENDOR_ID); + STORE_LE16((u16 *) &mdev_state->vconfig[PCI_SUBSYSTEM_ID], + MDPY_PCI_SUBDEVICE_ID); + + STORE_LE16((u16 *) &mdev_state->vconfig[PCI_COMMAND], + PCI_COMMAND_IO | PCI_COMMAND_MEMORY); + STORE_LE16((u16 *) &mdev_state->vconfig[PCI_STATUS], + PCI_STATUS_CAP_LIST); + STORE_LE16((u16 *) &mdev_state->vconfig[PCI_CLASS_DEVICE], + PCI_CLASS_DISPLAY_OTHER); + mdev_state->vconfig[PCI_CLASS_REVISION] = 0x01; + + STORE_LE32((u32 *) &mdev_state->vconfig[PCI_BASE_ADDRESS_0], + PCI_BASE_ADDRESS_SPACE_MEMORY | + PCI_BASE_ADDRESS_MEM_TYPE_32 | + PCI_BASE_ADDRESS_MEM_PREFETCH); + mdev_state->bar_mask = ~(mdev_state->memsize) + 1; + + /* vendor specific capability for the config registers */ + mdev_state->vconfig[PCI_CAPABILITY_LIST] = MDPY_VENDORCAP_OFFSET; + mdev_state->vconfig[MDPY_VENDORCAP_OFFSET + 0] = 0x09; /* vendor cap */ + mdev_state->vconfig[MDPY_VENDORCAP_OFFSET + 1] = 0x00; /* next ptr */ + mdev_state->vconfig[MDPY_VENDORCAP_OFFSET + 2] = MDPY_VENDORCAP_SIZE; + STORE_LE32((u32 *) &mdev_state->vconfig[MDPY_FORMAT_OFFSET], + mdev_state->type->format); + STORE_LE32((u32 *) &mdev_state->vconfig[MDPY_WIDTH_OFFSET], + mdev_state->type->width); + STORE_LE32((u32 *) &mdev_state->vconfig[MDPY_HEIGHT_OFFSET], + mdev_state->type->height); +} + +static void handle_pci_cfg_write(struct mdev_state *mdev_state, u16 offset, + char *buf, u32 count) +{ + struct device *dev = mdev_dev(mdev_state->mdev); + u32 cfg_addr; + + switch (offset) { + case PCI_BASE_ADDRESS_0: + cfg_addr = *(u32 *)buf; + + if (cfg_addr == 0xffffffff) { + cfg_addr = (cfg_addr & mdev_state->bar_mask); + } else { + cfg_addr &= PCI_BASE_ADDRESS_MEM_MASK; + if (cfg_addr) + dev_info(dev, "BAR0 @ 0x%x\n", cfg_addr); + } + + cfg_addr |= (mdev_state->vconfig[offset] & + ~PCI_BASE_ADDRESS_MEM_MASK); + STORE_LE32(&mdev_state->vconfig[offset], cfg_addr); + break; + } +} + +static ssize_t mdev_access(struct mdev_state *mdev_state, char *buf, + size_t count, loff_t pos, bool is_write) +{ + int ret = 0; + + mutex_lock(&mdev_state->ops_lock); + + if (pos < MDPY_CONFIG_SPACE_SIZE) { + if (is_write) + handle_pci_cfg_write(mdev_state, pos, buf, count); + else + memcpy(buf, (mdev_state->vconfig + pos), count); + + } else if ((pos >= MDPY_MEMORY_BAR_OFFSET) && + (pos + count <= + MDPY_MEMORY_BAR_OFFSET + mdev_state->memsize)) { + pos -= MDPY_MEMORY_BAR_OFFSET; + if (is_write) + memcpy(mdev_state->memblk, buf, count); + else + memcpy(buf, mdev_state->memblk, count); + + } else { + dev_info(mdev_state->vdev.dev, + "%s: %s @0x%llx (unhandled)\n", __func__, + is_write ? "WR" : "RD", pos); + ret = -1; + goto accessfailed; + } + + ret = count; + + +accessfailed: + mutex_unlock(&mdev_state->ops_lock); + + return ret; +} + +static int mdpy_reset(struct mdev_state *mdev_state) +{ + u32 stride, i; + + /* initialize with gray gradient */ + stride = mdev_state->type->width * mdev_state->type->bytepp; + for (i = 0; i < mdev_state->type->height; i++) + memset(mdev_state->memblk + i * stride, + i * 255 / mdev_state->type->height, + stride); + return 0; +} + +static int mdpy_init_dev(struct vfio_device *vdev) +{ + struct mdev_state *mdev_state = + container_of(vdev, struct mdev_state, vdev); + struct mdev_device *mdev = to_mdev_device(vdev->dev); + const struct mdpy_type *type = + container_of(mdev->type, struct mdpy_type, type); + u32 fbsize; + int ret = -ENOMEM; + + mdev_state->vconfig = kzalloc(MDPY_CONFIG_SPACE_SIZE, GFP_KERNEL); + if (!mdev_state->vconfig) + return ret; + + fbsize = roundup_pow_of_two(type->width * type->height * type->bytepp); + + mdev_state->memblk = vmalloc_user(fbsize); + if (!mdev_state->memblk) + goto out_vconfig; + + mutex_init(&mdev_state->ops_lock); + mdev_state->mdev = mdev; + mdev_state->type = type; + mdev_state->memsize = fbsize; + mdpy_create_config_space(mdev_state); + mdpy_reset(mdev_state); + + dev_info(vdev->dev, "%s: %s (%dx%d)\n", __func__, type->type.pretty_name, + type->width, type->height); + return 0; + +out_vconfig: + kfree(mdev_state->vconfig); + return ret; +} + +static int mdpy_probe(struct mdev_device *mdev) +{ + struct mdev_state *mdev_state; + int ret; + + mdev_state = vfio_alloc_device(mdev_state, vdev, &mdev->dev, + &mdpy_dev_ops); + if (IS_ERR(mdev_state)) + return PTR_ERR(mdev_state); + + ret = vfio_register_emulated_iommu_dev(&mdev_state->vdev); + if (ret) + goto err_put_vdev; + dev_set_drvdata(&mdev->dev, mdev_state); + return 0; + +err_put_vdev: + vfio_put_device(&mdev_state->vdev); + return ret; +} + +static void mdpy_release_dev(struct vfio_device *vdev) +{ + struct mdev_state *mdev_state = + container_of(vdev, struct mdev_state, vdev); + + vfree(mdev_state->memblk); + kfree(mdev_state->vconfig); +} + +static void mdpy_remove(struct mdev_device *mdev) +{ + struct mdev_state *mdev_state = dev_get_drvdata(&mdev->dev); + + dev_info(&mdev->dev, "%s\n", __func__); + + vfio_unregister_group_dev(&mdev_state->vdev); + vfio_put_device(&mdev_state->vdev); +} + +static ssize_t mdpy_read(struct vfio_device *vdev, char __user *buf, + size_t count, loff_t *ppos) +{ + struct mdev_state *mdev_state = + container_of(vdev, struct mdev_state, vdev); + unsigned int done = 0; + int ret; + + while (count) { + size_t filled; + + if (count >= 4 && !(*ppos % 4)) { + u32 val; + + ret = mdev_access(mdev_state, (char *)&val, sizeof(val), + *ppos, false); + if (ret <= 0) + goto read_err; + + if (copy_to_user(buf, &val, sizeof(val))) + goto read_err; + + filled = 4; + } else if (count >= 2 && !(*ppos % 2)) { + u16 val; + + ret = mdev_access(mdev_state, (char *)&val, sizeof(val), + *ppos, false); + if (ret <= 0) + goto read_err; + + if (copy_to_user(buf, &val, sizeof(val))) + goto read_err; + + filled = 2; + } else { + u8 val; + + ret = mdev_access(mdev_state, (char *)&val, sizeof(val), + *ppos, false); + if (ret <= 0) + goto read_err; + + if (copy_to_user(buf, &val, sizeof(val))) + goto read_err; + + filled = 1; + } + + count -= filled; + done += filled; + *ppos += filled; + buf += filled; + } + + return done; + +read_err: + return -EFAULT; +} + +static ssize_t mdpy_write(struct vfio_device *vdev, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct mdev_state *mdev_state = + container_of(vdev, struct mdev_state, vdev); + unsigned int done = 0; + int ret; + + while (count) { + size_t filled; + + if (count >= 4 && !(*ppos % 4)) { + u32 val; + + if (copy_from_user(&val, buf, sizeof(val))) + goto write_err; + + ret = mdev_access(mdev_state, (char *)&val, sizeof(val), + *ppos, true); + if (ret <= 0) + goto write_err; + + filled = 4; + } else if (count >= 2 && !(*ppos % 2)) { + u16 val; + + if (copy_from_user(&val, buf, sizeof(val))) + goto write_err; + + ret = mdev_access(mdev_state, (char *)&val, sizeof(val), + *ppos, true); + if (ret <= 0) + goto write_err; + + filled = 2; + } else { + u8 val; + + if (copy_from_user(&val, buf, sizeof(val))) + goto write_err; + + ret = mdev_access(mdev_state, (char *)&val, sizeof(val), + *ppos, true); + if (ret <= 0) + goto write_err; + + filled = 1; + } + count -= filled; + done += filled; + *ppos += filled; + buf += filled; + } + + return done; +write_err: + return -EFAULT; +} + +static int mdpy_mmap(struct vfio_device *vdev, struct vm_area_struct *vma) +{ + struct mdev_state *mdev_state = + container_of(vdev, struct mdev_state, vdev); + + if (vma->vm_pgoff != MDPY_MEMORY_BAR_OFFSET >> PAGE_SHIFT) + return -EINVAL; + if (vma->vm_end < vma->vm_start) + return -EINVAL; + if (vma->vm_end - vma->vm_start > mdev_state->memsize) + return -EINVAL; + if ((vma->vm_flags & VM_SHARED) == 0) + return -EINVAL; + + return remap_vmalloc_range(vma, mdev_state->memblk, 0); +} + +static int mdpy_ioctl_get_region_info(struct vfio_device *vdev, + struct vfio_region_info *region_info, + struct vfio_info_cap *caps) +{ + struct mdev_state *mdev_state = + container_of(vdev, struct mdev_state, vdev); + + if (region_info->index >= VFIO_PCI_NUM_REGIONS && + region_info->index != MDPY_DISPLAY_REGION) + return -EINVAL; + + switch (region_info->index) { + case VFIO_PCI_CONFIG_REGION_INDEX: + region_info->offset = 0; + region_info->size = MDPY_CONFIG_SPACE_SIZE; + region_info->flags = (VFIO_REGION_INFO_FLAG_READ | + VFIO_REGION_INFO_FLAG_WRITE); + break; + case VFIO_PCI_BAR0_REGION_INDEX: + case MDPY_DISPLAY_REGION: + region_info->offset = MDPY_MEMORY_BAR_OFFSET; + region_info->size = mdev_state->memsize; + region_info->flags = (VFIO_REGION_INFO_FLAG_READ | + VFIO_REGION_INFO_FLAG_WRITE | + VFIO_REGION_INFO_FLAG_MMAP); + break; + default: + region_info->size = 0; + region_info->offset = 0; + region_info->flags = 0; + } + + return 0; +} + +static int mdpy_get_irq_info(struct vfio_irq_info *irq_info) +{ + irq_info->count = 0; + return 0; +} + +static int mdpy_get_device_info(struct vfio_device_info *dev_info) +{ + dev_info->flags = VFIO_DEVICE_FLAGS_PCI; + dev_info->num_regions = VFIO_PCI_NUM_REGIONS; + dev_info->num_irqs = VFIO_PCI_NUM_IRQS; + return 0; +} + +static int mdpy_query_gfx_plane(struct mdev_state *mdev_state, + struct vfio_device_gfx_plane_info *plane) +{ + if (plane->flags & VFIO_GFX_PLANE_TYPE_PROBE) { + if (plane->flags == (VFIO_GFX_PLANE_TYPE_PROBE | + VFIO_GFX_PLANE_TYPE_REGION)) + return 0; + return -EINVAL; + } + + if (plane->flags != VFIO_GFX_PLANE_TYPE_REGION) + return -EINVAL; + + plane->drm_format = mdev_state->type->format; + plane->width = mdev_state->type->width; + plane->height = mdev_state->type->height; + plane->stride = (mdev_state->type->width * + mdev_state->type->bytepp); + plane->size = mdev_state->memsize; + plane->region_index = MDPY_DISPLAY_REGION; + + /* unused */ + plane->drm_format_mod = 0; + plane->x_pos = 0; + plane->y_pos = 0; + plane->x_hot = 0; + plane->y_hot = 0; + + return 0; +} + +static long mdpy_ioctl(struct vfio_device *vdev, unsigned int cmd, + unsigned long arg) +{ + int ret = 0; + unsigned long minsz; + struct mdev_state *mdev_state = + container_of(vdev, struct mdev_state, vdev); + + switch (cmd) { + case VFIO_DEVICE_GET_INFO: + { + struct vfio_device_info info; + + minsz = offsetofend(struct vfio_device_info, num_irqs); + + if (copy_from_user(&info, (void __user *)arg, minsz)) + return -EFAULT; + + if (info.argsz < minsz) + return -EINVAL; + + ret = mdpy_get_device_info(&info); + if (ret) + return ret; + + memcpy(&mdev_state->dev_info, &info, sizeof(info)); + + if (copy_to_user((void __user *)arg, &info, minsz)) + return -EFAULT; + + return 0; + } + + case VFIO_DEVICE_GET_IRQ_INFO: + { + struct vfio_irq_info info; + + minsz = offsetofend(struct vfio_irq_info, count); + + if (copy_from_user(&info, (void __user *)arg, minsz)) + return -EFAULT; + + if ((info.argsz < minsz) || + (info.index >= mdev_state->dev_info.num_irqs)) + return -EINVAL; + + ret = mdpy_get_irq_info(&info); + if (ret) + return ret; + + if (copy_to_user((void __user *)arg, &info, minsz)) + return -EFAULT; + + return 0; + } + + case VFIO_DEVICE_QUERY_GFX_PLANE: + { + struct vfio_device_gfx_plane_info plane = {}; + + minsz = offsetofend(struct vfio_device_gfx_plane_info, + region_index); + + if (copy_from_user(&plane, (void __user *)arg, minsz)) + return -EFAULT; + + if (plane.argsz < minsz) + return -EINVAL; + + ret = mdpy_query_gfx_plane(mdev_state, &plane); + if (ret) + return ret; + + if (copy_to_user((void __user *)arg, &plane, minsz)) + return -EFAULT; + + return 0; + } + + case VFIO_DEVICE_SET_IRQS: + return -EINVAL; + + case VFIO_DEVICE_RESET: + return mdpy_reset(mdev_state); + } + return -ENOTTY; +} + +static ssize_t +resolution_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct mdev_state *mdev_state = dev_get_drvdata(dev); + + return sprintf(buf, "%dx%d\n", + mdev_state->type->width, + mdev_state->type->height); +} +static DEVICE_ATTR_RO(resolution); + +static struct attribute *mdev_dev_attrs[] = { + &dev_attr_resolution.attr, + NULL, +}; + +static const struct attribute_group mdev_dev_group = { + .name = "vendor", + .attrs = mdev_dev_attrs, +}; + +static const struct attribute_group *mdev_dev_groups[] = { + &mdev_dev_group, + NULL, +}; + +static ssize_t mdpy_show_description(struct mdev_type *mtype, char *buf) +{ + struct mdpy_type *type = container_of(mtype, struct mdpy_type, type); + + return sprintf(buf, "virtual display, %dx%d framebuffer\n", + type->width, type->height); +} + +static const struct vfio_device_ops mdpy_dev_ops = { + .init = mdpy_init_dev, + .release = mdpy_release_dev, + .read = mdpy_read, + .write = mdpy_write, + .ioctl = mdpy_ioctl, + .get_region_info_caps = mdpy_ioctl_get_region_info, + .mmap = mdpy_mmap, + .bind_iommufd = vfio_iommufd_emulated_bind, + .unbind_iommufd = vfio_iommufd_emulated_unbind, + .attach_ioas = vfio_iommufd_emulated_attach_ioas, + .detach_ioas = vfio_iommufd_emulated_detach_ioas, +}; + +static struct mdev_driver mdpy_driver = { + .device_api = VFIO_DEVICE_API_PCI_STRING, + .max_instances = 4, + .driver = { + .name = "mdpy", + .owner = THIS_MODULE, + .mod_name = KBUILD_MODNAME, + .dev_groups = mdev_dev_groups, + }, + .probe = mdpy_probe, + .remove = mdpy_remove, + .show_description = mdpy_show_description, +}; + +static const struct file_operations vd_fops = { + .owner = THIS_MODULE, +}; + +static void mdpy_device_release(struct device *dev) +{ + /* nothing */ +} + +static int __init mdpy_dev_init(void) +{ + int ret = 0; + + ret = alloc_chrdev_region(&mdpy_devt, 0, MINORMASK + 1, MDPY_NAME); + if (ret < 0) { + pr_err("Error: failed to register mdpy_dev, err: %d\n", ret); + return ret; + } + cdev_init(&mdpy_cdev, &vd_fops); + cdev_add(&mdpy_cdev, mdpy_devt, MINORMASK + 1); + pr_info("%s: major %d\n", __func__, MAJOR(mdpy_devt)); + + ret = mdev_register_driver(&mdpy_driver); + if (ret) + goto err_cdev; + + ret = class_register(&mdpy_class); + if (ret) + goto err_driver; + mdpy_dev.class = &mdpy_class; + mdpy_dev.release = mdpy_device_release; + dev_set_name(&mdpy_dev, "%s", MDPY_NAME); + + ret = device_register(&mdpy_dev); + if (ret) + goto err_put; + + ret = mdev_register_parent(&mdpy_parent, &mdpy_dev, &mdpy_driver, + mdpy_mdev_types, + ARRAY_SIZE(mdpy_mdev_types)); + if (ret) + goto err_device; + + return 0; + +err_device: + device_del(&mdpy_dev); +err_put: + put_device(&mdpy_dev); + class_unregister(&mdpy_class); +err_driver: + mdev_unregister_driver(&mdpy_driver); +err_cdev: + cdev_del(&mdpy_cdev); + unregister_chrdev_region(mdpy_devt, MINORMASK + 1); + return ret; +} + +static void __exit mdpy_dev_exit(void) +{ + mdpy_dev.bus = NULL; + mdev_unregister_parent(&mdpy_parent); + + device_unregister(&mdpy_dev); + mdev_unregister_driver(&mdpy_driver); + cdev_del(&mdpy_cdev); + unregister_chrdev_region(mdpy_devt, MINORMASK + 1); + class_unregister(&mdpy_class); +} + +module_param_named(count, mdpy_driver.max_instances, int, 0444); +MODULE_PARM_DESC(count, "number of " MDPY_NAME " devices"); + +module_init(mdpy_dev_init) +module_exit(mdpy_dev_exit) -- cgit v1.3.1