LookingGlass/module/kvmfr.c

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/**
* Looking Glass
* Copyright © 2017-2021 The Looking Glass Authors
* https://looking-glass.io
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc., 59
* Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#define PCI_KVMFR_VENDOR_ID 0x1af4 //Red Hat Inc,
#define PCI_KVMFR_DEVICE_ID 0x1110 //Inter-VM shared memory
#include <linux/device.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/dma-buf.h>
#include <linux/highmem.h>
2020-03-10 13:27:42 +00:00
#include <linux/version.h>
#include <asm/io.h>
#include "kvmfr.h"
DEFINE_MUTEX(minor_lock);
DEFINE_IDR(kvmfr_idr);
#define KVMFR_DEV_NAME "kvmfr"
#define KVMFR_MAX_DEVICES 10
static int static_size_mb[KVMFR_MAX_DEVICES];
static int static_count;
module_param_array(static_size_mb, int, &static_count, 0000);
MODULE_PARM_DESC(static_size_mb, "List of static devices to create in MiB");
struct kvmfr_info
{
int major;
struct class * pClass;
};
static struct kvmfr_info *kvmfr;
enum kvmfr_type
{
KVMFR_TYPE_PCI,
KVMFR_TYPE_STATIC,
};
struct kvmfr_dev
{
unsigned long size;
int minor;
dev_t devNo;
struct device * pDev;
struct dev_pagemap pgmap;
void * addr;
enum kvmfr_type type;
};
struct kvmfrbuf
{
struct kvmfr_dev * kdev;
pgoff_t pagecount;
unsigned long offset;
struct page ** pages;
};
static vm_fault_t kvmfr_vm_fault(struct vm_fault *vmf)
{
struct vm_area_struct *vma = vmf->vma;
struct kvmfrbuf *kbuf = (struct kvmfrbuf *)vma->vm_private_data;
vmf->page = kbuf->pages[vmf->pgoff];
get_page(vmf->page);
return 0;
}
static const struct vm_operations_struct kvmfr_vm_ops =
{
.fault = kvmfr_vm_fault
};
static struct sg_table * map_kvmfrbuf(struct dma_buf_attachment *at,
enum dma_data_direction direction)
{
struct kvmfrbuf *kbuf = at->dmabuf->priv;
struct sg_table *sg;
int ret;
sg = kzalloc(sizeof(*sg), GFP_KERNEL);
if (!sg)
return ERR_PTR(-ENOMEM);
ret = sg_alloc_table_from_pages(sg, kbuf->pages, kbuf->pagecount,
0, kbuf->pagecount << PAGE_SHIFT, GFP_KERNEL);
if (ret < 0)
goto err;
if (!dma_map_sg(at->dev, sg->sgl, sg->nents, direction))
{
ret = -EINVAL;
goto err;
}
return sg;
err:
sg_free_table(sg);
kfree(sg);
return ERR_PTR(ret);
}
static void unmap_kvmfrbuf(struct dma_buf_attachment * at, struct sg_table * sg, enum dma_data_direction direction)
{
dma_unmap_sg(at->dev, sg->sgl, sg->nents, direction);
sg_free_table(sg);
kfree(sg);
}
static void release_kvmfrbuf(struct dma_buf * buf)
{
struct kvmfrbuf *kbuf = (struct kvmfrbuf *)buf->priv;
kfree(kbuf->pages);
kfree(kbuf);
}
static int mmap_kvmfrbuf(struct dma_buf * buf, struct vm_area_struct * vma)
{
struct kvmfrbuf * kbuf = (struct kvmfrbuf *)buf->priv;
unsigned long size = vma->vm_end - vma->vm_start;
unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
if ((offset + size > (kbuf->pagecount << PAGE_SHIFT)) || (offset + size < offset))
return -EINVAL;
if ((vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)
return -EINVAL;
switch (kbuf->kdev->type)
{
case KVMFR_TYPE_PCI:
vma->vm_ops = &kvmfr_vm_ops;
vma->vm_private_data = buf->priv;
return 0;
case KVMFR_TYPE_STATIC:
return remap_vmalloc_range(vma, kbuf->kdev->addr + kbuf->offset, vma->vm_pgoff);
default:
return -EINVAL;
}
}
static const struct dma_buf_ops kvmfrbuf_ops =
{
.map_dma_buf = map_kvmfrbuf,
.unmap_dma_buf = unmap_kvmfrbuf,
.release = release_kvmfrbuf,
.mmap = mmap_kvmfrbuf
};
static long kvmfr_dmabuf_create(struct kvmfr_dev * kdev, struct file * filp, unsigned long arg)
{
struct kvmfr_dmabuf_create create;
DEFINE_DMA_BUF_EXPORT_INFO(exp_kdev);
struct kvmfrbuf * kbuf;
struct dma_buf * buf;
u32 i;
u8 *p;
int ret = -EINVAL;
if (copy_from_user(&create, (void __user *)arg,
sizeof(create)))
return -EFAULT;
if (!IS_ALIGNED(create.offset, PAGE_SIZE) ||
!IS_ALIGNED(create.size , PAGE_SIZE))
{
printk("kvmfr: buffer not aligned to 0x%lx bytes", PAGE_SIZE);
return -EINVAL;
}
if ((create.offset + create.size > kdev->size) || (create.offset + create.size < create.offset))
return -EINVAL;
kbuf = kzalloc(sizeof(struct kvmfrbuf), GFP_KERNEL);
if (!kbuf)
return -ENOMEM;
kbuf->kdev = kdev;
kbuf->pagecount = create.size >> PAGE_SHIFT;
kbuf->offset = create.offset;
kbuf->pages = kmalloc_array(kbuf->pagecount, sizeof(*kbuf->pages), GFP_KERNEL);
if (!kbuf->pages)
{
ret = -ENOMEM;
goto err;
}
p = ((u8*)kdev->addr) + create.offset;
switch (kdev->type)
{
case KVMFR_TYPE_PCI:
for (i = 0; i < kbuf->pagecount; ++i)
{
kbuf->pages[i] = virt_to_page(p);
p += PAGE_SIZE;
}
break;
case KVMFR_TYPE_STATIC:
for (i = 0; i < kbuf->pagecount; ++i)
{
kbuf->pages[i] = vmalloc_to_page(p);
p += PAGE_SIZE;
}
break;
}
exp_kdev.ops = &kvmfrbuf_ops;
exp_kdev.size = create.size;
exp_kdev.priv = kbuf;
exp_kdev.flags = O_RDWR;
buf = dma_buf_export(&exp_kdev);
if (IS_ERR(buf))
{
ret = PTR_ERR(buf);
goto err;
}
printk("kvmfr_dmabuf_create: offset: %llu, size: %llu\n", create.offset, create.size);
return dma_buf_fd(buf, create.flags & KVMFR_DMABUF_FLAG_CLOEXEC ? O_CLOEXEC : 0);
err:
kfree(kbuf->pages);
kfree(kbuf);
return ret;
}
static long device_ioctl(struct file * filp, unsigned int ioctl, unsigned long arg)
{
struct kvmfr_dev * kdev;
long ret;
kdev = (struct kvmfr_dev *)idr_find(&kvmfr_idr, iminor(filp->f_inode));
if (!kdev)
return -EINVAL;
switch(ioctl)
{
case KVMFR_DMABUF_CREATE:
ret = kvmfr_dmabuf_create(kdev, filp, arg);
break;
case KVMFR_DMABUF_GETSIZE:
ret = kdev->size;
break;
default:
return -ENOTTY;
}
return ret;
}
static vm_fault_t pci_mmap_fault(struct vm_fault *vmf)
{
struct vm_area_struct * vma = vmf->vma;
struct kvmfr_dev * kdev = (struct kvmfr_dev *)vma->vm_private_data;
vmf->page = virt_to_page(kdev->addr + (vmf->pgoff << PAGE_SHIFT));
get_page(vmf->page);
return 0;
}
static const struct vm_operations_struct pci_mmap_ops =
{
.fault = pci_mmap_fault
};
static int device_mmap(struct file * filp, struct vm_area_struct * vma)
{
struct kvmfr_dev * kdev;
unsigned long size = vma->vm_end - vma->vm_start;
unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
kdev = (struct kvmfr_dev *)idr_find(&kvmfr_idr, iminor(filp->f_inode));
if (!kdev)
return -EINVAL;
if ((offset + size > kdev->size) || (offset + size < offset))
return -EINVAL;
printk(KERN_INFO "mmap kvmfr%d: %lx-%lx with size %lu offset %lu\n",
kdev->minor, vma->vm_start, vma->vm_end, size, offset);
switch (kdev->type)
{
case KVMFR_TYPE_PCI:
vma->vm_ops = &pci_mmap_ops;
vma->vm_private_data = kdev;
return 0;
case KVMFR_TYPE_STATIC:
return remap_vmalloc_range(vma, kdev->addr, vma->vm_pgoff);
default:
return -ENODEV;
}
}
static struct file_operations fops =
{
.owner = THIS_MODULE,
.unlocked_ioctl = device_ioctl,
.mmap = device_mmap,
};
static int kvmfr_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
{
struct kvmfr_dev *kdev;
kdev = kzalloc(sizeof(struct kvmfr_dev), GFP_KERNEL);
if (!kdev)
return -ENOMEM;
if (pci_enable_device(dev))
goto out_free;
if (pci_request_regions(dev, KVMFR_DEV_NAME))
goto out_disable;
kdev->size = pci_resource_len(dev, 2);
kdev->type = KVMFR_TYPE_PCI;
mutex_lock(&minor_lock);
kdev->minor = idr_alloc(&kvmfr_idr, kdev, 0, KVMFR_MAX_DEVICES, GFP_KERNEL);
if (kdev->minor < 0)
{
mutex_unlock(&minor_lock);
goto out_release;
}
mutex_unlock(&minor_lock);
kdev->devNo = MKDEV(kvmfr->major, kdev->minor);
kdev->pDev = device_create(kvmfr->pClass, NULL, kdev->devNo, NULL, KVMFR_DEV_NAME "%d", kdev->minor);
if (IS_ERR(kdev->pDev))
goto out_unminor;
#if LINUX_VERSION_CODE < KERNEL_VERSION(5, 10, 0)
kdev->pgmap.res.start = pci_resource_start(dev, 2);
kdev->pgmap.res.end = pci_resource_end (dev, 2);
kdev->pgmap.res.flags = pci_resource_flags(dev, 2);
#else
kdev->pgmap.range.start = pci_resource_start(dev, 2);
kdev->pgmap.range.end = pci_resource_end (dev, 2);
kdev->pgmap.nr_range = 1;
#endif
#if LINUX_VERSION_CODE < KERNEL_VERSION(5, 9, 0)
kdev->pgmap.type = MEMORY_DEVICE_DEVDAX;
#else
kdev->pgmap.type = MEMORY_DEVICE_GENERIC;
#endif
kdev->addr = devm_memremap_pages(&dev->dev, &kdev->pgmap);
if (IS_ERR(kdev->addr))
goto out_destroy;
pci_set_drvdata(dev, kdev);
return 0;
out_destroy:
device_destroy(kvmfr->pClass, kdev->devNo);
out_unminor:
mutex_lock(&minor_lock);
idr_remove(&kvmfr_idr, kdev->minor);
mutex_unlock(&minor_lock);
out_release:
pci_release_regions(dev);
out_disable:
pci_disable_device(dev);
out_free:
kfree(kdev);
return -ENODEV;
}
static void kvmfr_pci_remove(struct pci_dev *dev)
{
struct kvmfr_dev *kdev = pci_get_drvdata(dev);
devm_memunmap_pages(&dev->dev, &kdev->pgmap);
device_destroy(kvmfr->pClass, kdev->devNo);
mutex_lock(&minor_lock);
idr_remove(&kvmfr_idr, kdev->minor);
mutex_unlock(&minor_lock);
pci_release_regions(dev);
pci_disable_device(dev);
kfree(kdev);
}
static struct pci_device_id kvmfr_pci_ids[] =
{
{
.vendor = PCI_KVMFR_VENDOR_ID,
.device = PCI_KVMFR_DEVICE_ID,
.subvendor = PCI_ANY_ID,
.subdevice = PCI_ANY_ID
},
{ 0, }
};
static struct pci_driver kvmfr_pci_driver =
{
.name = KVMFR_DEV_NAME,
.id_table = kvmfr_pci_ids,
.probe = kvmfr_pci_probe,
.remove = kvmfr_pci_remove
};
static int create_static_device_unlocked(int size_mb)
{
struct kvmfr_dev * kdev;
int ret = -ENODEV;
kdev = kzalloc(sizeof(struct kvmfr_dev), GFP_KERNEL);
if (!kdev)
return -ENOMEM;
kdev->size = size_mb * 1024 * 1024;
kdev->type = KVMFR_TYPE_STATIC;
kdev->addr = vmalloc_user(kdev->size);
if (!kdev->addr)
{
printk(KERN_ERR "kvmfr: failed to allocate memory for static device: %d MiB\n", size_mb);
ret = -ENOMEM;
goto out_free;
}
kdev->minor = idr_alloc(&kvmfr_idr, kdev, 0, KVMFR_MAX_DEVICES, GFP_KERNEL);
if (kdev->minor < 0)
goto out_release;
kdev->devNo = MKDEV(kvmfr->major, kdev->minor);
kdev->pDev = device_create(kvmfr->pClass, NULL, kdev->devNo, NULL, KVMFR_DEV_NAME "%d", kdev->minor);
if (IS_ERR(kdev->pDev))
goto out_unminor;
return 0;
out_unminor:
idr_remove(&kvmfr_idr, kdev->minor);
out_release:
vfree(kdev->addr);
out_free:
kfree(kdev);
return ret;
}
static void free_static_device_unlocked(struct kvmfr_dev * kdev)
{
device_destroy(kvmfr->pClass, kdev->devNo);
idr_remove(&kvmfr_idr, kdev->minor);
vfree(kdev->addr);
kfree(kdev);
}
static void free_static_devices(void)
{
int id;
struct kvmfr_dev * kdev;
mutex_lock(&minor_lock);
idr_for_each_entry(&kvmfr_idr, kdev, id)
free_static_device_unlocked(kdev);
mutex_unlock(&minor_lock);
}
static int create_static_devices(void)
{
int i;
int ret = 0;
mutex_lock(&minor_lock);
printk(KERN_INFO "kvmfr: creating %d static devices\n", static_count);
for (i = 0; i < static_count; ++i)
{
ret = create_static_device_unlocked(static_size_mb[i]);
if (ret < 0)
break;
}
mutex_unlock(&minor_lock);
if (ret < 0)
free_static_devices();
return ret;
}
static int __init kvmfr_module_init(void)
{
int ret;
kvmfr = kzalloc(sizeof(struct kvmfr_info), GFP_KERNEL);
if (!kvmfr)
return -ENOMEM;
kvmfr->major = register_chrdev(0, KVMFR_DEV_NAME, &fops);
if (kvmfr->major < 0)
goto out_free;
kvmfr->pClass = class_create(THIS_MODULE, KVMFR_DEV_NAME);
if (IS_ERR(kvmfr->pClass))
goto out_unreg;
ret = create_static_devices();
if (ret < 0)
goto out_class_destroy;
ret = pci_register_driver(&kvmfr_pci_driver);
if (ret < 0)
goto out_free_static;
return 0;
out_free_static:
free_static_devices();
out_class_destroy:
class_destroy(kvmfr->pClass);
out_unreg:
unregister_chrdev(kvmfr->major, KVMFR_DEV_NAME);
out_free:
kfree(kvmfr);
kvmfr = NULL;
return -ENODEV;
}
static void __exit kvmfr_module_exit(void)
{
pci_unregister_driver(&kvmfr_pci_driver);
free_static_devices();
class_destroy(kvmfr->pClass);
unregister_chrdev(kvmfr->major, KVMFR_DEV_NAME);
kfree(kvmfr);
kvmfr = NULL;
}
module_init(kvmfr_module_init);
module_exit(kvmfr_module_exit);
MODULE_DEVICE_TABLE(pci, kvmfr_pci_ids);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Geoffrey McRae <geoff@hostfission.com>");
MODULE_AUTHOR("Guanzhong Chen <quantum2048@gmail.com>");
MODULE_VERSION("0.0.7");