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[kvmfr] added the ability to obtain a dmabuf of the ivshmem memory

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This is to enable the ability to use dri3 to create dmabuf backed
pixmaps directly.
This commit is contained in:
Geoffrey McRae 2020-01-13 13:39:24 +11:00
parent 6aeafc6651
commit 788f885759
4 changed files with 428 additions and 32 deletions
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2
VERSION
View file

@ -1 +1 @@
B1-85-g1aadf91901+1
B1-86-g6aeafc6651+1

10
module/Makefile
View file

@ -3,14 +3,20 @@ USER := $(shell whoami)
KVER ?= $(shell uname -r)
KDIR ?= /lib/modules/$(KVER)/build
all:
all: test
make -C $(KDIR) M=$(PWD) modules
clean:
make -C $(KDIR) M=$(PWD) clean
test: all
test:
gcc test.c -Wall -Werror -g -Og -o test
load: all
grep -q '^uio' /proc/modules || sudo modprobe uio
grep -q '^kvmfr' /proc/modules && sudo rmmod kvmfr || true
sudo insmod ./kvmfr.ko
sudo chown $(USER) /dev/uio0
sudo chown $(USER) /dev/kvmfr0
.PHONY: test

396
module/kvmfr.c
View file

@ -25,73 +25,367 @@ Place, Suite 330, Boston, MA 02111-1307 USA
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/uio_driver.h>
#include <linux/fs.h>
#include <linux/dma-buf.h>
#include <linux/highmem.h>
#include <asm/io.h>
#include "kvmfr.h"
DEFINE_MUTEX(minor_lock);
DEFINE_IDR(kvmfr_idr);
#define KVMFR_UIO_NAME "KVMFR"
#define KVMFR_UIO_VER "0.0.2"
#define KVMFR_DEV_NAME "kvmfr"
#define KVMFR_MAX_DEVICES 10
struct kvmfr_info
{
int major;
struct class * pClass;
};
static struct kvmfr_info *kvmfr;
struct kvmfr_dev
{
struct pci_dev * dev;
struct uio_info uio;
int minor;
dev_t devNo;
struct device * pDev;
void * addr;
};
struct kvmfrbuf
{
struct kvmfr_dev * kdev;
pgoff_t pagecount;
struct dev_pagemap * pgmap;
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;
pgoff_t pg;
for (pg = 0; pg < kbuf->pagecount; pg++)
put_page(kbuf->pages[pg]);
devm_memunmap_pages(&kbuf->kdev->dev->dev, kbuf->pgmap);
kfree(kbuf->pgmap);
kfree(kbuf->pages);
kfree(kbuf);
}
static void * kmap_kvmfrbuf(struct dma_buf * buf, unsigned long page_num)
{
struct kvmfrbuf * kbuf = (struct kvmfrbuf *)buf->priv;
struct page * page = kbuf->pages[page_num];
return kmap(page);
}
static void kunmap_kvmfrbuf(struct dma_buf * buf, unsigned long page_num, void * vaddr)
{
kunmap(vaddr);
}
static int mmap_kvmfrbuf(struct dma_buf * buf, struct vm_area_struct * vma)
{
if ((vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)
return -EINVAL;
vma->vm_ops = &kvmfr_vm_ops;
vma->vm_private_data = buf->priv;
return 0;
}
static const struct dma_buf_ops kvmfrbuf_ops =
{
.map_dma_buf = map_kvmfrbuf,
.unmap_dma_buf = unmap_kvmfrbuf,
.release = release_kvmfrbuf,
.map = kmap_kvmfrbuf,
.unmap = kunmap_kvmfrbuf,
.mmap = mmap_kvmfrbuf
};
inline static unsigned long get_min_align(void)
{
if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP))
return PAGES_PER_SUBSECTION;
else
return PAGES_PER_SECTION;
}
static long kvmfr_dmabuf_create(struct kvmfr_dev * kdev, struct file * filp, unsigned long arg)
{
const unsigned long min_align = get_min_align();
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, min_align) ||
!IS_ALIGNED(create.size , min_align))
{
printk("kvmfr: buffer not aligned to 0x%lx bytes", min_align << PAGE_SHIFT);
return -EINVAL;
}
if (create.offset + create.size > pci_resource_len(kdev->dev, 2))
return -EINVAL;
kbuf = kzalloc(sizeof(struct kvmfrbuf), GFP_KERNEL);
if (!kbuf)
return -ENOMEM;
kbuf->kdev = kdev;
kbuf->pagecount = (create.size - create.offset) >> PAGE_SHIFT;
kbuf->pgmap = kzalloc(sizeof(*kbuf->pgmap), GFP_KERNEL);
if (!kbuf->pgmap)
{
ret = -ENOMEM;
goto err;
}
kbuf->pgmap->res.start = pci_resource_start(kdev->dev, 2) + create.offset;
kbuf->pgmap->res.end = kbuf->pgmap->res.start + create.size - 1;
kbuf->pgmap->res.flags = pci_resource_flags(kdev->dev, 2);
kbuf->pgmap->type = MEMORY_DEVICE_DEVDAX;
kdev->addr = devm_memremap_pages(&kdev->dev->dev, kbuf->pgmap);
if (IS_ERR(kdev->addr))
{
ret = PTR_ERR(kdev->addr);
goto err;
}
kbuf->pages = kmalloc_array(kbuf->pagecount, sizeof(*kbuf->pages), GFP_KERNEL);
if (!kbuf->pages)
{
ret = -ENOMEM;
goto err_unmap;
}
p = kdev->addr;
for(i = 0; i < kbuf->pagecount; ++i)
{
kbuf->pages[i] = virt_to_page(p);
p += PAGE_SIZE;
}
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_unmap:
devm_memunmap_pages(&kdev->dev->dev, kbuf->pgmap);
err:
kfree(kbuf->pgmap);
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_GETALIGN:
ret = get_min_align() << PAGE_SHIFT;
break;
case KVMFR_DMABUF_GETSIZE:
ret = pci_resource_len(kdev->dev, 2);
break;
default:
return -ENOTTY;
}
return ret;
}
static struct file_operations fops =
{
.owner = THIS_MODULE,
.unlocked_ioctl = device_ioctl
};
static int kvmfr_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
{
struct uio_info *info;
struct kvmfr_dev *kdev;
info = kzalloc(sizeof(struct uio_info), GFP_KERNEL);
if (!info)
kdev = kzalloc(sizeof(struct kvmfr_dev), GFP_KERNEL);
if (!kdev)
return -ENOMEM;
kdev->dev = dev;
if (pci_enable_device(dev))
goto out_free;
if (pci_request_regions(dev, "kvmfr"))
if (pci_request_regions(dev, KVMFR_DEV_NAME))
goto out_disable;
info->mem[0].addr = pci_resource_start(dev, 2);
if (!info->mem[0].addr)
kdev->uio.mem[0].addr = pci_resource_start(dev, 2);
if (!kdev->uio.mem[0].addr)
goto out_release;
info->mem[0].internal_addr = ioremap_wt(
kdev->uio.mem[0].internal_addr = ioremap_wt(
pci_resource_start(dev, 2),
pci_resource_len (dev, 2)
);
if (!info->mem[0].internal_addr)
if (!kdev->uio.mem[0].internal_addr)
goto out_release;
info->mem[0].size = pci_resource_len(dev, 2);
info->mem[0].memtype = UIO_MEM_PHYS;
info->name = "KVMFR";
info->version = "0.0.1";
info->irq = 0;
info->irq_flags = 0;
info->handler = NULL;
kdev->uio.mem[0].size = pci_resource_len(dev, 2);
kdev->uio.mem[0].memtype = UIO_MEM_PHYS;
kdev->uio.name = KVMFR_UIO_NAME;
kdev->uio.version = KVMFR_UIO_VER;
kdev->uio.irq = 0;
kdev->uio.irq_flags = 0;
kdev->uio.handler = NULL;
if (uio_register_device(&dev->dev, info))
if (uio_register_device(&dev->dev, &kdev->uio))
goto out_unmap;
pci_set_drvdata(dev, info);
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_unreg;
}
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;
pci_set_drvdata(dev, kdev);
return 0;
out_unminor:
mutex_lock(&minor_lock);
idr_remove(&kvmfr_idr, kdev->minor);
mutex_unlock(&minor_lock);
out_unreg:
uio_unregister_device(&kdev->uio);
out_unmap:
printk("unmap\n");
iounmap(info->mem[0].internal_addr);
iounmap(kdev->uio.mem[0].internal_addr);
out_release:
printk("release\n");
pci_release_regions(dev);
out_disable:
printk("disable\n");
pci_disable_device(dev);
out_free:
printk("free\n");
kfree(info);
kfree(kdev);
return -ENODEV;
}
static void kvmfr_pci_remove(struct pci_dev *dev)
{
struct uio_info *info = pci_get_drvdata(dev);
struct kvmfr_dev *kdev = pci_get_drvdata(dev);
uio_unregister_device(info);
device_destroy(kvmfr->pClass, kdev->devNo);
mutex_lock(&minor_lock);
idr_remove(&kvmfr_idr, kdev->minor);
mutex_unlock(&minor_lock);
uio_unregister_device(&kdev->uio);
pci_release_regions(dev);
pci_disable_device(dev);
iounmap(info->mem[0].internal_addr);
iounmap(kdev->uio.mem[0].internal_addr);
kfree(info);
kfree(kdev);
}
static struct pci_device_id kvmfr_pci_ids[] =
@ -107,13 +401,57 @@ static struct pci_device_id kvmfr_pci_ids[] =
static struct pci_driver kvmfr_pci_driver =
{
.name = "kvmfr",
.name = KVMFR_DEV_NAME,
.id_table = kvmfr_pci_ids,
.probe = kvmfr_pci_probe,
.remove = kvmfr_pci_remove
};
module_pci_driver(kvmfr_pci_driver);
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 = pci_register_driver(&kvmfr_pci_driver);
if (ret < 0)
goto out_class_destroy;
return 0;
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);
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");

52
module/test.c Normal file
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@ -0,0 +1,52 @@
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/syscall.h>
#include <sys/mman.h>
#include "kvmfr.h"
int main()
{
int fd = open("/dev/kvmfr0", O_RDWR);
if (fd < 0)
{
perror("open");
return -1;
}
unsigned long size = ioctl(fd, KVMFR_DMABUF_GETSIZE , 0);
unsigned long alignment = ioctl(fd, KVMFR_DMABUF_GETALIGN, 0);
printf("Size: %lu MiB, Alignment: %lu MiB\n", size / 1024 / 1024, alignment / 1024 / 1024);
struct kvmfr_dmabuf_create create =
{
.flags = KVMFR_DMABUF_FLAG_CLOEXEC,
.offset = 0x0,
.size = size,
};
int dmaFd = ioctl(fd, KVMFR_DMABUF_CREATE, &create);
if (dmaFd < 0)
{
perror("ioctl");
return -1;
}
void * mem = mmap(NULL, create.size, PROT_READ | PROT_WRITE, MAP_SHARED, dmaFd, 0);
if (!mem)
{
perror("mmap");
return -1;
}
memset(mem, 0xAA, create.size);
munmap(mem, create.size);
close(fd);
return 0;
}