Commit 79a463be authored by Xie Yongji's avatar Xie Yongji Committed by Michael S. Tsirkin
Browse files

vduse: Support registering userspace memory for IOVA regions 



Introduce two ioctls: VDUSE_IOTLB_REG_UMEM and
VDUSE_IOTLB_DEREG_UMEM to support registering
and de-registering userspace memory for IOVA
regions.

Now it only supports registering userspace memory
for bounce buffer region in virtio-vdpa case.

Signed-off-by: default avatarXie Yongji <xieyongji@bytedance.com>
Acked-by: default avatarJason Wang <jasowang@redhat.com>
Message-Id: <20220803045523.23851-5-xieyongji@bytedance.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 6c77ed22

drivers/vdpa/vdpa_user/vduse_dev.c

+141 −0
Original line number Diff line number Diff line
@@ -21,6 +21,8 @@ 
#include <linux/uio.h>

#include <linux/vdpa.h>

#include <linux/nospec.h>

#include <linux/vmalloc.h>

#include <linux/sched/mm.h>

#include <uapi/linux/vduse.h>

#include <uapi/linux/vdpa.h>

#include <uapi/linux/virtio_config.h>
@@ -64,6 +66,13 @@ struct vduse_vdpa { 
	struct vduse_dev *dev;

};



struct vduse_umem {

	unsigned long iova;

	unsigned long npages;

	struct page **pages;

	struct mm_struct *mm;

};



struct vduse_dev {

	struct vduse_vdpa *vdev;

	struct device *dev;
@@ -95,6 +104,8 @@ struct vduse_dev { 
	u8 status;

	u32 vq_num;

	u32 vq_align;

	struct vduse_umem *umem;

	struct mutex mem_lock;

};



struct vduse_dev_msg {
@@ -917,6 +928,102 @@ static int vduse_dev_queue_irq_work(struct vduse_dev *dev, 
	return ret;

}



static int vduse_dev_dereg_umem(struct vduse_dev *dev,

				u64 iova, u64 size)

{

	int ret;



	mutex_lock(&dev->mem_lock);

	ret = -ENOENT;

	if (!dev->umem)

		goto unlock;



	ret = -EINVAL;

	if (dev->umem->iova != iova || size != dev->domain->bounce_size)

		goto unlock;



	vduse_domain_remove_user_bounce_pages(dev->domain);

	unpin_user_pages_dirty_lock(dev->umem->pages,

				    dev->umem->npages, true);

	atomic64_sub(dev->umem->npages, &dev->umem->mm->pinned_vm);

	mmdrop(dev->umem->mm);

	vfree(dev->umem->pages);

	kfree(dev->umem);

	dev->umem = NULL;

	ret = 0;

unlock:

	mutex_unlock(&dev->mem_lock);

	return ret;

}



static int vduse_dev_reg_umem(struct vduse_dev *dev,

			      u64 iova, u64 uaddr, u64 size)

{

	struct page **page_list = NULL;

	struct vduse_umem *umem = NULL;

	long pinned = 0;

	unsigned long npages, lock_limit;

	int ret;



	if (!dev->domain->bounce_map ||

	    size != dev->domain->bounce_size ||

	    iova != 0 || uaddr & ~PAGE_MASK)

		return -EINVAL;



	mutex_lock(&dev->mem_lock);

	ret = -EEXIST;

	if (dev->umem)

		goto unlock;



	ret = -ENOMEM;

	npages = size >> PAGE_SHIFT;

	page_list = __vmalloc(array_size(npages, sizeof(struct page *)),

			      GFP_KERNEL_ACCOUNT);

	umem = kzalloc(sizeof(*umem), GFP_KERNEL);

	if (!page_list || !umem)

		goto unlock;



	mmap_read_lock(current->mm);



	lock_limit = PFN_DOWN(rlimit(RLIMIT_MEMLOCK));

	if (npages + atomic64_read(&current->mm->pinned_vm) > lock_limit)

		goto out;



	pinned = pin_user_pages(uaddr, npages, FOLL_LONGTERM | FOLL_WRITE,

				page_list, NULL);

	if (pinned != npages) {

		ret = pinned < 0 ? pinned : -ENOMEM;

		goto out;

	}



	ret = vduse_domain_add_user_bounce_pages(dev->domain,

						 page_list, pinned);

	if (ret)

		goto out;



	atomic64_add(npages, &current->mm->pinned_vm);



	umem->pages = page_list;

	umem->npages = pinned;

	umem->iova = iova;

	umem->mm = current->mm;

	mmgrab(current->mm);



	dev->umem = umem;

out:

	if (ret && pinned > 0)

		unpin_user_pages(page_list, pinned);



	mmap_read_unlock(current->mm);

unlock:

	if (ret) {

		vfree(page_list);

		kfree(umem);

	}

	mutex_unlock(&dev->mem_lock);

	return ret;

}



static long vduse_dev_ioctl(struct file *file, unsigned int cmd,

			    unsigned long arg)

{
@@ -1089,6 +1196,38 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd, 
		ret = vduse_dev_queue_irq_work(dev, &dev->vqs[index].inject);

		break;

	}

	case VDUSE_IOTLB_REG_UMEM: {

		struct vduse_iova_umem umem;



		ret = -EFAULT;

		if (copy_from_user(&umem, argp, sizeof(umem)))

			break;



		ret = -EINVAL;

		if (!is_mem_zero((const char *)umem.reserved,

				 sizeof(umem.reserved)))

			break;



		ret = vduse_dev_reg_umem(dev, umem.iova,

					 umem.uaddr, umem.size);

		break;

	}

	case VDUSE_IOTLB_DEREG_UMEM: {

		struct vduse_iova_umem umem;



		ret = -EFAULT;

		if (copy_from_user(&umem, argp, sizeof(umem)))

			break;



		ret = -EINVAL;

		if (!is_mem_zero((const char *)umem.reserved,

				 sizeof(umem.reserved)))

			break;



		ret = vduse_dev_dereg_umem(dev, umem.iova,

					   umem.size);

		break;

	}

	default:

		ret = -ENOIOCTLCMD;

		break;
@@ -1101,6 +1240,7 @@ static int vduse_dev_release(struct inode *inode, struct file *file) 
{

	struct vduse_dev *dev = file->private_data;



	vduse_dev_dereg_umem(dev, 0, dev->domain->bounce_size);

	spin_lock(&dev->msg_lock);

	/* Make sure the inflight messages can processed after reconncection */

	list_splice_init(&dev->recv_list, &dev->send_list);
@@ -1163,6 +1303,7 @@ static struct vduse_dev *vduse_dev_create(void) 
		return NULL;



	mutex_init(&dev->lock);

	mutex_init(&dev->mem_lock);

	spin_lock_init(&dev->msg_lock);

	INIT_LIST_HEAD(&dev->send_list);

	INIT_LIST_HEAD(&dev->recv_list);

include/uapi/linux/vduse.h

+23 −0
Original line number Diff line number Diff line
@@ -210,6 +210,29 @@ struct vduse_vq_eventfd { 
 */

#define VDUSE_VQ_INJECT_IRQ	_IOW(VDUSE_BASE, 0x17, __u32)



/**

 * struct vduse_iova_umem - userspace memory configuration for one IOVA region

 * @uaddr: start address of userspace memory, it must be aligned to page size

 * @iova: start of the IOVA region

 * @size: size of the IOVA region

 * @reserved: for future use, needs to be initialized to zero

 *

 * Structure used by VDUSE_IOTLB_REG_UMEM and VDUSE_IOTLB_DEREG_UMEM

 * ioctls to register/de-register userspace memory for IOVA regions

 */

struct vduse_iova_umem {

	__u64 uaddr;

	__u64 iova;

	__u64 size;

	__u64 reserved[3];

};



/* Register userspace memory for IOVA regions */

#define VDUSE_IOTLB_REG_UMEM	_IOW(VDUSE_BASE, 0x18, struct vduse_iova_umem)



/* De-register the userspace memory. Caller should set iova and size field. */

#define VDUSE_IOTLB_DEREG_UMEM	_IOW(VDUSE_BASE, 0x19, struct vduse_iova_umem)



/* The control messages definition for read(2)/write(2) on /dev/vduse/$NAME */



/**