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Message-ID: <CACGkMEvTw966i2cB4u9_-SfrWG2yj7VqTXHak8YmOqpjcGfSDw@mail.gmail.com>
Date: Wed, 20 Jul 2022 17:08:26 +0800
From: Jason Wang <jasowang@...hat.com>
To: Xie Yongji <xieyongji@...edance.com>
Cc: mst <mst@...hat.com>, Liu Xiaodong <xiaodong.liu@...el.com>,
Maxime Coquelin <maxime.coquelin@...hat.com>,
Stefan Hajnoczi <stefanha@...hat.com>,
songmuchun@...edance.com,
virtualization <virtualization@...ts.linux-foundation.org>,
linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 4/5] vduse: Support registering userspace memory for
IOVA regions
On Wed, Jul 20, 2022 at 12:42 PM Xie Yongji <xieyongji@...edance.com> wrote:
>
> 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: Xie Yongji <xieyongji@...edance.com>
Acked-by: Jason Wang <jasowang@...hat.com>
> ---
> drivers/vdpa/vdpa_user/vduse_dev.c | 141 +++++++++++++++++++++++++++++
> include/uapi/linux/vduse.h | 23 +++++
> 2 files changed, 164 insertions(+)
>
> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
> index 3bc27de58f46..eedff0a3885a 100644
> --- a/drivers/vdpa/vdpa_user/vduse_dev.c
> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> @@ -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(¤t->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, ¤t->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);
> diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h
> index 7cfe1c1280c0..9885e0571f09 100644
> --- a/include/uapi/linux/vduse.h
> +++ b/include/uapi/linux/vduse.h
> @@ -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 */
>
> /**
> --
> 2.20.1
>
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