| Message ID | 20230602121653.80017-19-yi.l.liu@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add vfio_device cdev for iommufd support | expand |
On Fri, 2 Jun 2023 05:16:47 -0700 Yi Liu <yi.l.liu@intel.com> wrote: > This adds ioctl for userspace to bind device cdev fd to iommufd. > > VFIO_DEVICE_BIND_IOMMUFD: bind device to an iommufd, hence gain DMA > control provided by the iommufd. open_device > op is called after bind_iommufd op. > > Tested-by: Yanting Jiang <yanting.jiang@intel.com> > Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> > Tested-by: Terrence Xu <terrence.xu@intel.com> > Signed-off-by: Yi Liu <yi.l.liu@intel.com> > --- > drivers/vfio/device_cdev.c | 123 +++++++++++++++++++++++++++++++++++++ > drivers/vfio/vfio.h | 13 ++++ > drivers/vfio/vfio_main.c | 5 ++ > include/linux/vfio.h | 3 +- > include/uapi/linux/vfio.h | 27 ++++++++ > 5 files changed, 170 insertions(+), 1 deletion(-) > > diff --git a/drivers/vfio/device_cdev.c b/drivers/vfio/device_cdev.c > index 1c640016a824..a4498ddbe774 100644 > --- a/drivers/vfio/device_cdev.c > +++ b/drivers/vfio/device_cdev.c > @@ -3,6 +3,7 @@ > * Copyright (c) 2023 Intel Corporation. > */ > #include <linux/vfio.h> > +#include <linux/iommufd.h> > > #include "vfio.h" > > @@ -44,6 +45,128 @@ int vfio_device_fops_cdev_open(struct inode *inode, struct file *filep) > return ret; > } > > +static void vfio_device_get_kvm_safe(struct vfio_device_file *df) > +{ > + spin_lock(&df->kvm_ref_lock); > + if (df->kvm) > + _vfio_device_get_kvm_safe(df->device, df->kvm); > + spin_unlock(&df->kvm_ref_lock); > +} > + > +void vfio_df_cdev_close(struct vfio_device_file *df) > +{ > + struct vfio_device *device = df->device; > + > + /* > + * In the time of close, there is no contention with another one > + * changing this flag. So read df->access_granted without lock > + * and no smp_load_acquire() is ok. > + */ > + if (!df->access_granted) > + return; > + > + mutex_lock(&device->dev_set->lock); > + vfio_df_close(df); > + vfio_device_put_kvm(device); > + iommufd_ctx_put(df->iommufd); > + device->cdev_opened = false; > + mutex_unlock(&device->dev_set->lock); > + vfio_device_unblock_group(device); > +} > + > +static struct iommufd_ctx *vfio_get_iommufd_from_fd(int fd) > +{ > + struct iommufd_ctx *iommufd; > + struct fd f; > + > + f = fdget(fd); > + if (!f.file) > + return ERR_PTR(-EBADF); > + > + iommufd = iommufd_ctx_from_file(f.file); > + > + fdput(f); > + return iommufd; > +} > + > +long vfio_df_ioctl_bind_iommufd(struct vfio_device_file *df, > + struct vfio_device_bind_iommufd __user *arg) > +{ > + struct vfio_device *device = df->device; > + struct vfio_device_bind_iommufd bind; > + unsigned long minsz; > + int ret; > + > + static_assert(__same_type(arg->out_devid, df->devid)); > + > + minsz = offsetofend(struct vfio_device_bind_iommufd, out_devid); > + > + if (copy_from_user(&bind, arg, minsz)) > + return -EFAULT; > + > + if (bind.argsz < minsz || bind.flags || bind.iommufd < 0) > + return -EINVAL; > + > + /* BIND_IOMMUFD only allowed for cdev fds */ > + if (df->group) > + return -EINVAL; > + > + ret = vfio_device_block_group(device); > + if (ret) > + return ret; > + > + mutex_lock(&device->dev_set->lock); > + /* one device cannot be bound twice */ > + if (df->access_granted) { > + ret = -EINVAL; > + goto out_unlock; > + } > + > + df->iommufd = vfio_get_iommufd_from_fd(bind.iommufd); > + if (IS_ERR(df->iommufd)) { > + ret = PTR_ERR(df->iommufd); > + df->iommufd = NULL; > + goto out_unlock; > + } > + > + /* > + * Before the device open, get the KVM pointer currently > + * associated with the device file (if there is) and obtain > + * a reference. This reference is held until device closed. > + * Save the pointer in the device for use by drivers. > + */ > + vfio_device_get_kvm_safe(df); > + > + ret = vfio_df_open(df); > + if (ret) > + goto out_put_kvm; > + > + ret = copy_to_user(&arg->out_devid, &df->devid, > + sizeof(df->devid)) ? -EFAULT : 0; > + if (ret) > + goto out_close_device; > + > + /* > + * Paired with smp_load_acquire() in vfio_device_fops::ioctl/ > + * read/write/mmap > + */ > + smp_store_release(&df->access_granted, true); > + device->cdev_opened = true; > + mutex_unlock(&device->dev_set->lock); > + return 0; > + > +out_close_device: > + vfio_df_close(df); > +out_put_kvm: > + vfio_device_put_kvm(device); > + iommufd_ctx_put(df->iommufd); > + df->iommufd = NULL; > +out_unlock: > + mutex_unlock(&device->dev_set->lock); > + vfio_device_unblock_group(device); > + return ret; > +} > + > static char *vfio_device_devnode(const struct device *dev, umode_t *mode) > { > return kasprintf(GFP_KERNEL, "vfio/devices/%s", dev_name(dev)); > diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h > index d12b5b524bfc..42de40d2cd4d 100644 > --- a/drivers/vfio/vfio.h > +++ b/drivers/vfio/vfio.h > @@ -287,6 +287,9 @@ static inline void vfio_device_del(struct vfio_device *device) > } > > int vfio_device_fops_cdev_open(struct inode *inode, struct file *filep); > +void vfio_df_cdev_close(struct vfio_device_file *df); > +long vfio_df_ioctl_bind_iommufd(struct vfio_device_file *df, > + struct vfio_device_bind_iommufd __user *arg); > int vfio_cdev_init(struct class *device_class); > void vfio_cdev_cleanup(void); > #else > @@ -310,6 +313,16 @@ static inline int vfio_device_fops_cdev_open(struct inode *inode, > return 0; > } > > +static inline void vfio_df_cdev_close(struct vfio_device_file *df) > +{ > +} > + > +static inline long vfio_df_ioctl_bind_iommufd(struct vfio_device_file *df, > + struct vfio_device_bind_iommufd __user *arg) > +{ > + return -EOPNOTSUPP; > +} > + > static inline int vfio_cdev_init(struct class *device_class) > { > return 0; > diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c > index ef55af75f459..9ba4d420eda2 100644 > --- a/drivers/vfio/vfio_main.c > +++ b/drivers/vfio/vfio_main.c > @@ -572,6 +572,8 @@ static int vfio_device_fops_release(struct inode *inode, struct file *filep) > > if (df->group) > vfio_df_group_close(df); > + else > + vfio_df_cdev_close(df); > > vfio_device_put_registration(device); > > @@ -1145,6 +1147,9 @@ static long vfio_device_fops_unl_ioctl(struct file *filep, > struct vfio_device *device = df->device; > int ret; > > + if (cmd == VFIO_DEVICE_BIND_IOMMUFD) > + return vfio_df_ioctl_bind_iommufd(df, (void __user *)arg); > + > /* Paired with smp_store_release() following vfio_df_open() */ > if (!smp_load_acquire(&df->access_granted)) > return -EINVAL; > diff --git a/include/linux/vfio.h b/include/linux/vfio.h > index 83cc5dc28b7a..e80a8ac86e46 100644 > --- a/include/linux/vfio.h > +++ b/include/linux/vfio.h > @@ -66,6 +66,7 @@ struct vfio_device { > struct iommufd_device *iommufd_device; > bool iommufd_attached; > #endif > + bool cdev_opened:1; Perhaps a more strongly defined data type here as well and roll iommufd_attached into the same bit field scheme. > }; > > /** > @@ -170,7 +171,7 @@ vfio_iommufd_device_hot_reset_devid(struct vfio_device *vdev, > > static inline bool vfio_device_cdev_opened(struct vfio_device *device) > { > - return false; > + return device->cdev_opened; > } > > /** > diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h > index f753124e1c82..7296012b7f36 100644 > --- a/include/uapi/linux/vfio.h > +++ b/include/uapi/linux/vfio.h > @@ -194,6 +194,33 @@ struct vfio_group_status { > > /* --------------- IOCTLs for DEVICE file descriptors --------------- */ > > +/* > + * VFIO_DEVICE_BIND_IOMMUFD - _IOR(VFIO_TYPE, VFIO_BASE + 18, > + * struct vfio_device_bind_iommufd) > + * @argsz: User filled size of this data. > + * @flags: Must be 0. > + * @iommufd: iommufd to bind. > + * @out_devid: The device id generated by this bind. devid is a handle for > + * this device/iommufd bond and can be used in IOMMUFD commands. > + * > + * Bind a vfio_device to the specified iommufd. > + * > + * User is restricted from accessing the device before the binding operation > + * is completed. > + * > + * Unbind is automatically conducted when device fd is closed. > + * > + * Return: 0 on success, -errno on failure. > + */ > +struct vfio_device_bind_iommufd { > + __u32 argsz; > + __u32 flags; > + __s32 iommufd; > + __u32 out_devid; > +}; > + > +#define VFIO_DEVICE_BIND_IOMMUFD _IO(VFIO_TYPE, VFIO_BASE + 18) > + Why are we still defining device ioctls 18-20 before existing device ioctls? 18 should be defined after 17... Thanks, Alex > /** > * VFIO_DEVICE_GET_INFO - _IOR(VFIO_TYPE, VFIO_BASE + 7, > * struct vfio_device_info)
> From: Alex Williamson <alex.williamson@redhat.com> > Sent: Tuesday, June 13, 2023 6:27 AM > > On Fri, 2 Jun 2023 05:16:47 -0700 > Yi Liu <yi.l.liu@intel.com> wrote: > > > This adds ioctl for userspace to bind device cdev fd to iommufd. > > > > VFIO_DEVICE_BIND_IOMMUFD: bind device to an iommufd, hence gain DMA > > control provided by the iommufd. open_device > > op is called after bind_iommufd op. > > > > Tested-by: Yanting Jiang <yanting.jiang@intel.com> > > Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> > > Tested-by: Terrence Xu <terrence.xu@intel.com> > > Signed-off-by: Yi Liu <yi.l.liu@intel.com> > > --- > > drivers/vfio/device_cdev.c | 123 +++++++++++++++++++++++++++++++++++++ > > drivers/vfio/vfio.h | 13 ++++ > > drivers/vfio/vfio_main.c | 5 ++ > > include/linux/vfio.h | 3 +- > > include/uapi/linux/vfio.h | 27 ++++++++ > > 5 files changed, 170 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/vfio/device_cdev.c b/drivers/vfio/device_cdev.c > > index 1c640016a824..a4498ddbe774 100644 > > --- a/drivers/vfio/device_cdev.c > > +++ b/drivers/vfio/device_cdev.c > > @@ -3,6 +3,7 @@ > > * Copyright (c) 2023 Intel Corporation. > > */ > > #include <linux/vfio.h> > > +#include <linux/iommufd.h> > > > > #include "vfio.h" > > > > @@ -44,6 +45,128 @@ int vfio_device_fops_cdev_open(struct inode *inode, struct > file *filep) > > return ret; > > } > > > > +static void vfio_device_get_kvm_safe(struct vfio_device_file *df) > > +{ > > + spin_lock(&df->kvm_ref_lock); > > + if (df->kvm) > > + _vfio_device_get_kvm_safe(df->device, df->kvm); > > + spin_unlock(&df->kvm_ref_lock); > > +} > > + > > +void vfio_df_cdev_close(struct vfio_device_file *df) > > +{ > > + struct vfio_device *device = df->device; > > + > > + /* > > + * In the time of close, there is no contention with another one > > + * changing this flag. So read df->access_granted without lock > > + * and no smp_load_acquire() is ok. > > + */ > > + if (!df->access_granted) > > + return; > > + > > + mutex_lock(&device->dev_set->lock); > > + vfio_df_close(df); > > + vfio_device_put_kvm(device); > > + iommufd_ctx_put(df->iommufd); > > + device->cdev_opened = false; > > + mutex_unlock(&device->dev_set->lock); > > + vfio_device_unblock_group(device); > > +} > > + > > +static struct iommufd_ctx *vfio_get_iommufd_from_fd(int fd) > > +{ > > + struct iommufd_ctx *iommufd; > > + struct fd f; > > + > > + f = fdget(fd); > > + if (!f.file) > > + return ERR_PTR(-EBADF); > > + > > + iommufd = iommufd_ctx_from_file(f.file); > > + > > + fdput(f); > > + return iommufd; > > +} > > + > > +long vfio_df_ioctl_bind_iommufd(struct vfio_device_file *df, > > + struct vfio_device_bind_iommufd __user *arg) > > +{ > > + struct vfio_device *device = df->device; > > + struct vfio_device_bind_iommufd bind; > > + unsigned long minsz; > > + int ret; > > + > > + static_assert(__same_type(arg->out_devid, df->devid)); > > + > > + minsz = offsetofend(struct vfio_device_bind_iommufd, out_devid); > > + > > + if (copy_from_user(&bind, arg, minsz)) > > + return -EFAULT; > > + > > + if (bind.argsz < minsz || bind.flags || bind.iommufd < 0) > > + return -EINVAL; > > + > > + /* BIND_IOMMUFD only allowed for cdev fds */ > > + if (df->group) > > + return -EINVAL; > > + > > + ret = vfio_device_block_group(device); > > + if (ret) > > + return ret; > > + > > + mutex_lock(&device->dev_set->lock); > > + /* one device cannot be bound twice */ > > + if (df->access_granted) { > > + ret = -EINVAL; > > + goto out_unlock; > > + } > > + > > + df->iommufd = vfio_get_iommufd_from_fd(bind.iommufd); > > + if (IS_ERR(df->iommufd)) { > > + ret = PTR_ERR(df->iommufd); > > + df->iommufd = NULL; > > + goto out_unlock; > > + } > > + > > + /* > > + * Before the device open, get the KVM pointer currently > > + * associated with the device file (if there is) and obtain > > + * a reference. This reference is held until device closed. > > + * Save the pointer in the device for use by drivers. > > + */ > > + vfio_device_get_kvm_safe(df); > > + > > + ret = vfio_df_open(df); > > + if (ret) > > + goto out_put_kvm; > > + > > + ret = copy_to_user(&arg->out_devid, &df->devid, > > + sizeof(df->devid)) ? -EFAULT : 0; > > + if (ret) > > + goto out_close_device; > > + > > + /* > > + * Paired with smp_load_acquire() in vfio_device_fops::ioctl/ > > + * read/write/mmap > > + */ > > + smp_store_release(&df->access_granted, true); > > + device->cdev_opened = true; > > + mutex_unlock(&device->dev_set->lock); > > + return 0; > > + > > +out_close_device: > > + vfio_df_close(df); > > +out_put_kvm: > > + vfio_device_put_kvm(device); > > + iommufd_ctx_put(df->iommufd); > > + df->iommufd = NULL; > > +out_unlock: > > + mutex_unlock(&device->dev_set->lock); > > + vfio_device_unblock_group(device); > > + return ret; > > +} > > + > > static char *vfio_device_devnode(const struct device *dev, umode_t *mode) > > { > > return kasprintf(GFP_KERNEL, "vfio/devices/%s", dev_name(dev)); > > diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h > > index d12b5b524bfc..42de40d2cd4d 100644 > > --- a/drivers/vfio/vfio.h > > +++ b/drivers/vfio/vfio.h > > @@ -287,6 +287,9 @@ static inline void vfio_device_del(struct vfio_device *device) > > } > > > > int vfio_device_fops_cdev_open(struct inode *inode, struct file *filep); > > +void vfio_df_cdev_close(struct vfio_device_file *df); > > +long vfio_df_ioctl_bind_iommufd(struct vfio_device_file *df, > > + struct vfio_device_bind_iommufd __user *arg); > > int vfio_cdev_init(struct class *device_class); > > void vfio_cdev_cleanup(void); > > #else > > @@ -310,6 +313,16 @@ static inline int vfio_device_fops_cdev_open(struct inode > *inode, > > return 0; > > } > > > > +static inline void vfio_df_cdev_close(struct vfio_device_file *df) > > +{ > > +} > > + > > +static inline long vfio_df_ioctl_bind_iommufd(struct vfio_device_file *df, > > + struct vfio_device_bind_iommufd __user > *arg) > > +{ > > + return -EOPNOTSUPP; > > +} > > + > > static inline int vfio_cdev_init(struct class *device_class) > > { > > return 0; > > diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c > > index ef55af75f459..9ba4d420eda2 100644 > > --- a/drivers/vfio/vfio_main.c > > +++ b/drivers/vfio/vfio_main.c > > @@ -572,6 +572,8 @@ static int vfio_device_fops_release(struct inode *inode, struct > file *filep) > > > > if (df->group) > > vfio_df_group_close(df); > > + else > > + vfio_df_cdev_close(df); > > > > vfio_device_put_registration(device); > > > > @@ -1145,6 +1147,9 @@ static long vfio_device_fops_unl_ioctl(struct file *filep, > > struct vfio_device *device = df->device; > > int ret; > > > > + if (cmd == VFIO_DEVICE_BIND_IOMMUFD) > > + return vfio_df_ioctl_bind_iommufd(df, (void __user *)arg); > > + > > /* Paired with smp_store_release() following vfio_df_open() */ > > if (!smp_load_acquire(&df->access_granted)) > > return -EINVAL; > > diff --git a/include/linux/vfio.h b/include/linux/vfio.h > > index 83cc5dc28b7a..e80a8ac86e46 100644 > > --- a/include/linux/vfio.h > > +++ b/include/linux/vfio.h > > @@ -66,6 +66,7 @@ struct vfio_device { > > struct iommufd_device *iommufd_device; > > bool iommufd_attached; > > #endif > > + bool cdev_opened:1; > > Perhaps a more strongly defined data type here as well and roll > iommufd_attached into the same bit field scheme. Ok, then needs to make iommufd_attached always defined. > > > }; > > > > /** > > @@ -170,7 +171,7 @@ vfio_iommufd_device_hot_reset_devid(struct vfio_device > *vdev, > > > > static inline bool vfio_device_cdev_opened(struct vfio_device *device) > > { > > - return false; > > + return device->cdev_opened; > > } > > > > /** > > diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h > > index f753124e1c82..7296012b7f36 100644 > > --- a/include/uapi/linux/vfio.h > > +++ b/include/uapi/linux/vfio.h > > @@ -194,6 +194,33 @@ struct vfio_group_status { > > > > /* --------------- IOCTLs for DEVICE file descriptors --------------- */ > > > > +/* > > + * VFIO_DEVICE_BIND_IOMMUFD - _IOR(VFIO_TYPE, VFIO_BASE + 18, > > + * struct vfio_device_bind_iommufd) > > + * @argsz: User filled size of this data. > > + * @flags: Must be 0. > > + * @iommufd: iommufd to bind. > > + * @out_devid: The device id generated by this bind. devid is a handle for > > + * this device/iommufd bond and can be used in IOMMUFD commands. > > + * > > + * Bind a vfio_device to the specified iommufd. > > + * > > + * User is restricted from accessing the device before the binding operation > > + * is completed. > > + * > > + * Unbind is automatically conducted when device fd is closed. > > + * > > + * Return: 0 on success, -errno on failure. > > + */ > > +struct vfio_device_bind_iommufd { > > + __u32 argsz; > > + __u32 flags; > > + __s32 iommufd; > > + __u32 out_devid; > > +}; > > + > > +#define VFIO_DEVICE_BIND_IOMMUFD _IO(VFIO_TYPE, VFIO_BASE + 18) > > + > > Why are we still defining device ioctls 18-20 before existing device > ioctls? 18 should be defined after 17... Thanks, Yes. I put it here as it is supposed to be the first doable ioctl for cdev fds. But you are right, it should be ordered by offset. Regards, Yi Liu > Alex > > > /** > > * VFIO_DEVICE_GET_INFO - _IOR(VFIO_TYPE, VFIO_BASE + 7, > > * struct vfio_device_info)
On Tue, 13 Jun 2023 05:48:46 +0000 "Liu, Yi L" <yi.l.liu@intel.com> wrote: > > From: Alex Williamson <alex.williamson@redhat.com> > > Sent: Tuesday, June 13, 2023 6:27 AM > > > > On Fri, 2 Jun 2023 05:16:47 -0700 > > Yi Liu <yi.l.liu@intel.com> wrote: > > > > > This adds ioctl for userspace to bind device cdev fd to iommufd. > > > > > > VFIO_DEVICE_BIND_IOMMUFD: bind device to an iommufd, hence gain DMA > > > control provided by the iommufd. open_device > > > op is called after bind_iommufd op. > > > > > > Tested-by: Yanting Jiang <yanting.jiang@intel.com> > > > Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> > > > Tested-by: Terrence Xu <terrence.xu@intel.com> > > > Signed-off-by: Yi Liu <yi.l.liu@intel.com> > > > --- > > > drivers/vfio/device_cdev.c | 123 +++++++++++++++++++++++++++++++++++++ > > > drivers/vfio/vfio.h | 13 ++++ > > > drivers/vfio/vfio_main.c | 5 ++ > > > include/linux/vfio.h | 3 +- > > > include/uapi/linux/vfio.h | 27 ++++++++ > > > 5 files changed, 170 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/vfio/device_cdev.c b/drivers/vfio/device_cdev.c > > > index 1c640016a824..a4498ddbe774 100644 > > > --- a/drivers/vfio/device_cdev.c > > > +++ b/drivers/vfio/device_cdev.c > > > @@ -3,6 +3,7 @@ > > > * Copyright (c) 2023 Intel Corporation. > > > */ > > > #include <linux/vfio.h> > > > +#include <linux/iommufd.h> > > > > > > #include "vfio.h" > > > > > > @@ -44,6 +45,128 @@ int vfio_device_fops_cdev_open(struct inode *inode, struct > > file *filep) > > > return ret; > > > } > > > > > > +static void vfio_device_get_kvm_safe(struct vfio_device_file *df) > > > +{ > > > + spin_lock(&df->kvm_ref_lock); > > > + if (df->kvm) > > > + _vfio_device_get_kvm_safe(df->device, df->kvm); > > > + spin_unlock(&df->kvm_ref_lock); > > > +} > > > + > > > +void vfio_df_cdev_close(struct vfio_device_file *df) > > > +{ > > > + struct vfio_device *device = df->device; > > > + > > > + /* > > > + * In the time of close, there is no contention with another one > > > + * changing this flag. So read df->access_granted without lock > > > + * and no smp_load_acquire() is ok. > > > + */ > > > + if (!df->access_granted) > > > + return; > > > + > > > + mutex_lock(&device->dev_set->lock); > > > + vfio_df_close(df); > > > + vfio_device_put_kvm(device); > > > + iommufd_ctx_put(df->iommufd); > > > + device->cdev_opened = false; > > > + mutex_unlock(&device->dev_set->lock); > > > + vfio_device_unblock_group(device); > > > +} > > > + > > > +static struct iommufd_ctx *vfio_get_iommufd_from_fd(int fd) > > > +{ > > > + struct iommufd_ctx *iommufd; > > > + struct fd f; > > > + > > > + f = fdget(fd); > > > + if (!f.file) > > > + return ERR_PTR(-EBADF); > > > + > > > + iommufd = iommufd_ctx_from_file(f.file); > > > + > > > + fdput(f); > > > + return iommufd; > > > +} > > > + > > > +long vfio_df_ioctl_bind_iommufd(struct vfio_device_file *df, > > > + struct vfio_device_bind_iommufd __user *arg) > > > +{ > > > + struct vfio_device *device = df->device; > > > + struct vfio_device_bind_iommufd bind; > > > + unsigned long minsz; > > > + int ret; > > > + > > > + static_assert(__same_type(arg->out_devid, df->devid)); > > > + > > > + minsz = offsetofend(struct vfio_device_bind_iommufd, out_devid); > > > + > > > + if (copy_from_user(&bind, arg, minsz)) > > > + return -EFAULT; > > > + > > > + if (bind.argsz < minsz || bind.flags || bind.iommufd < 0) > > > + return -EINVAL; > > > + > > > + /* BIND_IOMMUFD only allowed for cdev fds */ > > > + if (df->group) > > > + return -EINVAL; > > > + > > > + ret = vfio_device_block_group(device); > > > + if (ret) > > > + return ret; > > > + > > > + mutex_lock(&device->dev_set->lock); > > > + /* one device cannot be bound twice */ > > > + if (df->access_granted) { > > > + ret = -EINVAL; > > > + goto out_unlock; > > > + } > > > + > > > + df->iommufd = vfio_get_iommufd_from_fd(bind.iommufd); > > > + if (IS_ERR(df->iommufd)) { > > > + ret = PTR_ERR(df->iommufd); > > > + df->iommufd = NULL; > > > + goto out_unlock; > > > + } > > > + > > > + /* > > > + * Before the device open, get the KVM pointer currently > > > + * associated with the device file (if there is) and obtain > > > + * a reference. This reference is held until device closed. > > > + * Save the pointer in the device for use by drivers. > > > + */ > > > + vfio_device_get_kvm_safe(df); > > > + > > > + ret = vfio_df_open(df); > > > + if (ret) > > > + goto out_put_kvm; > > > + > > > + ret = copy_to_user(&arg->out_devid, &df->devid, > > > + sizeof(df->devid)) ? -EFAULT : 0; > > > + if (ret) > > > + goto out_close_device; > > > + > > > + /* > > > + * Paired with smp_load_acquire() in vfio_device_fops::ioctl/ > > > + * read/write/mmap > > > + */ > > > + smp_store_release(&df->access_granted, true); > > > + device->cdev_opened = true; > > > + mutex_unlock(&device->dev_set->lock); > > > + return 0; > > > + > > > +out_close_device: > > > + vfio_df_close(df); > > > +out_put_kvm: > > > + vfio_device_put_kvm(device); > > > + iommufd_ctx_put(df->iommufd); > > > + df->iommufd = NULL; > > > +out_unlock: > > > + mutex_unlock(&device->dev_set->lock); > > > + vfio_device_unblock_group(device); > > > + return ret; > > > +} > > > + > > > static char *vfio_device_devnode(const struct device *dev, umode_t *mode) > > > { > > > return kasprintf(GFP_KERNEL, "vfio/devices/%s", dev_name(dev)); > > > diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h > > > index d12b5b524bfc..42de40d2cd4d 100644 > > > --- a/drivers/vfio/vfio.h > > > +++ b/drivers/vfio/vfio.h > > > @@ -287,6 +287,9 @@ static inline void vfio_device_del(struct vfio_device *device) > > > } > > > > > > int vfio_device_fops_cdev_open(struct inode *inode, struct file *filep); > > > +void vfio_df_cdev_close(struct vfio_device_file *df); > > > +long vfio_df_ioctl_bind_iommufd(struct vfio_device_file *df, > > > + struct vfio_device_bind_iommufd __user *arg); > > > int vfio_cdev_init(struct class *device_class); > > > void vfio_cdev_cleanup(void); > > > #else > > > @@ -310,6 +313,16 @@ static inline int vfio_device_fops_cdev_open(struct inode > > *inode, > > > return 0; > > > } > > > > > > +static inline void vfio_df_cdev_close(struct vfio_device_file *df) > > > +{ > > > +} > > > + > > > +static inline long vfio_df_ioctl_bind_iommufd(struct vfio_device_file *df, > > > + struct vfio_device_bind_iommufd __user > > *arg) > > > +{ > > > + return -EOPNOTSUPP; > > > +} > > > + > > > static inline int vfio_cdev_init(struct class *device_class) > > > { > > > return 0; > > > diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c > > > index ef55af75f459..9ba4d420eda2 100644 > > > --- a/drivers/vfio/vfio_main.c > > > +++ b/drivers/vfio/vfio_main.c > > > @@ -572,6 +572,8 @@ static int vfio_device_fops_release(struct inode *inode, struct > > file *filep) > > > > > > if (df->group) > > > vfio_df_group_close(df); > > > + else > > > + vfio_df_cdev_close(df); > > > > > > vfio_device_put_registration(device); > > > > > > @@ -1145,6 +1147,9 @@ static long vfio_device_fops_unl_ioctl(struct file *filep, > > > struct vfio_device *device = df->device; > > > int ret; > > > > > > + if (cmd == VFIO_DEVICE_BIND_IOMMUFD) > > > + return vfio_df_ioctl_bind_iommufd(df, (void __user *)arg); > > > + > > > /* Paired with smp_store_release() following vfio_df_open() */ > > > if (!smp_load_acquire(&df->access_granted)) > > > return -EINVAL; > > > diff --git a/include/linux/vfio.h b/include/linux/vfio.h > > > index 83cc5dc28b7a..e80a8ac86e46 100644 > > > --- a/include/linux/vfio.h > > > +++ b/include/linux/vfio.h > > > @@ -66,6 +66,7 @@ struct vfio_device { > > > struct iommufd_device *iommufd_device; > > > bool iommufd_attached; > > > #endif > > > + bool cdev_opened:1; > > > > Perhaps a more strongly defined data type here as well and roll > > iommufd_attached into the same bit field scheme. > > Ok, then needs to make iommufd_attached always defined. That does not follow. Thanks, Alex
> From: Alex Williamson <alex.williamson@redhat.com> > Sent: Tuesday, June 13, 2023 10:18 PM > > > > diff --git a/include/linux/vfio.h b/include/linux/vfio.h > > > > index 83cc5dc28b7a..e80a8ac86e46 100644 > > > > --- a/include/linux/vfio.h > > > > +++ b/include/linux/vfio.h > > > > @@ -66,6 +66,7 @@ struct vfio_device { > > > > struct iommufd_device *iommufd_device; > > > > bool iommufd_attached; > > > > #endif > > > > + bool cdev_opened:1; > > > > > > Perhaps a more strongly defined data type here as well and roll > > > iommufd_attached into the same bit field scheme. > > > > Ok, then needs to make iommufd_attached always defined. > > That does not follow. Thanks, Well, I meant the iommufd_attached now is defined only when CONFIG_IOMMUFD is enabled. To toll it with cdev_opened, needs to change this. Regards, Yi Liu
On Tue, 13 Jun 2023 14:28:43 +0000 "Liu, Yi L" <yi.l.liu@intel.com> wrote: > > From: Alex Williamson <alex.williamson@redhat.com> > > Sent: Tuesday, June 13, 2023 10:18 PM > > > > > > diff --git a/include/linux/vfio.h b/include/linux/vfio.h > > > > > index 83cc5dc28b7a..e80a8ac86e46 100644 > > > > > --- a/include/linux/vfio.h > > > > > +++ b/include/linux/vfio.h > > > > > @@ -66,6 +66,7 @@ struct vfio_device { > > > > > struct iommufd_device *iommufd_device; > > > > > bool iommufd_attached; > > > > > #endif > > > > > + bool cdev_opened:1; > > > > > > > > Perhaps a more strongly defined data type here as well and roll > > > > iommufd_attached into the same bit field scheme. > > > > > > Ok, then needs to make iommufd_attached always defined. > > > > That does not follow. Thanks, > > Well, I meant the iommufd_attached now is defined only when > CONFIG_IOMMUFD is enabled. To toll it with cdev_opened, needs > to change this. Understood, but I don't think it's true. If defined we use one more bit of the bit field, which is a consideration when we approach filling it, but we're not using bit-shift operations to address these bits, so why does it matter if one has compiler conditional usage? Thanks, Alex
> From: Alex Williamson <alex.williamson@redhat.com> > Sent: Tuesday, June 13, 2023 10:40 PM > > On Tue, 13 Jun 2023 14:28:43 +0000 > "Liu, Yi L" <yi.l.liu@intel.com> wrote: > > > > From: Alex Williamson <alex.williamson@redhat.com> > > > Sent: Tuesday, June 13, 2023 10:18 PM > > > > > > > > diff --git a/include/linux/vfio.h b/include/linux/vfio.h > > > > > > index 83cc5dc28b7a..e80a8ac86e46 100644 > > > > > > --- a/include/linux/vfio.h > > > > > > +++ b/include/linux/vfio.h > > > > > > @@ -66,6 +66,7 @@ struct vfio_device { > > > > > > struct iommufd_device *iommufd_device; > > > > > > bool iommufd_attached; > > > > > > #endif > > > > > > + bool cdev_opened:1; > > > > > > > > > > Perhaps a more strongly defined data type here as well and roll > > > > > iommufd_attached into the same bit field scheme. > > > > > > > > Ok, then needs to make iommufd_attached always defined. > > > > > > That does not follow. Thanks, > > > > Well, I meant the iommufd_attached now is defined only when > > CONFIG_IOMMUFD is enabled. To toll it with cdev_opened, needs > > to change this. > > Understood, but I don't think it's true. If defined we use one more > bit of the bit field, which is a consideration when we approach filling > it, but we're not using bit-shift operations to address these bits, so > why does it matter if one has compiler conditional usage? Thanks, Aha, I see. So you are suggesting something like the below. Is it? #if IS_ENABLED(CONFIG_IOMMUFD) struct iommufd_device *iommufd_device; u8 iommufd_attached:1; #endif u8 cdev_opened:1; Regards, Yi Liu
On Tue, 13 Jun 2023 14:42:46 +0000 "Liu, Yi L" <yi.l.liu@intel.com> wrote: > > From: Alex Williamson <alex.williamson@redhat.com> > > Sent: Tuesday, June 13, 2023 10:40 PM > > > > On Tue, 13 Jun 2023 14:28:43 +0000 > > "Liu, Yi L" <yi.l.liu@intel.com> wrote: > > > > > > From: Alex Williamson <alex.williamson@redhat.com> > > > > Sent: Tuesday, June 13, 2023 10:18 PM > > > > > > > > > > diff --git a/include/linux/vfio.h b/include/linux/vfio.h > > > > > > > index 83cc5dc28b7a..e80a8ac86e46 100644 > > > > > > > --- a/include/linux/vfio.h > > > > > > > +++ b/include/linux/vfio.h > > > > > > > @@ -66,6 +66,7 @@ struct vfio_device { > > > > > > > struct iommufd_device *iommufd_device; > > > > > > > bool iommufd_attached; > > > > > > > #endif > > > > > > > + bool cdev_opened:1; > > > > > > > > > > > > Perhaps a more strongly defined data type here as well and roll > > > > > > iommufd_attached into the same bit field scheme. > > > > > > > > > > Ok, then needs to make iommufd_attached always defined. > > > > > > > > That does not follow. Thanks, > > > > > > Well, I meant the iommufd_attached now is defined only when > > > CONFIG_IOMMUFD is enabled. To toll it with cdev_opened, needs > > > to change this. > > > > Understood, but I don't think it's true. If defined we use one more > > bit of the bit field, which is a consideration when we approach filling > > it, but we're not using bit-shift operations to address these bits, so > > why does it matter if one has compiler conditional usage? Thanks, > > Aha, I see. So you are suggesting something like the below. Is it? > > #if IS_ENABLED(CONFIG_IOMMUFD) > struct iommufd_device *iommufd_device; > u8 iommufd_attached:1; > #endif > u8 cdev_opened:1; Precisely. Thanks, Alex
On Fri, Jun 02, 2023 at 05:16:47AM -0700, Yi Liu wrote: > This adds ioctl for userspace to bind device cdev fd to iommufd. > > VFIO_DEVICE_BIND_IOMMUFD: bind device to an iommufd, hence gain DMA > control provided by the iommufd. open_device > op is called after bind_iommufd op. > > Tested-by: Yanting Jiang <yanting.jiang@intel.com> > Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> > Tested-by: Terrence Xu <terrence.xu@intel.com> > Signed-off-by: Yi Liu <yi.l.liu@intel.com> > --- > drivers/vfio/device_cdev.c | 123 +++++++++++++++++++++++++++++++++++++ > drivers/vfio/vfio.h | 13 ++++ > drivers/vfio/vfio_main.c | 5 ++ > include/linux/vfio.h | 3 +- > include/uapi/linux/vfio.h | 27 ++++++++ > 5 files changed, 170 insertions(+), 1 deletion(-) > > diff --git a/drivers/vfio/device_cdev.c b/drivers/vfio/device_cdev.c > index 1c640016a824..a4498ddbe774 100644 > --- a/drivers/vfio/device_cdev.c > +++ b/drivers/vfio/device_cdev.c > @@ -3,6 +3,7 @@ > * Copyright (c) 2023 Intel Corporation. > */ > #include <linux/vfio.h> > +#include <linux/iommufd.h> > > #include "vfio.h" > > @@ -44,6 +45,128 @@ int vfio_device_fops_cdev_open(struct inode *inode, struct file *filep) > return ret; > } > > +static void vfio_device_get_kvm_safe(struct vfio_device_file *df) > +{ > + spin_lock(&df->kvm_ref_lock); > + if (df->kvm) > + _vfio_device_get_kvm_safe(df->device, df->kvm); > + spin_unlock(&df->kvm_ref_lock); > +} I'm surprised symbol_get() can be called from a spinlock, but it sure looks like it can.. Also moving the if kvm is null test into _vfio_device_get_kvm_safe() will save a few lines. Also shouldn't be called _vfio_device... > +void vfio_df_cdev_close(struct vfio_device_file *df) > +{ > + struct vfio_device *device = df->device; > + > + /* > + * In the time of close, there is no contention with another one > + * changing this flag. So read df->access_granted without lock > + * and no smp_load_acquire() is ok. > + */ > + if (!df->access_granted) > + return; > + > + mutex_lock(&device->dev_set->lock); > + vfio_df_close(df); > + vfio_device_put_kvm(device); > + iommufd_ctx_put(df->iommufd); > + device->cdev_opened = false; > + mutex_unlock(&device->dev_set->lock); > + vfio_device_unblock_group(device); > +} Lets call this vfio_df_unbind_iommufd() and put it near vfio_df_ioctl_bind_iommufd() > static struct iommufd_ctx *vfio_get_iommufd_from_fd(int fd) This can probably be an iommufd function: iommufd_ctx_from_fd(int fd) > +long vfio_df_ioctl_bind_iommufd(struct vfio_device_file *df, > + struct vfio_device_bind_iommufd __user *arg) > +{ > + ret = copy_to_user(&arg->out_devid, &df->devid, > + sizeof(df->devid)) ? -EFAULT : 0; > + if (ret) > + goto out_close_device; > + > + /* > + * Paired with smp_load_acquire() in vfio_device_fops::ioctl/ > + * read/write/mmap > + */ > + smp_store_release(&df->access_granted, true); > + device->cdev_opened = true; Move the cdev_opened up above the release just for consistency. Jason
> From: Jason Gunthorpe <jgg@nvidia.com> > Sent: Saturday, June 24, 2023 12:15 AM > > } > > > > +static void vfio_device_get_kvm_safe(struct vfio_device_file *df) > > +{ > > + spin_lock(&df->kvm_ref_lock); > > + if (df->kvm) > > + _vfio_device_get_kvm_safe(df->device, df->kvm); > > + spin_unlock(&df->kvm_ref_lock); > > +} > > I'm surprised symbol_get() can be called from a spinlock, but it sure > looks like it can.. > > Also moving the if kvm is null test into _vfio_device_get_kvm_safe() > will save a few lines. > > Also shouldn't be called _vfio_device... Ah, any suggestion on the naming? How about vfio_device_get_kvm_safe_locked()? Regards, Yi Liu
On Mon, Jun 26, 2023 at 08:34:26AM +0000, Liu, Yi L wrote: > > From: Jason Gunthorpe <jgg@nvidia.com> > > Sent: Saturday, June 24, 2023 12:15 AM > > > > } > > > > > > +static void vfio_device_get_kvm_safe(struct vfio_device_file *df) > > > +{ > > > + spin_lock(&df->kvm_ref_lock); > > > + if (df->kvm) > > > + _vfio_device_get_kvm_safe(df->device, df->kvm); > > > + spin_unlock(&df->kvm_ref_lock); > > > +} > > > > I'm surprised symbol_get() can be called from a spinlock, but it sure > > looks like it can.. > > > > Also moving the if kvm is null test into _vfio_device_get_kvm_safe() > > will save a few lines. > > > > Also shouldn't be called _vfio_device... > > Ah, any suggestion on the naming? How about vfio_device_get_kvm_safe_locked()? I thought you were using _df_ now for these functions? Jason
> From: Jason Gunthorpe <jgg@nvidia.com> > Sent: Monday, June 26, 2023 8:56 PM > > On Mon, Jun 26, 2023 at 08:34:26AM +0000, Liu, Yi L wrote: > > > From: Jason Gunthorpe <jgg@nvidia.com> > > > Sent: Saturday, June 24, 2023 12:15 AM > > > > > > } > > > > > > > > +static void vfio_device_get_kvm_safe(struct vfio_device_file *df) > > > > +{ > > > > + spin_lock(&df->kvm_ref_lock); > > > > + if (df->kvm) > > > > + _vfio_device_get_kvm_safe(df->device, df->kvm); > > > > + spin_unlock(&df->kvm_ref_lock); > > > > +} > > > > > > I'm surprised symbol_get() can be called from a spinlock, but it sure > > > looks like it can.. > > > > > > Also moving the if kvm is null test into _vfio_device_get_kvm_safe() > > > will save a few lines. > > > > > > Also shouldn't be called _vfio_device... > > > > Ah, any suggestion on the naming? How about vfio_device_get_kvm_safe_locked()? > > I thought you were using _df_ now for these functions? > I see. Your point is passing df to _vfio_device_get_kvm_safe(() and test the df->kvm within it. Hence rename it to be _df_. I think group path should be ok with this change as well. Let me make it. Regards, Yi Liu
> From: Liu, Yi L <yi.l.liu@intel.com> > Sent: Monday, June 26, 2023 9:35 PM > > > From: Jason Gunthorpe <jgg@nvidia.com> > > Sent: Monday, June 26, 2023 8:56 PM > > > > On Mon, Jun 26, 2023 at 08:34:26AM +0000, Liu, Yi L wrote: > > > > From: Jason Gunthorpe <jgg@nvidia.com> > > > > Sent: Saturday, June 24, 2023 12:15 AM > > > > > > > > } > > > > > > > > > > +static void vfio_device_get_kvm_safe(struct vfio_device_file *df) > > > > > +{ > > > > > + spin_lock(&df->kvm_ref_lock); > > > > > + if (df->kvm) > > > > > + _vfio_device_get_kvm_safe(df->device, df->kvm); > > > > > + spin_unlock(&df->kvm_ref_lock); > > > > > +} > > > > > > > > I'm surprised symbol_get() can be called from a spinlock, but it sure > > > > looks like it can.. > > > > > > > > Also moving the if kvm is null test into _vfio_device_get_kvm_safe() > > > > will save a few lines. > > > > > > > > Also shouldn't be called _vfio_device... > > > > > > Ah, any suggestion on the naming? How about vfio_device_get_kvm_safe_locked()? > > > > I thought you were using _df_ now for these functions? > > > > I see. Your point is passing df to _vfio_device_get_kvm_safe(() and > test the df->kvm within it. Hence rename it to be _df_. I think group > path should be ok with this change as well. Let me make it. To pass vfio_device_file to _vfio_device_get_kvm_safe(), needs to make the below changes to the group path. If just wants to test null kvm in the _vfio_device_get_kvm_safe(), maybe simpler to keep the current parameters and just move the null kvm test within this function. Is it? diff --git a/drivers/vfio/group.c b/drivers/vfio/group.c index 41a09a2df690..c2e880c15c44 100644 --- a/drivers/vfio/group.c +++ b/drivers/vfio/group.c @@ -157,15 +157,15 @@ static int vfio_group_ioctl_set_container(struct vfio_group *group, return ret; } -static void vfio_device_group_get_kvm_safe(struct vfio_device *device) +static void vfio_device_group_get_kvm_safe(struct vfio_device_file *df) { - spin_lock(&device->group->kvm_ref_lock); - if (!device->group->kvm) - goto unlock; - - _vfio_device_get_kvm_safe(device, device->group->kvm); + struct vfio_device *device = df->device; -unlock: + spin_lock(&device->group->kvm_ref_lock); + spin_lock(&df->kvm_ref_lock); + df->kvm = device->group->kvm; + _vfio_df_get_kvm_safe(df); + spin_unlock(&df->kvm_ref_lock); spin_unlock(&device->group->kvm_ref_lock); } @@ -189,7 +189,7 @@ static int vfio_df_group_open(struct vfio_device_file *df) * the pointer in the device for use by drivers. */ if (device->open_count == 0) - vfio_device_group_get_kvm_safe(device); + vfio_device_group_get_kvm_safe(df); df->iommufd = device->group->iommufd; if (df->iommufd && vfio_device_is_noiommu(device) && device->open_count == 0) { diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h index fb8f2fac3d23..066766d43bdc 100644 --- a/drivers/vfio/vfio.h +++ b/drivers/vfio/vfio.h @@ -340,11 +340,10 @@ enum { vfio_noiommu = false }; #endif #ifdef CONFIG_HAVE_KVM -void _vfio_device_get_kvm_safe(struct vfio_device *device, struct kvm *kvm); +void _vfio_df_get_kvm_safe(struct vfio_device_file *df); void vfio_device_put_kvm(struct vfio_device *device); #else -static inline void _vfio_device_get_kvm_safe(struct vfio_device *device, - struct kvm *kvm) +static inline void _vfio_df_get_kvm_safe(struct vfio_device_file *df) { } diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c index 8a9ebcc6980b..4e6ea2943d28 100644 --- a/drivers/vfio/vfio_main.c +++ b/drivers/vfio/vfio_main.c @@ -373,14 +373,22 @@ void vfio_unregister_group_dev(struct vfio_device *device) EXPORT_SYMBOL_GPL(vfio_unregister_group_dev); #ifdef CONFIG_HAVE_KVM -void _vfio_device_get_kvm_safe(struct vfio_device *device, struct kvm *kvm) +void _vfio_df_get_kvm_safe(struct vfio_device_file *df) { + struct vfio_device *device = df->device; void (*pfn)(struct kvm *kvm); bool (*fn)(struct kvm *kvm); + struct kvm *kvm; bool ret; + lockdep_assert_held(&df->kvm_ref_lock); lockdep_assert_held(&device->dev_set->lock); + kvm = df->kvm; + + if (!kvm) + return; + pfn = symbol_get(kvm_put_kvm); if (WARN_ON(!pfn)) return;
On Mon, Jun 26, 2023 at 02:51:29PM +0000, Liu, Yi L wrote: > > > > > > > > Ah, any suggestion on the naming? How about vfio_device_get_kvm_safe_locked()? > > > > > > I thought you were using _df_ now for these functions? > > > > > > > I see. Your point is passing df to _vfio_device_get_kvm_safe(() and > > test the df->kvm within it. Hence rename it to be _df_. I think group > > path should be ok with this change as well. Let me make it. > > To pass vfio_device_file to _vfio_device_get_kvm_safe(), needs to make > the below changes to the group path. If just wants to test null kvm in the > _vfio_device_get_kvm_safe(), maybe simpler to keep the current parameters > and just move the null kvm test within this function. Is it? This does seem a bit nicer, yes > diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c > index 8a9ebcc6980b..4e6ea2943d28 100644 > --- a/drivers/vfio/vfio_main.c > +++ b/drivers/vfio/vfio_main.c > @@ -373,14 +373,22 @@ void vfio_unregister_group_dev(struct vfio_device *device) > EXPORT_SYMBOL_GPL(vfio_unregister_group_dev); > > #ifdef CONFIG_HAVE_KVM > -void _vfio_device_get_kvm_safe(struct vfio_device *device, struct kvm *kvm) > +void _vfio_df_get_kvm_safe(struct vfio_device_file *df) But still avoid the leading _ here Jason
> From: Jason Gunthorpe <jgg@nvidia.com> > Sent: Wednesday, June 28, 2023 10:34 PM > > On Mon, Jun 26, 2023 at 02:51:29PM +0000, Liu, Yi L wrote: > > > > > > > > > > Ah, any suggestion on the naming? How about > vfio_device_get_kvm_safe_locked()? > > > > > > > > I thought you were using _df_ now for these functions? > > > > > > > > > > I see. Your point is passing df to _vfio_device_get_kvm_safe(() and > > > test the df->kvm within it. Hence rename it to be _df_. I think group > > > path should be ok with this change as well. Let me make it. > > > > To pass vfio_device_file to _vfio_device_get_kvm_safe(), needs to make > > the below changes to the group path. If just wants to test null kvm in the > > _vfio_device_get_kvm_safe(), maybe simpler to keep the current parameters > > and just move the null kvm test within this function. Is it? > > This does seem a bit nicer, yes > > > diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c > > index 8a9ebcc6980b..4e6ea2943d28 100644 > > --- a/drivers/vfio/vfio_main.c > > +++ b/drivers/vfio/vfio_main.c > > @@ -373,14 +373,22 @@ void vfio_unregister_group_dev(struct vfio_device *device) > > EXPORT_SYMBOL_GPL(vfio_unregister_group_dev); > > > > #ifdef CONFIG_HAVE_KVM > > -void _vfio_device_get_kvm_safe(struct vfio_device *device, struct kvm *kvm) > > +void _vfio_df_get_kvm_safe(struct vfio_device_file *df) > > But still avoid the leading _ here Ok, I'll move the kvm pointer test to _vfio_device_get_kvm_safe() And also rename it as vfio_device_get_kvm_safe() Regards, Yi Liu
diff --git a/drivers/vfio/device_cdev.c b/drivers/vfio/device_cdev.c index 1c640016a824..a4498ddbe774 100644 --- a/drivers/vfio/device_cdev.c +++ b/drivers/vfio/device_cdev.c @@ -3,6 +3,7 @@ * Copyright (c) 2023 Intel Corporation. */ #include <linux/vfio.h> +#include <linux/iommufd.h> #include "vfio.h" @@ -44,6 +45,128 @@ int vfio_device_fops_cdev_open(struct inode *inode, struct file *filep) return ret; } +static void vfio_device_get_kvm_safe(struct vfio_device_file *df) +{ + spin_lock(&df->kvm_ref_lock); + if (df->kvm) + _vfio_device_get_kvm_safe(df->device, df->kvm); + spin_unlock(&df->kvm_ref_lock); +} + +void vfio_df_cdev_close(struct vfio_device_file *df) +{ + struct vfio_device *device = df->device; + + /* + * In the time of close, there is no contention with another one + * changing this flag. So read df->access_granted without lock + * and no smp_load_acquire() is ok. + */ + if (!df->access_granted) + return; + + mutex_lock(&device->dev_set->lock); + vfio_df_close(df); + vfio_device_put_kvm(device); + iommufd_ctx_put(df->iommufd); + device->cdev_opened = false; + mutex_unlock(&device->dev_set->lock); + vfio_device_unblock_group(device); +} + +static struct iommufd_ctx *vfio_get_iommufd_from_fd(int fd) +{ + struct iommufd_ctx *iommufd; + struct fd f; + + f = fdget(fd); + if (!f.file) + return ERR_PTR(-EBADF); + + iommufd = iommufd_ctx_from_file(f.file); + + fdput(f); + return iommufd; +} + +long vfio_df_ioctl_bind_iommufd(struct vfio_device_file *df, + struct vfio_device_bind_iommufd __user *arg) +{ + struct vfio_device *device = df->device; + struct vfio_device_bind_iommufd bind; + unsigned long minsz; + int ret; + + static_assert(__same_type(arg->out_devid, df->devid)); + + minsz = offsetofend(struct vfio_device_bind_iommufd, out_devid); + + if (copy_from_user(&bind, arg, minsz)) + return -EFAULT; + + if (bind.argsz < minsz || bind.flags || bind.iommufd < 0) + return -EINVAL; + + /* BIND_IOMMUFD only allowed for cdev fds */ + if (df->group) + return -EINVAL; + + ret = vfio_device_block_group(device); + if (ret) + return ret; + + mutex_lock(&device->dev_set->lock); + /* one device cannot be bound twice */ + if (df->access_granted) { + ret = -EINVAL; + goto out_unlock; + } + + df->iommufd = vfio_get_iommufd_from_fd(bind.iommufd); + if (IS_ERR(df->iommufd)) { + ret = PTR_ERR(df->iommufd); + df->iommufd = NULL; + goto out_unlock; + } + + /* + * Before the device open, get the KVM pointer currently + * associated with the device file (if there is) and obtain + * a reference. This reference is held until device closed. + * Save the pointer in the device for use by drivers. + */ + vfio_device_get_kvm_safe(df); + + ret = vfio_df_open(df); + if (ret) + goto out_put_kvm; + + ret = copy_to_user(&arg->out_devid, &df->devid, + sizeof(df->devid)) ? -EFAULT : 0; + if (ret) + goto out_close_device; + + /* + * Paired with smp_load_acquire() in vfio_device_fops::ioctl/ + * read/write/mmap + */ + smp_store_release(&df->access_granted, true); + device->cdev_opened = true; + mutex_unlock(&device->dev_set->lock); + return 0; + +out_close_device: + vfio_df_close(df); +out_put_kvm: + vfio_device_put_kvm(device); + iommufd_ctx_put(df->iommufd); + df->iommufd = NULL; +out_unlock: + mutex_unlock(&device->dev_set->lock); + vfio_device_unblock_group(device); + return ret; +} + static char *vfio_device_devnode(const struct device *dev, umode_t *mode) { return kasprintf(GFP_KERNEL, "vfio/devices/%s", dev_name(dev)); diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h index d12b5b524bfc..42de40d2cd4d 100644 --- a/drivers/vfio/vfio.h +++ b/drivers/vfio/vfio.h @@ -287,6 +287,9 @@ static inline void vfio_device_del(struct vfio_device *device) } int vfio_device_fops_cdev_open(struct inode *inode, struct file *filep); +void vfio_df_cdev_close(struct vfio_device_file *df); +long vfio_df_ioctl_bind_iommufd(struct vfio_device_file *df, + struct vfio_device_bind_iommufd __user *arg); int vfio_cdev_init(struct class *device_class); void vfio_cdev_cleanup(void); #else @@ -310,6 +313,16 @@ static inline int vfio_device_fops_cdev_open(struct inode *inode, return 0; } +static inline void vfio_df_cdev_close(struct vfio_device_file *df) +{ +} + +static inline long vfio_df_ioctl_bind_iommufd(struct vfio_device_file *df, + struct vfio_device_bind_iommufd __user *arg) +{ + return -EOPNOTSUPP; +} + static inline int vfio_cdev_init(struct class *device_class) { return 0; diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c index ef55af75f459..9ba4d420eda2 100644 --- a/drivers/vfio/vfio_main.c +++ b/drivers/vfio/vfio_main.c @@ -572,6 +572,8 @@ static int vfio_device_fops_release(struct inode *inode, struct file *filep) if (df->group) vfio_df_group_close(df); + else + vfio_df_cdev_close(df); vfio_device_put_registration(device); @@ -1145,6 +1147,9 @@ static long vfio_device_fops_unl_ioctl(struct file *filep, struct vfio_device *device = df->device; int ret; + if (cmd == VFIO_DEVICE_BIND_IOMMUFD) + return vfio_df_ioctl_bind_iommufd(df, (void __user *)arg); + /* Paired with smp_store_release() following vfio_df_open() */ if (!smp_load_acquire(&df->access_granted)) return -EINVAL; diff --git a/include/linux/vfio.h b/include/linux/vfio.h index 83cc5dc28b7a..e80a8ac86e46 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -66,6 +66,7 @@ struct vfio_device { struct iommufd_device *iommufd_device; bool iommufd_attached; #endif + bool cdev_opened:1; }; /** @@ -170,7 +171,7 @@ vfio_iommufd_device_hot_reset_devid(struct vfio_device *vdev, static inline bool vfio_device_cdev_opened(struct vfio_device *device) { - return false; + return device->cdev_opened; } /** diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index f753124e1c82..7296012b7f36 100644 --- a/include/uapi/linux/vfio.h +++ b/include/uapi/linux/vfio.h @@ -194,6 +194,33 @@ struct vfio_group_status { /* --------------- IOCTLs for DEVICE file descriptors --------------- */ +/* + * VFIO_DEVICE_BIND_IOMMUFD - _IOR(VFIO_TYPE, VFIO_BASE + 18, + * struct vfio_device_bind_iommufd) + * @argsz: User filled size of this data. + * @flags: Must be 0. + * @iommufd: iommufd to bind. + * @out_devid: The device id generated by this bind. devid is a handle for + * this device/iommufd bond and can be used in IOMMUFD commands. + * + * Bind a vfio_device to the specified iommufd. + * + * User is restricted from accessing the device before the binding operation + * is completed. + * + * Unbind is automatically conducted when device fd is closed. + * + * Return: 0 on success, -errno on failure. + */ +struct vfio_device_bind_iommufd { + __u32 argsz; + __u32 flags; + __s32 iommufd; + __u32 out_devid; +}; + +#define VFIO_DEVICE_BIND_IOMMUFD _IO(VFIO_TYPE, VFIO_BASE + 18) + /** * VFIO_DEVICE_GET_INFO - _IOR(VFIO_TYPE, VFIO_BASE + 7, * struct vfio_device_info)
This adds ioctl for userspace to bind device cdev fd to iommufd. VFIO_DEVICE_BIND_IOMMUFD: bind device to an iommufd, hence gain DMA control provided by the iommufd. open_device op is called after bind_iommufd op. Tested-by: Yanting Jiang <yanting.jiang@intel.com> Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> Tested-by: Terrence Xu <terrence.xu@intel.com> Signed-off-by: Yi Liu <yi.l.liu@intel.com> --- drivers/vfio/device_cdev.c | 123 +++++++++++++++++++++++++++++++++++++ drivers/vfio/vfio.h | 13 ++++ drivers/vfio/vfio_main.c | 5 ++ include/linux/vfio.h | 3 +- include/uapi/linux/vfio.h | 27 ++++++++ 5 files changed, 170 insertions(+), 1 deletion(-)