diff mbox series

[v3,09/14] vfio/type1: Support binding guest page tables to PASID

Message ID 1592988927-48009-10-git-send-email-yi.l.liu@intel.com (mailing list archive)
State New, archived
Headers show
Series vfio: expose virtual Shared Virtual Addressing to VMs | expand

Commit Message

Liu, Yi L June 24, 2020, 8:55 a.m. UTC
Nesting translation allows two-levels/stages page tables, with 1st level
for guest translations (e.g. GVA->GPA), 2nd level for host translations
(e.g. GPA->HPA). This patch adds interface for binding guest page tables
to a PASID. This PASID must have been allocated to user space before the
binding request.

Cc: Kevin Tian <kevin.tian@intel.com>
CC: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
---
v2 -> v3:
*) use __iommu_sva_unbind_gpasid() for unbind call issued by VFIO
https://lore.kernel.org/linux-iommu/1592931837-58223-6-git-send-email-jacob.jun.pan@linux.intel.com/

v1 -> v2:
*) rename subject from "vfio/type1: Bind guest page tables to host"
*) remove VFIO_IOMMU_BIND, introduce VFIO_IOMMU_NESTING_OP to support bind/
   unbind guet page table
*) replaced vfio_iommu_for_each_dev() with a group level loop since this
   series enforces one group per container w/ nesting type as start.
*) rename vfio_bind/unbind_gpasid_fn() to vfio_dev_bind/unbind_gpasid_fn()
*) vfio_dev_unbind_gpasid() always successful
*) use vfio_mm->pasid_lock to avoid race between PASID free and page table
   bind/unbind
---
 drivers/vfio/vfio_iommu_type1.c | 169 ++++++++++++++++++++++++++++++++++++++++
 drivers/vfio/vfio_pasid.c       |  30 +++++++
 include/linux/vfio.h            |  20 +++++
 include/uapi/linux/vfio.h       |  30 +++++++
 4 files changed, 249 insertions(+)

Comments

Alex Williamson July 2, 2020, 9:19 p.m. UTC | #1
On Wed, 24 Jun 2020 01:55:22 -0700
Liu Yi L <yi.l.liu@intel.com> wrote:

> Nesting translation allows two-levels/stages page tables, with 1st level
> for guest translations (e.g. GVA->GPA), 2nd level for host translations
> (e.g. GPA->HPA). This patch adds interface for binding guest page tables
> to a PASID. This PASID must have been allocated to user space before the
> binding request.
> 
> Cc: Kevin Tian <kevin.tian@intel.com>
> CC: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Cc: Alex Williamson <alex.williamson@redhat.com>
> Cc: Eric Auger <eric.auger@redhat.com>
> Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
> Cc: Joerg Roedel <joro@8bytes.org>
> Cc: Lu Baolu <baolu.lu@linux.intel.com>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.com>
> Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> ---
> v2 -> v3:
> *) use __iommu_sva_unbind_gpasid() for unbind call issued by VFIO
> https://lore.kernel.org/linux-iommu/1592931837-58223-6-git-send-email-jacob.jun.pan@linux.intel.com/
> 
> v1 -> v2:
> *) rename subject from "vfio/type1: Bind guest page tables to host"
> *) remove VFIO_IOMMU_BIND, introduce VFIO_IOMMU_NESTING_OP to support bind/
>    unbind guet page table
> *) replaced vfio_iommu_for_each_dev() with a group level loop since this
>    series enforces one group per container w/ nesting type as start.
> *) rename vfio_bind/unbind_gpasid_fn() to vfio_dev_bind/unbind_gpasid_fn()
> *) vfio_dev_unbind_gpasid() always successful
> *) use vfio_mm->pasid_lock to avoid race between PASID free and page table
>    bind/unbind
> ---
>  drivers/vfio/vfio_iommu_type1.c | 169 ++++++++++++++++++++++++++++++++++++++++
>  drivers/vfio/vfio_pasid.c       |  30 +++++++
>  include/linux/vfio.h            |  20 +++++
>  include/uapi/linux/vfio.h       |  30 +++++++
>  4 files changed, 249 insertions(+)
> 
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index d0891c5..5926533 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -148,6 +148,33 @@ struct vfio_regions {
>  #define DIRTY_BITMAP_PAGES_MAX	 ((u64)INT_MAX)
>  #define DIRTY_BITMAP_SIZE_MAX	 DIRTY_BITMAP_BYTES(DIRTY_BITMAP_PAGES_MAX)
>  
> +struct domain_capsule {
> +	struct vfio_group *group;
> +	struct iommu_domain *domain;
> +	void *data;
> +};
> +
> +/* iommu->lock must be held */
> +static struct vfio_group *vfio_find_nesting_group(struct vfio_iommu *iommu)
> +{
> +	struct vfio_domain *d;
> +	struct vfio_group *g, *group = NULL;
> +
> +	if (!iommu->nesting_info)
> +		return NULL;
> +
> +	/* only support singleton container with nesting type */
> +	list_for_each_entry(d, &iommu->domain_list, next) {
> +		list_for_each_entry(g, &d->group_list, next) {
> +			if (!group) {
> +				group = g;
> +				break;
> +			}


We break out of the inner loop only to pointlessly continue in the
outer loop when we could simply return g and remove the second group
pointer altogether (use "group" instead of "g" if so).


> +		}
> +	}
> +	return group;
> +}
> +
>  static int put_pfn(unsigned long pfn, int prot);
>  
>  static struct vfio_group *vfio_iommu_find_iommu_group(struct vfio_iommu *iommu,
> @@ -2351,6 +2378,48 @@ static int vfio_iommu_resv_refresh(struct vfio_iommu *iommu,
>  	return ret;
>  }
>  
> +static int vfio_dev_bind_gpasid_fn(struct device *dev, void *data)
> +{
> +	struct domain_capsule *dc = (struct domain_capsule *)data;
> +	unsigned long arg = *(unsigned long *) dc->data;
> +
> +	return iommu_sva_bind_gpasid(dc->domain, dev, (void __user *) arg);
> +}
> +
> +static int vfio_dev_unbind_gpasid_fn(struct device *dev, void *data)
> +{
> +	struct domain_capsule *dc = (struct domain_capsule *)data;
> +	unsigned long arg = *(unsigned long *) dc->data;
> +
> +	iommu_sva_unbind_gpasid(dc->domain, dev, (void __user *) arg);
> +	return 0;
> +}
> +
> +static int __vfio_dev_unbind_gpasid_fn(struct device *dev, void *data)
> +{
> +	struct domain_capsule *dc = (struct domain_capsule *)data;
> +	struct iommu_gpasid_bind_data *unbind_data =
> +				(struct iommu_gpasid_bind_data *) dc->data;
> +
> +	__iommu_sva_unbind_gpasid(dc->domain, dev, unbind_data);
> +	return 0;
> +}
> +
> +static void vfio_group_unbind_gpasid_fn(ioasid_t pasid, void *data)
> +{
> +	struct domain_capsule *dc = (struct domain_capsule *) data;
> +	struct iommu_gpasid_bind_data unbind_data;
> +
> +	unbind_data.argsz = offsetof(struct iommu_gpasid_bind_data, vendor);
> +	unbind_data.flags = 0;
> +	unbind_data.hpasid = pasid;
> +
> +	dc->data = &unbind_data;
> +
> +	iommu_group_for_each_dev(dc->group->iommu_group,
> +				 dc, __vfio_dev_unbind_gpasid_fn);
> +}
> +
>  static void vfio_iommu_type1_detach_group(void *iommu_data,
>  					  struct iommu_group *iommu_group)
>  {
> @@ -2394,6 +2463,21 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
>  		if (!group)
>  			continue;
>  
> +		if (iommu->nesting_info && iommu->vmm &&
> +		    (iommu->nesting_info->features &
> +					IOMMU_NESTING_FEAT_BIND_PGTBL)) {
> +			struct domain_capsule dc = { .group = group,
> +						     .domain = domain->domain,
> +						     .data = NULL };
> +
> +			/*
> +			 * Unbind page tables bound with system wide PASIDs
> +			 * which are allocated to user space.
> +			 */
> +			vfio_mm_for_each_pasid(iommu->vmm, &dc,
> +					       vfio_group_unbind_gpasid_fn);
> +		}
> +
>  		vfio_iommu_detach_group(domain, group);
>  		update_dirty_scope = !group->pinned_page_dirty_scope;
>  		list_del(&group->next);
> @@ -2942,6 +3026,89 @@ static int vfio_iommu_type1_pasid_request(struct vfio_iommu *iommu,
>  	}
>  }
>  
> +static long vfio_iommu_handle_pgtbl_op(struct vfio_iommu *iommu,
> +				       bool is_bind, unsigned long arg)
> +{
> +	struct iommu_nesting_info *info;
> +	struct domain_capsule dc = { .data = &arg };
> +	struct vfio_group *group;
> +	struct vfio_domain *domain;
> +	int ret;
> +
> +	mutex_lock(&iommu->lock);
> +
> +	info = iommu->nesting_info;
> +	if (!info || !(info->features & IOMMU_NESTING_FEAT_BIND_PGTBL)) {
> +		ret = -ENOTSUPP;
> +		goto out_unlock_iommu;
> +	}
> +
> +	if (!iommu->vmm) {
> +		ret = -EINVAL;
> +		goto out_unlock_iommu;
> +	}
> +
> +	group = vfio_find_nesting_group(iommu);
> +	if (!group) {
> +		ret = -EINVAL;
> +		goto out_unlock_iommu;
> +	}
> +
> +	domain = list_first_entry(&iommu->domain_list,
> +				      struct vfio_domain, next);
> +	dc.group = group;
> +	dc.domain = domain->domain;
> +
> +	/* Avoid race with other containers within the same process */
> +	vfio_mm_pasid_lock(iommu->vmm);
> +
> +	if (is_bind) {
> +		ret = iommu_group_for_each_dev(group->iommu_group, &dc,
> +					       vfio_dev_bind_gpasid_fn);
> +		if (ret)
> +			iommu_group_for_each_dev(group->iommu_group, &dc,
> +						 vfio_dev_unbind_gpasid_fn);
> +	} else {
> +		iommu_group_for_each_dev(group->iommu_group,
> +					 &dc, vfio_dev_unbind_gpasid_fn);
> +		ret = 0;
> +	}
> +
> +	vfio_mm_pasid_unlock(iommu->vmm);
> +out_unlock_iommu:
> +	mutex_unlock(&iommu->lock);
> +	return ret;
> +}
> +
> +static long vfio_iommu_type1_nesting_op(struct vfio_iommu *iommu,
> +					unsigned long arg)
> +{
> +	struct vfio_iommu_type1_nesting_op hdr;
> +	unsigned int minsz;
> +	int ret;
> +
> +	minsz = offsetofend(struct vfio_iommu_type1_nesting_op, flags);
> +
> +	if (copy_from_user(&hdr, (void __user *)arg, minsz))
> +		return -EFAULT;
> +
> +	if (hdr.argsz < minsz || hdr.flags & ~VFIO_NESTING_OP_MASK)
> +		return -EINVAL;
> +
> +	switch (hdr.flags & VFIO_NESTING_OP_MASK) {
> +	case VFIO_IOMMU_NESTING_OP_BIND_PGTBL:
> +		ret = vfio_iommu_handle_pgtbl_op(iommu, true, arg + minsz);
> +		break;
> +	case VFIO_IOMMU_NESTING_OP_UNBIND_PGTBL:
> +		ret = vfio_iommu_handle_pgtbl_op(iommu, false, arg + minsz);
> +		break;
> +	default:
> +		ret = -EINVAL;
> +	}
> +
> +	return ret;
> +}
> +
>  static long vfio_iommu_type1_ioctl(void *iommu_data,
>  				   unsigned int cmd, unsigned long arg)
>  {
> @@ -2960,6 +3127,8 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
>  		return vfio_iommu_type1_dirty_pages(iommu, arg);
>  	case VFIO_IOMMU_PASID_REQUEST:
>  		return vfio_iommu_type1_pasid_request(iommu, arg);
> +	case VFIO_IOMMU_NESTING_OP:
> +		return vfio_iommu_type1_nesting_op(iommu, arg);
>  	}
>  
>  	return -ENOTTY;
> diff --git a/drivers/vfio/vfio_pasid.c b/drivers/vfio/vfio_pasid.c
> index 2ea9f1a..20f1e72 100644
> --- a/drivers/vfio/vfio_pasid.c
> +++ b/drivers/vfio/vfio_pasid.c
> @@ -30,6 +30,7 @@ struct vfio_mm {
>  	struct kref		kref;
>  	struct vfio_mm_token	token;
>  	int			ioasid_sid;
> +	struct mutex		pasid_lock;


Introducing holes in the data structure again, mind the alignment.
This wastes 8 byte.  Thanks,

Alex


>  	int			pasid_quota;
>  	struct list_head	next;
>  };
> @@ -97,6 +98,7 @@ struct vfio_mm *vfio_mm_get_from_task(struct task_struct *task)
>  	kref_init(&vmm->kref);
>  	vmm->token.val = (unsigned long long) mm;
>  	vmm->pasid_quota = pasid_quota;
> +	mutex_init(&vmm->pasid_lock);
>  
>  	list_add(&vmm->next, &vfio_pasid.vfio_mm_list);
>  out:
> @@ -134,12 +136,40 @@ void vfio_pasid_free_range(struct vfio_mm *vmm,
>  	 * IOASID core will notify PASID users (e.g. IOMMU driver) to
>  	 * teardown necessary structures depending on the to-be-freed
>  	 * PASID.
> +	 * Hold pasid_lock to avoid race with PASID usages like bind/
> +	 * unbind page tables to requested PASID.
>  	 */
> +	mutex_lock(&vmm->pasid_lock);
>  	for (; pasid <= max; pasid++)
>  		ioasid_free(pasid);
> +	mutex_unlock(&vmm->pasid_lock);
>  }
>  EXPORT_SYMBOL_GPL(vfio_pasid_free_range);
>  
> +int vfio_mm_for_each_pasid(struct vfio_mm *vmm, void *data,
> +			   void (*fn)(ioasid_t id, void *data))
> +{
> +	int ret;
> +
> +	mutex_lock(&vmm->pasid_lock);
> +	ret = ioasid_set_for_each_ioasid(vmm->ioasid_sid, fn, data);
> +	mutex_unlock(&vmm->pasid_lock);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(vfio_mm_for_each_pasid);
> +
> +void vfio_mm_pasid_lock(struct vfio_mm *vmm)
> +{
> +	mutex_lock(&vmm->pasid_lock);
> +}
> +EXPORT_SYMBOL_GPL(vfio_mm_pasid_lock);
> +
> +void vfio_mm_pasid_unlock(struct vfio_mm *vmm)
> +{
> +	mutex_unlock(&vmm->pasid_lock);
> +}
> +EXPORT_SYMBOL_GPL(vfio_mm_pasid_unlock);
> +
>  static int __init vfio_pasid_init(void)
>  {
>  	mutex_init(&vfio_pasid.vfio_mm_lock);
> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> index 8e60a32..9028a09 100644
> --- a/include/linux/vfio.h
> +++ b/include/linux/vfio.h
> @@ -105,6 +105,11 @@ int vfio_mm_ioasid_sid(struct vfio_mm *vmm);
>  extern int vfio_pasid_alloc(struct vfio_mm *vmm, int min, int max);
>  extern void vfio_pasid_free_range(struct vfio_mm *vmm,
>  					ioasid_t min, ioasid_t max);
> +extern int vfio_mm_for_each_pasid(struct vfio_mm *vmm, void *data,
> +				  void (*fn)(ioasid_t id, void *data));
> +extern void vfio_mm_pasid_lock(struct vfio_mm *vmm);
> +extern void vfio_mm_pasid_unlock(struct vfio_mm *vmm);
> +
>  #else
>  static inline struct vfio_mm *vfio_mm_get_from_task(struct task_struct *task)
>  {
> @@ -129,6 +134,21 @@ static inline void vfio_pasid_free_range(struct vfio_mm *vmm,
>  					  ioasid_t min, ioasid_t max)
>  {
>  }
> +
> +static inline int vfio_mm_for_each_pasid(struct vfio_mm *vmm, void *data,
> +					 void (*fn)(ioasid_t id, void *data))
> +{
> +	return -ENOTTY;
> +}
> +
> +static inline void vfio_mm_pasid_lock(struct vfio_mm *vmm)
> +{
> +}
> +
> +static inline void vfio_mm_pasid_unlock(struct vfio_mm *vmm)
> +{
> +}
> +
>  #endif /* CONFIG_VFIO_PASID */
>  
>  /*
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index 657b2db..2c9def8 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -1198,6 +1198,36 @@ struct vfio_iommu_type1_pasid_request {
>  
>  #define VFIO_IOMMU_PASID_REQUEST	_IO(VFIO_TYPE, VFIO_BASE + 18)
>  
> +/**
> + * VFIO_IOMMU_NESTING_OP - _IOW(VFIO_TYPE, VFIO_BASE + 19,
> + *				struct vfio_iommu_type1_nesting_op)
> + *
> + * This interface allows user space to utilize the nesting IOMMU
> + * capabilities as reported through VFIO_IOMMU_GET_INFO.
> + *
> + * @data[] types defined for each op:
> + * +=================+===============================================+
> + * | NESTING OP      |                  @data[]                      |
> + * +=================+===============================================+
> + * | BIND_PGTBL      |      struct iommu_gpasid_bind_data            |
> + * +-----------------+-----------------------------------------------+
> + * | UNBIND_PGTBL    |      struct iommu_gpasid_bind_data            |
> + * +-----------------+-----------------------------------------------+
> + *
> + * returns: 0 on success, -errno on failure.
> + */
> +struct vfio_iommu_type1_nesting_op {
> +	__u32	argsz;
> +	__u32	flags;
> +#define VFIO_NESTING_OP_MASK	(0xffff) /* lower 16-bits for op */
> +	__u8	data[];
> +};
> +
> +#define VFIO_IOMMU_NESTING_OP_BIND_PGTBL	(0)
> +#define VFIO_IOMMU_NESTING_OP_UNBIND_PGTBL	(1)
> +
> +#define VFIO_IOMMU_NESTING_OP		_IO(VFIO_TYPE, VFIO_BASE + 19)
> +
>  /* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU -------- */
>  
>  /*
Liu, Yi L July 3, 2020, 6:46 a.m. UTC | #2
Hi Alex,

> From: Alex Williamson <alex.williamson@redhat.com>
> Sent: Friday, July 3, 2020 5:20 AM
> 
> On Wed, 24 Jun 2020 01:55:22 -0700
> Liu Yi L <yi.l.liu@intel.com> wrote:
> 
> > Nesting translation allows two-levels/stages page tables, with 1st
> > level for guest translations (e.g. GVA->GPA), 2nd level for host
> > translations (e.g. GPA->HPA). This patch adds interface for binding
> > guest page tables to a PASID. This PASID must have been allocated to
> > user space before the binding request.
> >
> > Cc: Kevin Tian <kevin.tian@intel.com>
> > CC: Jacob Pan <jacob.jun.pan@linux.intel.com>
> > Cc: Alex Williamson <alex.williamson@redhat.com>
> > Cc: Eric Auger <eric.auger@redhat.com>
> > Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
> > Cc: Joerg Roedel <joro@8bytes.org>
> > Cc: Lu Baolu <baolu.lu@linux.intel.com>
> > Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.com>
> > Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
> > Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> > ---
> > v2 -> v3:
> > *) use __iommu_sva_unbind_gpasid() for unbind call issued by VFIO
> > https://lore.kernel.org/linux-iommu/1592931837-58223-6-git-send-email-
> > jacob.jun.pan@linux.intel.com/
> >
> > v1 -> v2:
> > *) rename subject from "vfio/type1: Bind guest page tables to host"
> > *) remove VFIO_IOMMU_BIND, introduce VFIO_IOMMU_NESTING_OP to
> support bind/
> >    unbind guet page table
> > *) replaced vfio_iommu_for_each_dev() with a group level loop since this
> >    series enforces one group per container w/ nesting type as start.
> > *) rename vfio_bind/unbind_gpasid_fn() to
> > vfio_dev_bind/unbind_gpasid_fn()
> > *) vfio_dev_unbind_gpasid() always successful
> > *) use vfio_mm->pasid_lock to avoid race between PASID free and page table
> >    bind/unbind
> > ---
> >  drivers/vfio/vfio_iommu_type1.c | 169
> ++++++++++++++++++++++++++++++++++++++++
> >  drivers/vfio/vfio_pasid.c       |  30 +++++++
> >  include/linux/vfio.h            |  20 +++++
> >  include/uapi/linux/vfio.h       |  30 +++++++
> >  4 files changed, 249 insertions(+)
> >
> > diff --git a/drivers/vfio/vfio_iommu_type1.c
> > b/drivers/vfio/vfio_iommu_type1.c index d0891c5..5926533 100644
> > --- a/drivers/vfio/vfio_iommu_type1.c
> > +++ b/drivers/vfio/vfio_iommu_type1.c
> > @@ -148,6 +148,33 @@ struct vfio_regions {
> >  #define DIRTY_BITMAP_PAGES_MAX	 ((u64)INT_MAX)
> >  #define DIRTY_BITMAP_SIZE_MAX
> DIRTY_BITMAP_BYTES(DIRTY_BITMAP_PAGES_MAX)
> >
> > +struct domain_capsule {
> > +	struct vfio_group *group;
> > +	struct iommu_domain *domain;
> > +	void *data;
> > +};
> > +
> > +/* iommu->lock must be held */
> > +static struct vfio_group *vfio_find_nesting_group(struct vfio_iommu
> > +*iommu) {
> > +	struct vfio_domain *d;
> > +	struct vfio_group *g, *group = NULL;
> > +
> > +	if (!iommu->nesting_info)
> > +		return NULL;
> > +
> > +	/* only support singleton container with nesting type */
> > +	list_for_each_entry(d, &iommu->domain_list, next) {
> > +		list_for_each_entry(g, &d->group_list, next) {
> > +			if (!group) {
> > +				group = g;
> > +				break;
> > +			}
> 
> 
> We break out of the inner loop only to pointlessly continue in the outer loop
> when we could simply return g and remove the second group pointer altogether
> (use "group" instead of "g" if so).

how about below? :-)

	/* only support singleton container with nesting type */
	list_for_each_entry(d, &iommu->domain_list, next) {
		list_for_each_entry(group, &d->group_list, next) {
			break;
		}
	}

> 
> > +		}
> > +	}
> > +	return group;
> > +}
> > +
> >  static int put_pfn(unsigned long pfn, int prot);
> >
> >  static struct vfio_group *vfio_iommu_find_iommu_group(struct
> > vfio_iommu *iommu, @@ -2351,6 +2378,48 @@ static int
> vfio_iommu_resv_refresh(struct vfio_iommu *iommu,
> >  	return ret;
> >  }
> >
> > +static int vfio_dev_bind_gpasid_fn(struct device *dev, void *data) {
> > +	struct domain_capsule *dc = (struct domain_capsule *)data;
> > +	unsigned long arg = *(unsigned long *) dc->data;
> > +
> > +	return iommu_sva_bind_gpasid(dc->domain, dev, (void __user *) arg);
> > +}
> > +
> > +static int vfio_dev_unbind_gpasid_fn(struct device *dev, void *data)
> > +{
> > +	struct domain_capsule *dc = (struct domain_capsule *)data;
> > +	unsigned long arg = *(unsigned long *) dc->data;
> > +
> > +	iommu_sva_unbind_gpasid(dc->domain, dev, (void __user *) arg);
> > +	return 0;
> > +}
> > +
> > +static int __vfio_dev_unbind_gpasid_fn(struct device *dev, void
> > +*data) {
> > +	struct domain_capsule *dc = (struct domain_capsule *)data;
> > +	struct iommu_gpasid_bind_data *unbind_data =
> > +				(struct iommu_gpasid_bind_data *) dc->data;
> > +
> > +	__iommu_sva_unbind_gpasid(dc->domain, dev, unbind_data);
> > +	return 0;
> > +}
> > +
> > +static void vfio_group_unbind_gpasid_fn(ioasid_t pasid, void *data) {
> > +	struct domain_capsule *dc = (struct domain_capsule *) data;
> > +	struct iommu_gpasid_bind_data unbind_data;
> > +
> > +	unbind_data.argsz = offsetof(struct iommu_gpasid_bind_data, vendor);
> > +	unbind_data.flags = 0;
> > +	unbind_data.hpasid = pasid;
> > +
> > +	dc->data = &unbind_data;
> > +
> > +	iommu_group_for_each_dev(dc->group->iommu_group,
> > +				 dc, __vfio_dev_unbind_gpasid_fn); }
> > +
> >  static void vfio_iommu_type1_detach_group(void *iommu_data,
> >  					  struct iommu_group *iommu_group)
> { @@ -2394,6 +2463,21 @@
> > static void vfio_iommu_type1_detach_group(void *iommu_data,
> >  		if (!group)
> >  			continue;
> >
> > +		if (iommu->nesting_info && iommu->vmm &&
> > +		    (iommu->nesting_info->features &
> > +					IOMMU_NESTING_FEAT_BIND_PGTBL)) {
> > +			struct domain_capsule dc = { .group = group,
> > +						     .domain = domain->domain,
> > +						     .data = NULL };
> > +
> > +			/*
> > +			 * Unbind page tables bound with system wide PASIDs
> > +			 * which are allocated to user space.
> > +			 */
> > +			vfio_mm_for_each_pasid(iommu->vmm, &dc,
> > +					       vfio_group_unbind_gpasid_fn);
> > +		}
> > +
> >  		vfio_iommu_detach_group(domain, group);
> >  		update_dirty_scope = !group->pinned_page_dirty_scope;
> >  		list_del(&group->next);
> > @@ -2942,6 +3026,89 @@ static int vfio_iommu_type1_pasid_request(struct
> vfio_iommu *iommu,
> >  	}
> >  }
> >
> > +static long vfio_iommu_handle_pgtbl_op(struct vfio_iommu *iommu,
> > +				       bool is_bind, unsigned long arg) {
> > +	struct iommu_nesting_info *info;
> > +	struct domain_capsule dc = { .data = &arg };
> > +	struct vfio_group *group;
> > +	struct vfio_domain *domain;
> > +	int ret;
> > +
> > +	mutex_lock(&iommu->lock);
> > +
> > +	info = iommu->nesting_info;
> > +	if (!info || !(info->features & IOMMU_NESTING_FEAT_BIND_PGTBL)) {
> > +		ret = -ENOTSUPP;
> > +		goto out_unlock_iommu;
> > +	}
> > +
> > +	if (!iommu->vmm) {
> > +		ret = -EINVAL;
> > +		goto out_unlock_iommu;
> > +	}
> > +
> > +	group = vfio_find_nesting_group(iommu);
> > +	if (!group) {
> > +		ret = -EINVAL;
> > +		goto out_unlock_iommu;
> > +	}
> > +
> > +	domain = list_first_entry(&iommu->domain_list,
> > +				      struct vfio_domain, next);
> > +	dc.group = group;
> > +	dc.domain = domain->domain;
> > +
> > +	/* Avoid race with other containers within the same process */
> > +	vfio_mm_pasid_lock(iommu->vmm);
> > +
> > +	if (is_bind) {
> > +		ret = iommu_group_for_each_dev(group->iommu_group, &dc,
> > +					       vfio_dev_bind_gpasid_fn);
> > +		if (ret)
> > +			iommu_group_for_each_dev(group->iommu_group,
> &dc,
> > +						 vfio_dev_unbind_gpasid_fn);
> > +	} else {
> > +		iommu_group_for_each_dev(group->iommu_group,
> > +					 &dc, vfio_dev_unbind_gpasid_fn);
> > +		ret = 0;
> > +	}
> > +
> > +	vfio_mm_pasid_unlock(iommu->vmm);
> > +out_unlock_iommu:
> > +	mutex_unlock(&iommu->lock);
> > +	return ret;
> > +}
> > +
> > +static long vfio_iommu_type1_nesting_op(struct vfio_iommu *iommu,
> > +					unsigned long arg)
> > +{
> > +	struct vfio_iommu_type1_nesting_op hdr;
> > +	unsigned int minsz;
> > +	int ret;
> > +
> > +	minsz = offsetofend(struct vfio_iommu_type1_nesting_op, flags);
> > +
> > +	if (copy_from_user(&hdr, (void __user *)arg, minsz))
> > +		return -EFAULT;
> > +
> > +	if (hdr.argsz < minsz || hdr.flags & ~VFIO_NESTING_OP_MASK)
> > +		return -EINVAL;
> > +
> > +	switch (hdr.flags & VFIO_NESTING_OP_MASK) {
> > +	case VFIO_IOMMU_NESTING_OP_BIND_PGTBL:
> > +		ret = vfio_iommu_handle_pgtbl_op(iommu, true, arg + minsz);
> > +		break;
> > +	case VFIO_IOMMU_NESTING_OP_UNBIND_PGTBL:
> > +		ret = vfio_iommu_handle_pgtbl_op(iommu, false, arg + minsz);
> > +		break;
> > +	default:
> > +		ret = -EINVAL;
> > +	}
> > +
> > +	return ret;
> > +}
> > +
> >  static long vfio_iommu_type1_ioctl(void *iommu_data,
> >  				   unsigned int cmd, unsigned long arg)  { @@ -
> 2960,6 +3127,8 @@
> > static long vfio_iommu_type1_ioctl(void *iommu_data,
> >  		return vfio_iommu_type1_dirty_pages(iommu, arg);
> >  	case VFIO_IOMMU_PASID_REQUEST:
> >  		return vfio_iommu_type1_pasid_request(iommu, arg);
> > +	case VFIO_IOMMU_NESTING_OP:
> > +		return vfio_iommu_type1_nesting_op(iommu, arg);
> >  	}
> >
> >  	return -ENOTTY;
> > diff --git a/drivers/vfio/vfio_pasid.c b/drivers/vfio/vfio_pasid.c
> > index 2ea9f1a..20f1e72 100644
> > --- a/drivers/vfio/vfio_pasid.c
> > +++ b/drivers/vfio/vfio_pasid.c
> > @@ -30,6 +30,7 @@ struct vfio_mm {
> >  	struct kref		kref;
> >  	struct vfio_mm_token	token;
> >  	int			ioasid_sid;
> > +	struct mutex		pasid_lock;
> 
> 
> Introducing holes in the data structure again, mind the alignment.
> This wastes 8 byte.  Thanks,

sure. also it's likely to remove @pasid_quota. so it should avoid the
hole as well.

Regards,
Yi Liu

> Alex
> 
> 
> >  	int			pasid_quota;
> >  	struct list_head	next;
> >  };
> > @@ -97,6 +98,7 @@ struct vfio_mm *vfio_mm_get_from_task(struct
> task_struct *task)
> >  	kref_init(&vmm->kref);
> >  	vmm->token.val = (unsigned long long) mm;
> >  	vmm->pasid_quota = pasid_quota;
> > +	mutex_init(&vmm->pasid_lock);
> >
> >  	list_add(&vmm->next, &vfio_pasid.vfio_mm_list);
> >  out:
> > @@ -134,12 +136,40 @@ void vfio_pasid_free_range(struct vfio_mm *vmm,
> >  	 * IOASID core will notify PASID users (e.g. IOMMU driver) to
> >  	 * teardown necessary structures depending on the to-be-freed
> >  	 * PASID.
> > +	 * Hold pasid_lock to avoid race with PASID usages like bind/
> > +	 * unbind page tables to requested PASID.
> >  	 */
> > +	mutex_lock(&vmm->pasid_lock);
> >  	for (; pasid <= max; pasid++)
> >  		ioasid_free(pasid);
> > +	mutex_unlock(&vmm->pasid_lock);
> >  }
> >  EXPORT_SYMBOL_GPL(vfio_pasid_free_range);
> >
> > +int vfio_mm_for_each_pasid(struct vfio_mm *vmm, void *data,
> > +			   void (*fn)(ioasid_t id, void *data)) {
> > +	int ret;
> > +
> > +	mutex_lock(&vmm->pasid_lock);
> > +	ret = ioasid_set_for_each_ioasid(vmm->ioasid_sid, fn, data);
> > +	mutex_unlock(&vmm->pasid_lock);
> > +	return ret;
> > +}
> > +EXPORT_SYMBOL_GPL(vfio_mm_for_each_pasid);
> > +
> > +void vfio_mm_pasid_lock(struct vfio_mm *vmm) {
> > +	mutex_lock(&vmm->pasid_lock);
> > +}
> > +EXPORT_SYMBOL_GPL(vfio_mm_pasid_lock);
> > +
> > +void vfio_mm_pasid_unlock(struct vfio_mm *vmm) {
> > +	mutex_unlock(&vmm->pasid_lock);
> > +}
> > +EXPORT_SYMBOL_GPL(vfio_mm_pasid_unlock);
> > +
> >  static int __init vfio_pasid_init(void)  {
> >  	mutex_init(&vfio_pasid.vfio_mm_lock);
> > diff --git a/include/linux/vfio.h b/include/linux/vfio.h index
> > 8e60a32..9028a09 100644
> > --- a/include/linux/vfio.h
> > +++ b/include/linux/vfio.h
> > @@ -105,6 +105,11 @@ int vfio_mm_ioasid_sid(struct vfio_mm *vmm);
> > extern int vfio_pasid_alloc(struct vfio_mm *vmm, int min, int max);
> > extern void vfio_pasid_free_range(struct vfio_mm *vmm,
> >  					ioasid_t min, ioasid_t max);
> > +extern int vfio_mm_for_each_pasid(struct vfio_mm *vmm, void *data,
> > +				  void (*fn)(ioasid_t id, void *data)); extern void
> > +vfio_mm_pasid_lock(struct vfio_mm *vmm); extern void
> > +vfio_mm_pasid_unlock(struct vfio_mm *vmm);
> > +
> >  #else
> >  static inline struct vfio_mm *vfio_mm_get_from_task(struct
> > task_struct *task)  { @@ -129,6 +134,21 @@ static inline void
> > vfio_pasid_free_range(struct vfio_mm *vmm,
> >  					  ioasid_t min, ioasid_t max)
> >  {
> >  }
> > +
> > +static inline int vfio_mm_for_each_pasid(struct vfio_mm *vmm, void *data,
> > +					 void (*fn)(ioasid_t id, void *data)) {
> > +	return -ENOTTY;
> > +}
> > +
> > +static inline void vfio_mm_pasid_lock(struct vfio_mm *vmm) { }
> > +
> > +static inline void vfio_mm_pasid_unlock(struct vfio_mm *vmm) { }
> > +
> >  #endif /* CONFIG_VFIO_PASID */
> >
> >  /*
> > diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> > index 657b2db..2c9def8 100644
> > --- a/include/uapi/linux/vfio.h
> > +++ b/include/uapi/linux/vfio.h
> > @@ -1198,6 +1198,36 @@ struct vfio_iommu_type1_pasid_request {
> >
> >  #define VFIO_IOMMU_PASID_REQUEST	_IO(VFIO_TYPE, VFIO_BASE + 18)
> >
> > +/**
> > + * VFIO_IOMMU_NESTING_OP - _IOW(VFIO_TYPE, VFIO_BASE + 19,
> > + *				struct vfio_iommu_type1_nesting_op)
> > + *
> > + * This interface allows user space to utilize the nesting IOMMU
> > + * capabilities as reported through VFIO_IOMMU_GET_INFO.
> > + *
> > + * @data[] types defined for each op:
> > + *
> +=================+===========================================
> ====+
> > + * | NESTING OP      |                  @data[]                      |
> > + *
> +=================+===========================================
> ====+
> > + * | BIND_PGTBL      |      struct iommu_gpasid_bind_data            |
> > + * +-----------------+-----------------------------------------------+
> > + * | UNBIND_PGTBL    |      struct iommu_gpasid_bind_data            |
> > + *
> > ++-----------------+-----------------------------------------------+
> > + *
> > + * returns: 0 on success, -errno on failure.
> > + */
> > +struct vfio_iommu_type1_nesting_op {
> > +	__u32	argsz;
> > +	__u32	flags;
> > +#define VFIO_NESTING_OP_MASK	(0xffff) /* lower 16-bits for op */
> > +	__u8	data[];
> > +};
> > +
> > +#define VFIO_IOMMU_NESTING_OP_BIND_PGTBL	(0)
> > +#define VFIO_IOMMU_NESTING_OP_UNBIND_PGTBL	(1)
> > +
> > +#define VFIO_IOMMU_NESTING_OP		_IO(VFIO_TYPE,
> VFIO_BASE + 19)
> > +
> >  /* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU
> > -------- */
> >
> >  /*
diff mbox series

Patch

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index d0891c5..5926533 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -148,6 +148,33 @@  struct vfio_regions {
 #define DIRTY_BITMAP_PAGES_MAX	 ((u64)INT_MAX)
 #define DIRTY_BITMAP_SIZE_MAX	 DIRTY_BITMAP_BYTES(DIRTY_BITMAP_PAGES_MAX)
 
+struct domain_capsule {
+	struct vfio_group *group;
+	struct iommu_domain *domain;
+	void *data;
+};
+
+/* iommu->lock must be held */
+static struct vfio_group *vfio_find_nesting_group(struct vfio_iommu *iommu)
+{
+	struct vfio_domain *d;
+	struct vfio_group *g, *group = NULL;
+
+	if (!iommu->nesting_info)
+		return NULL;
+
+	/* only support singleton container with nesting type */
+	list_for_each_entry(d, &iommu->domain_list, next) {
+		list_for_each_entry(g, &d->group_list, next) {
+			if (!group) {
+				group = g;
+				break;
+			}
+		}
+	}
+	return group;
+}
+
 static int put_pfn(unsigned long pfn, int prot);
 
 static struct vfio_group *vfio_iommu_find_iommu_group(struct vfio_iommu *iommu,
@@ -2351,6 +2378,48 @@  static int vfio_iommu_resv_refresh(struct vfio_iommu *iommu,
 	return ret;
 }
 
+static int vfio_dev_bind_gpasid_fn(struct device *dev, void *data)
+{
+	struct domain_capsule *dc = (struct domain_capsule *)data;
+	unsigned long arg = *(unsigned long *) dc->data;
+
+	return iommu_sva_bind_gpasid(dc->domain, dev, (void __user *) arg);
+}
+
+static int vfio_dev_unbind_gpasid_fn(struct device *dev, void *data)
+{
+	struct domain_capsule *dc = (struct domain_capsule *)data;
+	unsigned long arg = *(unsigned long *) dc->data;
+
+	iommu_sva_unbind_gpasid(dc->domain, dev, (void __user *) arg);
+	return 0;
+}
+
+static int __vfio_dev_unbind_gpasid_fn(struct device *dev, void *data)
+{
+	struct domain_capsule *dc = (struct domain_capsule *)data;
+	struct iommu_gpasid_bind_data *unbind_data =
+				(struct iommu_gpasid_bind_data *) dc->data;
+
+	__iommu_sva_unbind_gpasid(dc->domain, dev, unbind_data);
+	return 0;
+}
+
+static void vfio_group_unbind_gpasid_fn(ioasid_t pasid, void *data)
+{
+	struct domain_capsule *dc = (struct domain_capsule *) data;
+	struct iommu_gpasid_bind_data unbind_data;
+
+	unbind_data.argsz = offsetof(struct iommu_gpasid_bind_data, vendor);
+	unbind_data.flags = 0;
+	unbind_data.hpasid = pasid;
+
+	dc->data = &unbind_data;
+
+	iommu_group_for_each_dev(dc->group->iommu_group,
+				 dc, __vfio_dev_unbind_gpasid_fn);
+}
+
 static void vfio_iommu_type1_detach_group(void *iommu_data,
 					  struct iommu_group *iommu_group)
 {
@@ -2394,6 +2463,21 @@  static void vfio_iommu_type1_detach_group(void *iommu_data,
 		if (!group)
 			continue;
 
+		if (iommu->nesting_info && iommu->vmm &&
+		    (iommu->nesting_info->features &
+					IOMMU_NESTING_FEAT_BIND_PGTBL)) {
+			struct domain_capsule dc = { .group = group,
+						     .domain = domain->domain,
+						     .data = NULL };
+
+			/*
+			 * Unbind page tables bound with system wide PASIDs
+			 * which are allocated to user space.
+			 */
+			vfio_mm_for_each_pasid(iommu->vmm, &dc,
+					       vfio_group_unbind_gpasid_fn);
+		}
+
 		vfio_iommu_detach_group(domain, group);
 		update_dirty_scope = !group->pinned_page_dirty_scope;
 		list_del(&group->next);
@@ -2942,6 +3026,89 @@  static int vfio_iommu_type1_pasid_request(struct vfio_iommu *iommu,
 	}
 }
 
+static long vfio_iommu_handle_pgtbl_op(struct vfio_iommu *iommu,
+				       bool is_bind, unsigned long arg)
+{
+	struct iommu_nesting_info *info;
+	struct domain_capsule dc = { .data = &arg };
+	struct vfio_group *group;
+	struct vfio_domain *domain;
+	int ret;
+
+	mutex_lock(&iommu->lock);
+
+	info = iommu->nesting_info;
+	if (!info || !(info->features & IOMMU_NESTING_FEAT_BIND_PGTBL)) {
+		ret = -ENOTSUPP;
+		goto out_unlock_iommu;
+	}
+
+	if (!iommu->vmm) {
+		ret = -EINVAL;
+		goto out_unlock_iommu;
+	}
+
+	group = vfio_find_nesting_group(iommu);
+	if (!group) {
+		ret = -EINVAL;
+		goto out_unlock_iommu;
+	}
+
+	domain = list_first_entry(&iommu->domain_list,
+				      struct vfio_domain, next);
+	dc.group = group;
+	dc.domain = domain->domain;
+
+	/* Avoid race with other containers within the same process */
+	vfio_mm_pasid_lock(iommu->vmm);
+
+	if (is_bind) {
+		ret = iommu_group_for_each_dev(group->iommu_group, &dc,
+					       vfio_dev_bind_gpasid_fn);
+		if (ret)
+			iommu_group_for_each_dev(group->iommu_group, &dc,
+						 vfio_dev_unbind_gpasid_fn);
+	} else {
+		iommu_group_for_each_dev(group->iommu_group,
+					 &dc, vfio_dev_unbind_gpasid_fn);
+		ret = 0;
+	}
+
+	vfio_mm_pasid_unlock(iommu->vmm);
+out_unlock_iommu:
+	mutex_unlock(&iommu->lock);
+	return ret;
+}
+
+static long vfio_iommu_type1_nesting_op(struct vfio_iommu *iommu,
+					unsigned long arg)
+{
+	struct vfio_iommu_type1_nesting_op hdr;
+	unsigned int minsz;
+	int ret;
+
+	minsz = offsetofend(struct vfio_iommu_type1_nesting_op, flags);
+
+	if (copy_from_user(&hdr, (void __user *)arg, minsz))
+		return -EFAULT;
+
+	if (hdr.argsz < minsz || hdr.flags & ~VFIO_NESTING_OP_MASK)
+		return -EINVAL;
+
+	switch (hdr.flags & VFIO_NESTING_OP_MASK) {
+	case VFIO_IOMMU_NESTING_OP_BIND_PGTBL:
+		ret = vfio_iommu_handle_pgtbl_op(iommu, true, arg + minsz);
+		break;
+	case VFIO_IOMMU_NESTING_OP_UNBIND_PGTBL:
+		ret = vfio_iommu_handle_pgtbl_op(iommu, false, arg + minsz);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
 static long vfio_iommu_type1_ioctl(void *iommu_data,
 				   unsigned int cmd, unsigned long arg)
 {
@@ -2960,6 +3127,8 @@  static long vfio_iommu_type1_ioctl(void *iommu_data,
 		return vfio_iommu_type1_dirty_pages(iommu, arg);
 	case VFIO_IOMMU_PASID_REQUEST:
 		return vfio_iommu_type1_pasid_request(iommu, arg);
+	case VFIO_IOMMU_NESTING_OP:
+		return vfio_iommu_type1_nesting_op(iommu, arg);
 	}
 
 	return -ENOTTY;
diff --git a/drivers/vfio/vfio_pasid.c b/drivers/vfio/vfio_pasid.c
index 2ea9f1a..20f1e72 100644
--- a/drivers/vfio/vfio_pasid.c
+++ b/drivers/vfio/vfio_pasid.c
@@ -30,6 +30,7 @@  struct vfio_mm {
 	struct kref		kref;
 	struct vfio_mm_token	token;
 	int			ioasid_sid;
+	struct mutex		pasid_lock;
 	int			pasid_quota;
 	struct list_head	next;
 };
@@ -97,6 +98,7 @@  struct vfio_mm *vfio_mm_get_from_task(struct task_struct *task)
 	kref_init(&vmm->kref);
 	vmm->token.val = (unsigned long long) mm;
 	vmm->pasid_quota = pasid_quota;
+	mutex_init(&vmm->pasid_lock);
 
 	list_add(&vmm->next, &vfio_pasid.vfio_mm_list);
 out:
@@ -134,12 +136,40 @@  void vfio_pasid_free_range(struct vfio_mm *vmm,
 	 * IOASID core will notify PASID users (e.g. IOMMU driver) to
 	 * teardown necessary structures depending on the to-be-freed
 	 * PASID.
+	 * Hold pasid_lock to avoid race with PASID usages like bind/
+	 * unbind page tables to requested PASID.
 	 */
+	mutex_lock(&vmm->pasid_lock);
 	for (; pasid <= max; pasid++)
 		ioasid_free(pasid);
+	mutex_unlock(&vmm->pasid_lock);
 }
 EXPORT_SYMBOL_GPL(vfio_pasid_free_range);
 
+int vfio_mm_for_each_pasid(struct vfio_mm *vmm, void *data,
+			   void (*fn)(ioasid_t id, void *data))
+{
+	int ret;
+
+	mutex_lock(&vmm->pasid_lock);
+	ret = ioasid_set_for_each_ioasid(vmm->ioasid_sid, fn, data);
+	mutex_unlock(&vmm->pasid_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(vfio_mm_for_each_pasid);
+
+void vfio_mm_pasid_lock(struct vfio_mm *vmm)
+{
+	mutex_lock(&vmm->pasid_lock);
+}
+EXPORT_SYMBOL_GPL(vfio_mm_pasid_lock);
+
+void vfio_mm_pasid_unlock(struct vfio_mm *vmm)
+{
+	mutex_unlock(&vmm->pasid_lock);
+}
+EXPORT_SYMBOL_GPL(vfio_mm_pasid_unlock);
+
 static int __init vfio_pasid_init(void)
 {
 	mutex_init(&vfio_pasid.vfio_mm_lock);
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 8e60a32..9028a09 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -105,6 +105,11 @@  int vfio_mm_ioasid_sid(struct vfio_mm *vmm);
 extern int vfio_pasid_alloc(struct vfio_mm *vmm, int min, int max);
 extern void vfio_pasid_free_range(struct vfio_mm *vmm,
 					ioasid_t min, ioasid_t max);
+extern int vfio_mm_for_each_pasid(struct vfio_mm *vmm, void *data,
+				  void (*fn)(ioasid_t id, void *data));
+extern void vfio_mm_pasid_lock(struct vfio_mm *vmm);
+extern void vfio_mm_pasid_unlock(struct vfio_mm *vmm);
+
 #else
 static inline struct vfio_mm *vfio_mm_get_from_task(struct task_struct *task)
 {
@@ -129,6 +134,21 @@  static inline void vfio_pasid_free_range(struct vfio_mm *vmm,
 					  ioasid_t min, ioasid_t max)
 {
 }
+
+static inline int vfio_mm_for_each_pasid(struct vfio_mm *vmm, void *data,
+					 void (*fn)(ioasid_t id, void *data))
+{
+	return -ENOTTY;
+}
+
+static inline void vfio_mm_pasid_lock(struct vfio_mm *vmm)
+{
+}
+
+static inline void vfio_mm_pasid_unlock(struct vfio_mm *vmm)
+{
+}
+
 #endif /* CONFIG_VFIO_PASID */
 
 /*
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 657b2db..2c9def8 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -1198,6 +1198,36 @@  struct vfio_iommu_type1_pasid_request {
 
 #define VFIO_IOMMU_PASID_REQUEST	_IO(VFIO_TYPE, VFIO_BASE + 18)
 
+/**
+ * VFIO_IOMMU_NESTING_OP - _IOW(VFIO_TYPE, VFIO_BASE + 19,
+ *				struct vfio_iommu_type1_nesting_op)
+ *
+ * This interface allows user space to utilize the nesting IOMMU
+ * capabilities as reported through VFIO_IOMMU_GET_INFO.
+ *
+ * @data[] types defined for each op:
+ * +=================+===============================================+
+ * | NESTING OP      |                  @data[]                      |
+ * +=================+===============================================+
+ * | BIND_PGTBL      |      struct iommu_gpasid_bind_data            |
+ * +-----------------+-----------------------------------------------+
+ * | UNBIND_PGTBL    |      struct iommu_gpasid_bind_data            |
+ * +-----------------+-----------------------------------------------+
+ *
+ * returns: 0 on success, -errno on failure.
+ */
+struct vfio_iommu_type1_nesting_op {
+	__u32	argsz;
+	__u32	flags;
+#define VFIO_NESTING_OP_MASK	(0xffff) /* lower 16-bits for op */
+	__u8	data[];
+};
+
+#define VFIO_IOMMU_NESTING_OP_BIND_PGTBL	(0)
+#define VFIO_IOMMU_NESTING_OP_UNBIND_PGTBL	(1)
+
+#define VFIO_IOMMU_NESTING_OP		_IO(VFIO_TYPE, VFIO_BASE + 19)
+
 /* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU -------- */
 
 /*