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charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Wed, 24 Jun 2020 01:55:19 -0700 Liu Yi L wrote: > This patch allows user space to request PASID allocation/free, e.g. when > serving the request from the guest. > > PASIDs that are not freed by userspace are automatically freed when the > IOASID set is destroyed when process exits. > > Cc: Kevin Tian > CC: Jacob Pan > Cc: Alex Williamson > Cc: Eric Auger > Cc: Jean-Philippe Brucker > Cc: Joerg Roedel > Cc: Lu Baolu > Signed-off-by: Liu Yi L > Signed-off-by: Yi Sun > Signed-off-by: Jacob Pan > --- > v1 -> v2: > *) move the vfio_mm related code to be a seprate module > *) use a single structure for alloc/free, could support a range of PASIDs > *) fetch vfio_mm at group_attach time instead of at iommu driver open time > --- > drivers/vfio/Kconfig | 1 + > drivers/vfio/vfio_iommu_type1.c | 96 ++++++++++++++++++++++++++++++++++++++++- > drivers/vfio/vfio_pasid.c | 10 +++++ > include/linux/vfio.h | 6 +++ > include/uapi/linux/vfio.h | 36 ++++++++++++++++ > 5 files changed, 147 insertions(+), 2 deletions(-) > > diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig > index 3d8a108..95d90c6 100644 > --- a/drivers/vfio/Kconfig > +++ b/drivers/vfio/Kconfig > @@ -2,6 +2,7 @@ > config VFIO_IOMMU_TYPE1 > tristate > depends on VFIO > + select VFIO_PASID if (X86) > default n > > config VFIO_IOMMU_SPAPR_TCE > diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c > index 8c143d5..d0891c5 100644 > --- a/drivers/vfio/vfio_iommu_type1.c > +++ b/drivers/vfio/vfio_iommu_type1.c > @@ -73,6 +73,7 @@ struct vfio_iommu { > bool v2; > bool nesting; > struct iommu_nesting_info *nesting_info; > + struct vfio_mm *vmm; Structure alignment again. > bool dirty_page_tracking; > bool pinned_page_dirty_scope; > }; > @@ -1933,6 +1934,17 @@ static void vfio_iommu_iova_insert_copy(struct vfio_iommu *iommu, > > list_splice_tail(iova_copy, iova); > } > + > +static void vfio_iommu_release_nesting_info(struct vfio_iommu *iommu) > +{ > + if (iommu->vmm) { > + vfio_mm_put(iommu->vmm); > + iommu->vmm = NULL; > + } > + > + kfree(iommu->nesting_info); iommu->nesting_info = NULL; > +} > + > static int vfio_iommu_type1_attach_group(void *iommu_data, > struct iommu_group *iommu_group) > { > @@ -2067,6 +2079,25 @@ static int vfio_iommu_type1_attach_group(void *iommu_data, > goto out_detach; > } > iommu->nesting_info = info; > + > + if (info->features & IOMMU_NESTING_FEAT_SYSWIDE_PASID) { > + struct vfio_mm *vmm; > + int sid; > + > + vmm = vfio_mm_get_from_task(current); > + if (IS_ERR(vmm)) { > + ret = PTR_ERR(vmm); > + goto out_detach; > + } > + iommu->vmm = vmm; > + > + sid = vfio_mm_ioasid_sid(vmm); > + ret = iommu_domain_set_attr(domain->domain, > + DOMAIN_ATTR_IOASID_SID, > + &sid); This looks pretty dicey in the case of !CONFIG_VFIO_PASID, can we get here in that case? If so it looks like we're doing bad things with setting the domain->ioasid_sid. > + if (ret) > + goto out_detach; > + } > } > > /* Get aperture info */ > @@ -2178,7 +2209,8 @@ static int vfio_iommu_type1_attach_group(void *iommu_data, > return 0; > > out_detach: > - kfree(iommu->nesting_info); > + if (iommu->nesting_info) > + vfio_iommu_release_nesting_info(iommu); Make vfio_iommu_release_nesting_info() check iommu->nesting_info, then call it unconditionally? > vfio_iommu_detach_group(domain, group); > out_domain: > iommu_domain_free(domain->domain); > @@ -2380,7 +2412,8 @@ static void vfio_iommu_type1_detach_group(void *iommu_data, > else > vfio_iommu_unmap_unpin_reaccount(iommu); > > - kfree(iommu->nesting_info); > + if (iommu->nesting_info) > + vfio_iommu_release_nesting_info(iommu); > } > iommu_domain_free(domain->domain); > list_del(&domain->next); > @@ -2852,6 +2885,63 @@ static int vfio_iommu_type1_dirty_pages(struct vfio_iommu *iommu, > return -EINVAL; > } > > +static int vfio_iommu_type1_pasid_alloc(struct vfio_iommu *iommu, > + unsigned int min, > + unsigned int max) > +{ > + int ret = -ENOTSUPP; > + > + mutex_lock(&iommu->lock); > + if (iommu->vmm) > + ret = vfio_pasid_alloc(iommu->vmm, min, max); > + mutex_unlock(&iommu->lock); > + return ret; > +} > + > +static int vfio_iommu_type1_pasid_free(struct vfio_iommu *iommu, > + unsigned int min, > + unsigned int max) > +{ > + int ret = -ENOTSUPP; > + > + mutex_lock(&iommu->lock); > + if (iommu->vmm) { > + vfio_pasid_free_range(iommu->vmm, min, max); > + ret = 0; > + } > + mutex_unlock(&iommu->lock); > + return ret; > +} > + > +static int vfio_iommu_type1_pasid_request(struct vfio_iommu *iommu, > + unsigned long arg) > +{ > + struct vfio_iommu_type1_pasid_request req; > + unsigned long minsz; > + > + minsz = offsetofend(struct vfio_iommu_type1_pasid_request, range); > + > + if (copy_from_user(&req, (void __user *)arg, minsz)) > + return -EFAULT; > + > + if (req.argsz < minsz || (req.flags & ~VFIO_PASID_REQUEST_MASK)) > + return -EINVAL; > + > + if (req.range.min > req.range.max) Is it exploitable that a user can spin the kernel for a long time in the case of a free by calling this with [0, MAX_UINT] regardless of their actual allocations? > + return -EINVAL; > + > + switch (req.flags & VFIO_PASID_REQUEST_MASK) { > + case VFIO_IOMMU_ALLOC_PASID: > + return vfio_iommu_type1_pasid_alloc(iommu, > + req.range.min, req.range.max); > + case VFIO_IOMMU_FREE_PASID: > + return vfio_iommu_type1_pasid_free(iommu, > + req.range.min, req.range.max); > + default: > + return -EINVAL; > + } > +} > + > static long vfio_iommu_type1_ioctl(void *iommu_data, > unsigned int cmd, unsigned long arg) > { > @@ -2868,6 +2958,8 @@ static long vfio_iommu_type1_ioctl(void *iommu_data, > return vfio_iommu_type1_unmap_dma(iommu, arg); > case VFIO_IOMMU_DIRTY_PAGES: > return vfio_iommu_type1_dirty_pages(iommu, arg); > + case VFIO_IOMMU_PASID_REQUEST: > + return vfio_iommu_type1_pasid_request(iommu, arg); > } > > return -ENOTTY; > diff --git a/drivers/vfio/vfio_pasid.c b/drivers/vfio/vfio_pasid.c > index dd5b6d1..2ea9f1a 100644 > --- a/drivers/vfio/vfio_pasid.c > +++ b/drivers/vfio/vfio_pasid.c > @@ -54,6 +54,7 @@ void vfio_mm_put(struct vfio_mm *vmm) > { > kref_put_mutex(&vmm->kref, vfio_mm_release, &vfio_pasid.vfio_mm_lock); > } > +EXPORT_SYMBOL_GPL(vfio_mm_put); > > static void vfio_mm_get(struct vfio_mm *vmm) > { > @@ -103,6 +104,13 @@ struct vfio_mm *vfio_mm_get_from_task(struct task_struct *task) > mmput(mm); > return vmm; > } > +EXPORT_SYMBOL_GPL(vfio_mm_get_from_task); > + > +int vfio_mm_ioasid_sid(struct vfio_mm *vmm) > +{ > + return vmm->ioasid_sid; > +} > +EXPORT_SYMBOL_GPL(vfio_mm_ioasid_sid); > > int vfio_pasid_alloc(struct vfio_mm *vmm, int min, int max) > { > @@ -112,6 +120,7 @@ int vfio_pasid_alloc(struct vfio_mm *vmm, int min, int max) > > return (pasid == INVALID_IOASID) ? -ENOSPC : pasid; > } > +EXPORT_SYMBOL_GPL(vfio_pasid_alloc); > > void vfio_pasid_free_range(struct vfio_mm *vmm, > ioasid_t min, ioasid_t max) > @@ -129,6 +138,7 @@ void vfio_pasid_free_range(struct vfio_mm *vmm, > for (; pasid <= max; pasid++) > ioasid_free(pasid); > } > +EXPORT_SYMBOL_GPL(vfio_pasid_free_range); > > static int __init vfio_pasid_init(void) > { > diff --git a/include/linux/vfio.h b/include/linux/vfio.h > index 74e077d..8e60a32 100644 > --- a/include/linux/vfio.h > +++ b/include/linux/vfio.h > @@ -101,6 +101,7 @@ struct vfio_mm; > #if IS_ENABLED(CONFIG_VFIO_PASID) > extern struct vfio_mm *vfio_mm_get_from_task(struct task_struct *task); > extern void vfio_mm_put(struct vfio_mm *vmm); > +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); > @@ -114,6 +115,11 @@ static inline void vfio_mm_put(struct vfio_mm *vmm) > { > } > > +static inline int vfio_mm_ioasid_sid(struct vfio_mm *vmm) > +{ > + return -ENOTTY; > +} > + > static inline int vfio_pasid_alloc(struct vfio_mm *vmm, int min, int max) > { > return -ENOTTY; > diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h > index f1f39e1..657b2db 100644 > --- a/include/uapi/linux/vfio.h > +++ b/include/uapi/linux/vfio.h > @@ -1162,6 +1162,42 @@ struct vfio_iommu_type1_dirty_bitmap_get { > > #define VFIO_IOMMU_DIRTY_PAGES _IO(VFIO_TYPE, VFIO_BASE + 17) > > +/** > + * VFIO_IOMMU_PASID_REQUEST - _IOWR(VFIO_TYPE, VFIO_BASE + 18, > + * struct vfio_iommu_type1_pasid_request) > + * > + * PASID (Processor Address Space ID) is a PCIe concept for tagging > + * address spaces in DMA requests. When system-wide PASID allocation > + * is required by underlying iommu driver (e.g. Intel VT-d), this > + * provides an interface for userspace to request pasid alloc/free > + * for its assigned devices. Userspace should check the availability > + * of this API through VFIO_IOMMU_GET_INFO. > + * > + * @flags=VFIO_IOMMU_ALLOC_PASID, allocate a single PASID within @range. > + * @flags=VFIO_IOMMU_FREE_PASID, free the PASIDs within @range. > + * @range is [min, max], which means both @min and @max are inclusive. > + * ALLOC_PASID and FREE_PASID are mutually exclusive. > + * > + * returns: allocated PASID value on success, -errno on failure for > + * ALLOC_PASID; > + * 0 for FREE_PASID operation; > + */ > +struct vfio_iommu_type1_pasid_request { > + __u32 argsz; > +#define VFIO_IOMMU_ALLOC_PASID (1 << 0) > +#define VFIO_IOMMU_FREE_PASID (1 << 1) VFIO_IOMMU_PASID_FLAG_{ALLOC,FREE} would be more similar to other VFIO UAPI conventions. Thanks, Alex > + __u32 flags; > + struct { > + __u32 min; > + __u32 max; > + } range; > +}; > + > +#define VFIO_PASID_REQUEST_MASK (VFIO_IOMMU_ALLOC_PASID | \ > + VFIO_IOMMU_FREE_PASID) > + > +#define VFIO_IOMMU_PASID_REQUEST _IO(VFIO_TYPE, VFIO_BASE + 18) > + > /* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU -------- */ > > /* _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu