Hi Yi,
On 7/4/20 1:26 PM, 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 <kevin.tian@xxxxxxxxx>
> CC: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> Cc: Alex Williamson <alex.williamson@xxxxxxxxxx>
> Cc: Eric Auger <eric.auger@xxxxxxxxxx>
> Cc: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>
> Cc: Joerg Roedel <joro@xxxxxxxxxx>
> Cc: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> Signed-off-by: Liu Yi L <yi.l.liu@xxxxxxxxx>
> Signed-off-by: Yi Sun <yi.y.sun@xxxxxxxxxxxxxxx>
> Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> ---
> v3 -> v4:
> *) address comments from v3, except the below comment against the range
> of PASID_FREE request. needs more help on it.
> "> +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?"
>
> 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 | 84 +++++++++++++++++++++++++++++++++++++++++
> drivers/vfio/vfio_pasid.c | 10 +++++
> include/linux/vfio.h | 6 +++
> include/uapi/linux/vfio.h | 36 ++++++++++++++++++
> 5 files changed, 137 insertions(+)
>
> 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 80623b8..29726ca 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -76,6 +76,7 @@ struct vfio_iommu {
> bool dirty_page_tracking;
> bool pinned_page_dirty_scope;
> struct iommu_nesting_info *nesting_info;
> + struct vfio_mm *vmm;
> };
>
> struct vfio_domain {
> @@ -1937,6 +1938,11 @@ static void vfio_iommu_iova_insert_copy(struct vfio_iommu *iommu,
>
> 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;
> }
> @@ -2075,6 +2081,25 @@ 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);
> + if (ret)
> + goto out_detach;
> + }
> }
>
> /* Get aperture info */
> @@ -2860,6 +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 = -EOPNOTSUPP;
> +
> + 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 = -EOPNOTSUPP;
> +
> + 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)
> + return -EINVAL;
> +
> + switch (req.flags & VFIO_PASID_REQUEST_MASK) {
> + case VFIO_IOMMU_FLAG_ALLOC_PASID:
> + return vfio_iommu_type1_pasid_alloc(iommu,
> + req.range.min, req.range.max);
> + case VFIO_IOMMU_FLAG_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)
> {
> @@ -2876,6 +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 c46b870..6f907db 100644
> --- a/drivers/vfio/vfio_pasid.c
> +++ b/drivers/vfio/vfio_pasid.c
> @@ -53,6 +53,7 @@ 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);
I think this should be belong to [5/15]
>
> static void vfio_mm_get(struct vfio_mm *vmm)
> {
> @@ -104,6 +105,13 @@ struct vfio_mm *vfio_mm_get_from_task(struct task_struct *task)
> mmput(mm);
> return vmm;
> }
> +EXPORT_SYMBOL_GPL(vfio_mm_get_from_task);
same
> +
> +int vfio_mm_ioasid_sid(struct vfio_mm *vmm)
extern?
same
> +{
> + return vmm->ioasid_sid;
> +}
> +EXPORT_SYMBOL_GPL(vfio_mm_ioasid_sid);
>
> int vfio_pasid_alloc(struct vfio_mm *vmm, int min, int max)
> {
> @@ -113,6 +121,7 @@ int vfio_pasid_alloc(struct vfio_mm *vmm, int min, int max)
>
> return (pasid == INVALID_IOASID) ? -ENOSPC : pasid;
> }
> +EXPORT_SYMBOL_GPL(vfio_pasid_alloc);
same
>
> void vfio_pasid_free_range(struct vfio_mm *vmm,
> ioasid_t min, ioasid_t max)
> @@ -130,6 +139,7 @@ void vfio_pasid_free_range(struct vfio_mm *vmm,
> for (; pasid <= max; pasid++)
> ioasid_free(pasid);
> }
> +EXPORT_SYMBOL_GPL(vfio_pasid_free_range);
same
>
> static int __init vfio_pasid_init(void)
> {
> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> index 9da6468..35c922a 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 3e3de9c..fe267b8e 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -1169,6 +1169,42 @@ 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.
name the capability?
> + *
> + * @flags=VFIO_IOMMU_FLAG_ALLOC_PASID, allocate a single PASID within @range.
> + * @flags=VFIO_IOMMU_FLAG_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_FLAG_ALLOC_PASID (1 << 0)
> +#define VFIO_IOMMU_FLAG_FREE_PASID (1 << 1)
> + __u32 flags;> + struct {
> + __u32 min;
> + __u32 max;
> + } range;
> +};
> +
> +#define VFIO_PASID_REQUEST_MASK (VFIO_IOMMU_FLAG_ALLOC_PASID | \
> + VFIO_IOMMU_FLAG_FREE_PASID)
> +
> +#define VFIO_IOMMU_PASID_REQUEST _IO(VFIO_TYPE, VFIO_BASE + 18)
> +
> /* -------- Additional API for SPAPR TCE (Server POWERPC) IOMMU -------- */
>
> /*
>
Thanks
Eric
