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b=ZhSoPPqDaXKWFQfhMJt7nXhPFooRpplEESl6LlGOhAjmnCjHSTq0Ly9V1ePX5DvWsm9s+T iStoTRQZDi9F8YbWJWgCkROpXi8VhHhFUMFEP21MKT253rLgrkqP6Kvv7fi0nnfPgJywJD XIbJDGeHtemonc6Anurpskyx8sp7X90= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-13-CZHiQQ-SN-eFlbqOyIoz6A-1; Sun, 19 Jul 2020 11:39:07 -0400 X-MC-Unique: CZHiQQ-SN-eFlbqOyIoz6A-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E050810059A4; Sun, 19 Jul 2020 15:39:04 +0000 (UTC) Received: from [10.36.115.54] (ovpn-115-54.ams2.redhat.com [10.36.115.54]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D9A0E78492; Sun, 19 Jul 2020 15:38:54 +0000 (UTC) Subject: Re: [PATCH v5 07/15] vfio/type1: Add VFIO_IOMMU_PASID_REQUEST (alloc/free) To: Liu Yi L , alex.williamson@redhat.com, baolu.lu@linux.intel.com, joro@8bytes.org References: <1594552870-55687-1-git-send-email-yi.l.liu@intel.com> <1594552870-55687-8-git-send-email-yi.l.liu@intel.com> From: Auger Eric Message-ID: <6199a51b-3459-c596-e651-bb30d3b3d645@redhat.com> Date: Sun, 19 Jul 2020 17:38:53 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <1594552870-55687-8-git-send-email-yi.l.liu@intel.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Cc: jean-philippe@linaro.org, kevin.tian@intel.com, ashok.raj@intel.com, kvm@vger.kernel.org, stefanha@gmail.com, jun.j.tian@intel.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, yi.y.sun@intel.com, hao.wu@intel.com X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" Yi, On 7/12/20 1:21 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 > 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 > --- > v4 -> v5: > *) address comments from Eric Auger. > *) the comments for the PASID_FREE request is addressed in patch 5/15 of > this series. > > 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?" > https://lore.kernel.org/linux-iommu/20200702151832.048b44d1@x1.home/ > > 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 | 85 +++++++++++++++++++++++++++++++++++++++++ > drivers/vfio/vfio_pasid.c | 10 +++++ > include/linux/vfio.h | 6 +++ > include/uapi/linux/vfio.h | 37 ++++++++++++++++++ > 5 files changed, 139 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 ed80104..55b4065 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; > } > @@ -2071,6 +2077,26 @@ static int vfio_iommu_type1_attach_group(void *iommu_data, > iommu->nesting_info); > if (ret) > goto out_detach; > + > + if (iommu->nesting_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 */ > @@ -2855,6 +2881,63 @@ 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:not sure it is worth to introduce both vfio_iommu_type1_pasid_free/alloc helpers. You could take the lock above, and test iommu->vmm as well above. > + 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) > { > @@ -2871,6 +2954,8 @@ 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); > default: > return -ENOTTY; > } > diff --git a/drivers/vfio/vfio_pasid.c b/drivers/vfio/vfio_pasid.c > index 66e6054e..ebec244 100644 > --- a/drivers/vfio/vfio_pasid.c > +++ b/drivers/vfio/vfio_pasid.c > @@ -61,6 +61,7 @@ void vfio_mm_put(struct vfio_mm *vmm) > { > kref_put_mutex(&vmm->kref, vfio_mm_release, &vfio_mm_lock); > } > +EXPORT_SYMBOL_GPL(vfio_mm_put); > > static void vfio_mm_get(struct vfio_mm *vmm) > { > @@ -114,6 +115,13 @@ 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); > > /* > * Find PASID within @min and @max > @@ -197,6 +205,7 @@ int vfio_pasid_alloc(struct vfio_mm *vmm, int min, int max) > > return pasid; > } > +EXPORT_SYMBOL_GPL(vfio_pasid_alloc); > > void vfio_pasid_free_range(struct vfio_mm *vmm, > ioasid_t min, ioasid_t max) > @@ -213,6 +222,7 @@ void vfio_pasid_free_range(struct vfio_mm *vmm, > vfio_remove_pasid(vmm, vid); > mutex_unlock(&vmm->pasid_lock); > } > +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 31472a9..a111108 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); I still don't get why it does not take an extern as the other functions implemented in vfio_pasid.c and used in other modules. what's the difference? > 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 46a78af..96a115f 100644 > --- a/include/uapi/linux/vfio.h > +++ b/include/uapi/linux/vfio.h > @@ -1172,6 +1172,43 @@ 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 by the underlying > + * provides an interface for userspace to request pasid alloc/free > + * for its assigned devices. Userspace should check the availability > + * of this API by checking VFIO_IOMMU_TYPE1_INFO_CAP_NESTING through > + * VFIO_IOMMU_GET_INFO. > + * > + * @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 -------- */ > > /* > Otherwise, besides the pieces I would have put directly in the vfio_pasid module patch (EXPORT_SYMBOL_GPL and vfio_mm_ioasid_sid), looks good. Thanks Eric _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu