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Mon, 06 Jul 2020 10:52:36 -0400 X-MC-Unique: Hcz54taRNeu1kfUNbtkFeA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B243D18FF660; Mon, 6 Jul 2020 14:52:34 +0000 (UTC) Received: from [10.36.113.241] (ovpn-113-241.ams2.redhat.com [10.36.113.241]) by smtp.corp.redhat.com (Postfix) with ESMTPS id EAD7461462; Mon, 6 Jul 2020 14:52:25 +0000 (UTC) Subject: Re: [PATCH v4 05/15] vfio: Add PASID allocation/free support To: Liu Yi L , alex.williamson@redhat.com, baolu.lu@linux.intel.com, joro@8bytes.org References: <1593861989-35920-1-git-send-email-yi.l.liu@intel.com> <1593861989-35920-6-git-send-email-yi.l.liu@intel.com> From: Auger Eric Message-ID: <0d4ad4ac-ae89-a2ca-d302-94463ee5fc7f@redhat.com> Date: Mon, 6 Jul 2020 16:52:24 +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: <1593861989-35920-6-git-send-email-yi.l.liu@intel.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 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" Hi Yi, On 7/4/20 1:26 PM, Liu Yi L wrote: > Shared Virtual Addressing (a.k.a Shared Virtual Memory) allows sharing > multiple process virtual address spaces with the device for simplified > programming model. PASID is used to tag an virtual address space in DMA > requests and to identify the related translation structure in IOMMU. When > a PASID-capable device is assigned to a VM, we want the same capability > of using PASID to tag guest process virtual address spaces to achieve > virtual SVA (vSVA). > > PASID management for guest is vendor specific. Some vendors (e.g. Intel > VT-d) requires system-wide managed PASIDs cross all devices, regardless > of whether a device is used by host or assigned to guest. Other vendors > (e.g. ARM SMMU) may allow PASIDs managed per-device thus could be fully > delegated to the guest for assigned devices. > > For system-wide managed PASIDs, this patch introduces a vfio module to > handle explicit PASID alloc/free requests from guest. Allocated PASIDs > are associated to a process (or, mm_struct) in IOASID core. A vfio_mm > object is introduced to track mm_struct. Multiple VFIO containers within > a process share the same vfio_mm object. > > A quota mechanism is provided to prevent malicious user from exhausting > available PASIDs. Currently the quota is a global parameter applied to > all VFIO devices. In the future per-device quota might be supported too. > > Cc: Kevin Tian > CC: Jacob Pan > Cc: Eric Auger > Cc: Jean-Philippe Brucker > Cc: Joerg Roedel > Cc: Lu Baolu > Suggested-by: Alex Williamson > Signed-off-by: Liu Yi L > --- > v3 -> v4: > *) fix lock leam in vfio_mm_get_from_task() > *) drop pasid_quota field in struct vfio_mm > *) vfio_mm_get_from_task() returns ERR_PTR(-ENOTTY) when !CONFIG_VFIO_PASID > > v1 -> v2: > *) added in v2, split from the pasid alloc/free support of v1 > --- > drivers/vfio/Kconfig | 5 ++ > drivers/vfio/Makefile | 1 + > drivers/vfio/vfio_pasid.c | 152 ++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/vfio.h | 28 +++++++++ > 4 files changed, 186 insertions(+) > create mode 100644 drivers/vfio/vfio_pasid.c > > diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig > index fd17db9..3d8a108 100644 > --- a/drivers/vfio/Kconfig > +++ b/drivers/vfio/Kconfig > @@ -19,6 +19,11 @@ config VFIO_VIRQFD > depends on VFIO && EVENTFD > default n > > +config VFIO_PASID > + tristate > + depends on IOASID && VFIO > + default n > + > menuconfig VFIO > tristate "VFIO Non-Privileged userspace driver framework" > depends on IOMMU_API > diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile > index de67c47..bb836a3 100644 > --- a/drivers/vfio/Makefile > +++ b/drivers/vfio/Makefile > @@ -3,6 +3,7 @@ vfio_virqfd-y := virqfd.o > > obj-$(CONFIG_VFIO) += vfio.o > obj-$(CONFIG_VFIO_VIRQFD) += vfio_virqfd.o > +obj-$(CONFIG_VFIO_PASID) += vfio_pasid.o > obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_type1.o > obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o > obj-$(CONFIG_VFIO_SPAPR_EEH) += vfio_spapr_eeh.o > diff --git a/drivers/vfio/vfio_pasid.c b/drivers/vfio/vfio_pasid.c > new file mode 100644 > index 0000000..c46b870 > --- /dev/null > +++ b/drivers/vfio/vfio_pasid.c > @@ -0,0 +1,152 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Copyright (C) 2020 Intel Corporation. > + * Author: Liu Yi L > + * > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define DRIVER_VERSION "0.1" > +#define DRIVER_AUTHOR "Liu Yi L " > +#define DRIVER_DESC "PASID management for VFIO bus drivers" > + > +#define VFIO_DEFAULT_PASID_QUOTA 1000 > +static int pasid_quota = VFIO_DEFAULT_PASID_QUOTA; > +module_param_named(pasid_quota, pasid_quota, uint, 0444); > +MODULE_PARM_DESC(pasid_quota, > + " Set the quota for max number of PASIDs that an application is allowed to request (default 1000)"); > + > +struct vfio_mm_token { > + unsigned long long val; > +}; > + > +struct vfio_mm { > + struct kref kref; > + int ioasid_sid; > + struct list_head next; > + struct vfio_mm_token token; > +}; > + > +static struct vfio_pasid { > + struct mutex vfio_mm_lock; > + struct list_head vfio_mm_list; > +} vfio_pasid; > + > +/* called with vfio.vfio_mm_lock held */ > +static void vfio_mm_release(struct kref *kref) > +{ > + struct vfio_mm *vmm = container_of(kref, struct vfio_mm, kref); > + > + list_del(&vmm->next); > + mutex_unlock(&vfio_pasid.vfio_mm_lock); > + ioasid_free_set(vmm->ioasid_sid, true); > + kfree(vmm); > +} > + > +void vfio_mm_put(struct vfio_mm *vmm) > +{ > + kref_put_mutex(&vmm->kref, vfio_mm_release, &vfio_pasid.vfio_mm_lock); > +} > + > +static void vfio_mm_get(struct vfio_mm *vmm) > +{ > + kref_get(&vmm->kref); > +} > + > +struct vfio_mm *vfio_mm_get_from_task(struct task_struct *task) > +{ > + struct mm_struct *mm = get_task_mm(task); > + struct vfio_mm *vmm; > + unsigned long long val = (unsigned long long) mm; > + int ret; > + > + mutex_lock(&vfio_pasid.vfio_mm_lock); > + /* Search existing vfio_mm with current mm pointer */ > + list_for_each_entry(vmm, &vfio_pasid.vfio_mm_list, next) { > + if (vmm->token.val == val) { > + vfio_mm_get(vmm); > + goto out; > + } > + } > + > + vmm = kzalloc(sizeof(*vmm), GFP_KERNEL); > + if (!vmm) { > + vmm = ERR_PTR(-ENOMEM); > + goto out; > + } > + > + /* > + * IOASID core provides a 'IOASID set' concept to track all > + * PASIDs associated with a token. Here we use mm_struct as > + * the token and create a IOASID set per mm_struct. All the > + * containers of the process share the same IOASID set. > + */ > + ret = ioasid_alloc_set((struct ioasid_set *) mm, pasid_quota, > + &vmm->ioasid_sid); > + if (ret) { > + kfree(vmm); > + vmm = ERR_PTR(ret); > + goto out; > + } > + > + kref_init(&vmm->kref); > + vmm->token.val = val; > + > + list_add(&vmm->next, &vfio_pasid.vfio_mm_list); > +out: > + mutex_unlock(&vfio_pasid.vfio_mm_lock); > + mmput(mm); > + return vmm; > +} > + > +int vfio_pasid_alloc(struct vfio_mm *vmm, int min, int max) > +{ > + ioasid_t pasid; > + > + pasid = ioasid_alloc(vmm->ioasid_sid, min, max, NULL); > + > + return (pasid == INVALID_IOASID) ? -ENOSPC : pasid; > +} > + > +void vfio_pasid_free_range(struct vfio_mm *vmm, > + ioasid_t min, ioasid_t max) > +{ > + ioasid_t pasid = min; > + > + if (min > max) > + return; nit: is that check really useful? > + > + /* > + * IOASID core will notify PASID users (e.g. IOMMU driver) to > + * teardown necessary structures depending on the to-be-freed > + * PASID. > + */ > + for (; pasid <= max; pasid++) > + ioasid_free(pasid); > +} > + > +static int __init vfio_pasid_init(void) > +{ > + mutex_init(&vfio_pasid.vfio_mm_lock); > + INIT_LIST_HEAD(&vfio_pasid.vfio_mm_list); > + return 0; > +} > + > +static void __exit vfio_pasid_exit(void) > +{ > + WARN_ON(!list_empty(&vfio_pasid.vfio_mm_list)); Is it acceptable? Don't you need to cleanup everything here instead? Thanks Eric > +} > + > +module_init(vfio_pasid_init); > +module_exit(vfio_pasid_exit); > + > +MODULE_VERSION(DRIVER_VERSION); > +MODULE_LICENSE("GPL v2"); > +MODULE_AUTHOR(DRIVER_AUTHOR); > +MODULE_DESCRIPTION(DRIVER_DESC); > diff --git a/include/linux/vfio.h b/include/linux/vfio.h > index 38d3c6a..9da6468 100644 > --- a/include/linux/vfio.h > +++ b/include/linux/vfio.h > @@ -97,6 +97,34 @@ extern int vfio_register_iommu_driver(const struct vfio_iommu_driver_ops *ops); > extern void vfio_unregister_iommu_driver( > const struct vfio_iommu_driver_ops *ops); > > +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); > +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); > +#else > +static inline struct vfio_mm *vfio_mm_get_from_task(struct task_struct *task) > +{ > + return ERR_PTR(-ENOTTY); > +} > + > +static inline void vfio_mm_put(struct vfio_mm *vmm) > +{ > +} > + > +static inline int vfio_pasid_alloc(struct vfio_mm *vmm, int min, int max) > +{ > + return -ENOTTY; > +} > + > +static inline void vfio_pasid_free_range(struct vfio_mm *vmm, > + ioasid_t min, ioasid_t max) > +{ > +} > +#endif /* CONFIG_VFIO_PASID */ > + > /* > * External user API > */ > Thanks Eric _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu