From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 25AEA3C1C for ; Sun, 31 Jul 2022 13:51:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1659275504; x=1690811504; h=message-id:date:mime-version:cc:subject:to:references: from:in-reply-to:content-transfer-encoding; bh=Tjj8k1ZbSTJrdsm3wdlXChxe3eXQV6X+q+n/n7e9r+w=; b=Bg2B8K7s690lPl7NBTPer6iB+/qXWM1E20cetVp/NCFCpZ3Hpx2KVSIW hbE9Q9FwvSHkGXuY2oNiqvwgTQxLR945S3RMi8G9zwvDT80j0WePBJv6K TboBO84BH4FoV7xP1mBtxYpcsgYohY0i4HUcBYNNvsWKVsKvLA1bKrk9S hdudnBjaWXGYKprgPdqdANk0iafJlly54V/nv7xDXqmdn5F+dFT9kbZYt e+Y3RbsHzWCJCo2yXfSAYQXmSES4ucv5e2oG8Z9hc0KpNfuaTr1QVTaoW zQBnCE1pcC39tQ2fdqlmDpy+pYI2d0xqGXRCGaO7z/Z+AfuhV+HnhrZOl g==; X-IronPort-AV: E=McAfee;i="6400,9594,10425"; a="286555322" X-IronPort-AV: E=Sophos;i="5.93,206,1654585200"; d="scan'208";a="286555322" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Jul 2022 06:51:43 -0700 X-IronPort-AV: E=Sophos;i="5.93,206,1654585200"; d="scan'208";a="629933120" Received: from blu2-mobl3.ccr.corp.intel.com (HELO [10.254.208.191]) ([10.254.208.191]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Jul 2022 06:51:39 -0700 Message-ID: <5fc19287-98a6-02e9-ba06-d2148c29ead2@linux.intel.com> Date: Sun, 31 Jul 2022 21:51:36 +0800 Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Cc: baolu.lu@linux.intel.com, Eric Auger , Jacob jun Pan , Zhangfei Gao , Zhu Tony , iommu@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH v10 08/12] iommu/sva: Refactoring iommu_sva_bind/unbind_device() Content-Language: en-US To: Yi Liu , Joerg Roedel , Jason Gunthorpe , Christoph Hellwig , Kevin Tian , Ashok Raj , Will Deacon , Robin Murphy , Jean-Philippe Brucker , Dave Jiang , Vinod Koul References: <20220705050710.2887204-1-baolu.lu@linux.intel.com> <20220705050710.2887204-9-baolu.lu@linux.intel.com> From: Baolu Lu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 2022/7/31 20:55, Yi Liu wrote: > On 2022/7/5 13:07, Lu Baolu wrote: >> The existing iommu SVA interfaces are implemented by calling the SVA >> specific iommu ops provided by the IOMMU drivers. There's no need for >> any SVA specific ops in iommu_ops vector anymore as we can achieve >> this through the generic attach/detach_dev_pasid domain ops. >> >> This refactors the IOMMU SVA interfaces implementation by using the >> set/block_pasid_dev ops and align them with the concept of the SVA >> iommu domain. Put the new SVA code in the sva related file in order >> to make it self-contained. >> >> Signed-off-by: Lu Baolu >> Tested-by: Zhangfei Gao >> Tested-by: Tony Zhu >> --- >>   include/linux/iommu.h         |  67 +++++++++++-------- >>   drivers/iommu/iommu-sva-lib.c |  98 ++++++++++++++++++++++++++++ >>   drivers/iommu/iommu.c         | 119 ++++++++-------------------------- >>   3 files changed, 165 insertions(+), 119 deletions(-) >> >> diff --git a/include/linux/iommu.h b/include/linux/iommu.h >> index 42f0418dc22c..f59b0ecd3995 100644 >> --- a/include/linux/iommu.h >> +++ b/include/linux/iommu.h >> @@ -39,7 +39,6 @@ struct device; >>   struct iommu_domain; >>   struct iommu_domain_ops; >>   struct notifier_block; >> -struct iommu_sva; >>   struct iommu_fault_event; >>   struct iommu_dma_cookie; >> @@ -57,6 +56,14 @@ struct iommu_domain_geometry { >>       bool force_aperture;       /* DMA only allowed in mappable >> range? */ >>   }; >> +/** >> + * struct iommu_sva - handle to a device-mm bond >> + */ >> +struct iommu_sva { >> +    struct device        *dev; >> +    refcount_t        users; >> +}; >> + >>   /* Domain feature flags */ >>   #define __IOMMU_DOMAIN_PAGING    (1U << 0)  /* Support for >> iommu_map/unmap */ >>   #define __IOMMU_DOMAIN_DMA_API    (1U << 1)  /* Domain for use in >> DMA-API >> @@ -105,6 +112,7 @@ struct iommu_domain { >>           }; >>           struct {    /* IOMMU_DOMAIN_SVA */ >>               struct mm_struct *mm; >> +            struct iommu_sva bond; >>           }; >>       }; >>   }; >> @@ -638,13 +646,6 @@ struct iommu_fwspec { >>   /* ATS is supported */ >>   #define IOMMU_FWSPEC_PCI_RC_ATS            (1 << 0) >> -/** >> - * struct iommu_sva - handle to a device-mm bond >> - */ >> -struct iommu_sva { >> -    struct device            *dev; >> -}; >> - >>   int iommu_fwspec_init(struct device *dev, struct fwnode_handle >> *iommu_fwnode, >>                 const struct iommu_ops *ops); >>   void iommu_fwspec_free(struct device *dev); >> @@ -685,11 +686,6 @@ int iommu_dev_enable_feature(struct device *dev, >> enum iommu_dev_features f); >>   int iommu_dev_disable_feature(struct device *dev, enum >> iommu_dev_features f); >>   bool iommu_dev_feature_enabled(struct device *dev, enum >> iommu_dev_features f); >> -struct iommu_sva *iommu_sva_bind_device(struct device *dev, >> -                    struct mm_struct *mm); >> -void iommu_sva_unbind_device(struct iommu_sva *handle); >> -u32 iommu_sva_get_pasid(struct iommu_sva *handle); >> - >>   int iommu_device_use_default_domain(struct device *dev); >>   void iommu_device_unuse_default_domain(struct device *dev); >> @@ -703,6 +699,8 @@ int iommu_attach_device_pasid(struct iommu_domain >> *domain, struct device *dev, >>                     ioasid_t pasid); >>   void iommu_detach_device_pasid(struct iommu_domain *domain, struct >> device *dev, >>                      ioasid_t pasid); >> +struct iommu_domain * >> +iommu_get_domain_for_dev_pasid(struct device *dev, ioasid_t pasid); >>   #else /* CONFIG_IOMMU_API */ >>   struct iommu_ops {}; >> @@ -1033,21 +1031,6 @@ iommu_dev_disable_feature(struct device *dev, >> enum iommu_dev_features feat) >>       return -ENODEV; >>   } >> -static inline struct iommu_sva * >> -iommu_sva_bind_device(struct device *dev, struct mm_struct *mm) >> -{ >> -    return NULL; >> -} >> - >> -static inline void iommu_sva_unbind_device(struct iommu_sva *handle) >> -{ >> -} >> - >> -static inline u32 iommu_sva_get_pasid(struct iommu_sva *handle) >> -{ >> -    return IOMMU_PASID_INVALID; >> -} >> - >>   static inline struct iommu_fwspec *dev_iommu_fwspec_get(struct >> device *dev) >>   { >>       return NULL; >> @@ -1093,6 +1076,12 @@ static inline void >> iommu_detach_device_pasid(struct iommu_domain *domain, >>                            struct device *dev, ioasid_t pasid) >>   { >>   } >> + >> +static inline struct iommu_domain * >> +iommu_get_domain_for_dev_pasid(struct device *dev, ioasid_t pasid) >> +{ >> +    return NULL; >> +} >>   #endif /* CONFIG_IOMMU_API */ >>   /** >> @@ -1118,4 +1107,26 @@ void iommu_debugfs_setup(void); >>   static inline void iommu_debugfs_setup(void) {} >>   #endif >> +#ifdef CONFIG_IOMMU_SVA >> +struct iommu_sva *iommu_sva_bind_device(struct device *dev, >> +                    struct mm_struct *mm); >> +void iommu_sva_unbind_device(struct iommu_sva *handle); >> +u32 iommu_sva_get_pasid(struct iommu_sva *handle); >> +#else >> +static inline struct iommu_sva * >> +iommu_sva_bind_device(struct device *dev, struct mm_struct *mm) >> +{ >> +    return NULL; >> +} >> + >> +static inline void iommu_sva_unbind_device(struct iommu_sva *handle) >> +{ >> +} >> + >> +static inline u32 iommu_sva_get_pasid(struct iommu_sva *handle) >> +{ >> +    return IOMMU_PASID_INVALID; >> +} >> +#endif /* CONFIG_IOMMU_SVA */ >> + >>   #endif /* __LINUX_IOMMU_H */ >> diff --git a/drivers/iommu/iommu-sva-lib.c >> b/drivers/iommu/iommu-sva-lib.c >> index 106506143896..751366980232 100644 >> --- a/drivers/iommu/iommu-sva-lib.c >> +++ b/drivers/iommu/iommu-sva-lib.c >> @@ -4,6 +4,7 @@ >>    */ >>   #include >>   #include >> +#include >>   #include "iommu-sva-lib.h" >> @@ -69,3 +70,100 @@ struct mm_struct *iommu_sva_find(ioasid_t pasid) >>       return ioasid_find(&iommu_sva_pasid, pasid, __mmget_not_zero); >>   } >>   EXPORT_SYMBOL_GPL(iommu_sva_find); >> + >> +/** >> + * iommu_sva_bind_device() - Bind a process address space to a device >> + * @dev: the device >> + * @mm: the mm to bind, caller must hold a reference to mm_users >> + * >> + * Create a bond between device and address space, allowing the >> device to access >> + * the mm using the returned PASID. If a bond already exists between >> @device and >> + * @mm, it is returned and an additional reference is taken. Caller >> must call >> + * iommu_sva_unbind_device() to release each reference. >> + * >> + * iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_SVA) must be called >> first, to >> + * initialize the required SVA features. >> + * >> + * On error, returns an ERR_PTR value. >> + */ >> +struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct >> mm_struct *mm) >> +{ >> +    struct iommu_domain *domain; >> +    ioasid_t max_pasids; >> +    int ret = -EINVAL; >> + >> +    max_pasids = dev->iommu->max_pasids; >> +    if (!max_pasids) >> +        return ERR_PTR(-EOPNOTSUPP); >> + >> +    /* Allocate mm->pasid if necessary. */ >> +    ret = iommu_sva_alloc_pasid(mm, 1, max_pasids - 1); > > do we want to call mmgrab() before iomu_sva_alloc_pasid() to > avoid using mm without any reference? In your current code, > mmgrab() is called in iommu_sva_domain_alloc(). As the comment of this API states "caller must hold a reference to mm_users". Best regards, baolu