From patchwork Tue Jul 11 02:59:16 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yi Liu X-Patchwork-Id: 13308060 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id EB532EB64DC for ; Tue, 11 Jul 2023 02:59:58 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8389310E30A; Tue, 11 Jul 2023 02:59:56 +0000 (UTC) Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by gabe.freedesktop.org (Postfix) with ESMTPS id C945910E2F6; Tue, 11 Jul 2023 02:59:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1689044385; x=1720580385; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=H/WU8QHP1EZETv5YLM1j3Rj3y72wDkHHKLXyt83u7BY=; b=Zi4i31vkg0nVqPfkDAlIzCuSG1QIiVX/bDCV6szotm4Uc3eL3UqSEtXu Fi76JrTV7SiGGS+V40sbBLqSWZ3wJ2Nv9GmibvixOcJWJjDxO8+vL3No5 aDTxFAEBFE0reY4y+Gp83xWO0SiSbFAy5EIoK2CLVGJoteWo9dG7QIJ7Z TapqVNX6Z0Idq4/WjC1vscbkhnJN4IC9VeDT39xLTrnZTHLpsXxnu9Si4 fpDMI9eCjCg+CLlJIMXowGdR++c25UVFrIQA7CZVwoU9Mli66qr/8pfsC 2d26oE6kkE2eLyFlweV3ZV+jHOm1E5degYsH1lD5waxxKwr62k9AJgfQa g==; X-IronPort-AV: E=McAfee;i="6600,9927,10767"; a="361973120" X-IronPort-AV: E=Sophos;i="6.01,195,1684825200"; d="scan'208";a="361973120" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Jul 2023 19:59:45 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10767"; a="724250877" X-IronPort-AV: E=Sophos;i="6.01,195,1684825200"; d="scan'208";a="724250877" Received: from 984fee00a4c6.jf.intel.com ([10.165.58.231]) by fmsmga007.fm.intel.com with ESMTP; 10 Jul 2023 19:59:44 -0700 From: Yi Liu To: alex.williamson@redhat.com, jgg@nvidia.com, kevin.tian@intel.com Date: Mon, 10 Jul 2023 19:59:16 -0700 Message-Id: <20230711025928.6438-15-yi.l.liu@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230711025928.6438-1-yi.l.liu@intel.com> References: <20230711025928.6438-1-yi.l.liu@intel.com> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH v14 14/26] iommufd/device: Add iommufd_access_detach() API X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mjrosato@linux.ibm.com, jasowang@redhat.com, xudong.hao@intel.com, zhenzhong.duan@intel.com, peterx@redhat.com, terrence.xu@intel.com, chao.p.peng@linux.intel.com, linux-s390@vger.kernel.org, yi.l.liu@intel.com, kvm@vger.kernel.org, lulu@redhat.com, yanting.jiang@intel.com, joro@8bytes.org, nicolinc@nvidia.com, yan.y.zhao@intel.com, intel-gfx@lists.freedesktop.org, eric.auger@redhat.com, intel-gvt-dev@lists.freedesktop.org, yi.y.sun@linux.intel.com, clegoate@redhat.com, cohuck@redhat.com, shameerali.kolothum.thodi@huawei.com, suravee.suthikulpanit@amd.com, robin.murphy@arm.com Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" From: Nicolin Chen Previously, the detach routine is only done by the destroy(). And it was called by vfio_iommufd_emulated_unbind() when the device runs close(), so all the mappings in iopt were cleaned in that setup, when the call trace reaches this detach() routine. Now, there's a need of a detach uAPI, meaning that it does not only need a new iommufd_access_detach() API, but also requires access->ops->unmap() call as a cleanup. So add one. However, leaving that unprotected can introduce some potential of a race condition during the pin_/unpin_pages() call, where access->ioas->iopt is getting referenced. So, add an ioas_lock to protect the context of iopt referencings. Also, to allow the iommufd_access_unpin_pages() callback to happen via this unmap() call, add an ioas_unpin pointer, so the unpin routine won't be affected by the "access->ioas = NULL" trick. Reviewed-by: Kevin Tian Tested-by: Terrence Xu Tested-by: Nicolin Chen Tested-by: Matthew Rosato Tested-by: Yanting Jiang Tested-by: Shameer Kolothum Signed-off-by: Nicolin Chen Signed-off-by: Yi Liu Reviewed-by: Jason Gunthorpe --- drivers/iommu/iommufd/device.c | 74 +++++++++++++++++++++++-- drivers/iommu/iommufd/iommufd_private.h | 2 + include/linux/iommufd.h | 1 + 3 files changed, 72 insertions(+), 5 deletions(-) diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c index cd5d8ab907f9..59fec5783eb9 100644 --- a/drivers/iommu/iommufd/device.c +++ b/drivers/iommu/iommufd/device.c @@ -486,6 +486,7 @@ iommufd_access_create(struct iommufd_ctx *ictx, iommufd_ctx_get(ictx); iommufd_object_finalize(ictx, &access->obj); *id = access->obj.id; + mutex_init(&access->ioas_lock); return access; } EXPORT_SYMBOL_NS_GPL(iommufd_access_create, IOMMUFD); @@ -505,26 +506,60 @@ void iommufd_access_destroy(struct iommufd_access *access) } EXPORT_SYMBOL_NS_GPL(iommufd_access_destroy, IOMMUFD); +void iommufd_access_detach(struct iommufd_access *access) +{ + struct iommufd_ioas *cur_ioas = access->ioas; + + mutex_lock(&access->ioas_lock); + if (WARN_ON(!access->ioas)) + goto out; + /* + * Set ioas to NULL to block any further iommufd_access_pin_pages(). + * iommufd_access_unpin_pages() can continue using access->ioas_unpin. + */ + access->ioas = NULL; + + if (access->ops->unmap) { + mutex_unlock(&access->ioas_lock); + access->ops->unmap(access->data, 0, ULONG_MAX); + mutex_lock(&access->ioas_lock); + } + iopt_remove_access(&cur_ioas->iopt, access); + refcount_dec(&cur_ioas->obj.users); +out: + access->ioas_unpin = NULL; + mutex_unlock(&access->ioas_lock); +} +EXPORT_SYMBOL_NS_GPL(iommufd_access_detach, IOMMUFD); + int iommufd_access_attach(struct iommufd_access *access, u32 ioas_id) { struct iommufd_ioas *new_ioas; int rc = 0; - if (access->ioas) + mutex_lock(&access->ioas_lock); + if (WARN_ON(access->ioas || access->ioas_unpin)) { + mutex_unlock(&access->ioas_lock); return -EINVAL; + } new_ioas = iommufd_get_ioas(access->ictx, ioas_id); - if (IS_ERR(new_ioas)) + if (IS_ERR(new_ioas)) { + mutex_unlock(&access->ioas_lock); return PTR_ERR(new_ioas); + } rc = iopt_add_access(&new_ioas->iopt, access); if (rc) { + mutex_unlock(&access->ioas_lock); iommufd_put_object(&new_ioas->obj); return rc; } iommufd_ref_to_users(&new_ioas->obj); access->ioas = new_ioas; + access->ioas_unpin = new_ioas; + mutex_unlock(&access->ioas_lock); return 0; } EXPORT_SYMBOL_NS_GPL(iommufd_access_attach, IOMMUFD); @@ -579,8 +614,8 @@ void iommufd_access_notify_unmap(struct io_pagetable *iopt, unsigned long iova, void iommufd_access_unpin_pages(struct iommufd_access *access, unsigned long iova, unsigned long length) { - struct io_pagetable *iopt = &access->ioas->iopt; struct iopt_area_contig_iter iter; + struct io_pagetable *iopt; unsigned long last_iova; struct iopt_area *area; @@ -588,6 +623,17 @@ void iommufd_access_unpin_pages(struct iommufd_access *access, WARN_ON(check_add_overflow(iova, length - 1, &last_iova))) return; + mutex_lock(&access->ioas_lock); + /* + * The driver must be doing something wrong if it calls this before an + * iommufd_access_attach() or after an iommufd_access_detach(). + */ + if (WARN_ON(!access->ioas_unpin)) { + mutex_unlock(&access->ioas_lock); + return; + } + iopt = &access->ioas_unpin->iopt; + down_read(&iopt->iova_rwsem); iopt_for_each_contig_area(&iter, area, iopt, iova, last_iova) iopt_area_remove_access( @@ -597,6 +643,7 @@ void iommufd_access_unpin_pages(struct iommufd_access *access, min(last_iova, iopt_area_last_iova(area)))); WARN_ON(!iopt_area_contig_done(&iter)); up_read(&iopt->iova_rwsem); + mutex_unlock(&access->ioas_lock); } EXPORT_SYMBOL_NS_GPL(iommufd_access_unpin_pages, IOMMUFD); @@ -642,8 +689,8 @@ int iommufd_access_pin_pages(struct iommufd_access *access, unsigned long iova, unsigned long length, struct page **out_pages, unsigned int flags) { - struct io_pagetable *iopt = &access->ioas->iopt; struct iopt_area_contig_iter iter; + struct io_pagetable *iopt; unsigned long last_iova; struct iopt_area *area; int rc; @@ -658,6 +705,13 @@ int iommufd_access_pin_pages(struct iommufd_access *access, unsigned long iova, if (check_add_overflow(iova, length - 1, &last_iova)) return -EOVERFLOW; + mutex_lock(&access->ioas_lock); + if (!access->ioas) { + mutex_unlock(&access->ioas_lock); + return -ENOENT; + } + iopt = &access->ioas->iopt; + down_read(&iopt->iova_rwsem); iopt_for_each_contig_area(&iter, area, iopt, iova, last_iova) { unsigned long last = min(last_iova, iopt_area_last_iova(area)); @@ -688,6 +742,7 @@ int iommufd_access_pin_pages(struct iommufd_access *access, unsigned long iova, } up_read(&iopt->iova_rwsem); + mutex_unlock(&access->ioas_lock); return 0; err_remove: @@ -702,6 +757,7 @@ int iommufd_access_pin_pages(struct iommufd_access *access, unsigned long iova, iopt_area_last_iova(area)))); } up_read(&iopt->iova_rwsem); + mutex_unlock(&access->ioas_lock); return rc; } EXPORT_SYMBOL_NS_GPL(iommufd_access_pin_pages, IOMMUFD); @@ -721,8 +777,8 @@ EXPORT_SYMBOL_NS_GPL(iommufd_access_pin_pages, IOMMUFD); int iommufd_access_rw(struct iommufd_access *access, unsigned long iova, void *data, size_t length, unsigned int flags) { - struct io_pagetable *iopt = &access->ioas->iopt; struct iopt_area_contig_iter iter; + struct io_pagetable *iopt; struct iopt_area *area; unsigned long last_iova; int rc; @@ -732,6 +788,13 @@ int iommufd_access_rw(struct iommufd_access *access, unsigned long iova, if (check_add_overflow(iova, length - 1, &last_iova)) return -EOVERFLOW; + mutex_lock(&access->ioas_lock); + if (!access->ioas) { + mutex_unlock(&access->ioas_lock); + return -ENOENT; + } + iopt = &access->ioas->iopt; + down_read(&iopt->iova_rwsem); iopt_for_each_contig_area(&iter, area, iopt, iova, last_iova) { unsigned long last = min(last_iova, iopt_area_last_iova(area)); @@ -758,6 +821,7 @@ int iommufd_access_rw(struct iommufd_access *access, unsigned long iova, rc = -ENOENT; err_out: up_read(&iopt->iova_rwsem); + mutex_unlock(&access->ioas_lock); return rc; } EXPORT_SYMBOL_NS_GPL(iommufd_access_rw, IOMMUFD); diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h index b38e67d1988b..3dcaf86aab97 100644 --- a/drivers/iommu/iommufd/iommufd_private.h +++ b/drivers/iommu/iommufd/iommufd_private.h @@ -285,6 +285,8 @@ struct iommufd_access { struct iommufd_object obj; struct iommufd_ctx *ictx; struct iommufd_ioas *ioas; + struct iommufd_ioas *ioas_unpin; + struct mutex ioas_lock; const struct iommufd_access_ops *ops; void *data; unsigned long iova_alignment; diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h index 68defed9ea48..3a3216cb9482 100644 --- a/include/linux/iommufd.h +++ b/include/linux/iommufd.h @@ -48,6 +48,7 @@ iommufd_access_create(struct iommufd_ctx *ictx, const struct iommufd_access_ops *ops, void *data, u32 *id); void iommufd_access_destroy(struct iommufd_access *access); int iommufd_access_attach(struct iommufd_access *access, u32 ioas_id); +void iommufd_access_detach(struct iommufd_access *access); void iommufd_ctx_get(struct iommufd_ctx *ictx);