From patchwork Wed Mar 8 13:13:36 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yi Liu X-Patchwork-Id: 13165718 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 174ABC64EC4 for ; Wed, 8 Mar 2023 13:13:54 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id ABFD810E5D8; Wed, 8 Mar 2023 13:13:53 +0000 (UTC) Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by gabe.freedesktop.org (Postfix) with ESMTPS id 8ADA410E5D8; Wed, 8 Mar 2023 13:13:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1678281232; x=1709817232; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=/7uHDLMJQYCvcCQ6zBOH4f4vyYcLAIgagJQ2fPM8N2Y=; b=bwj0SczW3nN/qDtTw0/qO/MzYiLAqdnJJLP0w338dbN7p8iLZo2HSEVX 7ePs9OF1LKw4sG4062EQ6//RORnZfk+kKmRtE+5P/miCh5wRtKo2BD7wx e0aEagGWA/5K+Rxg7U1mQ+f+84sloeM5Kr3jL+9Eyzw8hsclZZ8viOvmi BdFF3fR3c3NBmFgxk23+OT/50VKtDZ6qVwyQviUa+XL/PCzuaYdg8kqJ3 aa25xbZniZI8MbP3lilko6sEzWnHAuuOQtYAdWNuVmB5sXp0ioulFRF/p c8tnc6xX0FPcv8faZ+t1snUQbmzWXGP7VBylII8seIJFCR+5vH55eCZ8S Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10642"; a="338474809" X-IronPort-AV: E=Sophos;i="5.98,243,1673942400"; d="scan'208";a="338474809" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Mar 2023 05:13:47 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10642"; a="670330907" X-IronPort-AV: E=Sophos;i="5.98,243,1673942400"; d="scan'208";a="670330907" Received: from 984fee00a4c6.jf.intel.com ([10.165.58.231]) by orsmga007.jf.intel.com with ESMTP; 08 Mar 2023 05:13:42 -0800 From: Yi Liu To: alex.williamson@redhat.com, jgg@nvidia.com, kevin.tian@intel.com Date: Wed, 8 Mar 2023 05:13:36 -0800 Message-Id: <20230308131340.459224-2-yi.l.liu@intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230308131340.459224-1-yi.l.liu@intel.com> References: <20230308131340.459224-1-yi.l.liu@intel.com> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH v1 1/5] iommufd: Create access in vfio_iommufd_emulated_bind() 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: linux-s390@vger.kernel.org, yi.l.liu@intel.com, yi.y.sun@linux.intel.com, mjrosato@linux.ibm.com, kvm@vger.kernel.org, intel-gvt-dev@lists.freedesktop.org, joro@8bytes.org, cohuck@redhat.com, xudong.hao@intel.com, peterx@redhat.com, yan.y.zhao@intel.com, eric.auger@redhat.com, terrence.xu@intel.com, nicolinc@nvidia.com, shameerali.kolothum.thodi@huawei.com, suravee.suthikulpanit@amd.com, intel-gfx@lists.freedesktop.org, chao.p.peng@linux.intel.com, lulu@redhat.com, robin.murphy@arm.com, jasowang@redhat.com Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" From: Nicolin Chen There are needs to created iommufd_access prior to have an IOAS and set IOAS later. Like the vfio device cdev needs to have an iommufd object to represent the bond (iommufd_access) and IOAS replacement. This moves iommufd_access_create() call into vfio_iommufd_emulated_bind(), making it symmetric with the __vfio_iommufd_access_destroy() call in vfio_iommufd_emulated_unbind(). This means an access is created/destroyed by the bind()/unbind(), and the vfio_iommufd_emulated_attach_ioas() only updates the access->ioas pointer. Since there's no longer an ioas_id input for iommufd_access_create(), add a new helper iommufd_access_set_ioas() to set access->ioas. We can later add a "replace" feature simply to the new iommufd_access_set_ioas() too. Leaving the access->ioas in vfio_iommufd_emulated_attach_ioas(), however, can introduce some potential of a race condition during pin_/unpin_pages() call where access->ioas->iopt is getting referenced. So, add an ioas_lock to protect it. Reviewed-by: Kevin Tian Signed-off-by: Nicolin Chen Signed-off-by: Yi Liu --- drivers/iommu/iommufd/device.c | 103 ++++++++++++++++++------ drivers/iommu/iommufd/iommufd_private.h | 1 + drivers/iommu/iommufd/selftest.c | 5 +- drivers/vfio/iommufd.c | 23 +++--- include/linux/iommufd.h | 3 +- 5 files changed, 100 insertions(+), 35 deletions(-) diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c index a0c66f47a65a..71c4d38994b3 100644 --- a/drivers/iommu/iommufd/device.c +++ b/drivers/iommu/iommufd/device.c @@ -412,9 +412,12 @@ void iommufd_access_destroy_object(struct iommufd_object *obj) struct iommufd_access *access = container_of(obj, struct iommufd_access, obj); - iopt_remove_access(&access->ioas->iopt, access); + if (access->ioas) { + iopt_remove_access(&access->ioas->iopt, access); + refcount_dec(&access->ioas->obj.users); + } iommufd_ctx_put(access->ictx); - refcount_dec(&access->ioas->obj.users); + mutex_destroy(&access->ioas_lock); } /** @@ -431,12 +434,10 @@ void iommufd_access_destroy_object(struct iommufd_object *obj) * The provided ops are required to use iommufd_access_pin_pages(). */ struct iommufd_access * -iommufd_access_create(struct iommufd_ctx *ictx, u32 ioas_id, +iommufd_access_create(struct iommufd_ctx *ictx, const struct iommufd_access_ops *ops, void *data) { struct iommufd_access *access; - struct iommufd_object *obj; - int rc; /* * There is no uAPI for the access object, but to keep things symmetric @@ -449,33 +450,18 @@ iommufd_access_create(struct iommufd_ctx *ictx, u32 ioas_id, access->data = data; access->ops = ops; - obj = iommufd_get_object(ictx, ioas_id, IOMMUFD_OBJ_IOAS); - if (IS_ERR(obj)) { - rc = PTR_ERR(obj); - goto out_abort; - } - access->ioas = container_of(obj, struct iommufd_ioas, obj); - iommufd_ref_to_users(obj); - if (ops->needs_pin_pages) access->iova_alignment = PAGE_SIZE; else access->iova_alignment = 1; - rc = iopt_add_access(&access->ioas->iopt, access); - if (rc) - goto out_put_ioas; /* The calling driver is a user until iommufd_access_destroy() */ refcount_inc(&access->obj.users); + mutex_init(&access->ioas_lock); access->ictx = ictx; iommufd_ctx_get(ictx); iommufd_object_finalize(ictx, &access->obj); return access; -out_put_ioas: - refcount_dec(&access->ioas->obj.users); -out_abort: - iommufd_object_abort(ictx, &access->obj); - return ERR_PTR(rc); } EXPORT_SYMBOL_NS_GPL(iommufd_access_create, IOMMUFD); @@ -494,6 +480,50 @@ void iommufd_access_destroy(struct iommufd_access *access) } EXPORT_SYMBOL_NS_GPL(iommufd_access_destroy, IOMMUFD); +int iommufd_access_set_ioas(struct iommufd_access *access, u32 ioas_id) +{ + struct iommufd_ioas *new_ioas = NULL, *cur_ioas; + struct iommufd_ctx *ictx = access->ictx; + struct iommufd_object *obj; + int rc = 0; + + if (ioas_id) { + obj = iommufd_get_object(ictx, ioas_id, IOMMUFD_OBJ_IOAS); + if (IS_ERR(obj)) + return PTR_ERR(obj); + new_ioas = container_of(obj, struct iommufd_ioas, obj); + } + + mutex_lock(&access->ioas_lock); + cur_ioas = access->ioas; + if (cur_ioas == new_ioas) + goto out_unlock; + + if (new_ioas) { + rc = iopt_add_access(&new_ioas->iopt, access); + if (rc) + goto out_unlock; + iommufd_ref_to_users(obj); + } + + if (cur_ioas) { + iopt_remove_access(&cur_ioas->iopt, access); + refcount_dec(&cur_ioas->obj.users); + } + + access->ioas = new_ioas; + mutex_unlock(&access->ioas_lock); + + return 0; + +out_unlock: + mutex_unlock(&access->ioas_lock); + if (new_ioas) + iommufd_put_object(obj); + return rc; +} +EXPORT_SYMBOL_NS_GPL(iommufd_access_set_ioas, IOMMUFD); + /** * iommufd_access_notify_unmap - Notify users of an iopt to stop using it * @iopt: iopt to work on @@ -544,8 +574,8 @@ 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; @@ -553,6 +583,13 @@ 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); + if (!access->ioas) { + mutex_unlock(&access->ioas_lock); + return; + } + iopt = &access->ioas->iopt; + down_read(&iopt->iova_rwsem); iopt_for_each_contig_area(&iter, area, iopt, iova, last_iova) iopt_area_remove_access( @@ -562,6 +599,7 @@ void iommufd_access_unpin_pages(struct iommufd_access *access, min(last_iova, iopt_area_last_iova(area)))); up_read(&iopt->iova_rwsem); WARN_ON(!iopt_area_contig_done(&iter)); + mutex_unlock(&access->ioas_lock); } EXPORT_SYMBOL_NS_GPL(iommufd_access_unpin_pages, IOMMUFD); @@ -607,8 +645,8 @@ 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; @@ -623,6 +661,13 @@ 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)); @@ -653,6 +698,7 @@ 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: @@ -667,6 +713,7 @@ 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); @@ -686,8 +733,8 @@ 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; @@ -697,6 +744,13 @@ 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)); @@ -723,6 +777,7 @@ 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 9d7f71510ca1..820251b83ae4 100644 --- a/drivers/iommu/iommufd/iommufd_private.h +++ b/drivers/iommu/iommufd/iommufd_private.h @@ -263,6 +263,7 @@ struct iommufd_access { struct iommufd_object obj; struct iommufd_ctx *ictx; struct iommufd_ioas *ioas; + struct mutex ioas_lock; const struct iommufd_access_ops *ops; void *data; unsigned long iova_alignment; diff --git a/drivers/iommu/iommufd/selftest.c b/drivers/iommu/iommufd/selftest.c index cfb5fe9a5e0e..db4011bdc8a9 100644 --- a/drivers/iommu/iommufd/selftest.c +++ b/drivers/iommu/iommufd/selftest.c @@ -571,7 +571,7 @@ static int iommufd_test_create_access(struct iommufd_ucmd *ucmd, } access = iommufd_access_create( - ucmd->ictx, ioas_id, + ucmd->ictx, (flags & MOCK_FLAGS_ACCESS_CREATE_NEEDS_PIN_PAGES) ? &selftest_access_ops_pin : &selftest_access_ops, @@ -580,6 +580,9 @@ static int iommufd_test_create_access(struct iommufd_ucmd *ucmd, rc = PTR_ERR(access); goto out_put_fdno; } + rc = iommufd_access_set_ioas(access, ioas_id); + if (rc) + goto out_destroy; cmd->create_access.out_access_fd = fdno; rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd)); if (rc) diff --git a/drivers/vfio/iommufd.c b/drivers/vfio/iommufd.c index db4efbd56042..1f87294c1931 100644 --- a/drivers/vfio/iommufd.c +++ b/drivers/vfio/iommufd.c @@ -138,10 +138,18 @@ static const struct iommufd_access_ops vfio_user_ops = { int vfio_iommufd_emulated_bind(struct vfio_device *vdev, struct iommufd_ctx *ictx, u32 *out_device_id) { + struct iommufd_access *user; + lockdep_assert_held(&vdev->dev_set->lock); - vdev->iommufd_ictx = ictx; iommufd_ctx_get(ictx); + user = iommufd_access_create(ictx, &vfio_user_ops, vdev); + if (IS_ERR(user)) { + iommufd_ctx_put(ictx); + return PTR_ERR(user); + } + vdev->iommufd_access = user; + vdev->iommufd_ictx = ictx; return 0; } EXPORT_SYMBOL_GPL(vfio_iommufd_emulated_bind); @@ -161,15 +169,12 @@ EXPORT_SYMBOL_GPL(vfio_iommufd_emulated_unbind); int vfio_iommufd_emulated_attach_ioas(struct vfio_device *vdev, u32 *pt_id) { - struct iommufd_access *user; - lockdep_assert_held(&vdev->dev_set->lock); - user = iommufd_access_create(vdev->iommufd_ictx, *pt_id, &vfio_user_ops, - vdev); - if (IS_ERR(user)) - return PTR_ERR(user); - vdev->iommufd_access = user; - return 0; + if (!vdev->iommufd_ictx) + return -EINVAL; + if (!vdev->iommufd_access) + return -ENOENT; + return iommufd_access_set_ioas(vdev->iommufd_access, *pt_id); } EXPORT_SYMBOL_GPL(vfio_iommufd_emulated_attach_ioas); diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h index c0b5b3ac34f1..247b11609c79 100644 --- a/include/linux/iommufd.h +++ b/include/linux/iommufd.h @@ -40,9 +40,10 @@ enum { }; struct iommufd_access * -iommufd_access_create(struct iommufd_ctx *ictx, u32 ioas_id, +iommufd_access_create(struct iommufd_ctx *ictx, const struct iommufd_access_ops *ops, void *data); void iommufd_access_destroy(struct iommufd_access *access); +int iommufd_access_set_ioas(struct iommufd_access *access, u32 ioas_id); void iommufd_ctx_get(struct iommufd_ctx *ictx);