From patchwork Mon Jun 24 06:53:09 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Kasireddy, Vivek" X-Patchwork-Id: 13709088 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.7]) (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 6208F3C099; Mon, 24 Jun 2024 07:21:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.7 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719213683; cv=none; b=AUULJFwOks3qfuX3zXPVT6hS8FVvTaEo0RUhq798TntisUUmmGIH2TTKwiyYecF2w2KJAhKXJytoShOssj1+5CDWRxhUU60uV86O/86X3LbZBigeL358D9/Rsk0avQxvtpcyJDRWEJ9yzJh1jhK2jrMdqONTAdqfo4ksGLMRdO0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719213683; c=relaxed/simple; bh=MSJJprILcfmTjSAIUrfkFgMpD14a45oMknilvPrEnN8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RM01+I8rjSMUwcveuS0LL/H8rkLqXFHVQaiiHMM31fJc8/qRVPeaWS6XjvX0ybqG7YHbprBUXioEXqeCxMMbV36BN0R8QqnKZEJgQcq991p1B2+pKzFPyi0W50wE2d/vDiwj/UUsQY9HKdQdCxRC/1w0ReDuEIDjyLCW4RK11A0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=GtDt0KK3; arc=none smtp.client-ip=192.198.163.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="GtDt0KK3" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1719213681; x=1750749681; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=MSJJprILcfmTjSAIUrfkFgMpD14a45oMknilvPrEnN8=; b=GtDt0KK3uhNqxJ4R41geqNxdpeJj6aQ36jc/5zk+DbEDGrM8IHxyYL9j E8m8Ya437y9c8cVLR74hnlH3CKKZrbnyWCPocIcrKme9VmN09y08cXteY tfqMDofllBOF8edzYCL0U1mWf5dPTnmkObBprP8X5TTOPhxWa5csacVX9 Sbf8aETsUzzxudhmbYnQBlVQgp5XAJqUK0Oj8Z3MSxXQQNjpd3XqmfCh9 6rDCxire5dnzNopSDhBcxOD4o6AbzStES2LzyugXD24QRYLNThPmR0uH5 hXhGUZJjO5hAOUhNPJxIXLg/XGtpA2aOSGNgIoeYWLxS8wSUq6UZqyakT A==; X-CSE-ConnectionGUID: gJW4fCtfTX6oh3vRsqHJ4A== X-CSE-MsgGUID: 7V1l3MCiSX2MipayE5N0lw== X-IronPort-AV: E=McAfee;i="6700,10204,11112"; a="41574851" X-IronPort-AV: E=Sophos;i="6.08,261,1712646000"; d="scan'208";a="41574851" Received: from fmviesa007.fm.intel.com ([10.60.135.147]) by fmvoesa101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Jun 2024 00:21:17 -0700 X-CSE-ConnectionGUID: +orOdddtRD6FTIGvmxYEfg== X-CSE-MsgGUID: quPbILWfQiCWTVhzEeQ34w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.08,261,1712646000"; d="scan'208";a="43085341" Received: from vkasired-desk2.fm.intel.com ([10.105.128.132]) by fmviesa007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Jun 2024 00:21:17 -0700 From: Vivek Kasireddy To: dri-devel@lists.freedesktop.org, kvm@vger.kernel.org, linux-rdma@vger.kernel.org Cc: Vivek Kasireddy , Jason Gunthorpe Subject: [PATCH v2 1/3] vfio: Export vfio device get and put registration helpers Date: Sun, 23 Jun 2024 23:53:09 -0700 Message-ID: <20240624065552.1572580-2-vivek.kasireddy@intel.com> X-Mailer: git-send-email 2.45.1 In-Reply-To: <20240624065552.1572580-1-vivek.kasireddy@intel.com> References: <20240624065552.1572580-1-vivek.kasireddy@intel.com> Precedence: bulk X-Mailing-List: linux-rdma@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 These helpers are useful for managing additional references taken on the device from other associated VFIO modules. Original-patch-by: Jason Gunthorpe Signed-off-by: Vivek Kasireddy --- drivers/vfio/vfio_main.c | 2 ++ include/linux/vfio.h | 2 ++ 2 files changed, 4 insertions(+) diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c index a5a62d9d963f..d06d4a9a3127 100644 --- a/drivers/vfio/vfio_main.c +++ b/drivers/vfio/vfio_main.c @@ -171,11 +171,13 @@ void vfio_device_put_registration(struct vfio_device *device) if (refcount_dec_and_test(&device->refcount)) complete(&device->comp); } +EXPORT_SYMBOL_GPL(vfio_device_put_registration); bool vfio_device_try_get_registration(struct vfio_device *device) { return refcount_inc_not_zero(&device->refcount); } +EXPORT_SYMBOL_GPL(vfio_device_try_get_registration); /* * VFIO driver API diff --git a/include/linux/vfio.h b/include/linux/vfio.h index 000a6cab2d31..2258b0585330 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -279,6 +279,8 @@ static inline void vfio_put_device(struct vfio_device *device) int vfio_register_group_dev(struct vfio_device *device); int vfio_register_emulated_iommu_dev(struct vfio_device *device); void vfio_unregister_group_dev(struct vfio_device *device); +bool vfio_device_try_get_registration(struct vfio_device *device); +void vfio_device_put_registration(struct vfio_device *device); int vfio_assign_device_set(struct vfio_device *device, void *set_id); unsigned int vfio_device_set_open_count(struct vfio_device_set *dev_set); From patchwork Mon Jun 24 06:53:10 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Kasireddy, Vivek" X-Patchwork-Id: 13709087 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.7]) (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 BC4B22EB1D; Mon, 24 Jun 2024 07:21:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.7 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; 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24 Jun 2024 00:21:17 -0700 X-CSE-ConnectionGUID: iJZc5fzHQrWO5IQR6xIEag== X-CSE-MsgGUID: 6O+ZIQVhS4G9errrfF+UKg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.08,261,1712646000"; d="scan'208";a="43085344" Received: from vkasired-desk2.fm.intel.com ([10.105.128.132]) by fmviesa007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Jun 2024 00:21:17 -0700 From: Vivek Kasireddy To: dri-devel@lists.freedesktop.org, kvm@vger.kernel.org, linux-rdma@vger.kernel.org Cc: Vivek Kasireddy Subject: [PATCH v2 2/3] vfio/pci: Share the core device pointer while invoking feature functions Date: Sun, 23 Jun 2024 23:53:10 -0700 Message-ID: <20240624065552.1572580-3-vivek.kasireddy@intel.com> X-Mailer: git-send-email 2.45.1 In-Reply-To: <20240624065552.1572580-1-vivek.kasireddy@intel.com> References: <20240624065552.1572580-1-vivek.kasireddy@intel.com> Precedence: bulk X-Mailing-List: linux-rdma@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 There is no need to share the main device pointer (struct vfio_device *) with all the feature functions as they only need the core device pointer. Therefore, extract the core device pointer once in the caller (vfio_pci_core_ioctl_feature) and share it instead. Signed-off-by: Vivek Kasireddy --- drivers/vfio/pci/vfio_pci_core.c | 30 +++++++++++++----------------- 1 file changed, 13 insertions(+), 17 deletions(-) diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c index 987c7921affa..3282ef2dddea 100644 --- a/drivers/vfio/pci/vfio_pci_core.c +++ b/drivers/vfio/pci/vfio_pci_core.c @@ -304,11 +304,9 @@ static int vfio_pci_runtime_pm_entry(struct vfio_pci_core_device *vdev, return 0; } -static int vfio_pci_core_pm_entry(struct vfio_device *device, u32 flags, +static int vfio_pci_core_pm_entry(struct vfio_pci_core_device *vdev, u32 flags, void __user *arg, size_t argsz) { - struct vfio_pci_core_device *vdev = - container_of(device, struct vfio_pci_core_device, vdev); int ret; ret = vfio_check_feature(flags, argsz, VFIO_DEVICE_FEATURE_SET, 0); @@ -325,12 +323,10 @@ static int vfio_pci_core_pm_entry(struct vfio_device *device, u32 flags, } static int vfio_pci_core_pm_entry_with_wakeup( - struct vfio_device *device, u32 flags, + struct vfio_pci_core_device *vdev, u32 flags, struct vfio_device_low_power_entry_with_wakeup __user *arg, size_t argsz) { - struct vfio_pci_core_device *vdev = - container_of(device, struct vfio_pci_core_device, vdev); struct vfio_device_low_power_entry_with_wakeup entry; struct eventfd_ctx *efdctx; int ret; @@ -381,11 +377,9 @@ static void vfio_pci_runtime_pm_exit(struct vfio_pci_core_device *vdev) up_write(&vdev->memory_lock); } -static int vfio_pci_core_pm_exit(struct vfio_device *device, u32 flags, +static int vfio_pci_core_pm_exit(struct vfio_pci_core_device *vdev, u32 flags, void __user *arg, size_t argsz) { - struct vfio_pci_core_device *vdev = - container_of(device, struct vfio_pci_core_device, vdev); int ret; ret = vfio_check_feature(flags, argsz, VFIO_DEVICE_FEATURE_SET, 0); @@ -1490,11 +1484,10 @@ long vfio_pci_core_ioctl(struct vfio_device *core_vdev, unsigned int cmd, } EXPORT_SYMBOL_GPL(vfio_pci_core_ioctl); -static int vfio_pci_core_feature_token(struct vfio_device *device, u32 flags, - uuid_t __user *arg, size_t argsz) +static int vfio_pci_core_feature_token(struct vfio_pci_core_device *vdev, + u32 flags, uuid_t __user *arg, + size_t argsz) { - struct vfio_pci_core_device *vdev = - container_of(device, struct vfio_pci_core_device, vdev); uuid_t uuid; int ret; @@ -1521,16 +1514,19 @@ static int vfio_pci_core_feature_token(struct vfio_device *device, u32 flags, int vfio_pci_core_ioctl_feature(struct vfio_device *device, u32 flags, void __user *arg, size_t argsz) { + struct vfio_pci_core_device *vdev = + container_of(device, struct vfio_pci_core_device, vdev); + switch (flags & VFIO_DEVICE_FEATURE_MASK) { case VFIO_DEVICE_FEATURE_LOW_POWER_ENTRY: - return vfio_pci_core_pm_entry(device, flags, arg, argsz); + return vfio_pci_core_pm_entry(vdev, flags, arg, argsz); case VFIO_DEVICE_FEATURE_LOW_POWER_ENTRY_WITH_WAKEUP: - return vfio_pci_core_pm_entry_with_wakeup(device, flags, + return vfio_pci_core_pm_entry_with_wakeup(vdev, flags, arg, argsz); case VFIO_DEVICE_FEATURE_LOW_POWER_EXIT: - return vfio_pci_core_pm_exit(device, flags, arg, argsz); + return vfio_pci_core_pm_exit(vdev, flags, arg, argsz); case VFIO_DEVICE_FEATURE_PCI_VF_TOKEN: - return vfio_pci_core_feature_token(device, flags, arg, argsz); + return vfio_pci_core_feature_token(vdev, flags, arg, argsz); 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24 Jun 2024 00:21:17 -0700 From: Vivek Kasireddy To: dri-devel@lists.freedesktop.org, kvm@vger.kernel.org, linux-rdma@vger.kernel.org Cc: Vivek Kasireddy , Jason Gunthorpe Subject: [PATCH v2 3/3] vfio/pci: Allow MMIO regions to be exported through dma-buf Date: Sun, 23 Jun 2024 23:53:11 -0700 Message-ID: <20240624065552.1572580-4-vivek.kasireddy@intel.com> X-Mailer: git-send-email 2.45.1 In-Reply-To: <20240624065552.1572580-1-vivek.kasireddy@intel.com> References: <20240624065552.1572580-1-vivek.kasireddy@intel.com> Precedence: bulk X-Mailing-List: linux-rdma@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From Jason Gunthorpe: "dma-buf has become a way to safely acquire a handle to non-struct page memory that can still have lifetime controlled by the exporter. Notably RDMA can now import dma-buf FDs and build them into MRs which allows for PCI P2P operations. Extend this to allow vfio-pci to export MMIO memory from PCI device BARs. The patch design loosely follows the pattern in commit db1a8dd916aa ("habanalabs: add support for dma-buf exporter") except this does not support pinning. Instead, this implements what, in the past, we've called a revocable attachment using move. In normal situations the attachment is pinned, as a BAR does not change physical address. However when the VFIO device is closed, or a PCI reset is issued, access to the MMIO memory is revoked. Revoked means that move occurs, but an attempt to immediately re-map the memory will fail. In the reset case a future move will be triggered when MMIO access returns. As both close and reset are under userspace control it is expected that userspace will suspend use of the dma-buf before doing these operations, the revoke is purely for kernel self-defense against a hostile userspace." Following enhancements are made to the original patch: - Add support for creating dmabuf from multiple areas (or ranges) - Add a mmap handler to provide CPU access to the dmabuf Original-patch-by: Jason Gunthorpe Signed-off-by: Vivek Kasireddy --- drivers/vfio/pci/Makefile | 1 + drivers/vfio/pci/dma_buf.c | 438 +++++++++++++++++++++++++++++ drivers/vfio/pci/vfio_pci_config.c | 22 +- drivers/vfio/pci/vfio_pci_core.c | 20 +- drivers/vfio/pci/vfio_pci_priv.h | 23 ++ include/linux/vfio_pci_core.h | 1 + include/uapi/linux/vfio.h | 25 ++ 7 files changed, 525 insertions(+), 5 deletions(-) create mode 100644 drivers/vfio/pci/dma_buf.c diff --git a/drivers/vfio/pci/Makefile b/drivers/vfio/pci/Makefile index cf00c0a7e55c..0cfdc9ede82f 100644 --- a/drivers/vfio/pci/Makefile +++ b/drivers/vfio/pci/Makefile @@ -2,6 +2,7 @@ vfio-pci-core-y := vfio_pci_core.o vfio_pci_intrs.o vfio_pci_rdwr.o vfio_pci_config.o vfio-pci-core-$(CONFIG_VFIO_PCI_ZDEV_KVM) += vfio_pci_zdev.o +vfio-pci-core-$(CONFIG_DMA_SHARED_BUFFER) += dma_buf.o obj-$(CONFIG_VFIO_PCI_CORE) += vfio-pci-core.o vfio-pci-y := vfio_pci.o diff --git a/drivers/vfio/pci/dma_buf.c b/drivers/vfio/pci/dma_buf.c new file mode 100644 index 000000000000..68760677c6a0 --- /dev/null +++ b/drivers/vfio/pci/dma_buf.c @@ -0,0 +1,438 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2024, NVIDIA CORPORATION & AFFILIATES. + */ +#include +#include +#include + +#include "vfio_pci_priv.h" + +MODULE_IMPORT_NS(DMA_BUF); + +struct vfio_pci_dma_buf { + struct dma_buf *dmabuf; + struct vfio_pci_core_device *vdev; + struct list_head dmabufs_elm; + unsigned int nr_ranges; + struct vfio_region_dma_range *dma_ranges; + unsigned int orig_nents; + bool revoked; +}; + +static vm_fault_t vfio_pci_dma_buf_fault(struct vm_fault *vmf) +{ + unsigned long addr = vmf->address - (vmf->pgoff << PAGE_SHIFT); + struct vm_area_struct *vma = vmf->vma; + struct vfio_pci_dma_buf *priv = vma->vm_private_data; + struct vfio_region_dma_range *dma_ranges = priv->dma_ranges; + unsigned long pfn, i, j; + phys_addr_t phys; + size_t offset; + + if (priv->revoked) + return VM_FAULT_SIGBUS; + + down_read(&priv->vdev->memory_lock); + + for (i = 0, j = 0; i < priv->nr_ranges && j < vma_pages(vma); i++) { + phys = pci_resource_start(priv->vdev->pdev, + dma_ranges[i].region_index); + phys += dma_ranges[i].offset; + + for (offset = 0; offset != dma_ranges[i].length;) { + pfn = (phys + offset) >> PAGE_SHIFT; + + if (vmf_insert_pfn(vma, addr, pfn) != VM_FAULT_NOPAGE) { + up_read(&priv->vdev->memory_lock); + return VM_FAULT_SIGBUS; + } + + addr += PAGE_SIZE; + offset += PAGE_SIZE; + if (++j == vma_pages(vma)) + break; + } + } + + up_read(&priv->vdev->memory_lock); + + return VM_FAULT_NOPAGE; +} + +static const struct vm_operations_struct vfio_pci_dma_buf_vmops = { + .fault = vfio_pci_dma_buf_fault, +}; + +static int vfio_pci_dma_buf_mmap(struct dma_buf *dmabuf, + struct vm_area_struct *vma) +{ + struct vfio_pci_dma_buf *priv = dmabuf->priv; + struct vfio_pci_core_device *vdev = priv->vdev; + struct vfio_region_dma_range *dma_ranges = priv->dma_ranges; + int i; + + if ((vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0) + return -EINVAL; + + for (i = 0; i < priv->nr_ranges; i++) + if (!vdev->bar_mmap_supported[dma_ranges[i].region_index]) + return -EINVAL; + + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); + vma->vm_ops = &vfio_pci_dma_buf_vmops; + vma->vm_private_data = priv; + vm_flags_set(vma, VM_ALLOW_ANY_UNCACHED | VM_IO | VM_PFNMAP | + VM_DONTEXPAND | VM_DONTDUMP); + return 0; +} + +static int vfio_pci_dma_buf_attach(struct dma_buf *dmabuf, + struct dma_buf_attachment *attachment) +{ + struct vfio_pci_dma_buf *priv = dmabuf->priv; + int rc; + + rc = pci_p2pdma_distance_many(priv->vdev->pdev, &attachment->dev, 1, + true); + if (rc < 0) + attachment->peer2peer = false; + return 0; +} + +static void vfio_pci_dma_buf_unpin(struct dma_buf_attachment *attachment) +{ +} + +static int vfio_pci_dma_buf_pin(struct dma_buf_attachment *attachment) +{ + /* + * Uses the dynamic interface but must always allow for + * dma_buf_move_notify() to do revoke + */ + return -EINVAL; +} + +static int populate_sgt(struct dma_buf_attachment *attachment, + enum dma_data_direction dir, + struct sg_table *sgt, size_t sgl_size) +{ + struct vfio_pci_dma_buf *priv = attachment->dmabuf->priv; + struct vfio_region_dma_range *dma_ranges = priv->dma_ranges; + size_t offset, chunk_size; + struct scatterlist *sgl; + dma_addr_t dma_addr; + phys_addr_t phys; + int i, j, ret; + + for_each_sgtable_sg(sgt, sgl, j) + sgl->length = 0; + + sgl = sgt->sgl; + for (i = 0; i < priv->nr_ranges; i++) { + phys = pci_resource_start(priv->vdev->pdev, + dma_ranges[i].region_index); + phys += dma_ranges[i].offset; + + /* + * Break the BAR's physical range up into max sized SGL's + * according to the device's requirement. + */ + for (offset = 0; offset != dma_ranges[i].length;) { + chunk_size = min(dma_ranges[i].length - offset, + sgl_size); + + /* + * Since the memory being mapped is a device memory + * it could never be in CPU caches. + */ + dma_addr = dma_map_resource(attachment->dev, + phys + offset, + chunk_size, dir, + DMA_ATTR_SKIP_CPU_SYNC); + ret = dma_mapping_error(attachment->dev, dma_addr); + if (ret) + goto err; + + sg_set_page(sgl, NULL, chunk_size, 0); + sg_dma_address(sgl) = dma_addr; + sg_dma_len(sgl) = chunk_size; + sgl = sg_next(sgl); + offset += chunk_size; + } + } + + return 0; +err: + for_each_sgtable_sg(sgt, sgl, j) { + if (!sg_dma_len(sgl)) + continue; + + dma_unmap_resource(attachment->dev, sg_dma_address(sgl), + sg_dma_len(sgl), + dir, DMA_ATTR_SKIP_CPU_SYNC); + } + + return ret; +} + +static struct sg_table * +vfio_pci_dma_buf_map(struct dma_buf_attachment *attachment, + enum dma_data_direction dir) +{ + size_t sgl_size = dma_get_max_seg_size(attachment->dev); + struct vfio_pci_dma_buf *priv = attachment->dmabuf->priv; + struct sg_table *sgt; + unsigned int nents; + int ret; + + dma_resv_assert_held(priv->dmabuf->resv); + + if (!attachment->peer2peer) + return ERR_PTR(-EPERM); + + if (priv->revoked) + return ERR_PTR(-ENODEV); + + sgt = kzalloc(sizeof(*sgt), GFP_KERNEL); + if (!sgt) + return ERR_PTR(-ENOMEM); + + nents = DIV_ROUND_UP(priv->dmabuf->size, sgl_size); + ret = sg_alloc_table(sgt, nents, GFP_KERNEL); + if (ret) + goto err_kfree_sgt; + + ret = populate_sgt(attachment, dir, sgt, sgl_size); + if (ret) + goto err_free_sgt; + + /* + * Because we are not going to include a CPU list we want to have some + * chance that other users will detect this by setting the orig_nents to + * 0 and using only nents (length of DMA list) when going over the sgl + */ + priv->orig_nents = sgt->orig_nents; + sgt->orig_nents = 0; + return sgt; + +err_free_sgt: + sg_free_table(sgt); +err_kfree_sgt: + kfree(sgt); + return ERR_PTR(ret); +} + +static void vfio_pci_dma_buf_unmap(struct dma_buf_attachment *attachment, + struct sg_table *sgt, + enum dma_data_direction dir) +{ + struct vfio_pci_dma_buf *priv = attachment->dmabuf->priv; + struct scatterlist *sgl; + int i; + + for_each_sgtable_dma_sg(sgt, sgl, i) + dma_unmap_resource(attachment->dev, + sg_dma_address(sgl), + sg_dma_len(sgl), + dir, DMA_ATTR_SKIP_CPU_SYNC); + + sgt->orig_nents = priv->orig_nents; + sg_free_table(sgt); + kfree(sgt); +} + +static void vfio_pci_dma_buf_release(struct dma_buf *dmabuf) +{ + struct vfio_pci_dma_buf *priv = dmabuf->priv; + + /* + * Either this or vfio_pci_dma_buf_cleanup() will remove from the list. + * The refcount prevents both. + */ + if (priv->vdev) { + down_write(&priv->vdev->memory_lock); + list_del_init(&priv->dmabufs_elm); + up_write(&priv->vdev->memory_lock); + vfio_device_put_registration(&priv->vdev->vdev); + } + kfree(priv); +} + +static const struct dma_buf_ops vfio_pci_dmabuf_ops = { + .attach = vfio_pci_dma_buf_attach, + .map_dma_buf = vfio_pci_dma_buf_map, + .pin = vfio_pci_dma_buf_pin, + .unpin = vfio_pci_dma_buf_unpin, + .release = vfio_pci_dma_buf_release, + .unmap_dma_buf = vfio_pci_dma_buf_unmap, + .mmap = vfio_pci_dma_buf_mmap, +}; + +static int check_dma_ranges(struct vfio_pci_dma_buf *priv, + uint64_t *dmabuf_size) +{ + struct vfio_region_dma_range *dma_ranges = priv->dma_ranges; + struct pci_dev *pdev = priv->vdev->pdev; + resource_size_t bar_size; + int i; + + for (i = 0; i < priv->nr_ranges; i++) { + /* + * For PCI the region_index is the BAR number like + * everything else. + */ + if (dma_ranges[i].region_index >= VFIO_PCI_ROM_REGION_INDEX) + return -EINVAL; + + if (!IS_ALIGNED(dma_ranges[i].offset, PAGE_SIZE) || + !IS_ALIGNED(dma_ranges[i].length, PAGE_SIZE)) + return -EINVAL; + + bar_size = pci_resource_len(pdev, dma_ranges[i].region_index); + if (dma_ranges[i].offset > bar_size || + dma_ranges[i].offset + dma_ranges[i].length > bar_size) + return -EINVAL; + + *dmabuf_size += dma_ranges[i].length; + } + + return 0; +} + +int vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 flags, + struct vfio_device_feature_dma_buf __user *arg, + size_t argsz) +{ + struct vfio_device_feature_dma_buf get_dma_buf; + struct vfio_region_dma_range *dma_ranges; + DEFINE_DMA_BUF_EXPORT_INFO(exp_info); + struct vfio_pci_dma_buf *priv; + uint64_t dmabuf_size = 0; + int ret; + + ret = vfio_check_feature(flags, argsz, VFIO_DEVICE_FEATURE_GET, + sizeof(get_dma_buf)); + if (ret != 1) + return ret; + + if (copy_from_user(&get_dma_buf, arg, sizeof(get_dma_buf))) + return -EFAULT; + + dma_ranges = memdup_array_user(&arg->dma_ranges, + get_dma_buf.nr_ranges, + sizeof(*dma_ranges)); + if (IS_ERR(dma_ranges)) + return PTR_ERR(dma_ranges); + + priv = kzalloc(sizeof(*priv), GFP_KERNEL); + if (!priv) { + kfree(dma_ranges); + return -ENOMEM; + } + + priv->vdev = vdev; + priv->nr_ranges = get_dma_buf.nr_ranges; + priv->dma_ranges = dma_ranges; + + ret = check_dma_ranges(priv, &dmabuf_size); + if (ret) + goto err_free_priv; + + if (!vfio_device_try_get_registration(&vdev->vdev)) { + ret = -ENODEV; + goto err_free_priv; + } + + exp_info.ops = &vfio_pci_dmabuf_ops; + exp_info.size = dmabuf_size; + exp_info.flags = get_dma_buf.open_flags; + exp_info.priv = priv; + + priv->dmabuf = dma_buf_export(&exp_info); + if (IS_ERR(priv->dmabuf)) { + ret = PTR_ERR(priv->dmabuf); + goto err_dev_put; + } + + /* dma_buf_put() now frees priv */ + INIT_LIST_HEAD(&priv->dmabufs_elm); + down_write(&vdev->memory_lock); + dma_resv_lock(priv->dmabuf->resv, NULL); + priv->revoked = !__vfio_pci_memory_enabled(vdev); + list_add_tail(&priv->dmabufs_elm, &vdev->dmabufs); + dma_resv_unlock(priv->dmabuf->resv); + up_write(&vdev->memory_lock); + + /* + * dma_buf_fd() consumes the reference, when the file closes the dmabuf + * will be released. + */ + return dma_buf_fd(priv->dmabuf, get_dma_buf.open_flags); + +err_dev_put: + vfio_device_put_registration(&vdev->vdev); +err_free_priv: + kfree(dma_ranges); + kfree(priv); + return ret; +} + +static void revoke_mmap_mappings(struct vfio_pci_dma_buf *priv) +{ + struct inode *inode = file_inode(priv->dmabuf->file); + + unmap_mapping_range(inode->i_mapping, 0, priv->dmabuf->size, true); +} + +void vfio_pci_dma_buf_move(struct vfio_pci_core_device *vdev, bool revoked) +{ + struct vfio_pci_dma_buf *priv; + struct vfio_pci_dma_buf *tmp; + + lockdep_assert_held_write(&vdev->memory_lock); + + list_for_each_entry_safe(priv, tmp, &vdev->dmabufs, dmabufs_elm) { + /* + * Returns true if a reference was successfully obtained. + * The caller must interlock with the dmabuf's release + * function in some way, such as RCU, to ensure that this + * is not called on freed memory. + */ + if (!get_file_rcu(&priv->dmabuf->file)) + continue; + + if (priv->revoked != revoked) { + dma_resv_lock(priv->dmabuf->resv, NULL); + priv->revoked = revoked; + dma_buf_move_notify(priv->dmabuf); + + if (revoked) + revoke_mmap_mappings(priv); + + dma_resv_unlock(priv->dmabuf->resv); + } + dma_buf_put(priv->dmabuf); + } +} + +void vfio_pci_dma_buf_cleanup(struct vfio_pci_core_device *vdev) +{ + struct vfio_pci_dma_buf *priv; + struct vfio_pci_dma_buf *tmp; + + down_write(&vdev->memory_lock); + list_for_each_entry_safe(priv, tmp, &vdev->dmabufs, dmabufs_elm) { + if (!get_file_rcu(&priv->dmabuf->file)) + continue; + dma_resv_lock(priv->dmabuf->resv, NULL); + list_del_init(&priv->dmabufs_elm); + priv->vdev = NULL; + priv->revoked = true; + dma_buf_move_notify(priv->dmabuf); + revoke_mmap_mappings(priv); + dma_resv_unlock(priv->dmabuf->resv); + vfio_device_put_registration(&vdev->vdev); + dma_buf_put(priv->dmabuf); + } + up_write(&vdev->memory_lock); +} diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c index 97422aafaa7b..5cd7ec4b5e40 100644 --- a/drivers/vfio/pci/vfio_pci_config.c +++ b/drivers/vfio/pci/vfio_pci_config.c @@ -585,10 +585,12 @@ static int vfio_basic_config_write(struct vfio_pci_core_device *vdev, int pos, virt_mem = !!(le16_to_cpu(*virt_cmd) & PCI_COMMAND_MEMORY); new_mem = !!(new_cmd & PCI_COMMAND_MEMORY); - if (!new_mem) + if (!new_mem) { vfio_pci_zap_and_down_write_memory_lock(vdev); - else + vfio_pci_dma_buf_move(vdev, true); + } else { down_write(&vdev->memory_lock); + } /* * If the user is writing mem/io enable (new_mem/io) and we @@ -623,6 +625,8 @@ static int vfio_basic_config_write(struct vfio_pci_core_device *vdev, int pos, *virt_cmd &= cpu_to_le16(~mask); *virt_cmd |= cpu_to_le16(new_cmd & mask); + if (__vfio_pci_memory_enabled(vdev)) + vfio_pci_dma_buf_move(vdev, false); up_write(&vdev->memory_lock); } @@ -703,12 +707,16 @@ static int __init init_pci_cap_basic_perm(struct perm_bits *perm) static void vfio_lock_and_set_power_state(struct vfio_pci_core_device *vdev, pci_power_t state) { - if (state >= PCI_D3hot) + if (state >= PCI_D3hot) { vfio_pci_zap_and_down_write_memory_lock(vdev); - else + vfio_pci_dma_buf_move(vdev, true); + } else { down_write(&vdev->memory_lock); + } vfio_pci_set_power_state(vdev, state); + if (__vfio_pci_memory_enabled(vdev)) + vfio_pci_dma_buf_move(vdev, false); up_write(&vdev->memory_lock); } @@ -896,7 +904,10 @@ static int vfio_exp_config_write(struct vfio_pci_core_device *vdev, int pos, if (!ret && (cap & PCI_EXP_DEVCAP_FLR)) { vfio_pci_zap_and_down_write_memory_lock(vdev); + vfio_pci_dma_buf_move(vdev, true); pci_try_reset_function(vdev->pdev); + if (__vfio_pci_memory_enabled(vdev)) + vfio_pci_dma_buf_move(vdev, true); up_write(&vdev->memory_lock); } } @@ -978,7 +989,10 @@ static int vfio_af_config_write(struct vfio_pci_core_device *vdev, int pos, if (!ret && (cap & PCI_AF_CAP_FLR) && (cap & PCI_AF_CAP_TP)) { vfio_pci_zap_and_down_write_memory_lock(vdev); + vfio_pci_dma_buf_move(vdev, true); pci_try_reset_function(vdev->pdev); + if (__vfio_pci_memory_enabled(vdev)) + vfio_pci_dma_buf_move(vdev, true); up_write(&vdev->memory_lock); } } diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c index 3282ef2dddea..154129133d5e 100644 --- a/drivers/vfio/pci/vfio_pci_core.c +++ b/drivers/vfio/pci/vfio_pci_core.c @@ -291,6 +291,8 @@ static int vfio_pci_runtime_pm_entry(struct vfio_pci_core_device *vdev, * semaphore. */ vfio_pci_zap_and_down_write_memory_lock(vdev); + vfio_pci_dma_buf_move(vdev, true); + if (vdev->pm_runtime_engaged) { up_write(&vdev->memory_lock); return -EINVAL; @@ -374,6 +376,8 @@ static void vfio_pci_runtime_pm_exit(struct vfio_pci_core_device *vdev) */ down_write(&vdev->memory_lock); __vfio_pci_runtime_pm_exit(vdev); + if (__vfio_pci_memory_enabled(vdev)) + vfio_pci_dma_buf_move(vdev, false); up_write(&vdev->memory_lock); } @@ -694,6 +698,8 @@ void vfio_pci_core_close_device(struct vfio_device *core_vdev) #endif vfio_pci_core_disable(vdev); + vfio_pci_dma_buf_cleanup(vdev); + mutex_lock(&vdev->igate); if (vdev->err_trigger) { eventfd_ctx_put(vdev->err_trigger); @@ -1238,7 +1244,10 @@ static int vfio_pci_ioctl_reset(struct vfio_pci_core_device *vdev, */ vfio_pci_set_power_state(vdev, PCI_D0); + vfio_pci_dma_buf_move(vdev, true); ret = pci_try_reset_function(vdev->pdev); + if (__vfio_pci_memory_enabled(vdev)) + vfio_pci_dma_buf_move(vdev, false); up_write(&vdev->memory_lock); return ret; @@ -1527,6 +1536,8 @@ int vfio_pci_core_ioctl_feature(struct vfio_device *device, u32 flags, return vfio_pci_core_pm_exit(vdev, flags, arg, argsz); case VFIO_DEVICE_FEATURE_PCI_VF_TOKEN: return vfio_pci_core_feature_token(vdev, flags, arg, argsz); + case VFIO_DEVICE_FEATURE_DMA_BUF: + return vfio_pci_core_feature_dma_buf(vdev, flags, arg, argsz); default: return -ENOTTY; } @@ -2077,6 +2088,7 @@ int vfio_pci_core_init_dev(struct vfio_device *core_vdev) INIT_LIST_HEAD(&vdev->dummy_resources_list); INIT_LIST_HEAD(&vdev->ioeventfds_list); INIT_LIST_HEAD(&vdev->sriov_pfs_item); + INIT_LIST_HEAD(&vdev->dmabufs); init_rwsem(&vdev->memory_lock); xa_init(&vdev->ctx); @@ -2459,11 +2471,17 @@ static int vfio_pci_dev_set_hot_reset(struct vfio_device_set *dev_set, * cause the PCI config space reset without restoring the original * state (saved locally in 'vdev->pm_save'). */ - list_for_each_entry(vdev, &dev_set->device_list, vdev.dev_set_list) + list_for_each_entry(vdev, &dev_set->device_list, vdev.dev_set_list) { + vfio_pci_dma_buf_move(vdev, true); vfio_pci_set_power_state(vdev, PCI_D0); + } ret = pci_reset_bus(pdev); + list_for_each_entry(vdev, &dev_set->device_list, vdev.dev_set_list) + if (__vfio_pci_memory_enabled(vdev)) + vfio_pci_dma_buf_move(vdev, false); + vdev = list_last_entry(&dev_set->device_list, struct vfio_pci_core_device, vdev.dev_set_list); diff --git a/drivers/vfio/pci/vfio_pci_priv.h b/drivers/vfio/pci/vfio_pci_priv.h index 5e4fa69aee16..09d3c300918c 100644 --- a/drivers/vfio/pci/vfio_pci_priv.h +++ b/drivers/vfio/pci/vfio_pci_priv.h @@ -101,4 +101,27 @@ static inline bool vfio_pci_is_vga(struct pci_dev *pdev) return (pdev->class >> 8) == PCI_CLASS_DISPLAY_VGA; } +#ifdef CONFIG_DMA_SHARED_BUFFER +int vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 flags, + struct vfio_device_feature_dma_buf __user *arg, + size_t argsz); +void vfio_pci_dma_buf_cleanup(struct vfio_pci_core_device *vdev); +void vfio_pci_dma_buf_move(struct vfio_pci_core_device *vdev, bool revoked); +#else +static int +vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 flags, + struct vfio_device_feature_dma_buf __user *arg, + size_t argsz) +{ + return -ENOTTY; +} +static inline void vfio_pci_dma_buf_cleanup(struct vfio_pci_core_device *vdev) +{ +} +static inline void vfio_pci_dma_buf_move(struct vfio_pci_core_device *vdev, + bool revoked) +{ +} +#endif + #endif diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h index f87067438ed4..3756e0904de2 100644 --- a/include/linux/vfio_pci_core.h +++ b/include/linux/vfio_pci_core.h @@ -94,6 +94,7 @@ struct vfio_pci_core_device { struct vfio_pci_core_device *sriov_pf_core_dev; struct notifier_block nb; struct rw_semaphore memory_lock; + struct list_head dmabufs; }; /* Will be exported for vfio pci drivers usage */ diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index 2b68e6cdf190..6f283dadacb7 100644 --- a/include/uapi/linux/vfio.h +++ b/include/uapi/linux/vfio.h @@ -1458,6 +1458,31 @@ struct vfio_device_feature_bus_master { }; #define VFIO_DEVICE_FEATURE_BUS_MASTER 10 +/** + * Upon VFIO_DEVICE_FEATURE_GET create a dma_buf fd for the + * regions selected. + * + * open_flags are the typical flags passed to open(2), eg O_RDWR, O_CLOEXEC, + * etc. offset/length specify a slice of the region to create the dmabuf from. + * nr_ranges is the total number of (P2P DMA) ranges that comprise the dmabuf. + * + * Return: The fd number on success, -1 and errno is set on failure. + */ +#define VFIO_DEVICE_FEATURE_DMA_BUF 11 + +struct vfio_region_dma_range { + __u32 region_index; + __u32 __pad; + __u64 offset; + __u64 length; +}; + +struct vfio_device_feature_dma_buf { + __u32 open_flags; + __u32 nr_ranges; + struct vfio_region_dma_range dma_ranges[]; +}; + /* -------- API for Type1 VFIO IOMMU -------- */ /**