From nobody Sun Oct 5 12:46:16 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 8DCEB15746F; Mon, 4 Aug 2025 13:01:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754312462; cv=none; b=iaD6fjR3Uwp3kS2kCVihYTmPiIayRlupkUXSDrUXIbMOLWec6qsHTyL8zXTBhK5JWfbP6e+06dJFG9TpGZkublHWG17MFpep/aHAgHJm+u122Dz1wcn/E+DuKQP8yA6UERO9OImEqEtNtttOHmTl2zB8FrOEi4g1vV+tn1GY/FU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754312462; c=relaxed/simple; bh=NGf1AYRJqA3TDpKjHdv56/eFxItdmJcxurU8Pl18z1c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=g6A340UqNlfK0xu9jocjAgV8N8dZt9YoGW3ZUXlnM/H7+qIK58hctE8jpt91JVeuE8nZFKuF5bGV8JHQGB2UEEd66JO0X0lgmTcffxQ1h9WuRQaPm5Q54aOPrQNEsUZr/hfWQrqxoPWCHX4Ednfr51S4+uD6x9UA0MtPRmYtjrc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=s2heiyEq; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="s2heiyEq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3FECEC4CEF7; Mon, 4 Aug 2025 13:01:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754312461; bh=NGf1AYRJqA3TDpKjHdv56/eFxItdmJcxurU8Pl18z1c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=s2heiyEqDcV3a7/Mlnc3aDnSnlB91n/iIZskVpJMq07doaJ4Y/+n8z6i9uQQ97TTI Jwn0N16sASMrrNaXjxejbTLPAT9lGF7/gcaarJFfI95wEN2Kz7h6p1b0JkTfrEfX1D VmbMlwmvB94SRPw2Xf00i3CbnZQu4DmD3LJOwOg2/BnEk/zOGMDtR/fPvAMB7TZrjt D2BZw3t3cwdHCfJg4yEMRZxnPlAGDpPyhGUZmjuuOELZDDsSP1Cj+D3TXKyV+f0pZ3 MnJhHXzeBublwqXE+kDR1RxC/k4p4smIMvq4VeNTH7oDc1ta1AFC3kGqyk5VZsiQTO Ve6+Tt4c6rKlg== From: Leon Romanovsky To: Alex Williamson Cc: Leon Romanovsky , Jason Gunthorpe , Andrew Morton , Bjorn Helgaas , =?UTF-8?q?Christian=20K=C3=B6nig?= , Christoph Hellwig , dri-devel@lists.freedesktop.org, iommu@lists.linux.dev, Jens Axboe , Joerg Roedel , kvm@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, Logan Gunthorpe , Marek Szyprowski , Robin Murphy , Sumit Semwal , Vivek Kasireddy , Will Deacon Subject: [PATCH v1 01/10] PCI/P2PDMA: Remove redundant bus_offset from map state Date: Mon, 4 Aug 2025 16:00:36 +0300 Message-ID: X-Mailer: git-send-email 2.50.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Leon Romanovsky Remove the bus_off field from pci_p2pdma_map_state since it duplicates information already available in the pgmap structure. The bus_offset is only used in one location (pci_p2pdma_bus_addr_map) and is always identical to pgmap->bus_offset. Reviewed-by: Christoph Hellwig Signed-off-by: Jason Gunthorpe Signed-off-by: Leon Romanovsky --- drivers/pci/p2pdma.c | 1 - include/linux/pci-p2pdma.h | 3 +-- 2 files changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index da5657a020074..274bb7bcc0bc5 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -1009,7 +1009,6 @@ void __pci_p2pdma_update_state(struct pci_p2pdma_map_= state *state, { state->pgmap =3D page_pgmap(page); state->map =3D pci_p2pdma_map_type(state->pgmap, dev); - state->bus_off =3D to_p2p_pgmap(state->pgmap)->bus_offset; } =20 /** diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h index 075c20b161d98..b502fc8b49bf9 100644 --- a/include/linux/pci-p2pdma.h +++ b/include/linux/pci-p2pdma.h @@ -146,7 +146,6 @@ enum pci_p2pdma_map_type { struct pci_p2pdma_map_state { struct dev_pagemap *pgmap; enum pci_p2pdma_map_type map; - u64 bus_off; }; =20 /* helper for pci_p2pdma_state(), do not use directly */ @@ -186,7 +185,7 @@ static inline dma_addr_t pci_p2pdma_bus_addr_map(struct pci_p2pdma_map_state *state, phys_addr_t pa= ddr) { WARN_ON_ONCE(state->map !=3D PCI_P2PDMA_MAP_BUS_ADDR); - return paddr + state->bus_off; + return paddr + to_p2p_pgmap(state->pgmap)->bus_offsetf; } =20 #endif /* _LINUX_PCI_P2P_H */ --=20 2.50.1 From nobody Sun Oct 5 12:46:16 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 5731F25DD0B; Mon, 4 Aug 2025 13:01:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754312471; cv=none; b=BgOJnDnMyHnDl1xQPHApcTKkn6gobgJbRuTgb/oBG7Fok3k/cwQSbVNq2uarkaA2mQ3m8WVq20yJD8cTusupqqajdQs09ku8xgFEN+VbLRZWQ8LAawyR07F4hRkfJEK+4dqfPPMMy/TIlePpVcChnGXcj9mtHPiYbj59BMtFdd8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754312471; c=relaxed/simple; bh=IsAPGOt4X9GgofJ03wHcNt89+lqwVxpNiacc/ZAdgvY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=B0WsSG3dsA4jXY2DeoQTLF0vfKyv4DMsdLoBmm4WNtEYEpXN5gZJc8iDSjmkYpeVIMVTGjBw3DidJP5YYjOlhGxrX0MrT5qzwi6emdrOMVjankYCKkJ1mCcuN/L37MFNiXPbaVnNHJjjiazOVsTeYB2C7xo9v7quYe/clKmN66Y= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=lx/dHHGf; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="lx/dHHGf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 244F5C4CEF8; Mon, 4 Aug 2025 13:01:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754312469; bh=IsAPGOt4X9GgofJ03wHcNt89+lqwVxpNiacc/ZAdgvY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lx/dHHGf3bljYS5iMfYR2uw9XW4XfVcuc2Wpo9YTyBdCM11iPwUZU2t5/Itv9MKbi rwK2L6dQjNwTlBIg+LQIpXG457Yk97rBIhYZPklfajJVIxImGyqdiM/ZUJGcvO788s lR7ulCLF5HVsFLBvYwAMXouFGCqOSZh/T5vh4oIyZZjnj8ZSIt7kAk7Xy8SepsDyoL S1dgxczXvnb94YzSKcDoNgfB2bQxvuZzVxxIz+hd5c8Ipo5WwHnbxoAeEJ2/lMzvny 38X4FK9PjZQga4hnMpPp35L3SzSVCvj60WEdf6yyiaQyKjc146PKeokwNFeV/8EmoD CL8axmfU2DGjQ== From: Leon Romanovsky To: Alex Williamson Cc: Leon Romanovsky , Jason Gunthorpe , Andrew Morton , Bjorn Helgaas , =?UTF-8?q?Christian=20K=C3=B6nig?= , Christoph Hellwig , dri-devel@lists.freedesktop.org, iommu@lists.linux.dev, Jens Axboe , Joerg Roedel , kvm@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, Logan Gunthorpe , Marek Szyprowski , Robin Murphy , Sumit Semwal , Vivek Kasireddy , Will Deacon Subject: [PATCH v1 02/10] PCI/P2PDMA: Separate the mmap() support from the core logic Date: Mon, 4 Aug 2025 16:00:37 +0300 Message-ID: <69a1a404aa3fd99b393ff5d470f114467e00c988.1754311439.git.leon@kernel.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Leon Romanovsky Currently the P2PDMA code requires a pgmap and a struct page to function. The was serving three important purposes: - DMA API compatibility, where scatterlist required a struct page as input - Life cycle management, the percpu_ref is used to prevent UAF during device hot unplug - A way to get the P2P provider data through the pci_p2pdma_pagemap The DMA API now has a new flow, and has gained phys_addr_t support, so it no longer needs struct pages to perform P2P mapping. Lifecycle management can be delegated to the user, DMABUF for instance has a suitable invalidation protocol that does not require struct page. Finding the P2P provider data can also be managed by the caller without need to look it up from the phys_addr. Split the P2PDMA code into two layers. The optional upper layer, effectively, provides a way to mmap() P2P memory into a VMA by providing struct page, pgmap, a genalloc and sysfs. The lower layer provides the actual P2P infrastructure and is wrapped up in a new struct p2pdma_provider. Rework the mmap layer to use new p2pdma_provider based APIs. Drivers that do not want to put P2P memory into VMA's can allocate a struct p2pdma_provider after probe() starts and free it before remove() completes. When DMA mapping the driver must convey the struct p2pdma_provider to the DMA mapping code along with a phys_addr of the MMIO BAR slice to map. The driver must ensure that no DMA mapping outlives the lifetime of the struct p2pdma_provider. The intended target of this new API layer is DMABUF. There is usually only a single p2pdma_provider for a DMABUF exporter. Most drivers can establish the p2pdma_provider during probe, access the single instance during DMABUF attach and use that to drive the DMA mapping. DMABUF provides an invalidation mechanism that can guarantee all DMA is halted and the DMA mappings are undone prior to destroying the struct p2pdma_provider. This ensures there is no UAF through DMABUFs that are lingering past driver removal. The new p2pdma_provider layer cannot be used to create P2P memory that can be mapped into VMA's, be used with pin_user_pages(), O_DIRECT, and so on. These use cases must still use the mmap() layer. The p2pdma_provider layer is principally for DMABUF-like use cases where DMABUF natively manages the life cycle and access instead of vmas/pin_user_pages()/struct page. Signed-off-by: Jason Gunthorpe Signed-off-by: Leon Romanovsky --- drivers/pci/p2pdma.c | 42 +++++++++++++++++++++----------------- include/linux/pci-p2pdma.h | 18 ++++++++++++---- 2 files changed, 37 insertions(+), 23 deletions(-) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 274bb7bcc0bc5..176a99232fdca 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -28,9 +28,8 @@ struct pci_p2pdma { }; =20 struct pci_p2pdma_pagemap { - struct pci_dev *provider; - u64 bus_offset; struct dev_pagemap pgmap; + struct p2pdma_provider mem; }; =20 static struct pci_p2pdma_pagemap *to_p2p_pgmap(struct dev_pagemap *pgmap) @@ -204,8 +203,8 @@ static void p2pdma_page_free(struct page *page) { struct pci_p2pdma_pagemap *pgmap =3D to_p2p_pgmap(page_pgmap(page)); /* safe to dereference while a reference is held to the percpu ref */ - struct pci_p2pdma *p2pdma =3D - rcu_dereference_protected(pgmap->provider->p2pdma, 1); + struct pci_p2pdma *p2pdma =3D rcu_dereference_protected( + to_pci_dev(pgmap->mem.owner)->p2pdma, 1); struct percpu_ref *ref; =20 gen_pool_free_owner(p2pdma->pool, (uintptr_t)page_to_virt(page), @@ -270,14 +269,15 @@ static int pci_p2pdma_setup(struct pci_dev *pdev) =20 static void pci_p2pdma_unmap_mappings(void *data) { - struct pci_dev *pdev =3D data; + struct pci_p2pdma_pagemap *p2p_pgmap =3D data; =20 /* * Removing the alloc attribute from sysfs will call * unmap_mapping_range() on the inode, teardown any existing userspace * mappings and prevent new ones from being created. */ - sysfs_remove_file_from_group(&pdev->dev.kobj, &p2pmem_alloc_attr.attr, + sysfs_remove_file_from_group(&p2p_pgmap->mem.owner->kobj, + &p2pmem_alloc_attr.attr, p2pmem_group.name); } =20 @@ -328,10 +328,9 @@ int pci_p2pdma_add_resource(struct pci_dev *pdev, int = bar, size_t size, pgmap->nr_range =3D 1; pgmap->type =3D MEMORY_DEVICE_PCI_P2PDMA; pgmap->ops =3D &p2pdma_pgmap_ops; - - p2p_pgmap->provider =3D pdev; - p2p_pgmap->bus_offset =3D pci_bus_address(pdev, bar) - - pci_resource_start(pdev, bar); + p2p_pgmap->mem.owner =3D &pdev->dev; + p2p_pgmap->mem.bus_offset =3D + pci_bus_address(pdev, bar) - pci_resource_start(pdev, bar); =20 addr =3D devm_memremap_pages(&pdev->dev, pgmap); if (IS_ERR(addr)) { @@ -340,7 +339,7 @@ int pci_p2pdma_add_resource(struct pci_dev *pdev, int b= ar, size_t size, } =20 error =3D devm_add_action_or_reset(&pdev->dev, pci_p2pdma_unmap_mappings, - pdev); + p2p_pgmap); if (error) goto pages_free; =20 @@ -973,16 +972,16 @@ void pci_p2pmem_publish(struct pci_dev *pdev, bool pu= blish) } EXPORT_SYMBOL_GPL(pci_p2pmem_publish); =20 -static enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pg= map, - struct device *dev) +static enum pci_p2pdma_map_type +pci_p2pdma_map_type(struct p2pdma_provider *provider, struct device *dev) { enum pci_p2pdma_map_type type =3D PCI_P2PDMA_MAP_NOT_SUPPORTED; - struct pci_dev *provider =3D to_p2p_pgmap(pgmap)->provider; + struct pci_dev *pdev =3D to_pci_dev(provider->owner); struct pci_dev *client; struct pci_p2pdma *p2pdma; int dist; =20 - if (!provider->p2pdma) + if (!pdev->p2pdma) return PCI_P2PDMA_MAP_NOT_SUPPORTED; =20 if (!dev_is_pci(dev)) @@ -991,7 +990,7 @@ static enum pci_p2pdma_map_type pci_p2pdma_map_type(str= uct dev_pagemap *pgmap, client =3D to_pci_dev(dev); =20 rcu_read_lock(); - p2pdma =3D rcu_dereference(provider->p2pdma); + p2pdma =3D rcu_dereference(pdev->p2pdma); =20 if (p2pdma) type =3D xa_to_value(xa_load(&p2pdma->map_types, @@ -999,7 +998,7 @@ static enum pci_p2pdma_map_type pci_p2pdma_map_type(str= uct dev_pagemap *pgmap, rcu_read_unlock(); =20 if (type =3D=3D PCI_P2PDMA_MAP_UNKNOWN) - return calc_map_type_and_dist(provider, client, &dist, true); + return calc_map_type_and_dist(pdev, client, &dist, true); =20 return type; } @@ -1007,8 +1006,13 @@ static enum pci_p2pdma_map_type pci_p2pdma_map_type(= struct dev_pagemap *pgmap, void __pci_p2pdma_update_state(struct pci_p2pdma_map_state *state, struct device *dev, struct page *page) { - state->pgmap =3D page_pgmap(page); - state->map =3D pci_p2pdma_map_type(state->pgmap, dev); + struct pci_p2pdma_pagemap *p2p_pgmap =3D to_p2p_pgmap(page_pgmap(page)); + + if (state->mem =3D=3D &p2p_pgmap->mem) + return; + + state->mem =3D &p2p_pgmap->mem; + state->map =3D pci_p2pdma_map_type(&p2p_pgmap->mem, dev); } =20 /** diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h index b502fc8b49bf9..27a2c399f47da 100644 --- a/include/linux/pci-p2pdma.h +++ b/include/linux/pci-p2pdma.h @@ -16,6 +16,16 @@ struct block_device; struct scatterlist; =20 +/** + * struct p2pdma_provider + * + * A p2pdma provider is a range of MMIO address space available to the CPU. + */ +struct p2pdma_provider { + struct device *owner; + u64 bus_offset; +}; + #ifdef CONFIG_PCI_P2PDMA int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size, u64 offset); @@ -144,10 +154,11 @@ enum pci_p2pdma_map_type { }; =20 struct pci_p2pdma_map_state { - struct dev_pagemap *pgmap; + struct p2pdma_provider *mem; enum pci_p2pdma_map_type map; }; =20 + /* helper for pci_p2pdma_state(), do not use directly */ void __pci_p2pdma_update_state(struct pci_p2pdma_map_state *state, struct device *dev, struct page *page); @@ -166,8 +177,7 @@ pci_p2pdma_state(struct pci_p2pdma_map_state *state, st= ruct device *dev, struct page *page) { if (IS_ENABLED(CONFIG_PCI_P2PDMA) && is_pci_p2pdma_page(page)) { - if (state->pgmap !=3D page_pgmap(page)) - __pci_p2pdma_update_state(state, dev, page); + __pci_p2pdma_update_state(state, dev, page); return state->map; } return PCI_P2PDMA_MAP_NONE; @@ -185,7 +195,7 @@ static inline dma_addr_t pci_p2pdma_bus_addr_map(struct pci_p2pdma_map_state *state, phys_addr_t pa= ddr) { WARN_ON_ONCE(state->map !=3D PCI_P2PDMA_MAP_BUS_ADDR); - return paddr + to_p2p_pgmap(state->pgmap)->bus_offsetf; + return paddr + state->mem->bus_offset; } =20 #endif /* _LINUX_PCI_P2P_H */ --=20 2.50.1 From nobody Sun Oct 5 12:46:16 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 2AAF615746F; Mon, 4 Aug 2025 13:01:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; 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Mon, 4 Aug 2025 13:01:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754312465; bh=8qxmxdh9Tl1pid/pFVwGchh9YQBVRkyxV5t2LJjeK0Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bWZsoudzAzvO8pANyunPUzEQJJpTb4SI9lnyweA+J2BaiCRFA+yvJ9L2XvETLSzoj 5Ynx8IGcsYZdCNO/cxfuBj1RSztqX+Z8uC2m6fd9z+YbS3bWcmM59QFZligyPQ2ykV Greycy0RMIuPVBkBZewbp1I5IzLOnDP5prFLmdEKPWbt2/5QEzBJc0mrXlSN4FYa1r s0qmCa2rlJfr/+BfdpfAFoTyH/uGWTuc1xbv5zPZFjZnOxKVg+Eupv3qSy7v0A6kUb w+LsFFEAYW5MYenbPxh9zRS/f8tQ26SkRNuuLInGtN1Z/+/xZV8RwpkjDwLLGkZ8qB el8r5GE0b0y0w== From: Leon Romanovsky To: Alex Williamson Cc: Leon Romanovsky , Jason Gunthorpe , Andrew Morton , Bjorn Helgaas , =?UTF-8?q?Christian=20K=C3=B6nig?= , Christoph Hellwig , dri-devel@lists.freedesktop.org, iommu@lists.linux.dev, Jens Axboe , Joerg Roedel , kvm@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, Logan Gunthorpe , Marek Szyprowski , Robin Murphy , Sumit Semwal , Vivek Kasireddy , Will Deacon Subject: [PATCH v1 03/10] PCI/P2PDMA: Simplify bus address mapping API Date: Mon, 4 Aug 2025 16:00:38 +0300 Message-ID: <87064f6a9ae9617fb0665c201e4643cc430c3779.1754311439.git.leon@kernel.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Leon Romanovsky Update the pci_p2pdma_bus_addr_map() function to take a direct pointer to the p2pdma_provider structure instead of the pci_p2pdma_map_state. This simplifies the API by removing the need for callers to extract the provider from the state structure. The change updates all callers across the kernel (block layer, IOMMU, DMA direct, and HMM) to pass the provider pointer directly, making the code more explicit and reducing unnecessary indirection. This also removes the runtime warning check since callers now have direct control over which provider they use. Signed-off-by: Leon Romanovsky --- block/blk-mq-dma.c | 2 +- drivers/iommu/dma-iommu.c | 4 ++-- include/linux/pci-p2pdma.h | 7 +++---- kernel/dma/direct.c | 4 ++-- mm/hmm.c | 2 +- 5 files changed, 9 insertions(+), 10 deletions(-) diff --git a/block/blk-mq-dma.c b/block/blk-mq-dma.c index d415088ed9fd2..430e51ec494a6 100644 --- a/block/blk-mq-dma.c +++ b/block/blk-mq-dma.c @@ -79,7 +79,7 @@ static inline bool blk_can_dma_map_iova(struct request *r= eq, =20 static bool blk_dma_map_bus(struct blk_dma_iter *iter, struct phys_vec *ve= c) { - iter->addr =3D pci_p2pdma_bus_addr_map(&iter->p2pdma, vec->paddr); + iter->addr =3D pci_p2pdma_bus_addr_map(iter->p2pdma.mem, vec->paddr); iter->len =3D vec->len; return true; } diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 69f85209be7ab..7c1c25ffb804d 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -1439,8 +1439,8 @@ int iommu_dma_map_sg(struct device *dev, struct scatt= erlist *sg, int nents, * as a bus address, __finalise_sg() will copy the dma * address into the output segment. */ - s->dma_address =3D pci_p2pdma_bus_addr_map(&p2pdma_state, - sg_phys(s)); + s->dma_address =3D pci_p2pdma_bus_addr_map( + p2pdma_state.mem, sg_phys(s)); sg_dma_len(s) =3D sg->length; sg_dma_mark_bus_address(s); continue; diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h index 27a2c399f47da..eef96636c67e6 100644 --- a/include/linux/pci-p2pdma.h +++ b/include/linux/pci-p2pdma.h @@ -186,16 +186,15 @@ pci_p2pdma_state(struct pci_p2pdma_map_state *state, = struct device *dev, /** * pci_p2pdma_bus_addr_map - Translate a physical address to a bus address * for a PCI_P2PDMA_MAP_BUS_ADDR transfer. - * @state: P2P state structure + * @provider: P2P provider structure * @paddr: physical address to map * * Map a physically contiguous PCI_P2PDMA_MAP_BUS_ADDR transfer. */ static inline dma_addr_t -pci_p2pdma_bus_addr_map(struct pci_p2pdma_map_state *state, phys_addr_t pa= ddr) +pci_p2pdma_bus_addr_map(struct p2pdma_provider *provider, phys_addr_t padd= r) { - WARN_ON_ONCE(state->map !=3D PCI_P2PDMA_MAP_BUS_ADDR); - return paddr + state->mem->bus_offset; + return paddr + provider->bus_offset; } =20 #endif /* _LINUX_PCI_P2P_H */ diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index 1062caac47e7b..3e058c99fe856 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -484,8 +484,8 @@ int dma_direct_map_sg(struct device *dev, struct scatte= rlist *sgl, int nents, } break; case PCI_P2PDMA_MAP_BUS_ADDR: - sg->dma_address =3D pci_p2pdma_bus_addr_map(&p2pdma_state, - sg_phys(sg)); + sg->dma_address =3D pci_p2pdma_bus_addr_map( + p2pdma_state.mem, sg_phys(sg)); sg_dma_mark_bus_address(sg); continue; default: diff --git a/mm/hmm.c b/mm/hmm.c index 6556c0e074ba8..012b78688fa18 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -751,7 +751,7 @@ dma_addr_t hmm_dma_map_pfn(struct device *dev, struct h= mm_dma_map *map, break; case PCI_P2PDMA_MAP_BUS_ADDR: pfns[idx] |=3D HMM_PFN_P2PDMA_BUS | HMM_PFN_DMA_MAPPED; - return pci_p2pdma_bus_addr_map(p2pdma_state, paddr); + return pci_p2pdma_bus_addr_map(p2pdma_state->mem, paddr); default: return DMA_MAPPING_ERROR; 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smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YHmPkb2Z; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="YHmPkb2Z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4D208C113CF; Mon, 4 Aug 2025 13:01:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754312479; bh=shbFCrguQ+Q62Ap9hJLmw0h65suWHRyjEkM0F3UHxeg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YHmPkb2ZICu7msk3ndQanlf7QcWUOtGgBVP0pneUrz1+uplUFzu5/35hMyi5h/09M lsE8QZMnzav84z3yLwgxwEgIhJYZxt1EH6Yq3J6RG588PreH8ElFqe+t8wGupxx5+s i8/zWRs5Mvgsm2z98ra6oEp2T29Df+SkribQsO9eFg+aD28XQp5BuCePYxiB9p1Vqp HXWMYF6w6FniFFbTwkxOCnKyuWbwCumpteZi/5QGoMoLxP1kbAFszBnv/1EjpZOYP5 xbr5cBN0XKEghu8pVfuo6ZVqoPAmOLycgu9CUAk7VkJkgaXHsRKJ81JVRqOd+oS5Lj u98Wc4xdYV8yA== From: Leon Romanovsky To: Alex Williamson Cc: Leon Romanovsky , Jason Gunthorpe , Andrew Morton , Bjorn Helgaas , =?UTF-8?q?Christian=20K=C3=B6nig?= , Christoph Hellwig , dri-devel@lists.freedesktop.org, iommu@lists.linux.dev, Jens Axboe , Joerg Roedel , kvm@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, Logan Gunthorpe , Marek Szyprowski , Robin Murphy , Sumit Semwal , Vivek Kasireddy , Will Deacon Subject: [PATCH v1 04/10] PCI/P2PDMA: Refactor to separate core P2P functionality from memory allocation Date: Mon, 4 Aug 2025 16:00:39 +0300 Message-ID: X-Mailer: git-send-email 2.50.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Leon Romanovsky Refactor the PCI P2PDMA subsystem to separate the core peer-to-peer DMA functionality from the optional memory allocation layer. This creates a two-tier architecture: The core layer provides P2P mapping functionality for physical addresses based on PCI device MMIO BARs and integrates with the DMA API for mapping operations. This layer is required for all P2PDMA users. The optional upper layer provides memory allocation capabilities including gen_pool allocator, struct page support, and sysfs interface for user space access. This separation allows subsystems like VFIO to use only the core P2P mapping functionality without the overhead of memory allocation features they don't need. The core functionality is now available through the new pci_p2pdma_enable() function that returns a p2pdma_provider structure. Signed-off-by: Leon Romanovsky --- drivers/pci/p2pdma.c | 118 ++++++++++++++++++++++++++----------- include/linux/pci-p2pdma.h | 5 ++ 2 files changed, 89 insertions(+), 34 deletions(-) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 176a99232fdca..24a6c8ff88520 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -25,11 +25,12 @@ struct pci_p2pdma { struct gen_pool *pool; bool p2pmem_published; struct xarray map_types; + struct p2pdma_provider mem; }; =20 struct pci_p2pdma_pagemap { struct dev_pagemap pgmap; - struct p2pdma_provider mem; + struct p2pdma_provider *mem; }; =20 static struct pci_p2pdma_pagemap *to_p2p_pgmap(struct dev_pagemap *pgmap) @@ -204,7 +205,7 @@ static void p2pdma_page_free(struct page *page) struct pci_p2pdma_pagemap *pgmap =3D to_p2p_pgmap(page_pgmap(page)); /* safe to dereference while a reference is held to the percpu ref */ struct pci_p2pdma *p2pdma =3D rcu_dereference_protected( - to_pci_dev(pgmap->mem.owner)->p2pdma, 1); + to_pci_dev(pgmap->mem->owner)->p2pdma, 1); struct percpu_ref *ref; =20 gen_pool_free_owner(p2pdma->pool, (uintptr_t)page_to_virt(page), @@ -227,44 +228,82 @@ static void pci_p2pdma_release(void *data) =20 /* Flush and disable pci_alloc_p2p_mem() */ pdev->p2pdma =3D NULL; - synchronize_rcu(); + if (p2pdma->pool) + synchronize_rcu(); + xa_destroy(&p2pdma->map_types); + + if (!p2pdma->pool) + return; =20 gen_pool_destroy(p2pdma->pool); sysfs_remove_group(&pdev->dev.kobj, &p2pmem_group); - xa_destroy(&p2pdma->map_types); } =20 -static int pci_p2pdma_setup(struct pci_dev *pdev) +/** + * pci_p2pdma_enable - Enable peer-to-peer DMA support for a PCI device + * @pdev: The PCI device to enable P2PDMA for + * + * This function initializes the peer-to-peer DMA infrastructure for a PCI + * device. It allocates and sets up the necessary data structures to suppo= rt + * P2PDMA operations, including mapping type tracking. + */ +struct p2pdma_provider *pci_p2pdma_enable(struct pci_dev *pdev) { - int error =3D -ENOMEM; struct pci_p2pdma *p2p; + int ret; + + p2p =3D rcu_dereference_protected(pdev->p2pdma, 1); + if (p2p) + /* PCI device was "rebound" to the driver */ + return &p2p->mem; =20 p2p =3D devm_kzalloc(&pdev->dev, sizeof(*p2p), GFP_KERNEL); if (!p2p) - return -ENOMEM; + return ERR_PTR(-ENOMEM); =20 xa_init(&p2p->map_types); + p2p->mem.owner =3D &pdev->dev; + /* On all p2p platforms bus_offset is the same for all BARs */ + p2p->mem.bus_offset =3D + pci_bus_address(pdev, 0) - pci_resource_start(pdev, 0); =20 - p2p->pool =3D gen_pool_create(PAGE_SHIFT, dev_to_node(&pdev->dev)); - if (!p2p->pool) - goto out; + ret =3D devm_add_action_or_reset(&pdev->dev, pci_p2pdma_release, pdev); + if (ret) + goto out_p2p; =20 - error =3D devm_add_action_or_reset(&pdev->dev, pci_p2pdma_release, pdev); - if (error) - goto out_pool_destroy; + rcu_assign_pointer(pdev->p2pdma, p2p); + return &p2p->mem; =20 - error =3D sysfs_create_group(&pdev->dev.kobj, &p2pmem_group); - if (error) +out_p2p: + devm_kfree(&pdev->dev, p2p); + return ERR_PTR(ret); +} +EXPORT_SYMBOL_GPL(pci_p2pdma_enable); + +static int pci_p2pdma_setup_pool(struct pci_dev *pdev) +{ + struct pci_p2pdma *p2pdma; + int ret; + + p2pdma =3D rcu_dereference_protected(pdev->p2pdma, 1); + if (p2pdma->pool) + /* We already setup pools, do nothing, */ + return 0; + + p2pdma->pool =3D gen_pool_create(PAGE_SHIFT, dev_to_node(&pdev->dev)); + if (!p2pdma->pool) + return -ENOMEM; + + ret =3D sysfs_create_group(&pdev->dev.kobj, &p2pmem_group); + if (ret) goto out_pool_destroy; =20 - rcu_assign_pointer(pdev->p2pdma, p2p); return 0; =20 out_pool_destroy: - gen_pool_destroy(p2p->pool); -out: - devm_kfree(&pdev->dev, p2p); - return error; + gen_pool_destroy(p2pdma->pool); + p2pdma->pool =3D NULL; + return ret; } =20 static void pci_p2pdma_unmap_mappings(void *data) @@ -276,7 +315,7 @@ static void pci_p2pdma_unmap_mappings(void *data) * unmap_mapping_range() on the inode, teardown any existing userspace * mappings and prevent new ones from being created. */ - sysfs_remove_file_from_group(&p2p_pgmap->mem.owner->kobj, + sysfs_remove_file_from_group(&p2p_pgmap->mem->owner->kobj, &p2pmem_alloc_attr.attr, p2pmem_group.name); } @@ -295,6 +334,7 @@ int pci_p2pdma_add_resource(struct pci_dev *pdev, int b= ar, size_t size, u64 offset) { struct pci_p2pdma_pagemap *p2p_pgmap; + struct p2pdma_provider *mem; struct dev_pagemap *pgmap; struct pci_p2pdma *p2pdma; void *addr; @@ -312,15 +352,25 @@ int pci_p2pdma_add_resource(struct pci_dev *pdev, int= bar, size_t size, if (size + offset > pci_resource_len(pdev, bar)) return -EINVAL; =20 - if (!pdev->p2pdma) { - error =3D pci_p2pdma_setup(pdev); + p2pdma =3D rcu_dereference_protected(pdev->p2pdma, 1); + if (!p2pdma) { + mem =3D pci_p2pdma_enable(pdev); + if (IS_ERR(mem)) + return PTR_ERR(mem); + + error =3D pci_p2pdma_setup_pool(pdev); if (error) return error; - } + + p2pdma =3D rcu_dereference_protected(pdev->p2pdma, 1); + } else + mem =3D &p2pdma->mem; =20 p2p_pgmap =3D devm_kzalloc(&pdev->dev, sizeof(*p2p_pgmap), GFP_KERNEL); - if (!p2p_pgmap) - return -ENOMEM; + if (!p2p_pgmap) { + error =3D -ENOMEM; + goto free_pool; + } =20 pgmap =3D &p2p_pgmap->pgmap; pgmap->range.start =3D pci_resource_start(pdev, bar) + offset; @@ -328,9 +378,7 @@ int pci_p2pdma_add_resource(struct pci_dev *pdev, int b= ar, size_t size, pgmap->nr_range =3D 1; pgmap->type =3D MEMORY_DEVICE_PCI_P2PDMA; pgmap->ops =3D &p2pdma_pgmap_ops; - p2p_pgmap->mem.owner =3D &pdev->dev; - p2p_pgmap->mem.bus_offset =3D - pci_bus_address(pdev, bar) - pci_resource_start(pdev, bar); + p2p_pgmap->mem =3D mem; =20 addr =3D devm_memremap_pages(&pdev->dev, pgmap); if (IS_ERR(addr)) { @@ -343,7 +391,6 @@ int pci_p2pdma_add_resource(struct pci_dev *pdev, int b= ar, size_t size, if (error) goto pages_free; =20 - p2pdma =3D rcu_dereference_protected(pdev->p2pdma, 1); error =3D gen_pool_add_owner(p2pdma->pool, (unsigned long)addr, pci_bus_address(pdev, bar) + offset, range_len(&pgmap->range), dev_to_node(&pdev->dev), @@ -359,7 +406,10 @@ int pci_p2pdma_add_resource(struct pci_dev *pdev, int = bar, size_t size, pages_free: devm_memunmap_pages(&pdev->dev, pgmap); pgmap_free: - devm_kfree(&pdev->dev, pgmap); + devm_kfree(&pdev->dev, p2p_pgmap); +free_pool: + sysfs_remove_group(&pdev->dev.kobj, &p2pmem_group); + gen_pool_destroy(p2pdma->pool); return error; } EXPORT_SYMBOL_GPL(pci_p2pdma_add_resource); @@ -1008,11 +1058,11 @@ void __pci_p2pdma_update_state(struct pci_p2pdma_ma= p_state *state, { struct pci_p2pdma_pagemap *p2p_pgmap =3D to_p2p_pgmap(page_pgmap(page)); =20 - if (state->mem =3D=3D &p2p_pgmap->mem) + if (state->mem =3D=3D p2p_pgmap->mem) return; =20 - state->mem =3D &p2p_pgmap->mem; - state->map =3D pci_p2pdma_map_type(&p2p_pgmap->mem, dev); + state->mem =3D p2p_pgmap->mem; + state->map =3D pci_p2pdma_map_type(p2p_pgmap->mem, dev); } =20 /** diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h index eef96636c67e6..83f11dc8659a7 100644 --- a/include/linux/pci-p2pdma.h +++ b/include/linux/pci-p2pdma.h @@ -27,6 +27,7 @@ struct p2pdma_provider { }; =20 #ifdef CONFIG_PCI_P2PDMA +struct p2pdma_provider *pci_p2pdma_enable(struct pci_dev *pdev); int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size, u64 offset); int pci_p2pdma_distance_many(struct pci_dev *provider, struct device **cli= ents, @@ -45,6 +46,10 @@ int pci_p2pdma_enable_store(const char *page, struct pci= _dev **p2p_dev, ssize_t pci_p2pdma_enable_show(char *page, struct pci_dev *p2p_dev, bool use_p2pdma); #else /* CONFIG_PCI_P2PDMA */ +static inline struct p2pdma_provider *pci_p2pdma_enable(struct pci_dev *pd= ev) +{ + return ERR_PTR(-EOPNOTSUPP); +} static inline int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size, u64 offset) { --=20 2.50.1 From nobody Sun Oct 5 12:46:16 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 1541826B75B; Mon, 4 Aug 2025 13:01:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754312475; cv=none; b=ZYEJ3z1KksUTCy0c2e+RTfI5pIeGAzKJDKJen6cPH9cpiCOVD12rTdQENmHbnFsducdcWnvp//bjUt500weMWZjSE50qfBt2X+8zoL/yvoCYYoAic/IwHQ2zox7hNpagi4Gy+T9fEqWri9wUk6fYjh28+X+S1kN5FeP4tLr4zwE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754312475; c=relaxed/simple; bh=9+ULuqPLLBXPgbHLXOPPCMvRNGtvNj8loKfxgbdD5Do=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=VBMZk8mNeirz1rbjSmrhNgp0HWGjcRZtwP0Jc6CLfVatMxuXnMXXuWYYRWXApdxBa5So46xsipxqU1yn+mhFaHeDCzFmoIB3deRje+rtvbNcdBfek6bzGuz9pLqqp7KjUVfooGUHFUx5RX69pAKkI8dHZuvNAZtWsfGJSsJQkn8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=BSb+/N/a; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="BSb+/N/a" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B5962C4CEE7; Mon, 4 Aug 2025 13:01:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754312474; bh=9+ULuqPLLBXPgbHLXOPPCMvRNGtvNj8loKfxgbdD5Do=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BSb+/N/auBoNeE0ABgzET5irnf1yxzaV2jqycRTIY9uSY26Xojp6pcdt2fYsHBR62 NhhOMdzczWKXgEWLOUDSZqvkCPLWEtTbTePU4iFUWxT/u7NH1zqH34SesIH+TNjYDl sxTY1HFoxjV6Pidr1+i+aN8Lx+sfDun4UuSXJlLlNc/MvvE4LpEuPESCA19atSOG+c NJcRoVsvAXpsJgQo1s+Kig4oPRAxJTL515mNQTezRMwXnnKJxEyz+H9MvzpXm5L4Wh BL//RZhNZxS8sZcD/bj0R9LCXKrlkVXrDIQMBbsyvNb0B1TuBkpvRugiUByizRCESe 64T8DE9SPbRUw== From: Leon Romanovsky To: Alex Williamson Cc: Leon Romanovsky , Jason Gunthorpe , Andrew Morton , Bjorn Helgaas , =?UTF-8?q?Christian=20K=C3=B6nig?= , Christoph Hellwig , dri-devel@lists.freedesktop.org, iommu@lists.linux.dev, Jens Axboe , Joerg Roedel , kvm@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, Logan Gunthorpe , Marek Szyprowski , Robin Murphy , Sumit Semwal , Vivek Kasireddy , Will Deacon Subject: [PATCH v1 05/10] PCI/P2PDMA: Export pci_p2pdma_map_type() function Date: Mon, 4 Aug 2025 16:00:40 +0300 Message-ID: X-Mailer: git-send-email 2.50.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Leon Romanovsky Export the pci_p2pdma_map_type() function to allow external modules and subsystems to determine the appropriate mapping type for P2PDMA transfers between a provider and target device. The function determines whether peer-to-peer DMA transfers can be done directly through PCI switches (PCI_P2PDMA_MAP_BUS_ADDR) or must go through the host bridge (PCI_P2PDMA_MAP_THRU_HOST_BRIDGE), or if the transfer is not supported at all. This export enables subsystems like VFIO to properly handle P2PDMA operations by querying the mapping type before attempting transfers, ensuring correct DMA address programming and error handling. Signed-off-by: Leon Romanovsky --- drivers/pci/p2pdma.c | 15 ++++++- include/linux/pci-p2pdma.h | 85 +++++++++++++++++++++----------------- 2 files changed, 59 insertions(+), 41 deletions(-) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 24a6c8ff88520..3fa1292c8d917 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -1022,8 +1022,18 @@ void pci_p2pmem_publish(struct pci_dev *pdev, bool p= ublish) } EXPORT_SYMBOL_GPL(pci_p2pmem_publish); =20 -static enum pci_p2pdma_map_type -pci_p2pdma_map_type(struct p2pdma_provider *provider, struct device *dev) +/** + * pci_p2pdma_map_type - Determine the mapping type for P2PDMA transfers + * @provider: P2PDMA provider structure + * @dev: Target device for the transfer + * + * Determines how peer-to-peer DMA transfers should be mapped between + * the provider and the target device. The mapping type indicates whether + * the transfer can be done directly through PCI switches or must go + * through the host bridge. + */ +enum pci_p2pdma_map_type pci_p2pdma_map_type(struct p2pdma_provider *provi= der, + struct device *dev) { enum pci_p2pdma_map_type type =3D PCI_P2PDMA_MAP_NOT_SUPPORTED; struct pci_dev *pdev =3D to_pci_dev(provider->owner); @@ -1052,6 +1062,7 @@ pci_p2pdma_map_type(struct p2pdma_provider *provider,= struct device *dev) =20 return type; } +EXPORT_SYMBOL_GPL(pci_p2pdma_map_type); =20 void __pci_p2pdma_update_state(struct pci_p2pdma_map_state *state, struct device *dev, struct page *page) diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h index 83f11dc8659a7..dea98baee5ce2 100644 --- a/include/linux/pci-p2pdma.h +++ b/include/linux/pci-p2pdma.h @@ -26,6 +26,45 @@ struct p2pdma_provider { u64 bus_offset; }; =20 +enum pci_p2pdma_map_type { + /* + * PCI_P2PDMA_MAP_UNKNOWN: Used internally as an initial state before + * the mapping type has been calculated. Exported routines for the API + * will never return this value. + */ + PCI_P2PDMA_MAP_UNKNOWN =3D 0, + + /* + * Not a PCI P2PDMA transfer. + */ + PCI_P2PDMA_MAP_NONE, + + /* + * PCI_P2PDMA_MAP_NOT_SUPPORTED: Indicates the transaction will + * traverse the host bridge and the host bridge is not in the + * allowlist. DMA Mapping routines should return an error when + * this is returned. + */ + PCI_P2PDMA_MAP_NOT_SUPPORTED, + + /* + * PCI_P2PDMA_MAP_BUS_ADDR: Indicates that two devices can talk to + * each other directly through a PCI switch and the transaction will + * not traverse the host bridge. Such a mapping should program + * the DMA engine with PCI bus addresses. + */ + PCI_P2PDMA_MAP_BUS_ADDR, + + /* + * PCI_P2PDMA_MAP_THRU_HOST_BRIDGE: Indicates two devices can talk + * to each other, but the transaction traverses a host bridge on the + * allowlist. In this case, a normal mapping either with CPU physical + * addresses (in the case of dma-direct) or IOVA addresses (in the + * case of IOMMUs) should be used to program the DMA engine. + */ + PCI_P2PDMA_MAP_THRU_HOST_BRIDGE, +}; + #ifdef CONFIG_PCI_P2PDMA struct p2pdma_provider *pci_p2pdma_enable(struct pci_dev *pdev); int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size, @@ -45,6 +84,8 @@ int pci_p2pdma_enable_store(const char *page, struct pci_= dev **p2p_dev, bool *use_p2pdma); ssize_t pci_p2pdma_enable_show(char *page, struct pci_dev *p2p_dev, bool use_p2pdma); +enum pci_p2pdma_map_type pci_p2pdma_map_type(struct p2pdma_provider *provi= der, + struct device *dev); #else /* CONFIG_PCI_P2PDMA */ static inline struct p2pdma_provider *pci_p2pdma_enable(struct pci_dev *pd= ev) { @@ -105,6 +146,11 @@ static inline ssize_t pci_p2pdma_enable_show(char *pag= e, { return sprintf(page, "none\n"); } +static inline enum pci_p2pdma_map_type +pci_p2pdma_map_type(struct p2pdma_provider *provider, struct device *dev) +{ + return PCI_P2PDMA_MAP_NOT_SUPPORTED; +} #endif /* CONFIG_PCI_P2PDMA */ =20 =20 @@ -119,45 +165,6 @@ static inline struct pci_dev *pci_p2pmem_find(struct d= evice *client) return pci_p2pmem_find_many(&client, 1); } =20 -enum pci_p2pdma_map_type { - /* - * PCI_P2PDMA_MAP_UNKNOWN: Used internally as an initial state before - * the mapping type has been calculated. Exported routines for the API - * will never return this value. - */ - PCI_P2PDMA_MAP_UNKNOWN =3D 0, - - /* - * Not a PCI P2PDMA transfer. - */ - PCI_P2PDMA_MAP_NONE, - - /* - * PCI_P2PDMA_MAP_NOT_SUPPORTED: Indicates the transaction will - * traverse the host bridge and the host bridge is not in the - * allowlist. DMA Mapping routines should return an error when - * this is returned. - */ - PCI_P2PDMA_MAP_NOT_SUPPORTED, - - /* - * PCI_P2PDMA_MAP_BUS_ADDR: Indicates that two devices can talk to - * each other directly through a PCI switch and the transaction will - * not traverse the host bridge. Such a mapping should program - * the DMA engine with PCI bus addresses. - */ - PCI_P2PDMA_MAP_BUS_ADDR, - - /* - * PCI_P2PDMA_MAP_THRU_HOST_BRIDGE: Indicates two devices can talk - * to each other, but the transaction traverses a host bridge on the - * allowlist. In this case, a normal mapping either with CPU physical - * addresses (in the case of dma-direct) or IOVA addresses (in the - * case of IOMMUs) should be used to program the DMA engine. - */ - PCI_P2PDMA_MAP_THRU_HOST_BRIDGE, -}; - struct pci_p2pdma_map_state { struct p2pdma_provider *mem; enum pci_p2pdma_map_type map; --=20 2.50.1 From nobody Sun Oct 5 12:46:16 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 1DE5827145F; Mon, 4 Aug 2025 13:01:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754312488; cv=none; b=jYKE+fL0xQ742m3diHvLuAuTd0nyadYe0hB3xMcK1Lyuc+y9YHj2vsdXHcNi6vfmAq/DhYGXbh3lpVDKszXxbcrhRLYhtiXL9U2d3JdGO4Fq7mwJRor7/lCK7JPj4hFIF5sQpSh8OFjnEMk89tbw/goq3IaX3AVpwr4dfE4m4bg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754312488; c=relaxed/simple; bh=WJztkfF0BW2A+ySSaoquKg9YWNFPhQS7np0spIG94dM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tfPUYq4Dfv8ft90ZzB1yPzgq6CE7SXgBiO1YVaVXCh7NN9C0v1ONMrF2udIZMorJMalVC+MlBa3jzk8eDbJzLO9qiwzefXPHNsIXrDE9tBPH5i89fe/EnQXgbFZKr/DFjtpHAMFLqz6JMfDH0wj37FQeBIw26WKed2iwj4WEag4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=U6NzdtAJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="U6NzdtAJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7276EC4CEE7; Mon, 4 Aug 2025 13:01:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754312487; bh=WJztkfF0BW2A+ySSaoquKg9YWNFPhQS7np0spIG94dM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=U6NzdtAJjvKqDoK99gNW74qBu86eRI6rmFzBpM7IVvzJUQY7rqGAQN18dEvkubRN+ Y+m2Fo7Oc72hbCrN1FXqElv4W8T7JunoHZHZdBliXv/iTcRC1rPep8PUQrlubuEuZr cFwuGmfnVgmrhV2o9d1afCl0k/XMtlNsC9nLQmxEP2s24dFZ8n2RnfdUPpO2rn7dOB MoocxgPp8LpCToe04kCbNp1Hzh4v8k8j5zfoFKNLnSjxSqf3tAvHQoqcLLzkSvxwBO AgExQp/Jj/LmCw9WJJmASCHqMVlKFvPl6JCk9IDacM3Sbg4LjdbUwhrCzOddAfA3am cOY6O/a9VKDKg== From: Leon Romanovsky To: Alex Williamson Cc: Leon Romanovsky , Jason Gunthorpe , Andrew Morton , Bjorn Helgaas , =?UTF-8?q?Christian=20K=C3=B6nig?= , Christoph Hellwig , dri-devel@lists.freedesktop.org, iommu@lists.linux.dev, Jens Axboe , Joerg Roedel , kvm@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, Logan Gunthorpe , Marek Szyprowski , Robin Murphy , Sumit Semwal , Vivek Kasireddy , Will Deacon Subject: [PATCH v1 06/10] types: move phys_vec definition to common header Date: Mon, 4 Aug 2025 16:00:41 +0300 Message-ID: X-Mailer: git-send-email 2.50.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Leon Romanovsky Move the struct phys_vec definition from block/blk-mq-dma.c to include/linux/types.h to make it available for use across the kernel. The phys_vec structure represents a physical address range with a length, which is used by the new physical address-based DMA mapping API. This structure is already used by the block layer and will be needed by upcoming VFIO patches for dma-buf operations. Moving this definition to types.h provides a centralized location for this common data structure and eliminates code duplication across subsystems that need to work with physical address ranges. Signed-off-by: Leon Romanovsky --- block/blk-mq-dma.c | 5 ----- include/linux/types.h | 5 +++++ 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/block/blk-mq-dma.c b/block/blk-mq-dma.c index 430e51ec494a6..8d2646ab27953 100644 --- a/block/blk-mq-dma.c +++ b/block/blk-mq-dma.c @@ -5,11 +5,6 @@ #include #include "blk.h" =20 -struct phys_vec { - phys_addr_t paddr; - u32 len; -}; - static bool blk_map_iter_next(struct request *req, struct req_iterator *it= er, struct phys_vec *vec) { diff --git a/include/linux/types.h b/include/linux/types.h index 6dfdb8e8e4c35..2bc56681b2e62 100644 --- a/include/linux/types.h +++ b/include/linux/types.h @@ -170,6 +170,11 @@ typedef u64 phys_addr_t; typedef u32 phys_addr_t; #endif =20 +struct phys_vec { + phys_addr_t paddr; + u32 len; +}; + typedef phys_addr_t resource_size_t; =20 /* --=20 2.50.1 From nobody Sun Oct 5 12:46:16 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 7D5B42701D0; Mon, 4 Aug 2025 13:01:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754312483; cv=none; b=TR5gJMMaesAJ0cIWJGKrqX+C6VMhbJWadAjwlViCBS060A8xDHrBKeDkCqCQOjbFUSQNOQ7VY/PEs61MdthZ5w5NLFZEPEtBVV6iFi0/NnvMM/T7Klu38NSYonvr6Ji6TifPk88A5/bjOB7abLZBiMADucx5Wz+bjrNMD7VGP1k= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754312483; c=relaxed/simple; bh=SvWpwCR2Wh2zkNow/WohcCYMP4E/fUfFI3S/vqkvZcI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=lECKcQx8jEOb5HshL7WM5HxWL5mR51onpU7zJyrooJryLn6dO+cqhh41wSlSCSjlAsBnB34KSI/rRDgEDNy+6mMALCOHUFHNQGB730eVfm/fM3GxbqrH5l3uez3GzNaK8xdvvOhmr8waM9of6rmq83SilFC0V7NuvbyywX12qs0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=uPXz+dDM; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="uPXz+dDM" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 999CDC4CEF0; Mon, 4 Aug 2025 13:01:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754312483; bh=SvWpwCR2Wh2zkNow/WohcCYMP4E/fUfFI3S/vqkvZcI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uPXz+dDMAvSwAXGZh2jpBdnIGjP5/4P1Bi7fU4KjhDdrrUhmuS+1iwLBL5/Ch7nk2 yoSNA9Nqk0pwb6Qm8dTt9S7pGFBR7xRykO/XC8Uiyvhy+ynoAVH44BcG/ZX1xrgjRr f7S5ch72l2xHSj/6lT+whhxF9B5bG6KmjYJAO73Fmp1/WoQ2Hb4aL4bB9D78/irFGp JphMh1g0mUZplgv7y2OWfetRViBhbKCFDEAjIP7BKLkCY6NDnd1IpcspTkDAVZgS2T un44QqqeeEqeR3lnRp4qaCLGlduD6sBnDTc2o9YBKANnMf+gPZLqYcG7UViKXRPDgK quBdiV2/cmkoA== From: Leon Romanovsky To: Alex Williamson Cc: Vivek Kasireddy , Jason Gunthorpe , Andrew Morton , Bjorn Helgaas , =?UTF-8?q?Christian=20K=C3=B6nig?= , Christoph Hellwig , dri-devel@lists.freedesktop.org, iommu@lists.linux.dev, Jens Axboe , Joerg Roedel , kvm@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, Logan Gunthorpe , Marek Szyprowski , Robin Murphy , Sumit Semwal , Will Deacon Subject: [PATCH v1 07/10] vfio: Export vfio device get and put registration helpers Date: Mon, 4 Aug 2025 16:00:42 +0300 Message-ID: X-Mailer: git-send-email 2.50.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Vivek Kasireddy 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 Signed-off-by: Leon Romanovsky --- 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 1fd261efc582d..620a3ee5d04db 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); =20 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); =20 /* * VFIO driver API diff --git a/include/linux/vfio.h b/include/linux/vfio.h index 707b00772ce1f..ba65bbdffd0b2 100644 --- a/include/linux/vfio.h +++ b/include/linux/vfio.h @@ -293,6 +293,8 @@ 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); =20 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); --=20 2.50.1 From nobody Sun Oct 5 12:46:16 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 20E412749E2; Mon, 4 Aug 2025 13:01:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754312502; cv=none; b=rYAled3tgRcrSwssIq/qAStoFIaUj+H6k7qrBfKxI4Zz312RouGOlYvAf/PyMclHpQxIQG6JA0d65ppYGtRCdMRGOjD1lc4FzNiGP2s1QA2GEHuMFjXFJA/nTUhgLppqVR//yRcoZZ+UaZ4HJ335uv13EKXutwrk3EekBCf5agI= ARC-Message-Signature: i=1; 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b=oV6re8fiGNwYDZzCzdRzp9XpjScFB7jHhr0bUqrsSd/RU8VD1+cDyB4db1ivcuz67 ZbqOoy4QDgWahTEBLZIkeuGoLDtCxufGY1mXb4uUNEIIogWWDZKxvNPNgmGAOQfthR M88oaFlWV16G0mYbetwlnMeQOqlSTPkZtmJgNfx1DBxt8qHsi8vzBGtgUSwzfG/EF/ +feKrcxhDRe2w3XUDGmoRDhE/Z6LPttQLNSWEXlBJ9NMAhEVqOVOLoQfSfWwEFlJa9 t+8VS5mhktJavv7v+cSijhYGtO53nybwj4RxWUn/B2l2HWenabrQ2aR3U+cNT0+v2t iMQ+fAg6U3ZtQ== From: Leon Romanovsky To: Alex Williamson Cc: Leon Romanovsky , Jason Gunthorpe , Andrew Morton , Bjorn Helgaas , =?UTF-8?q?Christian=20K=C3=B6nig?= , Christoph Hellwig , dri-devel@lists.freedesktop.org, iommu@lists.linux.dev, Jens Axboe , Joerg Roedel , kvm@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, Logan Gunthorpe , Marek Szyprowski , Robin Murphy , Sumit Semwal , Vivek Kasireddy , Will Deacon Subject: [PATCH v1 08/10] vfio/pci: Enable peer-to-peer DMA transactions by default Date: Mon, 4 Aug 2025 16:00:43 +0300 Message-ID: X-Mailer: git-send-email 2.50.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Leon Romanovsky Make sure that all VFIO PCI devices have peer-to-peer capabilities enables, so we would be able to export their MMIO memory through DMABUF, Signed-off-by: Leon Romanovsky --- drivers/vfio/pci/vfio_pci_core.c | 4 ++++ include/linux/vfio_pci_core.h | 1 + 2 files changed, 5 insertions(+) diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_c= ore.c index 31bdb9110cc0f..df9a32d3deac9 100644 --- a/drivers/vfio/pci/vfio_pci_core.c +++ b/drivers/vfio/pci/vfio_pci_core.c @@ -28,6 +28,7 @@ #include #include #include +#include #if IS_ENABLED(CONFIG_EEH) #include #endif @@ -2088,6 +2089,9 @@ int vfio_pci_core_init_dev(struct vfio_device *core_v= dev) INIT_LIST_HEAD(&vdev->dummy_resources_list); INIT_LIST_HEAD(&vdev->ioeventfds_list); INIT_LIST_HEAD(&vdev->sriov_pfs_item); + vdev->provider =3D pci_p2pdma_enable(vdev->pdev); + if (IS_ERR(vdev->provider)) + return PTR_ERR(vdev->provider); init_rwsem(&vdev->memory_lock); xa_init(&vdev->ctx); =20 diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h index fbb472dd99b36..b017fae251811 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 p2pdma_provider *provider; }; =20 /* Will be exported for vfio pci drivers usage */ --=20 2.50.1 From nobody Sun Oct 5 12:46:16 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 D5409262D0C; Mon, 4 Aug 2025 13:01:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754312493; cv=none; b=WnTmcQRObgKBLiFLN9IjsTvh51f7nLK4fMKZMcQ3c2+5X0aBktTphObjFXh8rc/x30/wB5ymFKGcbhu3Jgw87UzFyaEelSZUrRA+5RwKRcsG0ORtwRCNJy4U0TxvaS4A3LOo7d/3peTlJg5tSwjSNREJXhX+qkwsFRF2G7k13lA= ARC-Message-Signature: i=1; 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b=XV0KBsfIDTwl29M6z0s95tJW+KyseHoOT1FtNUuA7+11uf5VFDbx4XPmvH3RAay7j 3b3OY9xdFfQUubLEg9potVqnV8ZKrMGzGBVFuIaRSis5iYds7HEscoEET3vt3b7aVW Wb38mBNWStwtDdLorcaxEqG0WQSUSVGINJzOWhmBCdnBoA7d7Xfu4H5E4hUzOLw63C r6gwHS3+Lq7ACSqM34Y+gkfNfz+uK6NdX2FoWlyLjJ6zHmsa9rTHKU5zv0X/4Tpr4A JC0D9dUw8ptcgXALHLLrrV41fRYfElFDNWoO556VbtcsivLAvssORg5yGwoFwfHtWv +yzapMQI/iTaA== From: Leon Romanovsky To: Alex Williamson Cc: Vivek Kasireddy , Jason Gunthorpe , Andrew Morton , Bjorn Helgaas , =?UTF-8?q?Christian=20K=C3=B6nig?= , Christoph Hellwig , dri-devel@lists.freedesktop.org, iommu@lists.linux.dev, Jens Axboe , Joerg Roedel , kvm@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, Logan Gunthorpe , Marek Szyprowski , Robin Murphy , Sumit Semwal , Will Deacon Subject: [PATCH v1 09/10] vfio/pci: Share the core device pointer while invoking feature functions Date: Mon, 4 Aug 2025 16:00:44 +0300 Message-ID: X-Mailer: git-send-email 2.50.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Vivek Kasireddy 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 Signed-off-by: Leon Romanovsky --- 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_c= ore.c index df9a32d3deac9..b1863d84b11aa 100644 --- a/drivers/vfio/pci/vfio_pci_core.c +++ b/drivers/vfio/pci/vfio_pci_core.c @@ -300,11 +300,9 @@ static int vfio_pci_runtime_pm_entry(struct vfio_pci_c= ore_device *vdev, return 0; } =20 -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 f= lags, void __user *arg, size_t argsz) { - struct vfio_pci_core_device *vdev =3D - container_of(device, struct vfio_pci_core_device, vdev); int ret; =20 ret =3D vfio_check_feature(flags, argsz, VFIO_DEVICE_FEATURE_SET, 0); @@ -321,12 +319,10 @@ static int vfio_pci_core_pm_entry(struct vfio_device = *device, u32 flags, } =20 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 =3D - container_of(device, struct vfio_pci_core_device, vdev); struct vfio_device_low_power_entry_with_wakeup entry; struct eventfd_ctx *efdctx; int ret; @@ -377,11 +373,9 @@ static void vfio_pci_runtime_pm_exit(struct vfio_pci_c= ore_device *vdev) up_write(&vdev->memory_lock); } =20 -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 fl= ags, void __user *arg, size_t argsz) { - struct vfio_pci_core_device *vdev =3D - container_of(device, struct vfio_pci_core_device, vdev); int ret; =20 ret =3D vfio_check_feature(flags, argsz, VFIO_DEVICE_FEATURE_SET, 0); @@ -1474,11 +1468,10 @@ long vfio_pci_core_ioctl(struct vfio_device *core_v= dev, unsigned int cmd, } EXPORT_SYMBOL_GPL(vfio_pci_core_ioctl); =20 -static int vfio_pci_core_feature_token(struct vfio_device *device, u32 fla= gs, - 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 =3D - container_of(device, struct vfio_pci_core_device, vdev); uuid_t uuid; int ret; =20 @@ -1505,16 +1498,19 @@ 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 =3D + 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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smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=EckcSGki; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="EckcSGki" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E08A3C4CEF0; Mon, 4 Aug 2025 13:01:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754312497; bh=/BbRG9KlrveH/njZbFOIevsKMyAUr9+pk2igE0RXJZk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EckcSGkixZyZTiI9bPy/oFQaXMSXOt0HmOz9LTu4nv1bLeHjnwwjwkifQu/lVh+Bm YHSazs6F3zjYU84isNIdpmtdV5/utoG6BIM1HzH07vzMw/ziC02FhqriUM2ShXg7AM tGlgZLMSbeeTIws81k5l9PmQ0U/Shsf3Xxcg58WutWN0woQoFKVv9e6V1tsIfIbY9i yABhd9PCQ+G/tcLie3UxBmhwH0dr9L+hbPVrRztJ7/FK7bYFrP2YEEqktl9JJsbUCi iCE6+zR5zt6qRGVryPaOQVR9I5eCbxjzXLWNOpkVgomeJ5AeR4e4ZfifwAMaS+tmwp tZ+ZE6/Lmfa3A== From: Leon Romanovsky To: Alex Williamson Cc: Leon Romanovsky , Jason Gunthorpe , Andrew Morton , Bjorn Helgaas , =?UTF-8?q?Christian=20K=C3=B6nig?= , Christoph Hellwig , dri-devel@lists.freedesktop.org, iommu@lists.linux.dev, Jens Axboe , Joerg Roedel , kvm@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, Logan Gunthorpe , Marek Szyprowski , Robin Murphy , Sumit Semwal , Vivek Kasireddy , Will Deacon Subject: [PATCH v1 10/10] vfio/pci: Add dma-buf export support for MMIO regions Date: Mon, 4 Aug 2025 16:00:45 +0300 Message-ID: <5e043d8b95627441db6156e7f15e6e1658e9d537.1754311439.git.leon@kernel.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Leon Romanovsky Add support for exporting PCI device MMIO regions through dma-buf, enabling safe sharing of non-struct page memory with controlled lifetime management. This allows RDMA and other subsystems to import dma-buf FDs and build them into memory regions for PCI P2P operations. The implementation provides a revocable attachment mechanism using dma-buf move operations. MMIO regions are normally pinned as BARs don't change physical addresses, but access is revoked when the VFIO device is closed or a PCI reset is issued. This ensures kernel self-defense against potentially hostile userspace. Signed-off-by: Jason Gunthorpe Signed-off-by: Vivek Kasireddy Signed-off-by: Leon Romanovsky --- drivers/vfio/pci/Kconfig | 20 ++ drivers/vfio/pci/Makefile | 2 + drivers/vfio/pci/vfio_pci_config.c | 22 +- drivers/vfio/pci/vfio_pci_core.c | 25 +- drivers/vfio/pci/vfio_pci_dmabuf.c | 390 +++++++++++++++++++++++++++++ drivers/vfio/pci/vfio_pci_priv.h | 23 ++ include/linux/dma-buf.h | 1 + include/linux/vfio_pci_core.h | 3 + include/uapi/linux/vfio.h | 25 ++ 9 files changed, 506 insertions(+), 5 deletions(-) create mode 100644 drivers/vfio/pci/vfio_pci_dmabuf.c diff --git a/drivers/vfio/pci/Kconfig b/drivers/vfio/pci/Kconfig index 2b0172f546652..55ae888bf26ae 100644 --- a/drivers/vfio/pci/Kconfig +++ b/drivers/vfio/pci/Kconfig @@ -55,6 +55,26 @@ config VFIO_PCI_ZDEV_KVM =20 To enable s390x KVM vfio-pci extensions, say Y. =20 +config VFIO_PCI_DMABUF + bool "VFIO PCI extensions for DMA-BUF" + depends on VFIO_PCI_CORE + depends on PCI_P2PDMA && DMA_SHARED_BUFFER + default y + help + Enable support for VFIO PCI extensions that allow exporting + device MMIO regions as DMA-BUFs for peer devices to access via + peer-to-peer (P2P) DMA. + + This feature enables a VFIO-managed PCI device to export a portion + of its MMIO BAR as a DMA-BUF file descriptor, which can be passed + to other userspace drivers or kernel subsystems capable of + initiating DMA to that region. + + Say Y here if you want to enable VFIO DMABUF-based MMIO export + support for peer-to-peer DMA use cases. + + If unsure, say N. + source "drivers/vfio/pci/mlx5/Kconfig" =20 source "drivers/vfio/pci/hisilicon/Kconfig" diff --git a/drivers/vfio/pci/Makefile b/drivers/vfio/pci/Makefile index cf00c0a7e55c8..f9155e9c5f630 100644 --- a/drivers/vfio/pci/Makefile +++ b/drivers/vfio/pci/Makefile @@ -2,7 +2,9 @@ =20 vfio-pci-core-y :=3D vfio_pci_core.o vfio_pci_intrs.o vfio_pci_rdwr.o vfio= _pci_config.o vfio-pci-core-$(CONFIG_VFIO_PCI_ZDEV_KVM) +=3D vfio_pci_zdev.o + obj-$(CONFIG_VFIO_PCI_CORE) +=3D vfio-pci-core.o +vfio-pci-core-$(CONFIG_VFIO_PCI_DMABUF) +=3D vfio_pci_dmabuf.o =20 vfio-pci-y :=3D vfio_pci.o vfio-pci-$(CONFIG_VFIO_PCI_IGD) +=3D vfio_pci_igd.o diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci= _config.c index 8f02f236b5b4b..7e23387a43b4d 100644 --- a/drivers/vfio/pci/vfio_pci_config.c +++ b/drivers/vfio/pci/vfio_pci_config.c @@ -589,10 +589,12 @@ static int vfio_basic_config_write(struct vfio_pci_co= re_device *vdev, int pos, virt_mem =3D !!(le16_to_cpu(*virt_cmd) & PCI_COMMAND_MEMORY); new_mem =3D !!(new_cmd & PCI_COMMAND_MEMORY); =20 - 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); + } =20 /* * If the user is writing mem/io enable (new_mem/io) and we @@ -627,6 +629,8 @@ static int vfio_basic_config_write(struct vfio_pci_core= _device *vdev, int pos, *virt_cmd &=3D cpu_to_le16(~mask); *virt_cmd |=3D cpu_to_le16(new_cmd & mask); =20 + if (__vfio_pci_memory_enabled(vdev)) + vfio_pci_dma_buf_move(vdev, false); up_write(&vdev->memory_lock); } =20 @@ -707,12 +711,16 @@ 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 *vde= v, pci_power_t state) { - if (state >=3D PCI_D3hot) + if (state >=3D 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); + } =20 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); } =20 @@ -900,7 +908,10 @@ static int vfio_exp_config_write(struct vfio_pci_core_= device *vdev, int pos, =20 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); } } @@ -982,7 +993,10 @@ static int vfio_af_config_write(struct vfio_pci_core_d= evice *vdev, int pos, =20 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_c= ore.c index b1863d84b11aa..8e840ac413e9b 100644 --- a/drivers/vfio/pci/vfio_pci_core.c +++ b/drivers/vfio/pci/vfio_pci_core.c @@ -28,7 +28,9 @@ #include #include #include +#ifdef CONFIG_VFIO_PCI_DMABUF #include +#endif #if IS_ENABLED(CONFIG_EEH) #include #endif @@ -287,6 +289,8 @@ static int vfio_pci_runtime_pm_entry(struct vfio_pci_co= re_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; @@ -370,6 +374,8 @@ static void vfio_pci_runtime_pm_exit(struct vfio_pci_co= re_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); } =20 @@ -690,6 +696,8 @@ void vfio_pci_core_close_device(struct vfio_device *cor= e_vdev) #endif vfio_pci_core_disable(vdev); =20 + vfio_pci_dma_buf_cleanup(vdev); + mutex_lock(&vdev->igate); if (vdev->err_trigger) { eventfd_ctx_put(vdev->err_trigger); @@ -1222,7 +1230,10 @@ static int vfio_pci_ioctl_reset(struct vfio_pci_core= _device *vdev, */ vfio_pci_set_power_state(vdev, PCI_D0); =20 + vfio_pci_dma_buf_move(vdev, true); ret =3D pci_try_reset_function(vdev->pdev); + if (__vfio_pci_memory_enabled(vdev)) + vfio_pci_dma_buf_move(vdev, false); up_write(&vdev->memory_lock); =20 return ret; @@ -1511,6 +1522,8 @@ int vfio_pci_core_ioctl_feature(struct vfio_device *d= evice, 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; } @@ -2085,9 +2098,13 @@ 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); +#ifdef CONFIG_VFIO_PCI_DMABUF vdev->provider =3D pci_p2pdma_enable(vdev->pdev); if (IS_ERR(vdev->provider)) return PTR_ERR(vdev->provider); + + INIT_LIST_HEAD(&vdev->dmabufs); +#endif init_rwsem(&vdev->memory_lock); xa_init(&vdev->ctx); =20 @@ -2470,11 +2487,17 @@ static int vfio_pci_dev_set_hot_reset(struct vfio_d= evice_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); + } =20 ret =3D pci_reset_bus(pdev); =20 + 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 =3D list_last_entry(&dev_set->device_list, struct vfio_pci_core_device, vdev.dev_set_list); =20 diff --git a/drivers/vfio/pci/vfio_pci_dmabuf.c b/drivers/vfio/pci/vfio_pci= _dmabuf.c new file mode 100644 index 0000000000000..74ec05935d50a --- /dev/null +++ b/drivers/vfio/pci/vfio_pci_dmabuf.c @@ -0,0 +1,390 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2025, 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; + size_t size; + struct phys_vec *phys_vec; + u32 nr_ranges; + u8 revoked : 1; +}; + +static int vfio_pci_dma_buf_attach(struct dma_buf *dmabuf, + struct dma_buf_attachment *attachment) +{ + struct vfio_pci_dma_buf *priv =3D dmabuf->priv; + + if (!attachment->peer2peer) + return -EOPNOTSUPP; + + if (priv->revoked) + return -ENODEV; + + switch (pci_p2pdma_map_type(priv->vdev->provider, attachment->dev)) { + case PCI_P2PDMA_MAP_THRU_HOST_BRIDGE: + break; + case PCI_P2PDMA_MAP_BUS_ADDR: + /* + * There is no need in IOVA at all for this flow. + * We rely on attachment->priv =3D=3D NULL as a marker + * for this mode. + */ + return 0; + default: + return -EINVAL; + } + + attachment->priv =3D kzalloc(sizeof(struct dma_iova_state), GFP_KERNEL); + if (!attachment->priv) + return -ENOMEM; + + dma_iova_try_alloc(attachment->dev, attachment->priv, 0, priv->size); + return 0; +} + +static void vfio_pci_dma_buf_detach(struct dma_buf *dmabuf, + struct dma_buf_attachment *attachment) +{ + kfree(attachment->priv); +} + +static void fill_sg_entry(struct scatterlist *sgl, unsigned int length, + dma_addr_t addr) +{ + /* + * Follow the DMABUF rules for scatterlist, the struct page can be + * NULL'd for MMIO only memort. + */ + sg_set_page(sgl, NULL, length, 0); + sg_dma_address(sgl) =3D addr; + sg_dma_len(sgl) =3D length; +} + +static struct sg_table * +vfio_pci_dma_buf_map(struct dma_buf_attachment *attachment, + enum dma_data_direction dir) +{ + struct vfio_pci_dma_buf *priv =3D attachment->dmabuf->priv; + struct p2pdma_provider *provider =3D priv->vdev->provider; + struct dma_iova_state *state =3D attachment->priv; + struct phys_vec *phys_vec =3D priv->phys_vec; + unsigned long attrs =3D DMA_ATTR_MMIO; + unsigned int mapped_len =3D 9; + struct scatterlist *sgl; + struct sg_table *sgt; + dma_addr_t addr; + int ret, i; + + dma_resv_assert_held(priv->dmabuf->resv); + + sgt =3D kzalloc(sizeof(*sgt), GFP_KERNEL); + if (!sgt) + return ERR_PTR(-ENOMEM); + + ret =3D sg_alloc_table(sgt, 1, GFP_KERNEL | __GFP_ZERO); + if (ret) + goto err_kfree_sgt; + + sgl =3D sgt->sgl; + + for (i =3D 0; i < priv->nr_ranges; i++) { + if (!state) { + addr =3D pci_p2pdma_bus_addr_map(provider, + phys_vec[i].paddr); + } else if (dma_use_iova(state)) { + ret =3D dma_iova_link(attachment->dev, state, + phys_vec[i].paddr, 0, + phys_vec[i].len, dir, attrs); + if (ret) + goto err_unmap_dma; + + mapped_len +=3D phys_vec[i].len; + } else { + addr =3D dma_map_phys(attachment->dev, phys_vec[i].paddr, + phys_vec[i].len, dir, attrs); + ret =3D dma_mapping_error(attachment->dev, addr); + if (ret) + goto err_unmap_dma; + } + + if (!state || !dma_use_iova(state)) { + /* + * In IOVA case, there is only one SG entry which spans + * for whole IOVA address space. So there is no need + * to call to sg_next() here. + */ + fill_sg_entry(sgl, phys_vec[i].len, addr); + sgl =3D sg_next(sgl); + } + } + + if (state && dma_use_iova(state)) { + WARN_ON_ONCE(mapped_len !=3D priv->size); + ret =3D dma_iova_sync(attachment->dev, state, 0, mapped_len); + if (ret) + goto err_unmap_dma; + fill_sg_entry(sgl, mapped_len, state->addr); + } + + return sgt; + +err_unmap_dma: + if (!i || !state) + ; /* Do nothing */ + else if (dma_use_iova(state)) + dma_iova_destroy(attachment->dev, state, mapped_len, dir, + attrs); + else + for_each_sgtable_dma_sg(sgt, sgl, i) + dma_unmap_phys(attachment->dev, sg_dma_address(sgl), + sg_dma_len(sgl), dir, attrs); + 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 =3D attachment->dmabuf->priv; + struct dma_iova_state *state =3D attachment->priv; + unsigned long attrs =3D DMA_ATTR_MMIO; + struct scatterlist *sgl; + int i; + + if (!state) + ; /* Do nothing */ + else if (dma_use_iova(state)) + dma_iova_destroy(attachment->dev, state, priv->size, dir, + attrs); + else + for_each_sgtable_dma_sg(sgt, sgl, i) + dma_unmap_phys(attachment->dev, sg_dma_address(sgl), + sg_dma_len(sgl), dir, attrs); + + sg_free_table(sgt); + kfree(sgt); +} + +static void vfio_pci_dma_buf_release(struct dma_buf *dmabuf) +{ + struct vfio_pci_dma_buf *priv =3D 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->phys_vec); + kfree(priv); +} + +static const struct dma_buf_ops vfio_pci_dmabuf_ops =3D { + .attach =3D vfio_pci_dma_buf_attach, + .detach =3D vfio_pci_dma_buf_detach, + .map_dma_buf =3D vfio_pci_dma_buf_map, + .release =3D vfio_pci_dma_buf_release, + .unmap_dma_buf =3D vfio_pci_dma_buf_unmap, +}; + +static void dma_ranges_to_p2p_phys(struct vfio_pci_dma_buf *priv, + struct vfio_device_feature_dma_buf *dma_buf, + struct vfio_region_dma_range *dma_ranges) +{ + struct pci_dev *pdev =3D priv->vdev->pdev; + phys_addr_t pci_start; + int i; + + pci_start =3D pci_resource_start(pdev, dma_buf->region_index); + for (i =3D 0; i < dma_buf->nr_ranges; i++) { + priv->phys_vec[i].len =3D dma_ranges[i].length; + priv->phys_vec[i].paddr +=3D pci_start + dma_ranges[i].offset; + priv->size +=3D priv->phys_vec[i].len; + } + priv->nr_ranges =3D dma_buf->nr_ranges; +} + +static int validate_dmabuf_input(struct vfio_pci_core_device *vdev, + struct vfio_device_feature_dma_buf *dma_buf, + struct vfio_region_dma_range *dma_ranges) +{ + struct pci_dev *pdev =3D vdev->pdev; + u32 bar =3D dma_buf->region_index; + resource_size_t bar_size; + u64 sum; + int i; + + if (dma_buf->flags) + return -EINVAL; + /* + * For PCI the region_index is the BAR number like everything else. + */ + if (bar >=3D VFIO_PCI_ROM_REGION_INDEX) + return -ENODEV; + + if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM)) + return -EINVAL; + + bar_size =3D pci_resource_len(pdev, bar); + for (i =3D 0; i < dma_buf->nr_ranges; i++) { + u64 offset =3D dma_ranges[i].offset; + u64 len =3D dma_ranges[i].length; + + if (!PAGE_ALIGNED(offset) || !PAGE_ALIGNED(len)) + return -EINVAL; + + if (check_add_overflow(offset, len, &sum) || sum > bar_size) + return -EINVAL; + } + + return 0; +} + +int vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 f= lags, + struct vfio_device_feature_dma_buf __user *arg, + size_t argsz) +{ + struct vfio_device_feature_dma_buf get_dma_buf =3D {}; + struct vfio_region_dma_range *dma_ranges; + DEFINE_DMA_BUF_EXPORT_INFO(exp_info); + struct vfio_pci_dma_buf *priv; + int ret; + + ret =3D vfio_check_feature(flags, argsz, VFIO_DEVICE_FEATURE_GET, + sizeof(get_dma_buf)); + if (ret !=3D 1) + return ret; + + if (copy_from_user(&get_dma_buf, arg, sizeof(get_dma_buf))) + return -EFAULT; + + if (!get_dma_buf.nr_ranges) + return -EINVAL; + + dma_ranges =3D memdup_array_user(&arg->dma_ranges, get_dma_buf.nr_ranges, + sizeof(*dma_ranges)); + if (IS_ERR(dma_ranges)) + return PTR_ERR(dma_ranges); + + ret =3D validate_dmabuf_input(vdev, &get_dma_buf, dma_ranges); + if (ret) + return ret; + + priv =3D kzalloc(sizeof(*priv), GFP_KERNEL); + if (!priv) { + ret =3D -ENOMEM; + goto err_free_ranges; + } + priv->phys_vec =3D kcalloc(get_dma_buf.nr_ranges, sizeof(*priv->phys_vec), + GFP_KERNEL); + if (!priv->phys_vec) { + ret =3D -ENOMEM; + goto err_free_priv; + } + + priv->vdev =3D vdev; + dma_ranges_to_p2p_phys(priv, &get_dma_buf, dma_ranges); + kfree(dma_ranges); + dma_ranges =3D NULL; + + if (!vfio_device_try_get_registration(&vdev->vdev)) { + ret =3D -ENODEV; + goto err_free_phys; + } + + exp_info.ops =3D &vfio_pci_dmabuf_ops; + exp_info.size =3D priv->size; + exp_info.flags =3D get_dma_buf.open_flags; + exp_info.priv =3D priv; + + priv->dmabuf =3D dma_buf_export(&exp_info); + if (IS_ERR(priv->dmabuf)) { + ret =3D 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 =3D !__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_phys: + kfree(priv->phys_vec); +err_free_priv: + kfree(priv); +err_free_ranges: + kfree(dma_ranges); + return ret; +} + +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) { + if (!get_file_active(&priv->dmabuf->file)) + continue; + + if (priv->revoked !=3D revoked) { + dma_resv_lock(priv->dmabuf->resv, NULL); + priv->revoked =3D revoked; + dma_buf_move_notify(priv->dmabuf); + 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_active(&priv->dmabuf->file)) + continue; + + dma_resv_lock(priv->dmabuf->resv, NULL); + list_del_init(&priv->dmabufs_elm); + priv->vdev =3D NULL; + priv->revoked =3D true; + dma_buf_move_notify(priv->dmabuf); + 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_priv.h b/drivers/vfio/pci/vfio_pci_p= riv.h index a9972eacb2936..28a405f8b97c9 100644 --- a/drivers/vfio/pci/vfio_pci_priv.h +++ b/drivers/vfio/pci/vfio_pci_priv.h @@ -107,4 +107,27 @@ static inline bool vfio_pci_is_vga(struct pci_dev *pde= v) return (pdev->class >> 8) =3D=3D PCI_CLASS_DISPLAY_VGA; } =20 +#ifdef CONFIG_VFIO_PCI_DMABUF +int vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 f= lags, + 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 inline 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 *v= dev) +{ +} +static inline void vfio_pci_dma_buf_move(struct vfio_pci_core_device *vdev, + bool revoked) +{ +} +#endif + #endif diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index d58e329ac0e71..f14b413aae48d 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -483,6 +483,7 @@ struct dma_buf_attach_ops { * @dev: device attached to the buffer. * @node: list of dma_buf_attachment, protected by dma_resv lock of the dm= abuf. * @peer2peer: true if the importer can handle peer resources without page= s. + * #state: DMA structure to provide support for physical addresses DMA int= erface * @priv: exporter specific attachment data. * @importer_ops: importer operations for this attachment, if provided * dma_buf_map/unmap_attachment() must be called with the dma_resv lock he= ld. diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h index b017fae251811..548cbb51bf146 100644 --- a/include/linux/vfio_pci_core.h +++ b/include/linux/vfio_pci_core.h @@ -94,7 +94,10 @@ struct vfio_pci_core_device { struct vfio_pci_core_device *sriov_pf_core_dev; struct notifier_block nb; struct rw_semaphore memory_lock; +#ifdef CONFIG_VFIO_PCI_DMABUF struct p2pdma_provider *provider; + struct list_head dmabufs; +#endif }; =20 /* Will be exported for vfio pci drivers usage */ diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index 5764f315137f9..89f86dd2dffb2 100644 --- a/include/uapi/linux/vfio.h +++ b/include/uapi/linux/vfio.h @@ -1468,6 +1468,31 @@ struct vfio_device_feature_bus_master { }; #define VFIO_DEVICE_FEATURE_BUS_MASTER 10 =20 +/** + * 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_CLOEXE= C, + * etc. offset/length specify a slice of the region to create the dmabuf f= rom. + * nr_ranges is the total number of (P2P DMA) ranges that comprise the dma= buf. + * + * 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 { + __u64 offset; + __u64 length; +}; + +struct vfio_device_feature_dma_buf { + __u32 region_index; + __u32 open_flags; + __u32 flags; + __u32 nr_ranges; + struct vfio_region_dma_range dma_ranges[]; +}; + /* -------- API for Type1 VFIO IOMMU -------- */ =20 /** --=20 2.50.1