1016 lines
26 KiB
C
1016 lines
26 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* PCI Peer 2 Peer DMA support.
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*
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* Copyright (c) 2016-2018, Logan Gunthorpe
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* Copyright (c) 2016-2017, Microsemi Corporation
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* Copyright (c) 2017, Christoph Hellwig
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* Copyright (c) 2018, Eideticom Inc.
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*/
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#define pr_fmt(fmt) "pci-p2pdma: " fmt
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#include <linux/ctype.h>
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#include <linux/pci-p2pdma.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/genalloc.h>
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#include <linux/memremap.h>
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#include <linux/percpu-refcount.h>
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#include <linux/random.h>
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#include <linux/seq_buf.h>
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#include <linux/xarray.h>
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enum pci_p2pdma_map_type {
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PCI_P2PDMA_MAP_UNKNOWN = 0,
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PCI_P2PDMA_MAP_NOT_SUPPORTED,
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PCI_P2PDMA_MAP_BUS_ADDR,
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PCI_P2PDMA_MAP_THRU_HOST_BRIDGE,
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};
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struct pci_p2pdma {
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struct gen_pool *pool;
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bool p2pmem_published;
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struct xarray map_types;
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};
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struct pci_p2pdma_pagemap {
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struct dev_pagemap pgmap;
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struct pci_dev *provider;
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u64 bus_offset;
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};
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static struct pci_p2pdma_pagemap *to_p2p_pgmap(struct dev_pagemap *pgmap)
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{
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return container_of(pgmap, struct pci_p2pdma_pagemap, pgmap);
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}
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static ssize_t size_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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struct pci_dev *pdev = to_pci_dev(dev);
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struct pci_p2pdma *p2pdma;
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size_t size = 0;
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rcu_read_lock();
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p2pdma = rcu_dereference(pdev->p2pdma);
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if (p2pdma && p2pdma->pool)
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size = gen_pool_size(p2pdma->pool);
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rcu_read_unlock();
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return sysfs_emit(buf, "%zd\n", size);
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}
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static DEVICE_ATTR_RO(size);
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static ssize_t available_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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struct pci_dev *pdev = to_pci_dev(dev);
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struct pci_p2pdma *p2pdma;
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size_t avail = 0;
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rcu_read_lock();
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p2pdma = rcu_dereference(pdev->p2pdma);
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if (p2pdma && p2pdma->pool)
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avail = gen_pool_avail(p2pdma->pool);
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rcu_read_unlock();
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return sysfs_emit(buf, "%zd\n", avail);
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}
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static DEVICE_ATTR_RO(available);
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static ssize_t published_show(struct device *dev, struct device_attribute *attr,
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char *buf)
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{
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struct pci_dev *pdev = to_pci_dev(dev);
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struct pci_p2pdma *p2pdma;
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bool published = false;
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rcu_read_lock();
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p2pdma = rcu_dereference(pdev->p2pdma);
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if (p2pdma)
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published = p2pdma->p2pmem_published;
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rcu_read_unlock();
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return sysfs_emit(buf, "%d\n", published);
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}
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static DEVICE_ATTR_RO(published);
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static struct attribute *p2pmem_attrs[] = {
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&dev_attr_size.attr,
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&dev_attr_available.attr,
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&dev_attr_published.attr,
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NULL,
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};
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static const struct attribute_group p2pmem_group = {
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.attrs = p2pmem_attrs,
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.name = "p2pmem",
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};
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static void pci_p2pdma_release(void *data)
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{
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struct pci_dev *pdev = data;
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struct pci_p2pdma *p2pdma;
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p2pdma = rcu_dereference_protected(pdev->p2pdma, 1);
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if (!p2pdma)
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return;
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/* Flush and disable pci_alloc_p2p_mem() */
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pdev->p2pdma = NULL;
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synchronize_rcu();
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gen_pool_destroy(p2pdma->pool);
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sysfs_remove_group(&pdev->dev.kobj, &p2pmem_group);
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xa_destroy(&p2pdma->map_types);
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}
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static int pci_p2pdma_setup(struct pci_dev *pdev)
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{
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int error = -ENOMEM;
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struct pci_p2pdma *p2p;
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p2p = devm_kzalloc(&pdev->dev, sizeof(*p2p), GFP_KERNEL);
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if (!p2p)
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return -ENOMEM;
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xa_init(&p2p->map_types);
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p2p->pool = gen_pool_create(PAGE_SHIFT, dev_to_node(&pdev->dev));
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if (!p2p->pool)
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goto out;
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error = devm_add_action_or_reset(&pdev->dev, pci_p2pdma_release, pdev);
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if (error)
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goto out_pool_destroy;
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error = sysfs_create_group(&pdev->dev.kobj, &p2pmem_group);
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if (error)
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goto out_pool_destroy;
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rcu_assign_pointer(pdev->p2pdma, p2p);
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return 0;
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out_pool_destroy:
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gen_pool_destroy(p2p->pool);
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out:
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devm_kfree(&pdev->dev, p2p);
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return error;
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}
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/**
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* pci_p2pdma_add_resource - add memory for use as p2p memory
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* @pdev: the device to add the memory to
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* @bar: PCI BAR to add
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* @size: size of the memory to add, may be zero to use the whole BAR
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* @offset: offset into the PCI BAR
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*
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* The memory will be given ZONE_DEVICE struct pages so that it may
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* be used with any DMA request.
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*/
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int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size,
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u64 offset)
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{
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struct pci_p2pdma_pagemap *p2p_pgmap;
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struct dev_pagemap *pgmap;
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struct pci_p2pdma *p2pdma;
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void *addr;
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int error;
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if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM))
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return -EINVAL;
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if (offset >= pci_resource_len(pdev, bar))
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return -EINVAL;
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if (!size)
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size = pci_resource_len(pdev, bar) - offset;
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if (size + offset > pci_resource_len(pdev, bar))
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return -EINVAL;
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if (!pdev->p2pdma) {
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error = pci_p2pdma_setup(pdev);
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if (error)
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return error;
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}
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p2p_pgmap = devm_kzalloc(&pdev->dev, sizeof(*p2p_pgmap), GFP_KERNEL);
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if (!p2p_pgmap)
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return -ENOMEM;
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pgmap = &p2p_pgmap->pgmap;
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pgmap->range.start = pci_resource_start(pdev, bar) + offset;
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pgmap->range.end = pgmap->range.start + size - 1;
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pgmap->nr_range = 1;
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pgmap->type = MEMORY_DEVICE_PCI_P2PDMA;
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p2p_pgmap->provider = pdev;
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p2p_pgmap->bus_offset = pci_bus_address(pdev, bar) -
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pci_resource_start(pdev, bar);
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addr = devm_memremap_pages(&pdev->dev, pgmap);
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if (IS_ERR(addr)) {
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error = PTR_ERR(addr);
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goto pgmap_free;
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}
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p2pdma = rcu_dereference_protected(pdev->p2pdma, 1);
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error = gen_pool_add_owner(p2pdma->pool, (unsigned long)addr,
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pci_bus_address(pdev, bar) + offset,
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range_len(&pgmap->range), dev_to_node(&pdev->dev),
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&pgmap->ref);
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if (error)
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goto pages_free;
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pci_info(pdev, "added peer-to-peer DMA memory %#llx-%#llx\n",
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pgmap->range.start, pgmap->range.end);
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return 0;
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pages_free:
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devm_memunmap_pages(&pdev->dev, pgmap);
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pgmap_free:
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devm_kfree(&pdev->dev, pgmap);
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return error;
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}
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EXPORT_SYMBOL_GPL(pci_p2pdma_add_resource);
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/*
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* Note this function returns the parent PCI device with a
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* reference taken. It is the caller's responsibility to drop
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* the reference.
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*/
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static struct pci_dev *find_parent_pci_dev(struct device *dev)
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{
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struct device *parent;
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dev = get_device(dev);
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while (dev) {
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if (dev_is_pci(dev))
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return to_pci_dev(dev);
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parent = get_device(dev->parent);
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put_device(dev);
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dev = parent;
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}
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return NULL;
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}
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/*
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* Check if a PCI bridge has its ACS redirection bits set to redirect P2P
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* TLPs upstream via ACS. Returns 1 if the packets will be redirected
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* upstream, 0 otherwise.
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*/
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static int pci_bridge_has_acs_redir(struct pci_dev *pdev)
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{
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int pos;
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u16 ctrl;
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pos = pdev->acs_cap;
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if (!pos)
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return 0;
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pci_read_config_word(pdev, pos + PCI_ACS_CTRL, &ctrl);
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if (ctrl & (PCI_ACS_RR | PCI_ACS_CR | PCI_ACS_EC))
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return 1;
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return 0;
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}
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static void seq_buf_print_bus_devfn(struct seq_buf *buf, struct pci_dev *pdev)
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{
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if (!buf)
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return;
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seq_buf_printf(buf, "%s;", pci_name(pdev));
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}
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static bool cpu_supports_p2pdma(void)
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{
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#ifdef CONFIG_X86
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struct cpuinfo_x86 *c = &cpu_data(0);
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/* Any AMD CPU whose family ID is Zen or newer supports p2pdma */
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if (c->x86_vendor == X86_VENDOR_AMD && c->x86 >= 0x17)
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return true;
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#endif
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return false;
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}
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static const struct pci_p2pdma_whitelist_entry {
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unsigned short vendor;
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unsigned short device;
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enum {
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REQ_SAME_HOST_BRIDGE = 1 << 0,
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} flags;
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} pci_p2pdma_whitelist[] = {
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/* Intel Xeon E5/Core i7 */
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{PCI_VENDOR_ID_INTEL, 0x3c00, REQ_SAME_HOST_BRIDGE},
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{PCI_VENDOR_ID_INTEL, 0x3c01, REQ_SAME_HOST_BRIDGE},
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/* Intel Xeon E7 v3/Xeon E5 v3/Core i7 */
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{PCI_VENDOR_ID_INTEL, 0x2f00, REQ_SAME_HOST_BRIDGE},
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{PCI_VENDOR_ID_INTEL, 0x2f01, REQ_SAME_HOST_BRIDGE},
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/* Intel SkyLake-E */
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{PCI_VENDOR_ID_INTEL, 0x2030, 0},
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{PCI_VENDOR_ID_INTEL, 0x2031, 0},
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{PCI_VENDOR_ID_INTEL, 0x2032, 0},
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{PCI_VENDOR_ID_INTEL, 0x2033, 0},
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{PCI_VENDOR_ID_INTEL, 0x2020, 0},
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{PCI_VENDOR_ID_INTEL, 0x09a2, 0},
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{}
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};
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/*
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* This lookup function tries to find the PCI device corresponding to a given
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* host bridge.
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*
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* It assumes the host bridge device is the first PCI device in the
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* bus->devices list and that the devfn is 00.0. These assumptions should hold
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* for all the devices in the whitelist above.
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*
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* This function is equivalent to pci_get_slot(host->bus, 0), however it does
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* not take the pci_bus_sem lock seeing __host_bridge_whitelist() must not
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* sleep.
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*
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* For this to be safe, the caller should hold a reference to a device on the
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* bridge, which should ensure the host_bridge device will not be freed
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* or removed from the head of the devices list.
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*/
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static struct pci_dev *pci_host_bridge_dev(struct pci_host_bridge *host)
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{
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struct pci_dev *root;
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root = list_first_entry_or_null(&host->bus->devices,
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struct pci_dev, bus_list);
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if (!root)
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return NULL;
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if (root->devfn != PCI_DEVFN(0, 0))
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return NULL;
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return root;
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}
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static bool __host_bridge_whitelist(struct pci_host_bridge *host,
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bool same_host_bridge, bool warn)
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{
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struct pci_dev *root = pci_host_bridge_dev(host);
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const struct pci_p2pdma_whitelist_entry *entry;
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unsigned short vendor, device;
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if (!root)
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return false;
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vendor = root->vendor;
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device = root->device;
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for (entry = pci_p2pdma_whitelist; entry->vendor; entry++) {
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if (vendor != entry->vendor || device != entry->device)
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continue;
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if (entry->flags & REQ_SAME_HOST_BRIDGE && !same_host_bridge)
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return false;
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return true;
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}
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if (warn)
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pci_warn(root, "Host bridge not in P2PDMA whitelist: %04x:%04x\n",
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vendor, device);
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return false;
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}
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/*
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* If we can't find a common upstream bridge take a look at the root
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* complex and compare it to a whitelist of known good hardware.
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*/
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static bool host_bridge_whitelist(struct pci_dev *a, struct pci_dev *b,
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bool warn)
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{
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struct pci_host_bridge *host_a = pci_find_host_bridge(a->bus);
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struct pci_host_bridge *host_b = pci_find_host_bridge(b->bus);
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if (host_a == host_b)
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return __host_bridge_whitelist(host_a, true, warn);
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if (__host_bridge_whitelist(host_a, false, warn) &&
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__host_bridge_whitelist(host_b, false, warn))
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return true;
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return false;
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}
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static unsigned long map_types_idx(struct pci_dev *client)
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|
{
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return (pci_domain_nr(client->bus) << 16) |
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(client->bus->number << 8) | client->devfn;
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}
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|
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/*
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* Calculate the P2PDMA mapping type and distance between two PCI devices.
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|
*
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* If the two devices are the same PCI function, return
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* PCI_P2PDMA_MAP_BUS_ADDR and a distance of 0.
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|
*
|
||
|
* If they are two functions of the same device, return
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|
* PCI_P2PDMA_MAP_BUS_ADDR and a distance of 2 (one hop up to the bridge,
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|
* then one hop back down to another function of the same device).
|
||
|
*
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||
|
* In the case where two devices are connected to the same PCIe switch,
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|
* return a distance of 4. This corresponds to the following PCI tree:
|
||
|
*
|
||
|
* -+ Root Port
|
||
|
* \+ Switch Upstream Port
|
||
|
* +-+ Switch Downstream Port 0
|
||
|
* + \- Device A
|
||
|
* \-+ Switch Downstream Port 1
|
||
|
* \- Device B
|
||
|
*
|
||
|
* The distance is 4 because we traverse from Device A to Downstream Port 0
|
||
|
* to the common Switch Upstream Port, back down to Downstream Port 1 and
|
||
|
* then to Device B. The mapping type returned depends on the ACS
|
||
|
* redirection setting of the ports along the path.
|
||
|
*
|
||
|
* If ACS redirect is set on any port in the path, traffic between the
|
||
|
* devices will go through the host bridge, so return
|
||
|
* PCI_P2PDMA_MAP_THRU_HOST_BRIDGE; otherwise return
|
||
|
* PCI_P2PDMA_MAP_BUS_ADDR.
|
||
|
*
|
||
|
* Any two devices that have a data path that goes through the host bridge
|
||
|
* will consult a whitelist. If the host bridge is in the whitelist, return
|
||
|
* PCI_P2PDMA_MAP_THRU_HOST_BRIDGE with the distance set to the number of
|
||
|
* ports per above. If the device is not in the whitelist, return
|
||
|
* PCI_P2PDMA_MAP_NOT_SUPPORTED.
|
||
|
*/
|
||
|
static enum pci_p2pdma_map_type
|
||
|
calc_map_type_and_dist(struct pci_dev *provider, struct pci_dev *client,
|
||
|
int *dist, bool verbose)
|
||
|
{
|
||
|
enum pci_p2pdma_map_type map_type = PCI_P2PDMA_MAP_THRU_HOST_BRIDGE;
|
||
|
struct pci_dev *a = provider, *b = client, *bb;
|
||
|
bool acs_redirects = false;
|
||
|
struct pci_p2pdma *p2pdma;
|
||
|
struct seq_buf acs_list;
|
||
|
int acs_cnt = 0;
|
||
|
int dist_a = 0;
|
||
|
int dist_b = 0;
|
||
|
char buf[128];
|
||
|
|
||
|
seq_buf_init(&acs_list, buf, sizeof(buf));
|
||
|
|
||
|
/*
|
||
|
* Note, we don't need to take references to devices returned by
|
||
|
* pci_upstream_bridge() seeing we hold a reference to a child
|
||
|
* device which will already hold a reference to the upstream bridge.
|
||
|
*/
|
||
|
while (a) {
|
||
|
dist_b = 0;
|
||
|
|
||
|
if (pci_bridge_has_acs_redir(a)) {
|
||
|
seq_buf_print_bus_devfn(&acs_list, a);
|
||
|
acs_cnt++;
|
||
|
}
|
||
|
|
||
|
bb = b;
|
||
|
|
||
|
while (bb) {
|
||
|
if (a == bb)
|
||
|
goto check_b_path_acs;
|
||
|
|
||
|
bb = pci_upstream_bridge(bb);
|
||
|
dist_b++;
|
||
|
}
|
||
|
|
||
|
a = pci_upstream_bridge(a);
|
||
|
dist_a++;
|
||
|
}
|
||
|
|
||
|
*dist = dist_a + dist_b;
|
||
|
goto map_through_host_bridge;
|
||
|
|
||
|
check_b_path_acs:
|
||
|
bb = b;
|
||
|
|
||
|
while (bb) {
|
||
|
if (a == bb)
|
||
|
break;
|
||
|
|
||
|
if (pci_bridge_has_acs_redir(bb)) {
|
||
|
seq_buf_print_bus_devfn(&acs_list, bb);
|
||
|
acs_cnt++;
|
||
|
}
|
||
|
|
||
|
bb = pci_upstream_bridge(bb);
|
||
|
}
|
||
|
|
||
|
*dist = dist_a + dist_b;
|
||
|
|
||
|
if (!acs_cnt) {
|
||
|
map_type = PCI_P2PDMA_MAP_BUS_ADDR;
|
||
|
goto done;
|
||
|
}
|
||
|
|
||
|
if (verbose) {
|
||
|
acs_list.buffer[acs_list.len-1] = 0; /* drop final semicolon */
|
||
|
pci_warn(client, "ACS redirect is set between the client and provider (%s)\n",
|
||
|
pci_name(provider));
|
||
|
pci_warn(client, "to disable ACS redirect for this path, add the kernel parameter: pci=disable_acs_redir=%s\n",
|
||
|
acs_list.buffer);
|
||
|
}
|
||
|
acs_redirects = true;
|
||
|
|
||
|
map_through_host_bridge:
|
||
|
if (!cpu_supports_p2pdma() &&
|
||
|
!host_bridge_whitelist(provider, client, acs_redirects)) {
|
||
|
if (verbose)
|
||
|
pci_warn(client, "cannot be used for peer-to-peer DMA as the client and provider (%s) do not share an upstream bridge or whitelisted host bridge\n",
|
||
|
pci_name(provider));
|
||
|
map_type = PCI_P2PDMA_MAP_NOT_SUPPORTED;
|
||
|
}
|
||
|
done:
|
||
|
rcu_read_lock();
|
||
|
p2pdma = rcu_dereference(provider->p2pdma);
|
||
|
if (p2pdma)
|
||
|
xa_store(&p2pdma->map_types, map_types_idx(client),
|
||
|
xa_mk_value(map_type), GFP_KERNEL);
|
||
|
rcu_read_unlock();
|
||
|
return map_type;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* pci_p2pdma_distance_many - Determine the cumulative distance between
|
||
|
* a p2pdma provider and the clients in use.
|
||
|
* @provider: p2pdma provider to check against the client list
|
||
|
* @clients: array of devices to check (NULL-terminated)
|
||
|
* @num_clients: number of clients in the array
|
||
|
* @verbose: if true, print warnings for devices when we return -1
|
||
|
*
|
||
|
* Returns -1 if any of the clients are not compatible, otherwise returns a
|
||
|
* positive number where a lower number is the preferable choice. (If there's
|
||
|
* one client that's the same as the provider it will return 0, which is best
|
||
|
* choice).
|
||
|
*
|
||
|
* "compatible" means the provider and the clients are either all behind
|
||
|
* the same PCI root port or the host bridges connected to each of the devices
|
||
|
* are listed in the 'pci_p2pdma_whitelist'.
|
||
|
*/
|
||
|
int pci_p2pdma_distance_many(struct pci_dev *provider, struct device **clients,
|
||
|
int num_clients, bool verbose)
|
||
|
{
|
||
|
enum pci_p2pdma_map_type map;
|
||
|
bool not_supported = false;
|
||
|
struct pci_dev *pci_client;
|
||
|
int total_dist = 0;
|
||
|
int i, distance;
|
||
|
|
||
|
if (num_clients == 0)
|
||
|
return -1;
|
||
|
|
||
|
for (i = 0; i < num_clients; i++) {
|
||
|
pci_client = find_parent_pci_dev(clients[i]);
|
||
|
if (!pci_client) {
|
||
|
if (verbose)
|
||
|
dev_warn(clients[i],
|
||
|
"cannot be used for peer-to-peer DMA as it is not a PCI device\n");
|
||
|
return -1;
|
||
|
}
|
||
|
|
||
|
map = calc_map_type_and_dist(provider, pci_client, &distance,
|
||
|
verbose);
|
||
|
|
||
|
pci_dev_put(pci_client);
|
||
|
|
||
|
if (map == PCI_P2PDMA_MAP_NOT_SUPPORTED)
|
||
|
not_supported = true;
|
||
|
|
||
|
if (not_supported && !verbose)
|
||
|
break;
|
||
|
|
||
|
total_dist += distance;
|
||
|
}
|
||
|
|
||
|
if (not_supported)
|
||
|
return -1;
|
||
|
|
||
|
return total_dist;
|
||
|
}
|
||
|
EXPORT_SYMBOL_GPL(pci_p2pdma_distance_many);
|
||
|
|
||
|
/**
|
||
|
* pci_has_p2pmem - check if a given PCI device has published any p2pmem
|
||
|
* @pdev: PCI device to check
|
||
|
*/
|
||
|
bool pci_has_p2pmem(struct pci_dev *pdev)
|
||
|
{
|
||
|
struct pci_p2pdma *p2pdma;
|
||
|
bool res;
|
||
|
|
||
|
rcu_read_lock();
|
||
|
p2pdma = rcu_dereference(pdev->p2pdma);
|
||
|
res = p2pdma && p2pdma->p2pmem_published;
|
||
|
rcu_read_unlock();
|
||
|
|
||
|
return res;
|
||
|
}
|
||
|
EXPORT_SYMBOL_GPL(pci_has_p2pmem);
|
||
|
|
||
|
/**
|
||
|
* pci_p2pmem_find_many - find a peer-to-peer DMA memory device compatible with
|
||
|
* the specified list of clients and shortest distance (as determined
|
||
|
* by pci_p2pmem_dma())
|
||
|
* @clients: array of devices to check (NULL-terminated)
|
||
|
* @num_clients: number of client devices in the list
|
||
|
*
|
||
|
* If multiple devices are behind the same switch, the one "closest" to the
|
||
|
* client devices in use will be chosen first. (So if one of the providers is
|
||
|
* the same as one of the clients, that provider will be used ahead of any
|
||
|
* other providers that are unrelated). If multiple providers are an equal
|
||
|
* distance away, one will be chosen at random.
|
||
|
*
|
||
|
* Returns a pointer to the PCI device with a reference taken (use pci_dev_put
|
||
|
* to return the reference) or NULL if no compatible device is found. The
|
||
|
* found provider will also be assigned to the client list.
|
||
|
*/
|
||
|
struct pci_dev *pci_p2pmem_find_many(struct device **clients, int num_clients)
|
||
|
{
|
||
|
struct pci_dev *pdev = NULL;
|
||
|
int distance;
|
||
|
int closest_distance = INT_MAX;
|
||
|
struct pci_dev **closest_pdevs;
|
||
|
int dev_cnt = 0;
|
||
|
const int max_devs = PAGE_SIZE / sizeof(*closest_pdevs);
|
||
|
int i;
|
||
|
|
||
|
closest_pdevs = kmalloc(PAGE_SIZE, GFP_KERNEL);
|
||
|
if (!closest_pdevs)
|
||
|
return NULL;
|
||
|
|
||
|
while ((pdev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, pdev))) {
|
||
|
if (!pci_has_p2pmem(pdev))
|
||
|
continue;
|
||
|
|
||
|
distance = pci_p2pdma_distance_many(pdev, clients,
|
||
|
num_clients, false);
|
||
|
if (distance < 0 || distance > closest_distance)
|
||
|
continue;
|
||
|
|
||
|
if (distance == closest_distance && dev_cnt >= max_devs)
|
||
|
continue;
|
||
|
|
||
|
if (distance < closest_distance) {
|
||
|
for (i = 0; i < dev_cnt; i++)
|
||
|
pci_dev_put(closest_pdevs[i]);
|
||
|
|
||
|
dev_cnt = 0;
|
||
|
closest_distance = distance;
|
||
|
}
|
||
|
|
||
|
closest_pdevs[dev_cnt++] = pci_dev_get(pdev);
|
||
|
}
|
||
|
|
||
|
if (dev_cnt)
|
||
|
pdev = pci_dev_get(closest_pdevs[prandom_u32_max(dev_cnt)]);
|
||
|
|
||
|
for (i = 0; i < dev_cnt; i++)
|
||
|
pci_dev_put(closest_pdevs[i]);
|
||
|
|
||
|
kfree(closest_pdevs);
|
||
|
return pdev;
|
||
|
}
|
||
|
EXPORT_SYMBOL_GPL(pci_p2pmem_find_many);
|
||
|
|
||
|
/**
|
||
|
* pci_alloc_p2pmem - allocate peer-to-peer DMA memory
|
||
|
* @pdev: the device to allocate memory from
|
||
|
* @size: number of bytes to allocate
|
||
|
*
|
||
|
* Returns the allocated memory or NULL on error.
|
||
|
*/
|
||
|
void *pci_alloc_p2pmem(struct pci_dev *pdev, size_t size)
|
||
|
{
|
||
|
void *ret = NULL;
|
||
|
struct percpu_ref *ref;
|
||
|
struct pci_p2pdma *p2pdma;
|
||
|
|
||
|
/*
|
||
|
* Pairs with synchronize_rcu() in pci_p2pdma_release() to
|
||
|
* ensure pdev->p2pdma is non-NULL for the duration of the
|
||
|
* read-lock.
|
||
|
*/
|
||
|
rcu_read_lock();
|
||
|
p2pdma = rcu_dereference(pdev->p2pdma);
|
||
|
if (unlikely(!p2pdma))
|
||
|
goto out;
|
||
|
|
||
|
ret = (void *)gen_pool_alloc_owner(p2pdma->pool, size, (void **) &ref);
|
||
|
if (!ret)
|
||
|
goto out;
|
||
|
|
||
|
if (unlikely(!percpu_ref_tryget_live_rcu(ref))) {
|
||
|
gen_pool_free(p2pdma->pool, (unsigned long) ret, size);
|
||
|
ret = NULL;
|
||
|
goto out;
|
||
|
}
|
||
|
out:
|
||
|
rcu_read_unlock();
|
||
|
return ret;
|
||
|
}
|
||
|
EXPORT_SYMBOL_GPL(pci_alloc_p2pmem);
|
||
|
|
||
|
/**
|
||
|
* pci_free_p2pmem - free peer-to-peer DMA memory
|
||
|
* @pdev: the device the memory was allocated from
|
||
|
* @addr: address of the memory that was allocated
|
||
|
* @size: number of bytes that were allocated
|
||
|
*/
|
||
|
void pci_free_p2pmem(struct pci_dev *pdev, void *addr, size_t size)
|
||
|
{
|
||
|
struct percpu_ref *ref;
|
||
|
struct pci_p2pdma *p2pdma = rcu_dereference_protected(pdev->p2pdma, 1);
|
||
|
|
||
|
gen_pool_free_owner(p2pdma->pool, (uintptr_t)addr, size,
|
||
|
(void **) &ref);
|
||
|
percpu_ref_put(ref);
|
||
|
}
|
||
|
EXPORT_SYMBOL_GPL(pci_free_p2pmem);
|
||
|
|
||
|
/**
|
||
|
* pci_p2pmem_virt_to_bus - return the PCI bus address for a given virtual
|
||
|
* address obtained with pci_alloc_p2pmem()
|
||
|
* @pdev: the device the memory was allocated from
|
||
|
* @addr: address of the memory that was allocated
|
||
|
*/
|
||
|
pci_bus_addr_t pci_p2pmem_virt_to_bus(struct pci_dev *pdev, void *addr)
|
||
|
{
|
||
|
struct pci_p2pdma *p2pdma;
|
||
|
|
||
|
if (!addr)
|
||
|
return 0;
|
||
|
|
||
|
p2pdma = rcu_dereference_protected(pdev->p2pdma, 1);
|
||
|
if (!p2pdma)
|
||
|
return 0;
|
||
|
|
||
|
/*
|
||
|
* Note: when we added the memory to the pool we used the PCI
|
||
|
* bus address as the physical address. So gen_pool_virt_to_phys()
|
||
|
* actually returns the bus address despite the misleading name.
|
||
|
*/
|
||
|
return gen_pool_virt_to_phys(p2pdma->pool, (unsigned long)addr);
|
||
|
}
|
||
|
EXPORT_SYMBOL_GPL(pci_p2pmem_virt_to_bus);
|
||
|
|
||
|
/**
|
||
|
* pci_p2pmem_alloc_sgl - allocate peer-to-peer DMA memory in a scatterlist
|
||
|
* @pdev: the device to allocate memory from
|
||
|
* @nents: the number of SG entries in the list
|
||
|
* @length: number of bytes to allocate
|
||
|
*
|
||
|
* Return: %NULL on error or &struct scatterlist pointer and @nents on success
|
||
|
*/
|
||
|
struct scatterlist *pci_p2pmem_alloc_sgl(struct pci_dev *pdev,
|
||
|
unsigned int *nents, u32 length)
|
||
|
{
|
||
|
struct scatterlist *sg;
|
||
|
void *addr;
|
||
|
|
||
|
sg = kmalloc(sizeof(*sg), GFP_KERNEL);
|
||
|
if (!sg)
|
||
|
return NULL;
|
||
|
|
||
|
sg_init_table(sg, 1);
|
||
|
|
||
|
addr = pci_alloc_p2pmem(pdev, length);
|
||
|
if (!addr)
|
||
|
goto out_free_sg;
|
||
|
|
||
|
sg_set_buf(sg, addr, length);
|
||
|
*nents = 1;
|
||
|
return sg;
|
||
|
|
||
|
out_free_sg:
|
||
|
kfree(sg);
|
||
|
return NULL;
|
||
|
}
|
||
|
EXPORT_SYMBOL_GPL(pci_p2pmem_alloc_sgl);
|
||
|
|
||
|
/**
|
||
|
* pci_p2pmem_free_sgl - free a scatterlist allocated by pci_p2pmem_alloc_sgl()
|
||
|
* @pdev: the device to allocate memory from
|
||
|
* @sgl: the allocated scatterlist
|
||
|
*/
|
||
|
void pci_p2pmem_free_sgl(struct pci_dev *pdev, struct scatterlist *sgl)
|
||
|
{
|
||
|
struct scatterlist *sg;
|
||
|
int count;
|
||
|
|
||
|
for_each_sg(sgl, sg, INT_MAX, count) {
|
||
|
if (!sg)
|
||
|
break;
|
||
|
|
||
|
pci_free_p2pmem(pdev, sg_virt(sg), sg->length);
|
||
|
}
|
||
|
kfree(sgl);
|
||
|
}
|
||
|
EXPORT_SYMBOL_GPL(pci_p2pmem_free_sgl);
|
||
|
|
||
|
/**
|
||
|
* pci_p2pmem_publish - publish the peer-to-peer DMA memory for use by
|
||
|
* other devices with pci_p2pmem_find()
|
||
|
* @pdev: the device with peer-to-peer DMA memory to publish
|
||
|
* @publish: set to true to publish the memory, false to unpublish it
|
||
|
*
|
||
|
* Published memory can be used by other PCI device drivers for
|
||
|
* peer-2-peer DMA operations. Non-published memory is reserved for
|
||
|
* exclusive use of the device driver that registers the peer-to-peer
|
||
|
* memory.
|
||
|
*/
|
||
|
void pci_p2pmem_publish(struct pci_dev *pdev, bool publish)
|
||
|
{
|
||
|
struct pci_p2pdma *p2pdma;
|
||
|
|
||
|
rcu_read_lock();
|
||
|
p2pdma = rcu_dereference(pdev->p2pdma);
|
||
|
if (p2pdma)
|
||
|
p2pdma->p2pmem_published = publish;
|
||
|
rcu_read_unlock();
|
||
|
}
|
||
|
EXPORT_SYMBOL_GPL(pci_p2pmem_publish);
|
||
|
|
||
|
static enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap,
|
||
|
struct device *dev)
|
||
|
{
|
||
|
enum pci_p2pdma_map_type type = PCI_P2PDMA_MAP_NOT_SUPPORTED;
|
||
|
struct pci_dev *provider = to_p2p_pgmap(pgmap)->provider;
|
||
|
struct pci_dev *client;
|
||
|
struct pci_p2pdma *p2pdma;
|
||
|
|
||
|
if (!provider->p2pdma)
|
||
|
return PCI_P2PDMA_MAP_NOT_SUPPORTED;
|
||
|
|
||
|
if (!dev_is_pci(dev))
|
||
|
return PCI_P2PDMA_MAP_NOT_SUPPORTED;
|
||
|
|
||
|
client = to_pci_dev(dev);
|
||
|
|
||
|
rcu_read_lock();
|
||
|
p2pdma = rcu_dereference(provider->p2pdma);
|
||
|
|
||
|
if (p2pdma)
|
||
|
type = xa_to_value(xa_load(&p2pdma->map_types,
|
||
|
map_types_idx(client)));
|
||
|
rcu_read_unlock();
|
||
|
return type;
|
||
|
}
|
||
|
|
||
|
static int __pci_p2pdma_map_sg(struct pci_p2pdma_pagemap *p2p_pgmap,
|
||
|
struct device *dev, struct scatterlist *sg, int nents)
|
||
|
{
|
||
|
struct scatterlist *s;
|
||
|
int i;
|
||
|
|
||
|
for_each_sg(sg, s, nents, i) {
|
||
|
s->dma_address = sg_phys(s) + p2p_pgmap->bus_offset;
|
||
|
sg_dma_len(s) = s->length;
|
||
|
}
|
||
|
|
||
|
return nents;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* pci_p2pdma_map_sg_attrs - map a PCI peer-to-peer scatterlist for DMA
|
||
|
* @dev: device doing the DMA request
|
||
|
* @sg: scatter list to map
|
||
|
* @nents: elements in the scatterlist
|
||
|
* @dir: DMA direction
|
||
|
* @attrs: DMA attributes passed to dma_map_sg() (if called)
|
||
|
*
|
||
|
* Scatterlists mapped with this function should be unmapped using
|
||
|
* pci_p2pdma_unmap_sg_attrs().
|
||
|
*
|
||
|
* Returns the number of SG entries mapped or 0 on error.
|
||
|
*/
|
||
|
int pci_p2pdma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
|
||
|
int nents, enum dma_data_direction dir, unsigned long attrs)
|
||
|
{
|
||
|
struct pci_p2pdma_pagemap *p2p_pgmap =
|
||
|
to_p2p_pgmap(sg_page(sg)->pgmap);
|
||
|
|
||
|
switch (pci_p2pdma_map_type(sg_page(sg)->pgmap, dev)) {
|
||
|
case PCI_P2PDMA_MAP_THRU_HOST_BRIDGE:
|
||
|
return dma_map_sg_attrs(dev, sg, nents, dir, attrs);
|
||
|
case PCI_P2PDMA_MAP_BUS_ADDR:
|
||
|
return __pci_p2pdma_map_sg(p2p_pgmap, dev, sg, nents);
|
||
|
default:
|
||
|
WARN_ON_ONCE(1);
|
||
|
return 0;
|
||
|
}
|
||
|
}
|
||
|
EXPORT_SYMBOL_GPL(pci_p2pdma_map_sg_attrs);
|
||
|
|
||
|
/**
|
||
|
* pci_p2pdma_unmap_sg_attrs - unmap a PCI peer-to-peer scatterlist that was
|
||
|
* mapped with pci_p2pdma_map_sg()
|
||
|
* @dev: device doing the DMA request
|
||
|
* @sg: scatter list to map
|
||
|
* @nents: number of elements returned by pci_p2pdma_map_sg()
|
||
|
* @dir: DMA direction
|
||
|
* @attrs: DMA attributes passed to dma_unmap_sg() (if called)
|
||
|
*/
|
||
|
void pci_p2pdma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg,
|
||
|
int nents, enum dma_data_direction dir, unsigned long attrs)
|
||
|
{
|
||
|
enum pci_p2pdma_map_type map_type;
|
||
|
|
||
|
map_type = pci_p2pdma_map_type(sg_page(sg)->pgmap, dev);
|
||
|
|
||
|
if (map_type == PCI_P2PDMA_MAP_THRU_HOST_BRIDGE)
|
||
|
dma_unmap_sg_attrs(dev, sg, nents, dir, attrs);
|
||
|
}
|
||
|
EXPORT_SYMBOL_GPL(pci_p2pdma_unmap_sg_attrs);
|
||
|
|
||
|
/**
|
||
|
* pci_p2pdma_enable_store - parse a configfs/sysfs attribute store
|
||
|
* to enable p2pdma
|
||
|
* @page: contents of the value to be stored
|
||
|
* @p2p_dev: returns the PCI device that was selected to be used
|
||
|
* (if one was specified in the stored value)
|
||
|
* @use_p2pdma: returns whether to enable p2pdma or not
|
||
|
*
|
||
|
* Parses an attribute value to decide whether to enable p2pdma.
|
||
|
* The value can select a PCI device (using its full BDF device
|
||
|
* name) or a boolean (in any format kstrtobool() accepts). A false
|
||
|
* value disables p2pdma, a true value expects the caller
|
||
|
* to automatically find a compatible device and specifying a PCI device
|
||
|
* expects the caller to use the specific provider.
|
||
|
*
|
||
|
* pci_p2pdma_enable_show() should be used as the show operation for
|
||
|
* the attribute.
|
||
|
*
|
||
|
* Returns 0 on success
|
||
|
*/
|
||
|
int pci_p2pdma_enable_store(const char *page, struct pci_dev **p2p_dev,
|
||
|
bool *use_p2pdma)
|
||
|
{
|
||
|
struct device *dev;
|
||
|
|
||
|
dev = bus_find_device_by_name(&pci_bus_type, NULL, page);
|
||
|
if (dev) {
|
||
|
*use_p2pdma = true;
|
||
|
*p2p_dev = to_pci_dev(dev);
|
||
|
|
||
|
if (!pci_has_p2pmem(*p2p_dev)) {
|
||
|
pci_err(*p2p_dev,
|
||
|
"PCI device has no peer-to-peer memory: %s\n",
|
||
|
page);
|
||
|
pci_dev_put(*p2p_dev);
|
||
|
return -ENODEV;
|
||
|
}
|
||
|
|
||
|
return 0;
|
||
|
} else if ((page[0] == '0' || page[0] == '1') && !iscntrl(page[1])) {
|
||
|
/*
|
||
|
* If the user enters a PCI device that doesn't exist
|
||
|
* like "0000:01:00.1", we don't want kstrtobool to think
|
||
|
* it's a '0' when it's clearly not what the user wanted.
|
||
|
* So we require 0's and 1's to be exactly one character.
|
||
|
*/
|
||
|
} else if (!kstrtobool(page, use_p2pdma)) {
|
||
|
return 0;
|
||
|
}
|
||
|
|
||
|
pr_err("No such PCI device: %.*s\n", (int)strcspn(page, "\n"), page);
|
||
|
return -ENODEV;
|
||
|
}
|
||
|
EXPORT_SYMBOL_GPL(pci_p2pdma_enable_store);
|
||
|
|
||
|
/**
|
||
|
* pci_p2pdma_enable_show - show a configfs/sysfs attribute indicating
|
||
|
* whether p2pdma is enabled
|
||
|
* @page: contents of the stored value
|
||
|
* @p2p_dev: the selected p2p device (NULL if no device is selected)
|
||
|
* @use_p2pdma: whether p2pdma has been enabled
|
||
|
*
|
||
|
* Attributes that use pci_p2pdma_enable_store() should use this function
|
||
|
* to show the value of the attribute.
|
||
|
*
|
||
|
* Returns 0 on success
|
||
|
*/
|
||
|
ssize_t pci_p2pdma_enable_show(char *page, struct pci_dev *p2p_dev,
|
||
|
bool use_p2pdma)
|
||
|
{
|
||
|
if (!use_p2pdma)
|
||
|
return sprintf(page, "0\n");
|
||
|
|
||
|
if (!p2p_dev)
|
||
|
return sprintf(page, "1\n");
|
||
|
|
||
|
return sprintf(page, "%s\n", pci_name(p2p_dev));
|
||
|
}
|
||
|
EXPORT_SYMBOL_GPL(pci_p2pdma_enable_show);
|