@@ -124,6 +124,23 @@ config PCI_PASID
If unsure, say N.
+config PCI_P2PDMA
+ bool "PCI peer-to-peer transfer support"
+ depends on PCI && ZONE_DEVICE && EXPERT
+ select GENERIC_ALLOCATOR
+ help
+ Enableѕ drivers to do PCI peer-to-peer transactions to and from
+ BARs that are exposed in other devices that are the part of
+ the hierarchy where peer-to-peer DMA is guaranteed by the PCI
+ specification to work (ie. anything below a single PCI bridge).
+
+ Many PCIe root complexes do not support P2P transactions and
+ it's hard to tell which support it at all, so at this time, DMA
+ transations must be between devices behind the same root port.
+ (Typically behind a network of PCIe switches).
+
+ If unsure, say N.
+
config PCI_LABEL
def_bool y if (DMI || ACPI)
depends on PCI
@@ -25,6 +25,7 @@ obj-$(CONFIG_X86_INTEL_MID) += pci-mid.o
obj-$(CONFIG_PCI_SYSCALL) += syscall.o
obj-$(CONFIG_PCI_STUB) += pci-stub.o
obj-$(CONFIG_PCI_ECAM) += ecam.o
+obj-$(CONFIG_PCI_P2PDMA) += p2pdma.o
obj-$(CONFIG_XEN_PCIDEV_FRONTEND) += xen-pcifront.o
obj-y += host/
new file mode 100644
@@ -0,0 +1,694 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PCI Peer 2 Peer DMA support.
+ *
+ * Copyright (c) 2016-2018, Logan Gunthorpe
+ * Copyright (c) 2016-2017, Microsemi Corporation
+ * Copyright (c) 2017, Christoph Hellwig
+ * Copyright (c) 2018, Eideticom Inc.
+ *
+ */
+
+#include <linux/pci-p2pdma.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/genalloc.h>
+#include <linux/memremap.h>
+#include <linux/percpu-refcount.h>
+#include <linux/random.h>
+
+struct pci_p2pdma {
+ struct percpu_ref devmap_ref;
+ struct completion devmap_ref_done;
+ struct gen_pool *pool;
+ bool p2pmem_published;
+};
+
+static void pci_p2pdma_percpu_release(struct percpu_ref *ref)
+{
+ struct pci_p2pdma *p2p =
+ container_of(ref, struct pci_p2pdma, devmap_ref);
+
+ complete_all(&p2p->devmap_ref_done);
+}
+
+static void pci_p2pdma_percpu_kill(void *data)
+{
+ struct percpu_ref *ref = data;
+
+ if (percpu_ref_is_dying(ref))
+ return;
+
+ percpu_ref_kill(ref);
+}
+
+static void pci_p2pdma_release(void *data)
+{
+ struct pci_dev *pdev = data;
+
+ if (!pdev->p2pdma)
+ return;
+
+ wait_for_completion(&pdev->p2pdma->devmap_ref_done);
+ percpu_ref_exit(&pdev->p2pdma->devmap_ref);
+
+ gen_pool_destroy(pdev->p2pdma->pool);
+ pdev->p2pdma = NULL;
+}
+
+static int pci_p2pdma_setup(struct pci_dev *pdev)
+{
+ int error = -ENOMEM;
+ struct pci_p2pdma *p2p;
+
+ p2p = devm_kzalloc(&pdev->dev, sizeof(*p2p), GFP_KERNEL);
+ if (!p2p)
+ return -ENOMEM;
+
+ p2p->pool = gen_pool_create(PAGE_SHIFT, dev_to_node(&pdev->dev));
+ if (!p2p->pool)
+ goto out;
+
+ init_completion(&p2p->devmap_ref_done);
+ error = percpu_ref_init(&p2p->devmap_ref,
+ pci_p2pdma_percpu_release, 0, GFP_KERNEL);
+ if (error)
+ goto out_pool_destroy;
+
+ percpu_ref_switch_to_atomic_sync(&p2p->devmap_ref);
+
+ error = devm_add_action_or_reset(&pdev->dev, pci_p2pdma_release, pdev);
+ if (error)
+ goto out_pool_destroy;
+
+ pdev->p2pdma = p2p;
+
+ return 0;
+
+out_pool_destroy:
+ gen_pool_destroy(p2p->pool);
+out:
+ devm_kfree(&pdev->dev, p2p);
+ return error;
+}
+
+/**
+ * pci_p2pdma_add_resource - add memory for use as p2p memory
+ * @pdev: the device to add the memory to
+ * @bar: PCI BAR to add
+ * @size: size of the memory to add, may be zero to use the whole BAR
+ * @offset: offset into the PCI BAR
+ *
+ * The memory will be given ZONE_DEVICE struct pages so that it may
+ * be used with any DMA request.
+ */
+int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size,
+ u64 offset)
+{
+ struct dev_pagemap *pgmap;
+ void *addr;
+ int error;
+
+ if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM))
+ return -EINVAL;
+
+ if (offset >= pci_resource_len(pdev, bar))
+ return -EINVAL;
+
+ if (!size)
+ size = pci_resource_len(pdev, bar) - offset;
+
+ if (size + offset > pci_resource_len(pdev, bar))
+ return -EINVAL;
+
+ if (!pdev->p2pdma) {
+ error = pci_p2pdma_setup(pdev);
+ if (error)
+ return error;
+ }
+
+ pgmap = devm_kzalloc(&pdev->dev, sizeof(*pgmap), GFP_KERNEL);
+ if (!pgmap)
+ return -ENOMEM;
+
+ pgmap->res.start = pci_resource_start(pdev, bar) + offset;
+ pgmap->res.end = pgmap->res.start + size - 1;
+ pgmap->res.flags = pci_resource_flags(pdev, bar);
+ pgmap->ref = &pdev->p2pdma->devmap_ref;
+ pgmap->type = MEMORY_DEVICE_PCI_P2PDMA;
+
+ addr = devm_memremap_pages(&pdev->dev, pgmap);
+ if (IS_ERR(addr)) {
+ error = PTR_ERR(addr);
+ goto pgmap_free;
+ }
+
+ error = gen_pool_add_virt(pdev->p2pdma->pool, (unsigned long)addr,
+ pci_bus_address(pdev, bar) + offset,
+ resource_size(&pgmap->res), dev_to_node(&pdev->dev));
+ if (error)
+ goto pgmap_free;
+
+ error = devm_add_action_or_reset(&pdev->dev, pci_p2pdma_percpu_kill,
+ &pdev->p2pdma->devmap_ref);
+ if (error)
+ goto pgmap_free;
+
+ pci_info(pdev, "added peer-to-peer DMA memory %pR\n",
+ &pgmap->res);
+
+ return 0;
+
+pgmap_free:
+ devres_free(pgmap);
+ return error;
+}
+EXPORT_SYMBOL_GPL(pci_p2pdma_add_resource);
+
+static struct pci_dev *find_parent_pci_dev(struct device *dev)
+{
+ struct device *parent;
+
+ dev = get_device(dev);
+
+ while (dev) {
+ if (dev_is_pci(dev))
+ return to_pci_dev(dev);
+
+ parent = get_device(dev->parent);
+ put_device(dev);
+ dev = parent;
+ }
+
+ return NULL;
+}
+
+/*
+ * If a device is behind a switch, we try to find the upstream bridge
+ * port of the switch. This requires two calls to pci_upstream_bridge():
+ * one for the upstream port on the switch, one on the upstream port
+ * for the next level in the hierarchy. Because of this, devices connected
+ * to the root port will be rejected.
+ */
+static struct pci_dev *get_upstream_bridge_port(struct pci_dev *pdev)
+{
+ struct pci_dev *up1, *up2;
+
+ if (!pdev)
+ return NULL;
+
+ up1 = pci_dev_get(pci_upstream_bridge(pdev));
+ if (!up1)
+ return NULL;
+
+ up2 = pci_dev_get(pci_upstream_bridge(up1));
+ pci_dev_put(up1);
+
+ return up2;
+}
+
+/*
+ * Find the distance through the nearest common upstream bridge between
+ * two PCI devices.
+ *
+ * If the two devices are the same device then 0 will be returned.
+ *
+ * If there are two virtual functions of the same device behind the same
+ * bridge port then 2 will be returned (one step down to the bridge then
+ * one step back to the same device).
+ *
+ * In the case where two devices are connected to the same PCIe switch, the
+ * value 4 will be returned. This corresponds to the following PCI tree:
+ *
+ * -+ Root Port
+ * \+ Switch Upstream Port
+ * +-+ Switch Downstream Port
+ * + \- Device A
+ * \-+ Switch Downstream Port
+ * \- Device B
+ *
+ * The distance is 4 because we traverse from Device A through the downstream
+ * port of the switch, to the common upstream port, back up to the second
+ * downstream port and then to Device B.
+ *
+ * Any two devices that don't have a common upstream bridge will return -1.
+ * In this way devices on seperate root ports will be rejected, which
+ * is what we want for peer-to-peer seeing there's no way to determine
+ * if the root complex supports forwarding between root ports.
+ *
+ * In the case where two devices are connected to different PCIe switches
+ * this function will still return a positive distance as long as both
+ * switches evenutally have a common upstream bridge. Note this covers
+ * the case of using multiple PCIe switches to achieve a desired level of
+ * fan-out from a root port. The exact distance will be a function of the
+ * number of switches between Device A and Device B.
+ *
+ */
+static int upstream_bridge_distance(struct pci_dev *a,
+ struct pci_dev *b)
+{
+ int dist_a = 0;
+ int dist_b = 0;
+ struct pci_dev *aa, *bb = NULL, *tmp;
+
+ aa = pci_dev_get(a);
+
+ while (aa) {
+ dist_b = 0;
+
+ pci_dev_put(bb);
+ bb = pci_dev_get(b);
+
+ while (bb) {
+ if (aa == bb)
+ goto put_and_return;
+
+ tmp = pci_dev_get(pci_upstream_bridge(bb));
+ pci_dev_put(bb);
+ bb = tmp;
+
+ dist_b++;
+ }
+
+ tmp = pci_dev_get(pci_upstream_bridge(aa));
+ pci_dev_put(aa);
+ aa = tmp;
+
+ dist_a++;
+ }
+
+ dist_a = -1;
+ dist_b = 0;
+
+put_and_return:
+ pci_dev_put(bb);
+ pci_dev_put(aa);
+
+ return dist_a + dist_b;
+}
+
+struct pci_p2pdma_client {
+ struct list_head list;
+ struct pci_dev *client;
+ struct pci_dev *provider;
+};
+
+/**
+ * pci_p2pdma_add_client - allocate a new element in a client device list
+ * @head: list head of p2pdma clients
+ * @dev: device to add to the list
+ *
+ * This adds @dev to a list of clients used by a p2pdma device.
+ * This list should be passed to pci_p2pmem_find(). Once pci_p2pmem_find() has
+ * been called successfully, the list will be bound to a specific p2pdma
+ * device and new clients can only be added to the list if they are
+ * supported by that p2pdma device.
+ *
+ * The caller is expected to have a lock which protects @head as necessary
+ * so that none of the pci_p2p functions can be called concurrently
+ * on that list.
+ *
+ * Returns 0 if the client was successfully added.
+ */
+int pci_p2pdma_add_client(struct list_head *head, struct device *dev)
+{
+ struct pci_p2pdma_client *item, *new_item;
+ struct pci_dev *provider = NULL;
+ struct pci_dev *client;
+ int ret;
+
+ if (IS_ENABLED(CONFIG_DMA_VIRT_OPS) && dev->dma_ops == &dma_virt_ops) {
+ dev_warn(dev, "cannot be used for peer-to-peer DMA because the driver makes use of dma_virt_ops\n");
+ return -ENODEV;
+ }
+
+
+ client = find_parent_pci_dev(dev);
+ if (!client) {
+ dev_warn(dev, "cannot be used for peer-to-peer DMA as it is not a PCI device\n");
+ return -ENODEV;
+ }
+
+ item = list_first_entry_or_null(head, struct pci_p2pdma_client, list);
+ if (item && item->provider) {
+ provider = item->provider;
+
+ if (upstream_bridge_distance(provider, client) < 0) {
+ dev_warn(dev, "cannot be used for peer-to-peer DMA as the client and provider do not share an upstream bridge\n");
+
+ ret = -EXDEV;
+ goto put_client;
+ }
+ }
+
+ new_item = kzalloc(sizeof(*new_item), GFP_KERNEL);
+ if (!new_item) {
+ ret = -ENOMEM;
+ goto put_client;
+ }
+
+ new_item->client = client;
+ new_item->provider = pci_dev_get(provider);
+
+ list_add_tail(&new_item->list, head);
+
+ return 0;
+
+put_client:
+ pci_dev_put(client);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(pci_p2pdma_add_client);
+
+static void pci_p2pdma_client_free(struct pci_p2pdma_client *item)
+{
+ list_del(&item->list);
+ pci_dev_put(item->client);
+ pci_dev_put(item->provider);
+ kfree(item);
+}
+
+/**
+ * pci_p2pdma_remove_client - remove and free a p2pdma client
+ * @head: list head of p2pdma clients
+ * @dev: device to remove from the list
+ *
+ * This removes @dev from a list of clients used by a p2pdma device.
+ * The caller is expected to have a lock which protects @head as necessary
+ * so that none of the pci_p2p functions can be called concurrently
+ * on that list.
+ */
+void pci_p2pdma_remove_client(struct list_head *head, struct device *dev)
+{
+ struct pci_p2pdma_client *pos, *tmp;
+ struct pci_dev *pdev;
+
+ pdev = find_parent_pci_dev(dev);
+ if (!pdev)
+ return;
+
+ list_for_each_entry_safe(pos, tmp, head, list) {
+ if (pos->client != pdev)
+ continue;
+
+ pci_p2pdma_client_free(pos);
+ }
+
+ pci_dev_put(pdev);
+}
+EXPORT_SYMBOL_GPL(pci_p2pdma_remove_client);
+
+/**
+ * pci_p2pdma_client_list_free - free an entire list of p2pdma clients
+ * @head: list head of p2pdma clients
+ *
+ * This removes all devices in a list of clients used by a p2pdma device.
+ * The caller is expected to have a lock which protects @head as necessary
+ * so that none of the pci_p2pdma functions can be called concurrently
+ * on that list.
+ */
+void pci_p2pdma_client_list_free(struct list_head *head)
+{
+ struct pci_p2pdma_client *pos, *tmp;
+
+ list_for_each_entry_safe(pos, tmp, head, list)
+ pci_p2pdma_client_free(pos);
+}
+EXPORT_SYMBOL_GPL(pci_p2pdma_client_list_free);
+
+/**
+ * pci_p2pdma_distance - Determive the cumulative distance between
+ * a p2pdma provider and the clients in use.
+ * @provider: p2pdma provider to check against the client list
+ * @clients: list of devices to check (NULL-terminated)
+ *
+ * Returns -1 if any of the clients are not compatible (behind the same
+ * root port as the provider), otherwise returns a positive number where
+ * the lower number is the preferrable choice. (If there's one client
+ * that's the same as the provider it will return 0, which is best choice).
+ *
+ * For now, "compatible" means the provider and the clients are all behind
+ * the same PCI root port. This cuts out cases that may work but is safest
+ * for the user. Future work can expand this to white-list root complexes that
+ * can safely forward between each ports.
+ */
+int pci_p2pdma_distance(struct pci_dev *provider, struct list_head *clients)
+{
+ struct pci_p2pdma_client *pos;
+ int ret;
+ int distance = 0;
+
+ if (list_empty(clients))
+ return -1;
+
+ list_for_each_entry(pos, clients, list) {
+ ret = upstream_bridge_distance(provider, pos->client);
+ if (ret < 0)
+ goto no_match;
+
+ distance += ret;
+ }
+
+ ret = distance;
+
+no_match:
+ return ret;
+}
+EXPORT_SYMBOL_GPL(pci_p2pdma_distance);
+
+/**
+ * pci_p2pdma_assign_provider - Check compatibily (as per pci_p2pdma_distance)
+ * and assign a provider to a list of clients
+ * @provider: p2pdma provider to assign to the client list
+ * @clients: list of devices to check (NULL-terminated)
+ *
+ * Returns false if any of the clients are not compatible, true if the
+ * provider was successfully assigned to the clients.
+ */
+bool pci_p2pdma_assign_provider(struct pci_dev *provider,
+ struct list_head *clients)
+{
+ struct pci_p2pdma_client *pos;
+
+ if (pci_p2pdma_distance(provider, clients) < 0)
+ return false;
+
+ list_for_each_entry(pos, clients, list)
+ pos->provider = provider;
+
+ return true;
+}
+EXPORT_SYMBOL_GPL(pci_p2pdma_assign_provider);
+
+/**
+ * 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)
+{
+ return pdev->p2pdma && pdev->p2pdma->p2pmem_published;
+}
+EXPORT_SYMBOL_GPL(pci_has_p2pmem);
+
+/**
+ * pci_p2pmem_find - 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: list of devices to check (NULL-terminated)
+ *
+ * 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 are
+ * 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(struct list_head *clients)
+{
+ struct pci_dev *pdev = NULL;
+ struct pci_p2pdma_client *pos;
+ 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);
+
+ while ((pdev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, pdev))) {
+ if (!pci_has_p2pmem(pdev))
+ continue;
+
+ distance = pci_p2pdma_distance(pdev, clients);
+ 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]);
+
+ if (pdev)
+ list_for_each_entry(pos, clients, list)
+ pos->provider = pdev;
+
+ kfree(closest_pdevs);
+ return pdev;
+}
+EXPORT_SYMBOL_GPL(pci_p2pmem_find);
+
+/**
+ * pci_alloc_p2p_mem - 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;
+
+ if (unlikely(!pdev->p2pdma))
+ return NULL;
+
+ if (unlikely(!percpu_ref_tryget_live(&pdev->p2pdma->devmap_ref)))
+ return NULL;
+
+ ret = (void *)gen_pool_alloc(pdev->p2pdma->pool, size);
+
+ if (unlikely(!ret))
+ percpu_ref_put(&pdev->p2pdma->devmap_ref);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(pci_alloc_p2pmem);
+
+/**
+ * pci_free_p2pmem - allocate 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 was allocated
+ */
+void pci_free_p2pmem(struct pci_dev *pdev, void *addr, size_t size)
+{
+ gen_pool_free(pdev->p2pdma->pool, (uintptr_t)addr, size);
+ percpu_ref_put(&pdev->p2pdma->devmap_ref);
+}
+EXPORT_SYMBOL_GPL(pci_free_p2pmem);
+
+/**
+ * pci_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)
+{
+ if (!addr)
+ return 0;
+ if (!pdev->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(pdev->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
+ * @sgl: the allocated scatterlist
+ * @nents: the number of SG entries in the list
+ * @length: number of bytes to allocate
+ *
+ * Returns 0 on success
+ */
+struct scatterlist *pci_p2pmem_alloc_sgl(struct pci_dev *pdev,
+ unsigned int *nents, u32 length)
+{
+ struct scatterlist *sg;
+ void *addr;
+
+ sg = kzalloc(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
+ * @nents: the number of SG entries in the list
+ */
+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
+ * exlusive use of the device driver that registers the peer-to-peer
+ * memory.
+ */
+void pci_p2pmem_publish(struct pci_dev *pdev, bool publish)
+{
+ if (publish && !pdev->p2pdma)
+ return;
+
+ pdev->p2pdma->p2pmem_published = publish;
+}
+EXPORT_SYMBOL_GPL(pci_p2pmem_publish);
@@ -53,11 +53,16 @@ struct vmem_altmap {
* driver can hotplug the device memory using ZONE_DEVICE and with that memory
* type. Any page of a process can be migrated to such memory. However no one
* should be allow to pin such memory so that it can always be evicted.
+ *
+ * MEMORY_DEVICE_PCI_P2PDMA:
+ * Device memory residing in a PCI BAR intended for use with Peer-to-Peer
+ * transactions.
*/
enum memory_type {
MEMORY_DEVICE_HOST = 0,
MEMORY_DEVICE_PRIVATE,
MEMORY_DEVICE_PUBLIC,
+ MEMORY_DEVICE_PCI_P2PDMA,
};
/*
@@ -161,6 +166,19 @@ static inline void vmem_altmap_free(struct vmem_altmap *altmap,
}
#endif /* CONFIG_ZONE_DEVICE */
+#ifdef CONFIG_PCI_P2PDMA
+static inline bool is_pci_p2pdma_page(const struct page *page)
+{
+ return is_zone_device_page(page) &&
+ page->pgmap->type == MEMORY_DEVICE_PCI_P2PDMA;
+}
+#else /* CONFIG_PCI_P2PDMA */
+static inline bool is_pci_p2pdma_page(const struct page *page)
+{
+ return false;
+}
+#endif /* CONFIG_PCI_P2PDMA */
+
#if defined(CONFIG_DEVICE_PRIVATE) || defined(CONFIG_DEVICE_PUBLIC)
static inline bool is_device_private_page(const struct page *page)
{
new file mode 100644
@@ -0,0 +1,100 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * PCI Peer 2 Peer DMA support.
+ *
+ * Copyright (c) 2016-2018, Logan Gunthorpe
+ * Copyright (c) 2016-2017, Microsemi Corporation
+ * Copyright (c) 2017, Christoph Hellwig
+ * Copyright (c) 2018, Eideticom Inc.
+ *
+ */
+
+#ifndef _LINUX_PCI_P2PDMA_H
+#define _LINUX_PCI_P2PDMA_H
+
+#include <linux/pci.h>
+
+struct block_device;
+struct scatterlist;
+
+#ifdef CONFIG_PCI_P2PDMA
+int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size,
+ u64 offset);
+int pci_p2pdma_add_client(struct list_head *head, struct device *dev);
+void pci_p2pdma_remove_client(struct list_head *head, struct device *dev);
+void pci_p2pdma_client_list_free(struct list_head *head);
+int pci_p2pdma_distance(struct pci_dev *provider, struct list_head *clients);
+bool pci_p2pdma_assign_provider(struct pci_dev *provider,
+ struct list_head *clients);
+bool pci_has_p2pmem(struct pci_dev *pdev);
+struct pci_dev *pci_p2pmem_find(struct list_head *clients);
+void *pci_alloc_p2pmem(struct pci_dev *pdev, size_t size);
+void pci_free_p2pmem(struct pci_dev *pdev, void *addr, size_t size);
+pci_bus_addr_t pci_p2pmem_virt_to_bus(struct pci_dev *pdev, void *addr);
+struct scatterlist *pci_p2pmem_alloc_sgl(struct pci_dev *pdev,
+ unsigned int *nents, u32 length);
+void pci_p2pmem_free_sgl(struct pci_dev *pdev, struct scatterlist *sgl);
+void pci_p2pmem_publish(struct pci_dev *pdev, bool publish);
+#else /* CONFIG_PCI_P2PDMA */
+static inline int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar,
+ size_t size, u64 offset)
+{
+ return 0;
+}
+static inline int pci_p2pdma_add_client(struct list_head *head,
+ struct device *dev)
+{
+ return 0;
+}
+static inline void pci_p2pdma_remove_client(struct list_head *head,
+ struct device *dev)
+{
+}
+static inline void pci_p2pdma_client_list_free(struct list_head *head)
+{
+}
+static inline int pci_p2pdma_distance(struct pci_dev *provider,
+ struct list_head *clients)
+{
+ return -1;
+}
+static inline bool pci_p2pdma_assign_provider(struct pci_dev *provider,
+ struct list_head *clients)
+{
+ return false;
+}
+static inline bool pci_has_p2pmem(struct pci_dev *pdev)
+{
+ return false;
+}
+static inline struct pci_dev *pci_p2pmem_find(struct list_head *clients)
+{
+ return NULL;
+}
+static inline void *pci_alloc_p2pmem(struct pci_dev *pdev, size_t size)
+{
+ return NULL;
+}
+static inline void pci_free_p2pmem(struct pci_dev *pdev, void *addr,
+ size_t size)
+{
+}
+static inline pci_bus_addr_t pci_p2pmem_virt_to_bus(struct pci_dev *pdev,
+ void *addr)
+{
+ return 0;
+}
+static inline struct scatterlist * pci_p2pmem_alloc_sgl(struct pci_dev *pdev,
+ unsigned int *nents, u32 length)
+{
+ return NULL;
+}
+static inline void pci_p2pmem_free_sgl(struct pci_dev *pdev,
+ struct scatterlist *sgl)
+{
+}
+static inline void pci_p2pmem_publish(struct pci_dev *pdev, bool publish)
+{
+}
+#endif /* CONFIG_PCI_P2PDMA */
+#endif /* _LINUX_PCI_P2P_H */
@@ -277,6 +277,7 @@ struct pcie_link_state;
struct pci_vpd;
struct pci_sriov;
struct pci_ats;
+struct pci_p2pdma;
/* The pci_dev structure describes PCI devices */
struct pci_dev {
@@ -430,6 +431,9 @@ struct pci_dev {
#ifdef CONFIG_PCI_PASID
u16 pasid_features;
#endif
+#ifdef CONFIG_PCI_P2PDMA
+ struct pci_p2pdma *p2pdma;
+#endif
phys_addr_t rom; /* Physical address if not from BAR */
size_t romlen; /* Length if not from BAR */
char *driver_override; /* Driver name to force a match */