From a6e6fe6549f609f5c00c91e988da9d25f8ae8604 Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Mon, 12 Aug 2019 11:30:35 -0600 Subject: [PATCH 01/14] PCI/P2PDMA: Introduce private pagemap structure Move the PCI bus offset from the generic dev_pagemap structure to a specific pci_p2pdma_pagemap structure. This structure will grow in subsequent patches. Link: https://lore.kernel.org/r/20190730163545.4915-2-logang@deltatee.com Link: https://lore.kernel.org/r/20190812173048.9186-2-logang@deltatee.com Signed-off-by: Logan Gunthorpe Signed-off-by: Bjorn Helgaas Reviewed-by: Christoph Hellwig --- drivers/pci/p2pdma.c | 26 ++++++++++++++++++++------ include/linux/memremap.h | 1 - 2 files changed, 20 insertions(+), 7 deletions(-) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 234476226529..03e9c887bdfb 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -25,6 +25,16 @@ struct pci_p2pdma { bool p2pmem_published; }; +struct pci_p2pdma_pagemap { + struct dev_pagemap pgmap; + u64 bus_offset; +}; + +static struct pci_p2pdma_pagemap *to_p2p_pgmap(struct dev_pagemap *pgmap) +{ + return container_of(pgmap, struct pci_p2pdma_pagemap, pgmap); +} + static ssize_t size_show(struct device *dev, struct device_attribute *attr, char *buf) { @@ -135,6 +145,7 @@ static int pci_p2pdma_setup(struct pci_dev *pdev) int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size, u64 offset) { + struct pci_p2pdma_pagemap *p2p_pgmap; struct dev_pagemap *pgmap; void *addr; int error; @@ -157,14 +168,17 @@ int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size, return error; } - pgmap = devm_kzalloc(&pdev->dev, sizeof(*pgmap), GFP_KERNEL); - if (!pgmap) + p2p_pgmap = devm_kzalloc(&pdev->dev, sizeof(*p2p_pgmap), GFP_KERNEL); + if (!p2p_pgmap) return -ENOMEM; + + pgmap = &p2p_pgmap->pgmap; 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->type = MEMORY_DEVICE_PCI_P2PDMA; - pgmap->pci_p2pdma_bus_offset = pci_bus_address(pdev, bar) - + + p2p_pgmap->bus_offset = pci_bus_address(pdev, bar) - pci_resource_start(pdev, bar); addr = devm_memremap_pages(&pdev->dev, pgmap); @@ -720,7 +734,7 @@ EXPORT_SYMBOL_GPL(pci_p2pmem_publish); int pci_p2pdma_map_sg(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir) { - struct dev_pagemap *pgmap; + struct pci_p2pdma_pagemap *p2p_pgmap; struct scatterlist *s; phys_addr_t paddr; int i; @@ -736,10 +750,10 @@ int pci_p2pdma_map_sg(struct device *dev, struct scatterlist *sg, int nents, return 0; for_each_sg(sg, s, nents, i) { - pgmap = sg_page(s)->pgmap; + p2p_pgmap = to_p2p_pgmap(sg_page(s)->pgmap); paddr = sg_phys(s); - s->dma_address = paddr - pgmap->pci_p2pdma_bus_offset; + s->dma_address = paddr - p2p_pgmap->bus_offset; sg_dma_len(s) = s->length; } diff --git a/include/linux/memremap.h b/include/linux/memremap.h index f8a5b2a19945..b459518ce475 100644 --- a/include/linux/memremap.h +++ b/include/linux/memremap.h @@ -112,7 +112,6 @@ struct dev_pagemap { struct device *dev; enum memory_type type; unsigned int flags; - u64 pci_p2pdma_bus_offset; const struct dev_pagemap_ops *ops; }; From 0afea3814358c97e2964710ba16fbb0b54ceda0e Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Mon, 12 Aug 2019 11:30:36 -0600 Subject: [PATCH 02/14] PCI/P2PDMA: Add provider's pci_dev to pci_p2pdma_pagemap struct The provider will be needed to figure out how to map a device. Link: https://lore.kernel.org/r/20190730163545.4915-3-logang@deltatee.com Link: https://lore.kernel.org/r/20190812173048.9186-3-logang@deltatee.com Signed-off-by: Logan Gunthorpe Signed-off-by: Bjorn Helgaas Reviewed-by: Christoph Hellwig --- drivers/pci/p2pdma.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 03e9c887bdfb..93fbda14f4a9 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -27,6 +27,7 @@ struct pci_p2pdma { struct pci_p2pdma_pagemap { struct dev_pagemap pgmap; + struct pci_dev *provider; u64 bus_offset; }; @@ -178,6 +179,7 @@ int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size, pgmap->res.flags = pci_resource_flags(pdev, bar); pgmap->type = MEMORY_DEVICE_PCI_P2PDMA; + p2p_pgmap->provider = pdev; p2p_pgmap->bus_offset = pci_bus_address(pdev, bar) - pci_resource_start(pdev, bar); From 72583084e3fe333c27bc37527efe455d27eaf0b1 Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Mon, 12 Aug 2019 11:30:37 -0600 Subject: [PATCH 03/14] PCI/P2PDMA: Add constants for map type results to upstream_bridge_distance() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add constant flags to indicate how two devices will be mapped or if they are unsupported. upstream_bridge_distance() will now return the mapping type and the distance in a passed-by-reference argument. This helps annotate the code better, but the main reason is so we can use the information to store the required mapping method in an xarray. Link: https://lore.kernel.org/r/20190730163545.4915-4-logang@deltatee.com Link: https://lore.kernel.org/r/20190812173048.9186-4-logang@deltatee.com Signed-off-by: Logan Gunthorpe Signed-off-by: Bjorn Helgaas Reviewed-by: Christian König Reviewed-by: Christoph Hellwig --- drivers/pci/p2pdma.c | 95 +++++++++++++++++++++++++++----------------- 1 file changed, 58 insertions(+), 37 deletions(-) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 93fbda14f4a9..8f0688201aec 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -20,6 +20,13 @@ #include #include +enum pci_p2pdma_map_type { + PCI_P2PDMA_MAP_UNKNOWN = 0, + PCI_P2PDMA_MAP_NOT_SUPPORTED, + PCI_P2PDMA_MAP_BUS_ADDR, + PCI_P2PDMA_MAP_THRU_HOST_BRIDGE, +}; + struct pci_p2pdma { struct gen_pool *pool; bool p2pmem_published; @@ -313,34 +320,33 @@ static bool root_complex_whitelist(struct pci_dev *dev) * 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 separate PCIe root ports will be rejected, which - * is what we want for peer-to-peer seeing each PCIe root port defines a - * separate hierarchy domain and there's no way to determine whether the root - * complex supports forwarding between them. + * Any two devices that cannot communicate using p2pdma will return + * PCI_P2PDMA_MAP_NOT_SUPPORTED. * - * 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 eventually 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. + * Any two devices that have a data path that goes through the host bridge + * will consult a whitelist. If the host bridges are on the whitelist, + * this function will return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE. * - * If a bridge which has any ACS redirection bits set is in the path - * then this functions will return -2. This is so we reject any - * cases where the TLPs are forwarded up into the root complex. - * In this case, a list of all infringing bridge addresses will be - * populated in acs_list (assuming it's non-null) for printk purposes. + * If either bridge is not on the whitelist this function returns + * PCI_P2PDMA_MAP_NOT_SUPPORTED. + * + * If a bridge which has any ACS redirection bits set is in the path, + * acs_redirects will be set to true. In this case, a list of all infringing + * bridge addresses will be populated in acs_list (assuming it's non-null) + * for printk purposes. */ -static int upstream_bridge_distance(struct pci_dev *provider, - struct pci_dev *client, - struct seq_buf *acs_list) +static enum pci_p2pdma_map_type +upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client, + int *dist, bool *acs_redirects, struct seq_buf *acs_list) { struct pci_dev *a = provider, *b = client, *bb; int dist_a = 0; int dist_b = 0; int acs_cnt = 0; + if (acs_redirects) + *acs_redirects = false; + /* * Note, we don't need to take references to devices returned by * pci_upstream_bridge() seeing we hold a reference to a child @@ -369,15 +375,18 @@ static int upstream_bridge_distance(struct pci_dev *provider, dist_a++; } + if (dist) + *dist = dist_a + dist_b; + /* * Allow the connection if both devices are on a whitelisted root * complex, but add an arbitrary large value to the distance. */ if (root_complex_whitelist(provider) && root_complex_whitelist(client)) - return 0x1000 + dist_a + dist_b; + return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE; - return -1; + return PCI_P2PDMA_MAP_NOT_SUPPORTED; check_b_path_acs: bb = b; @@ -394,33 +403,44 @@ static int upstream_bridge_distance(struct pci_dev *provider, bb = pci_upstream_bridge(bb); } - if (acs_cnt) - return -2; + if (dist) + *dist = dist_a + dist_b; - return dist_a + dist_b; + if (acs_cnt) { + if (acs_redirects) + *acs_redirects = true; + + return PCI_P2PDMA_MAP_NOT_SUPPORTED; + } + + return PCI_P2PDMA_MAP_BUS_ADDR; } -static int upstream_bridge_distance_warn(struct pci_dev *provider, - struct pci_dev *client) +static enum pci_p2pdma_map_type +upstream_bridge_distance_warn(struct pci_dev *provider, struct pci_dev *client, + int *dist) { struct seq_buf acs_list; + bool acs_redirects; int ret; seq_buf_init(&acs_list, kmalloc(PAGE_SIZE, GFP_KERNEL), PAGE_SIZE); if (!acs_list.buffer) return -ENOMEM; - ret = upstream_bridge_distance(provider, client, &acs_list); - if (ret == -2) { - pci_warn(client, "cannot be used for peer-to-peer DMA as ACS redirect is set between the client and provider (%s)\n", + ret = upstream_bridge_distance(provider, client, dist, &acs_redirects, + &acs_list); + if (acs_redirects) { + pci_warn(client, "ACS redirect is set between the client and provider (%s)\n", pci_name(provider)); /* Drop final semicolon */ acs_list.buffer[acs_list.len-1] = 0; pci_warn(client, "to disable ACS redirect for this path, add the kernel parameter: pci=disable_acs_redir=%s\n", acs_list.buffer); + } - } else if (ret < 0) { - pci_warn(client, "cannot be used for peer-to-peer DMA as the client and provider (%s) do not share an upstream bridge\n", + if (ret == PCI_P2PDMA_MAP_NOT_SUPPORTED) { + 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)); } @@ -452,7 +472,8 @@ int pci_p2pdma_distance_many(struct pci_dev *provider, struct device **clients, { bool not_supported = false; struct pci_dev *pci_client; - int distance = 0; + int total_dist = 0; + int distance; int i, ret; if (num_clients == 0) @@ -477,26 +498,26 @@ int pci_p2pdma_distance_many(struct pci_dev *provider, struct device **clients, if (verbose) ret = upstream_bridge_distance_warn(provider, - pci_client); + pci_client, &distance); else ret = upstream_bridge_distance(provider, pci_client, - NULL); + &distance, NULL, NULL); pci_dev_put(pci_client); - if (ret < 0) + if (ret == PCI_P2PDMA_MAP_NOT_SUPPORTED) not_supported = true; if (not_supported && !verbose) break; - distance += ret; + total_dist += distance; } if (not_supported) return -1; - return distance; + return total_dist; } EXPORT_SYMBOL_GPL(pci_p2pdma_distance_many); From c6bfaeb573a6caae4b96885b8bad63ee57495c77 Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Mon, 12 Aug 2019 11:30:38 -0600 Subject: [PATCH 04/14] PCI/P2PDMA: Factor out __upstream_bridge_distance() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This is a prep patch to create a second level helper. There are no functional changes. The root complex whitelist code will be moved into this function in a subsequent patch. Link: https://lore.kernel.org/r/20190730163545.4915-5-logang@deltatee.com Link: https://lore.kernel.org/r/20190812173048.9186-5-logang@deltatee.com Signed-off-by: Logan Gunthorpe Signed-off-by: Bjorn Helgaas Reviewed-by: Christian König Reviewed-by: Christoph Hellwig --- drivers/pci/p2pdma.c | 88 ++++++++++++++++++++++++-------------------- 1 file changed, 48 insertions(+), 40 deletions(-) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 8f0688201aec..600ba6a7aa11 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -296,47 +296,8 @@ static bool root_complex_whitelist(struct pci_dev *dev) return false; } -/* - * 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 PCIe switch, - * 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 cannot communicate using p2pdma will return - * PCI_P2PDMA_MAP_NOT_SUPPORTED. - * - * Any two devices that have a data path that goes through the host bridge - * will consult a whitelist. If the host bridges are on the whitelist, - * this function will return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE. - * - * If either bridge is not on the whitelist this function returns - * PCI_P2PDMA_MAP_NOT_SUPPORTED. - * - * If a bridge which has any ACS redirection bits set is in the path, - * acs_redirects will be set to true. In this case, a list of all infringing - * bridge addresses will be populated in acs_list (assuming it's non-null) - * for printk purposes. - */ static enum pci_p2pdma_map_type -upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client, +__upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client, int *dist, bool *acs_redirects, struct seq_buf *acs_list) { struct pci_dev *a = provider, *b = client, *bb; @@ -416,6 +377,53 @@ upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client, return PCI_P2PDMA_MAP_BUS_ADDR; } +/* + * 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 PCIe switch, + * 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 cannot communicate using p2pdma will return + * PCI_P2PDMA_MAP_NOT_SUPPORTED. + * + * Any two devices that have a data path that goes through the host bridge + * will consult a whitelist. If the host bridges are on the whitelist, + * this function will return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE. + * + * If either bridge is not on the whitelist this function returns + * PCI_P2PDMA_MAP_NOT_SUPPORTED. + * + * If a bridge which has any ACS redirection bits set is in the path, + * acs_redirects will be set to true. In this case, a list of all infringing + * bridge addresses will be populated in acs_list (assuming it's non-null) + * for printk purposes. + */ +static enum pci_p2pdma_map_type +upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client, + int *dist, bool *acs_redirects, struct seq_buf *acs_list) +{ + return __upstream_bridge_distance(provider, client, dist, + acs_redirects, acs_list); +} + static enum pci_p2pdma_map_type upstream_bridge_distance_warn(struct pci_dev *provider, struct pci_dev *client, int *dist) From e2cbfbf78968db3e3a71cb989af17f4f6448bf49 Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Mon, 12 Aug 2019 11:30:39 -0600 Subject: [PATCH 05/14] PCI/P2PDMA: Apply host bridge whitelist for ACS MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When a P2PDMA transfer is rejected due to ACS being set, we can also check the whitelist and allow the transactions. Do this by pushing the whitelist check into the upstream_bridge_distance() function. Link: https://lore.kernel.org/r/20190730163545.4915-6-logang@deltatee.com Link: https://lore.kernel.org/r/20190812173048.9186-6-logang@deltatee.com Signed-off-by: Logan Gunthorpe Signed-off-by: Bjorn Helgaas Reviewed-by: Christian König Reviewed-by: Christoph Hellwig --- drivers/pci/p2pdma.c | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 600ba6a7aa11..f7f7e5862bab 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -339,15 +339,7 @@ __upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client, if (dist) *dist = dist_a + dist_b; - /* - * Allow the connection if both devices are on a whitelisted root - * complex, but add an arbitrary large value to the distance. - */ - if (root_complex_whitelist(provider) && - root_complex_whitelist(client)) - return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE; - - return PCI_P2PDMA_MAP_NOT_SUPPORTED; + return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE; check_b_path_acs: bb = b; @@ -371,7 +363,7 @@ __upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client, if (acs_redirects) *acs_redirects = true; - return PCI_P2PDMA_MAP_NOT_SUPPORTED; + return PCI_P2PDMA_MAP_THRU_HOST_BRIDGE; } return PCI_P2PDMA_MAP_BUS_ADDR; @@ -420,8 +412,18 @@ static enum pci_p2pdma_map_type upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client, int *dist, bool *acs_redirects, struct seq_buf *acs_list) { - return __upstream_bridge_distance(provider, client, dist, - acs_redirects, acs_list); + enum pci_p2pdma_map_type map_type; + + map_type = __upstream_bridge_distance(provider, client, dist, + acs_redirects, acs_list); + + if (map_type == PCI_P2PDMA_MAP_THRU_HOST_BRIDGE) { + if (!root_complex_whitelist(provider) || + !root_complex_whitelist(client)) + return PCI_P2PDMA_MAP_NOT_SUPPORTED; + } + + return map_type; } static enum pci_p2pdma_map_type From 2c84d818aee976390c055a417045a85c23d39662 Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Mon, 12 Aug 2019 11:30:40 -0600 Subject: [PATCH 06/14] PCI/P2PDMA: Factor out host_bridge_whitelist() Push both PCI devices into the whitelist checking function seeing some hardware will require us ensuring they are on the same host bridge. At the same time we rename root_complex_whitelist() to host_bridge_whitelist() to match the terminology used in the code. Link: https://lore.kernel.org/r/20190730163545.4915-7-logang@deltatee.com Link: https://lore.kernel.org/r/20190812173048.9186-7-logang@deltatee.com Signed-off-by: Logan Gunthorpe Signed-off-by: Bjorn Helgaas Reviewed-by: Christoph Hellwig --- drivers/pci/p2pdma.c | 31 ++++++++++++++++++++----------- 1 file changed, 20 insertions(+), 11 deletions(-) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index f7f7e5862bab..4b9f0903b340 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -269,19 +269,11 @@ static void seq_buf_print_bus_devfn(struct seq_buf *buf, struct pci_dev *pdev) seq_buf_printf(buf, "%s;", pci_name(pdev)); } -/* - * If we can't find a common upstream bridge take a look at the root - * complex and compare it to a whitelist of known good hardware. - */ -static bool root_complex_whitelist(struct pci_dev *dev) +static bool __host_bridge_whitelist(struct pci_host_bridge *host) { - struct pci_host_bridge *host = pci_find_host_bridge(dev->bus); struct pci_dev *root = pci_get_slot(host->bus, PCI_DEVFN(0, 0)); unsigned short vendor, device; - if (iommu_present(dev->dev.bus)) - return false; - if (!root) return false; @@ -296,6 +288,24 @@ static bool root_complex_whitelist(struct pci_dev *dev) return false; } +/* + * If we can't find a common upstream bridge take a look at the root + * complex and compare it to a whitelist of known good hardware. + */ +static bool host_bridge_whitelist(struct pci_dev *a, struct pci_dev *b) +{ + struct pci_host_bridge *host_a = pci_find_host_bridge(a->bus); + struct pci_host_bridge *host_b = pci_find_host_bridge(b->bus); + + if (iommu_present(a->dev.bus) || iommu_present(b->dev.bus)) + return false; + + if (__host_bridge_whitelist(host_a) && __host_bridge_whitelist(host_b)) + return true; + + return false; +} + static enum pci_p2pdma_map_type __upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client, int *dist, bool *acs_redirects, struct seq_buf *acs_list) @@ -418,8 +428,7 @@ upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client, acs_redirects, acs_list); if (map_type == PCI_P2PDMA_MAP_THRU_HOST_BRIDGE) { - if (!root_complex_whitelist(provider) || - !root_complex_whitelist(client)) + if (!host_bridge_whitelist(provider, client)) return PCI_P2PDMA_MAP_NOT_SUPPORTED; } From 494d63b0d5d0a481f6ac23bc61e94647ab9c4390 Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Mon, 12 Aug 2019 11:30:41 -0600 Subject: [PATCH 07/14] PCI/P2PDMA: Whitelist some Intel host bridges Intel devices do not have good support for P2P requests that span different host bridges as the transactions will cross the QPI/UPI bus and this does not perform well. Therefore, enable support for these devices only if the host bridges match. Add Intel devices that have been tested and are known to work. There are likely many others out there that will need to be tested and added. Link: https://lore.kernel.org/r/20190730163545.4915-8-logang@deltatee.com Link: https://lore.kernel.org/r/20190812173048.9186-8-logang@deltatee.com Signed-off-by: Logan Gunthorpe Signed-off-by: Bjorn Helgaas Reviewed-by: Christoph Hellwig --- drivers/pci/p2pdma.c | 38 ++++++++++++++++++++++++++++++++++---- 1 file changed, 34 insertions(+), 4 deletions(-) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 4b9f0903b340..2c4a8e92ed64 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -269,9 +269,30 @@ static void seq_buf_print_bus_devfn(struct seq_buf *buf, struct pci_dev *pdev) seq_buf_printf(buf, "%s;", pci_name(pdev)); } -static bool __host_bridge_whitelist(struct pci_host_bridge *host) +static const struct pci_p2pdma_whitelist_entry { + unsigned short vendor; + unsigned short device; + enum { + REQ_SAME_HOST_BRIDGE = 1 << 0, + } flags; +} pci_p2pdma_whitelist[] = { + /* AMD ZEN */ + {PCI_VENDOR_ID_AMD, 0x1450, 0}, + + /* Intel Xeon E5/Core i7 */ + {PCI_VENDOR_ID_INTEL, 0x3c00, REQ_SAME_HOST_BRIDGE}, + {PCI_VENDOR_ID_INTEL, 0x3c01, REQ_SAME_HOST_BRIDGE}, + /* Intel Xeon E7 v3/Xeon E5 v3/Core i7 */ + {PCI_VENDOR_ID_INTEL, 0x2f00, REQ_SAME_HOST_BRIDGE}, + {PCI_VENDOR_ID_INTEL, 0x2f01, REQ_SAME_HOST_BRIDGE}, + {} +}; + +static bool __host_bridge_whitelist(struct pci_host_bridge *host, + bool same_host_bridge) { struct pci_dev *root = pci_get_slot(host->bus, PCI_DEVFN(0, 0)); + const struct pci_p2pdma_whitelist_entry *entry; unsigned short vendor, device; if (!root) @@ -281,9 +302,14 @@ static bool __host_bridge_whitelist(struct pci_host_bridge *host) device = root->device; pci_dev_put(root); - /* AMD ZEN host bridges can do peer to peer */ - if (vendor == PCI_VENDOR_ID_AMD && device == 0x1450) + for (entry = pci_p2pdma_whitelist; entry->vendor; entry++) { + if (vendor != entry->vendor || device != entry->device) + continue; + if (entry->flags & REQ_SAME_HOST_BRIDGE && !same_host_bridge) + return false; + return true; + } return false; } @@ -300,7 +326,11 @@ static bool host_bridge_whitelist(struct pci_dev *a, struct pci_dev *b) if (iommu_present(a->dev.bus) || iommu_present(b->dev.bus)) return false; - if (__host_bridge_whitelist(host_a) && __host_bridge_whitelist(host_b)) + if (host_a == host_b) + return __host_bridge_whitelist(host_a, true); + + if (__host_bridge_whitelist(host_a, false) && + __host_bridge_whitelist(host_b, false)) return true; return false; From 2b9f4bb2a4fb77da4862f9ddf5209de2bcdaa0c0 Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Mon, 12 Aug 2019 11:30:42 -0600 Subject: [PATCH 08/14] PCI/P2PDMA: Add attrs argument to pci_p2pdma_map_sg() This is to match the dma_map_sg() API which this function will have to call in an future patch. Add a pci_p2pdma_map_sg_attrs() function and helper to call it with no attributes just like the dma_map_sg() function. Link: https://lore.kernel.org/r/20190730163545.4915-9-logang@deltatee.com Link: https://lore.kernel.org/r/20190812173048.9186-9-logang@deltatee.com Signed-off-by: Logan Gunthorpe Signed-off-by: Bjorn Helgaas Reviewed-by: Christoph Hellwig --- drivers/nvme/host/pci.c | 4 ++-- drivers/pci/p2pdma.c | 7 ++++--- include/linux/pci-p2pdma.h | 15 +++++++++++---- 3 files changed, 17 insertions(+), 9 deletions(-) diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index bb970ca82517..7747712054cd 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -832,8 +832,8 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req, goto out; if (is_pci_p2pdma_page(sg_page(iod->sg))) - nr_mapped = pci_p2pdma_map_sg(dev->dev, iod->sg, iod->nents, - rq_dma_dir(req)); + nr_mapped = pci_p2pdma_map_sg_attrs(dev->dev, iod->sg, + iod->nents, rq_dma_dir(req), DMA_ATTR_NO_WARN); else nr_mapped = dma_map_sg_attrs(dev->dev, iod->sg, iod->nents, rq_dma_dir(req), DMA_ATTR_NO_WARN); diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 2c4a8e92ed64..94fbacbcbbd0 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -798,13 +798,14 @@ EXPORT_SYMBOL_GPL(pci_p2pmem_publish); * @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 not be unmapped in any way. * * Returns the number of SG entries mapped or 0 on error. */ -int pci_p2pdma_map_sg(struct device *dev, struct scatterlist *sg, int nents, - enum dma_data_direction dir) +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; struct scatterlist *s; @@ -831,7 +832,7 @@ int pci_p2pdma_map_sg(struct device *dev, struct scatterlist *sg, int nents, return nents; } -EXPORT_SYMBOL_GPL(pci_p2pdma_map_sg); +EXPORT_SYMBOL_GPL(pci_p2pdma_map_sg_attrs); /** * pci_p2pdma_enable_store - parse a configfs/sysfs attribute store diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h index bca9bc3e5be7..7fd51954f93a 100644 --- a/include/linux/pci-p2pdma.h +++ b/include/linux/pci-p2pdma.h @@ -30,8 +30,8 @@ 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); -int pci_p2pdma_map_sg(struct device *dev, struct scatterlist *sg, int nents, - enum dma_data_direction dir); +int pci_p2pdma_map_sg_attrs(struct device *dev, struct scatterlist *sg, + int nents, enum dma_data_direction dir, unsigned long attrs); 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, @@ -81,8 +81,9 @@ static inline void pci_p2pmem_free_sgl(struct pci_dev *pdev, static inline void pci_p2pmem_publish(struct pci_dev *pdev, bool publish) { } -static inline int pci_p2pdma_map_sg(struct device *dev, - struct scatterlist *sg, int nents, enum dma_data_direction dir) +static inline int pci_p2pdma_map_sg_attrs(struct device *dev, + struct scatterlist *sg, int nents, enum dma_data_direction dir, + unsigned long attrs) { return 0; } @@ -111,4 +112,10 @@ static inline struct pci_dev *pci_p2pmem_find(struct device *client) return pci_p2pmem_find_many(&client, 1); } +static inline int pci_p2pdma_map_sg(struct device *dev, struct scatterlist *sg, + int nents, enum dma_data_direction dir) +{ + return pci_p2pdma_map_sg_attrs(dev, sg, nents, dir, 0); +} + #endif /* _LINUX_PCI_P2P_H */ From 7f73eac3a7137eabfb0c005c7ba55eb7994b9673 Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Mon, 12 Aug 2019 11:30:43 -0600 Subject: [PATCH 09/14] PCI/P2PDMA: Introduce pci_p2pdma_unmap_sg() Add pci_p2pdma_unmap_sg() to the two places that call pci_p2pdma_map_sg(). This is a prep patch to introduce correct mappings for p2pdma transactions that go through the root complex. Link: https://lore.kernel.org/r/20190730163545.4915-10-logang@deltatee.com Link: https://lore.kernel.org/r/20190812173048.9186-10-logang@deltatee.com Signed-off-by: Logan Gunthorpe Signed-off-by: Bjorn Helgaas Reviewed-by: Christoph Hellwig --- drivers/infiniband/core/rw.c | 6 ++++-- drivers/nvme/host/pci.c | 6 ++++-- drivers/pci/p2pdma.c | 18 +++++++++++++++++- include/linux/pci-p2pdma.h | 13 +++++++++++++ 4 files changed, 38 insertions(+), 5 deletions(-) diff --git a/drivers/infiniband/core/rw.c b/drivers/infiniband/core/rw.c index dce06108c8c3..5337393d4dfe 100644 --- a/drivers/infiniband/core/rw.c +++ b/drivers/infiniband/core/rw.c @@ -583,8 +583,10 @@ void rdma_rw_ctx_destroy(struct rdma_rw_ctx *ctx, struct ib_qp *qp, u8 port_num, break; } - /* P2PDMA contexts do not need to be unmapped */ - if (!is_pci_p2pdma_page(sg_page(sg))) + if (is_pci_p2pdma_page(sg_page(sg))) + pci_p2pdma_unmap_sg(qp->pd->device->dma_device, sg, + sg_cnt, dir); + else ib_dma_unmap_sg(qp->pd->device, sg, sg_cnt, dir); } EXPORT_SYMBOL(rdma_rw_ctx_destroy); diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index 7747712054cd..2348b15f6bd0 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -547,8 +547,10 @@ static void nvme_unmap_data(struct nvme_dev *dev, struct request *req) WARN_ON_ONCE(!iod->nents); - /* P2PDMA requests do not need to be unmapped */ - if (!is_pci_p2pdma_page(sg_page(iod->sg))) + if (is_pci_p2pdma_page(sg_page(iod->sg))) + pci_p2pdma_unmap_sg(dev->dev, iod->sg, iod->nents, + rq_dma_dir(req)); + else dma_unmap_sg(dev->dev, iod->sg, iod->nents, rq_dma_dir(req)); diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 94fbacbcbbd0..1eec7a5ec27e 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -800,7 +800,8 @@ EXPORT_SYMBOL_GPL(pci_p2pmem_publish); * @dir: DMA direction * @attrs: DMA attributes passed to dma_map_sg() (if called) * - * Scatterlists mapped with this function should not be unmapped in any way. + * 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. */ @@ -834,6 +835,21 @@ int pci_p2pdma_map_sg_attrs(struct device *dev, struct scatterlist *sg, } EXPORT_SYMBOL_GPL(pci_p2pdma_map_sg_attrs); +/** + * pci_p2pdma_unmap_sg - 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) +{ +} +EXPORT_SYMBOL_GPL(pci_p2pdma_unmap_sg_attrs); + /** * pci_p2pdma_enable_store - parse a configfs/sysfs attribute store * to enable p2pdma diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h index 7fd51954f93a..8318a97c9c61 100644 --- a/include/linux/pci-p2pdma.h +++ b/include/linux/pci-p2pdma.h @@ -32,6 +32,8 @@ void pci_p2pmem_free_sgl(struct pci_dev *pdev, struct scatterlist *sgl); void pci_p2pmem_publish(struct pci_dev *pdev, bool publish); int pci_p2pdma_map_sg_attrs(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir, unsigned long attrs); +void pci_p2pdma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg, + int nents, enum dma_data_direction dir, unsigned long attrs); 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, @@ -87,6 +89,11 @@ static inline int pci_p2pdma_map_sg_attrs(struct device *dev, { return 0; } +static inline void pci_p2pdma_unmap_sg_attrs(struct device *dev, + struct scatterlist *sg, int nents, enum dma_data_direction dir, + unsigned long attrs) +{ +} static inline int pci_p2pdma_enable_store(const char *page, struct pci_dev **p2p_dev, bool *use_p2pdma) { @@ -118,4 +125,10 @@ static inline int pci_p2pdma_map_sg(struct device *dev, struct scatterlist *sg, return pci_p2pdma_map_sg_attrs(dev, sg, nents, dir, 0); } +static inline void pci_p2pdma_unmap_sg(struct device *dev, + struct scatterlist *sg, int nents, enum dma_data_direction dir) +{ + pci_p2pdma_unmap_sg_attrs(dev, sg, nents, dir, 0); +} + #endif /* _LINUX_PCI_P2P_H */ From 142c242e6f12196f8064beb09198838611e029db Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Mon, 12 Aug 2019 11:30:44 -0600 Subject: [PATCH 10/14] PCI/P2PDMA: Factor out __pci_p2pdma_map_sg() Factor out the bus-only mapping into its own static function. No functional changes. The original pci_p2pdma_map_sg_attrs() will be used to decide whether this is an appropriate way to map. Link: https://lore.kernel.org/r/20190730163545.4915-11-logang@deltatee.com Link: https://lore.kernel.org/r/20190812173048.9186-11-logang@deltatee.com Signed-off-by: Logan Gunthorpe Signed-off-by: Bjorn Helgaas Reviewed-by: Christoph Hellwig --- drivers/pci/p2pdma.c | 53 +++++++++++++++++++++++++------------------- 1 file changed, 30 insertions(+), 23 deletions(-) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 1eec7a5ec27e..771b45605853 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -792,6 +792,33 @@ void pci_p2pmem_publish(struct pci_dev *pdev, bool publish) } EXPORT_SYMBOL_GPL(pci_p2pmem_publish); +static int __pci_p2pdma_map_sg(struct pci_p2pdma_pagemap *p2p_pgmap, + struct device *dev, struct scatterlist *sg, int nents) +{ + struct scatterlist *s; + phys_addr_t paddr; + int i; + + /* + * p2pdma mappings are not compatible with devices that use + * dma_virt_ops. If the upper layers do the right thing + * this should never happen because it will be prevented + * by the check in pci_p2pdma_distance_many() + */ + if (WARN_ON_ONCE(IS_ENABLED(CONFIG_DMA_VIRT_OPS) && + dev->dma_ops == &dma_virt_ops)) + return 0; + + for_each_sg(sg, s, nents, i) { + paddr = sg_phys(s); + + s->dma_address = paddr - p2p_pgmap->bus_offset; + sg_dma_len(s) = s->length; + } + + return nents; +} + /** * pci_p2pdma_map_sg - map a PCI peer-to-peer scatterlist for DMA * @dev: device doing the DMA request @@ -808,30 +835,10 @@ EXPORT_SYMBOL_GPL(pci_p2pmem_publish); 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; - struct scatterlist *s; - phys_addr_t paddr; - int i; + struct pci_p2pdma_pagemap *p2p_pgmap = + to_p2p_pgmap(sg_page(sg)->pgmap); - /* - * p2pdma mappings are not compatible with devices that use - * dma_virt_ops. If the upper layers do the right thing - * this should never happen because it will be prevented - * by the check in pci_p2pdma_distance_many() - */ - if (WARN_ON_ONCE(IS_ENABLED(CONFIG_DMA_VIRT_OPS) && - dev->dma_ops == &dma_virt_ops)) - return 0; - - for_each_sg(sg, s, nents, i) { - p2p_pgmap = to_p2p_pgmap(sg_page(s)->pgmap); - paddr = sg_phys(s); - - s->dma_address = paddr - p2p_pgmap->bus_offset; - sg_dma_len(s) = s->length; - } - - return nents; + return __pci_p2pdma_map_sg(p2p_pgmap, dev, sg, nents); } EXPORT_SYMBOL_GPL(pci_p2pdma_map_sg_attrs); From 110203bee05f33637ccb44f046f14edaea94bb4c Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Mon, 12 Aug 2019 11:30:45 -0600 Subject: [PATCH 11/14] PCI/P2PDMA: Store mapping method in an xarray When upstream_bridge_distance() is called, store the method required to map the DMA transfers in an xarray so it can be looked up efficiently on the hot path in pci_p2pdma_map_sg(). Link: https://lore.kernel.org/r/20190730163545.4915-12-logang@deltatee.com Link: https://lore.kernel.org/r/20190812173048.9186-12-logang@deltatee.com Signed-off-by: Logan Gunthorpe Signed-off-by: Bjorn Helgaas Reviewed-by: Christoph Hellwig --- drivers/pci/p2pdma.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 771b45605853..db8224ff6e80 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -19,6 +19,7 @@ #include #include #include +#include enum pci_p2pdma_map_type { PCI_P2PDMA_MAP_UNKNOWN = 0, @@ -30,6 +31,7 @@ enum pci_p2pdma_map_type { struct pci_p2pdma { struct gen_pool *pool; bool p2pmem_published; + struct xarray map_types; }; struct pci_p2pdma_pagemap { @@ -105,6 +107,7 @@ static void pci_p2pdma_release(void *data) gen_pool_destroy(p2pdma->pool); sysfs_remove_group(&pdev->dev.kobj, &p2pmem_group); + xa_destroy(&p2pdma->map_types); } static int pci_p2pdma_setup(struct pci_dev *pdev) @@ -116,6 +119,8 @@ static int pci_p2pdma_setup(struct pci_dev *pdev) if (!p2p) return -ENOMEM; + xa_init(&p2p->map_types); + p2p->pool = gen_pool_create(PAGE_SHIFT, dev_to_node(&pdev->dev)); if (!p2p->pool) goto out; @@ -409,6 +414,12 @@ __upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client, return PCI_P2PDMA_MAP_BUS_ADDR; } +static unsigned long map_types_idx(struct pci_dev *client) +{ + return (pci_domain_nr(client->bus) << 16) | + (client->bus->number << 8) | client->devfn; +} + /* * Find the distance through the nearest common upstream bridge between * two PCI devices. @@ -459,9 +470,13 @@ upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client, if (map_type == PCI_P2PDMA_MAP_THRU_HOST_BRIDGE) { if (!host_bridge_whitelist(provider, client)) - return PCI_P2PDMA_MAP_NOT_SUPPORTED; + map_type = PCI_P2PDMA_MAP_NOT_SUPPORTED; } + if (provider->p2pdma) + xa_store(&provider->p2pdma->map_types, map_types_idx(client), + xa_mk_value(map_type), GFP_KERNEL); + return map_type; } From 5d52e1abcd47957f5f4cae26659768655e3ac9f5 Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Mon, 12 Aug 2019 11:30:46 -0600 Subject: [PATCH 12/14] PCI/P2PDMA: dma_map() requests that traverse the host bridge Any requests that traverse the host bridge will need to be mapped into the IOMMU, so call dma_map_sg() inside pci_p2pdma_map_sg() when appropriate. Similarly, call dma_unmap_sg() inside pci_p2pdma_unmap_sg(). Link: https://lore.kernel.org/r/20190730163545.4915-13-logang@deltatee.com Link: https://lore.kernel.org/r/20190812173048.9186-13-logang@deltatee.com Signed-off-by: Logan Gunthorpe Signed-off-by: Bjorn Helgaas Reviewed-by: Christoph Hellwig --- drivers/pci/p2pdma.c | 40 +++++++++++++++++++++++++++++++++++++++- 1 file changed, 39 insertions(+), 1 deletion(-) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index db8224ff6e80..bca1ffc7075e 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -807,6 +807,16 @@ void pci_p2pmem_publish(struct pci_dev *pdev, bool publish) } EXPORT_SYMBOL_GPL(pci_p2pmem_publish); +static enum pci_p2pdma_map_type pci_p2pdma_map_type(struct pci_dev *provider, + struct pci_dev *client) +{ + if (!provider->p2pdma) + return PCI_P2PDMA_MAP_NOT_SUPPORTED; + + return xa_to_value(xa_load(&provider->p2pdma->map_types, + map_types_idx(client))); +} + static int __pci_p2pdma_map_sg(struct pci_p2pdma_pagemap *p2p_pgmap, struct device *dev, struct scatterlist *sg, int nents) { @@ -852,8 +862,22 @@ int pci_p2pdma_map_sg_attrs(struct device *dev, struct scatterlist *sg, { struct pci_p2pdma_pagemap *p2p_pgmap = to_p2p_pgmap(sg_page(sg)->pgmap); + struct pci_dev *client; - return __pci_p2pdma_map_sg(p2p_pgmap, dev, sg, nents); + if (WARN_ON_ONCE(!dev_is_pci(dev))) + return 0; + + client = to_pci_dev(dev); + + switch (pci_p2pdma_map_type(p2p_pgmap->provider, client)) { + 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); @@ -869,6 +893,20 @@ EXPORT_SYMBOL_GPL(pci_p2pdma_map_sg_attrs); void pci_p2pdma_unmap_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); + enum pci_p2pdma_map_type map_type; + struct pci_dev *client; + + if (WARN_ON_ONCE(!dev_is_pci(dev))) + return; + + client = to_pci_dev(dev); + + map_type = pci_p2pdma_map_type(p2p_pgmap->provider, client); + + 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); From 5daf40b039249ef98d49610d14293dca3464b91f Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Mon, 12 Aug 2019 11:30:47 -0600 Subject: [PATCH 13/14] PCI/P2PDMA: Allow IOMMU for host bridge whitelist Now that we map the requests correctly we can remove the iommu_present() restriction. Link: https://lore.kernel.org/r/20190730163545.4915-14-logang@deltatee.com Link: https://lore.kernel.org/r/20190812173048.9186-14-logang@deltatee.com Signed-off-by: Logan Gunthorpe Signed-off-by: Bjorn Helgaas Reviewed-by: Christoph Hellwig --- drivers/pci/p2pdma.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index bca1ffc7075e..d8c824097d26 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -18,7 +18,6 @@ #include #include #include -#include #include enum pci_p2pdma_map_type { @@ -328,9 +327,6 @@ static bool host_bridge_whitelist(struct pci_dev *a, struct pci_dev *b) struct pci_host_bridge *host_a = pci_find_host_bridge(a->bus); struct pci_host_bridge *host_b = pci_find_host_bridge(b->bus); - if (iommu_present(a->dev.bus) || iommu_present(b->dev.bus)) - return false; - if (host_a == host_b) return __host_bridge_whitelist(host_a, true); From 27235b15e4197b3a1014cf0ca0b08dbbf61a692b Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Mon, 12 Aug 2019 11:30:48 -0600 Subject: [PATCH 14/14] PCI/P2PDMA: Update pci_p2pdma_distance_many() documentation The comment describing pci_p2pdma_distance_many() still referred to the devices being behind the same root port. This no longer applies so reword the documentation. Link: https://lore.kernel.org/r/20190730163545.4915-15-logang@deltatee.com Link: https://lore.kernel.org/r/20190812173048.9186-15-logang@deltatee.com Signed-off-by: Logan Gunthorpe Signed-off-by: Bjorn Helgaas Reviewed-by: Christoph Hellwig --- drivers/pci/p2pdma.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index d8c824097d26..0608aae72ccc 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -517,15 +517,14 @@ upstream_bridge_distance_warn(struct pci_dev *provider, struct pci_dev *client, * @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 (behind the same - * root port as the provider), 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). + * 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). * - * 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. + * "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)