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From: Logan Gunthorpe <logang@deltatee.com>
To: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
	linux-nvme@lists.infradead.org, linux-rdma@vger.kernel.org
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	Christoph Hellwig <hch@lst.de>,
	Christian Koenig <Christian.Koenig@amd.com>,
	Jason Gunthorpe <jgg@mellanox.com>,
	Sagi Grimberg <sagi@grimberg.me>, Keith Busch <kbusch@kernel.org>,
	Jens Axboe <axboe@fb.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Eric Pilmore <epilmore@gigaio.com>,
	Stephen Bates <sbates@raithlin.com>,
	Logan Gunthorpe <logang@deltatee.com>
Subject: [PATCH v3 07/14] PCI/P2PDMA: Whitelist some Intel host bridges
Date: Mon, 12 Aug 2019 11:30:41 -0600
Message-ID: <20190812173048.9186-8-logang@deltatee.com> (raw)
In-Reply-To: <20190812173048.9186-1-logang@deltatee.com>

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
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
 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;
-- 
2.20.1


  parent reply index

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-12 17:30 [PATCH v3 00/14] PCI/P2PDMA: Support transactions that hit the host bridge Logan Gunthorpe
2019-08-12 17:30 ` [PATCH v3 01/14] PCI/P2PDMA: Introduce private pagemap structure Logan Gunthorpe
2019-08-16  8:06   ` Christoph Hellwig
2019-08-12 17:30 ` [PATCH v3 02/14] PCI/P2PDMA: Add provider's pci_dev to pci_p2pdma_pagemap struct Logan Gunthorpe
2019-08-16  8:06   ` Christoph Hellwig
2019-08-12 17:30 ` [PATCH v3 03/14] PCI/P2PDMA: Add constants for map type results to upstream_bridge_distance() Logan Gunthorpe
2019-08-16  8:08   ` Christoph Hellwig
2019-08-12 17:30 ` [PATCH v3 04/14] PCI/P2PDMA: Factor out __upstream_bridge_distance() Logan Gunthorpe
2019-08-16  8:08   ` Christoph Hellwig
2019-08-12 17:30 ` [PATCH v3 05/14] PCI/P2PDMA: Apply host bridge whitelist for ACS Logan Gunthorpe
2019-08-16  8:09   ` Christoph Hellwig
2019-08-12 17:30 ` [PATCH v3 06/14] PCI/P2PDMA: Factor out host_bridge_whitelist() Logan Gunthorpe
2019-08-16  8:09   ` Christoph Hellwig
2019-08-12 17:30 ` Logan Gunthorpe [this message]
2019-08-16  8:11   ` [PATCH v3 07/14] PCI/P2PDMA: Whitelist some Intel host bridges Christoph Hellwig
2019-08-12 17:30 ` [PATCH v3 08/14] PCI/P2PDMA: Add attrs argument to pci_p2pdma_map_sg() Logan Gunthorpe
2019-08-16  8:12   ` Christoph Hellwig
2019-08-12 17:30 ` [PATCH v3 09/14] PCI/P2PDMA: Introduce pci_p2pdma_unmap_sg() Logan Gunthorpe
2019-08-16  8:13   ` Christoph Hellwig
2019-08-12 17:30 ` [PATCH v3 10/14] PCI/P2PDMA: Factor out __pci_p2pdma_map_sg() Logan Gunthorpe
2019-08-16  8:14   ` Christoph Hellwig
2019-08-12 17:30 ` [PATCH v3 11/14] PCI/P2PDMA: Store mapping method in an xarray Logan Gunthorpe
2019-08-16  8:14   ` Christoph Hellwig
2019-08-12 17:30 ` [PATCH v3 12/14] PCI/P2PDMA: dma_map() requests that traverse the host bridge Logan Gunthorpe
2019-08-16  8:15   ` Christoph Hellwig
2019-08-12 17:30 ` [PATCH v3 13/14] PCI/P2PDMA: Allow IOMMU for host bridge whitelist Logan Gunthorpe
2019-08-16  8:16   ` Christoph Hellwig
2019-08-12 17:30 ` [PATCH v3 14/14] PCI/P2PDMA: Update pci_p2pdma_distance_many() documentation Logan Gunthorpe
2019-08-16  8:16   ` Christoph Hellwig
2019-08-16 13:45 ` [PATCH v3 00/14] PCI/P2PDMA: Support transactions that hit the host bridge Bjorn Helgaas

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