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* [PATCH v5 00/10]  Support using MSI interrupts in ntb_transport
@ 2019-05-23 22:30 Logan Gunthorpe
  2019-05-23 22:30 ` [PATCH v5 01/10] PCI/MSI: Support allocating virtual MSI interrupts Logan Gunthorpe
                   ` (10 more replies)
  0 siblings, 11 replies; 13+ messages in thread
From: Logan Gunthorpe @ 2019-05-23 22:30 UTC (permalink / raw)
  To: linux-kernel, linux-ntb, linux-pci, iommu, linux-kselftest,
	Jon Mason, Joerg Roedel
  Cc: Allen Hubbe, Dave Jiang, Serge Semin, Eric Pilmore,
	Bjorn Helgaas, Logan Gunthorpe

This is another resend as there has been no feedback since v4.
Seems Jon has been MIA this past cycle so hopefully he appears on the
list soon.

I've addressed the feedback so far and rebased on the latest kernel
and would like this to be considered for merging this cycle.

The only outstanding issue I know of is that it still will not work
with IDT hardware, but ntb_transport doesn't work with IDT hardware
and there is still no sensible common infrastructure to support
ntb_peer_mw_set_trans(). Thus, I decline to consider that complication
in this patchset. However, I'll be happy to review work that adds this
feature in the future.

Also, as the port number and resource index stuff is a bit complicated,
I made a quick out of tree test fixture to ensure it's correct[1]. As
an excerise I also wrote some test code[2] using the upcomming KUnit
feature.

Logan

[1] https://repl.it/repls/ExcitingPresentFile
[2] https://github.com/sbates130272/linux-p2pmem/commits/ntb_kunit

--

Changes in v5:

* Rebased onto v5.2-rc1 (plus the patches in ntb-next)

--

Changes in v4:

* Rebased onto v5.1-rc6 (No changes)

* Numerous grammar and spelling mistakes spotted by Bjorn

--

Changes in v3:

* Rebased onto v5.1-rc1 (Dropped the first two patches as they have
  been merged, and cleaned up some minor conflicts in the PCI tree)

* Added a new patch (#3) to calculate logical port numbers that
  are port numbers from 0 to (number of ports - 1). This is
  then used in ntb_peer_resource_idx() to fix the issues brought
  up by Serge.

* Fixed missing __iomem and iowrite calls (as noticed by Serge)

* Added patch 10 which describes ntb_msi_test in the documentation
  file (as requested by Serge)

* A couple other minor nits and documentation fixes

--

Changes in v2:

* Cleaned up the changes in intel_irq_remapping.c to make them
  less confusing and add a comment. (Per discussion with Jacob and
  Joerg)

* Fixed a nit from Bjorn and collected his Ack

* Added a Kconfig dependancy on CONFIG_PCI_MSI for CONFIG_NTB_MSI
  as the Kbuild robot hit a random config that didn't build
  without it.

* Worked in a callback for when the MSI descriptor changes so that
  the clients can resend the new address and data values to the peer.
  On my test system this was never necessary, but there may be
  other platforms where this can occur. I tested this by hacking
  in a path to rewrite the MSI descriptor when I change the cpu
  affinity of an IRQ. There's a bit of uncertainty over the latency
  of the change, but without hardware this can acctually occur on
  we can't test this. This was the result of a discussion with Dave.

--

This patch series adds optional support for using MSI interrupts instead
of NTB doorbells in ntb_transport. This is desirable seeing doorbells on
current hardware are quite slow and therefore switching to MSI interrupts
provides a significant performance gain. On switchtec hardware, a simple
apples-to-apples comparison shows ntb_netdev/iperf numbers going from
3.88Gb/s to 14.1Gb/s when switching to MSI interrupts.

To do this, a couple changes are required outside of the NTB tree:

1) The IOMMU must know to accept MSI requests from aliased bused numbers
seeing NTB hardware typically sends proxied request IDs through
additional requester IDs. The first patch in this series adds support
for the Intel IOMMU. A quirk to add these aliases for switchtec hardware
was already accepted. See commit ad281ecf1c7d ("PCI: Add DMA alias quirk
for Microsemi Switchtec NTB") for a description of NTB proxy IDs and why
this is necessary.

2) NTB transport (and other clients) may often need more MSI interrupts
than the NTB hardware actually advertises support for. However, seeing
these interrupts will not be triggered by the hardware but through an
NTB memory window, the hardware does not actually need support or need
to know about them. Therefore we add the concept of Virtual MSI
interrupts which are allocated just like any other MSI interrupt but
are not programmed into the hardware's MSI table. This is done in
Patch 2 and then made use of in Patch 3.

The remaining patches in this series add a library for dealing with MSI
interrupts, a test client and finally support in ntb_transport.

The series is based off of v5.1-rc6 plus the patches in ntb-next.
A git repo is available here:

https://github.com/sbates130272/linux-p2pmem/ ntb_transport_msi_v4

Thanks,

Logan

--

Logan Gunthorpe (10):
  PCI/MSI: Support allocating virtual MSI interrupts
  PCI/switchtec: Add module parameter to request more interrupts
  NTB: Introduce helper functions to calculate logical port number
  NTB: Introduce functions to calculate multi-port resource index
  NTB: Rename ntb.c to support multiple source files in the module
  NTB: Introduce MSI library
  NTB: Introduce NTB MSI Test Client
  NTB: Add ntb_msi_test support to ntb_test
  NTB: Add MSI interrupt support to ntb_transport
  NTB: Describe the ntb_msi_test client in the documentation.

 Documentation/ntb.txt                   |  27 ++
 drivers/ntb/Kconfig                     |  11 +
 drivers/ntb/Makefile                    |   3 +
 drivers/ntb/{ntb.c => core.c}           |   0
 drivers/ntb/msi.c                       | 415 +++++++++++++++++++++++
 drivers/ntb/ntb_transport.c             | 169 ++++++++-
 drivers/ntb/test/Kconfig                |   9 +
 drivers/ntb/test/Makefile               |   1 +
 drivers/ntb/test/ntb_msi_test.c         | 433 ++++++++++++++++++++++++
 drivers/pci/msi.c                       |  54 ++-
 drivers/pci/switch/switchtec.c          |  12 +-
 include/linux/msi.h                     |   8 +
 include/linux/ntb.h                     | 196 ++++++++++-
 include/linux/pci.h                     |   9 +
 tools/testing/selftests/ntb/ntb_test.sh |  54 ++-
 15 files changed, 1386 insertions(+), 15 deletions(-)
 rename drivers/ntb/{ntb.c => core.c} (100%)
 create mode 100644 drivers/ntb/msi.c
 create mode 100644 drivers/ntb/test/ntb_msi_test.c

--
2.20.1
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 13+ messages in thread

* [PATCH v5 01/10] PCI/MSI: Support allocating virtual MSI interrupts
  2019-05-23 22:30 [PATCH v5 00/10] Support using MSI interrupts in ntb_transport Logan Gunthorpe
@ 2019-05-23 22:30 ` Logan Gunthorpe
  2019-05-23 22:30 ` [PATCH v5 02/10] PCI/switchtec: Add module parameter to request more interrupts Logan Gunthorpe
                   ` (9 subsequent siblings)
  10 siblings, 0 replies; 13+ messages in thread
From: Logan Gunthorpe @ 2019-05-23 22:30 UTC (permalink / raw)
  To: linux-kernel, linux-ntb, linux-pci, iommu, linux-kselftest,
	Jon Mason, Joerg Roedel
  Cc: Allen Hubbe, Dave Jiang, Serge Semin, Eric Pilmore,
	Bjorn Helgaas, Logan Gunthorpe

For NTB devices, we want to be able to trigger MSI interrupts
through a memory window. In these cases we may want to use
more interrupts than the NTB PCI device has available in its MSI-X
table.

We allow for this by creating a new 'virtual' interrupt. These
interrupts are allocated as usual but are not programmed into the
MSI-X table (as there may not be space for them).

The MSI address and data will then handled through an NTB MSI library
introduced later in this series.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/pci/msi.c   | 54 +++++++++++++++++++++++++++++++++++++--------
 include/linux/msi.h |  8 +++++++
 include/linux/pci.h |  9 ++++++++
 3 files changed, 62 insertions(+), 9 deletions(-)

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 73986825d221..668bc16ef4d1 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -192,6 +192,9 @@ static void msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
 
 static void __iomem *pci_msix_desc_addr(struct msi_desc *desc)
 {
+	if (desc->msi_attrib.is_virtual)
+		return NULL;
+
 	return desc->mask_base +
 		desc->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE;
 }
@@ -206,14 +209,19 @@ static void __iomem *pci_msix_desc_addr(struct msi_desc *desc)
 u32 __pci_msix_desc_mask_irq(struct msi_desc *desc, u32 flag)
 {
 	u32 mask_bits = desc->masked;
+	void __iomem *desc_addr;
 
 	if (pci_msi_ignore_mask)
 		return 0;
+	desc_addr = pci_msix_desc_addr(desc);
+	if (!desc_addr)
+		return 0;
 
 	mask_bits &= ~PCI_MSIX_ENTRY_CTRL_MASKBIT;
 	if (flag)
 		mask_bits |= PCI_MSIX_ENTRY_CTRL_MASKBIT;
-	writel(mask_bits, pci_msix_desc_addr(desc) + PCI_MSIX_ENTRY_VECTOR_CTRL);
+
+	writel(mask_bits, desc_addr + PCI_MSIX_ENTRY_VECTOR_CTRL);
 
 	return mask_bits;
 }
@@ -273,6 +281,11 @@ void __pci_read_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
 	if (entry->msi_attrib.is_msix) {
 		void __iomem *base = pci_msix_desc_addr(entry);
 
+		if (!base) {
+			WARN_ON(1);
+			return;
+		}
+
 		msg->address_lo = readl(base + PCI_MSIX_ENTRY_LOWER_ADDR);
 		msg->address_hi = readl(base + PCI_MSIX_ENTRY_UPPER_ADDR);
 		msg->data = readl(base + PCI_MSIX_ENTRY_DATA);
@@ -303,6 +316,9 @@ void __pci_write_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
 	} else if (entry->msi_attrib.is_msix) {
 		void __iomem *base = pci_msix_desc_addr(entry);
 
+		if (!base)
+			goto skip;
+
 		writel(msg->address_lo, base + PCI_MSIX_ENTRY_LOWER_ADDR);
 		writel(msg->address_hi, base + PCI_MSIX_ENTRY_UPPER_ADDR);
 		writel(msg->data, base + PCI_MSIX_ENTRY_DATA);
@@ -327,7 +343,13 @@ void __pci_write_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
 					      msg->data);
 		}
 	}
+
+skip:
 	entry->msg = *msg;
+
+	if (entry->write_msi_msg)
+		entry->write_msi_msg(entry, entry->write_msi_msg_data);
+
 }
 
 void pci_write_msi_msg(unsigned int irq, struct msi_msg *msg)
@@ -550,6 +572,7 @@ msi_setup_entry(struct pci_dev *dev, int nvec, struct irq_affinity *affd)
 
 	entry->msi_attrib.is_msix	= 0;
 	entry->msi_attrib.is_64		= !!(control & PCI_MSI_FLAGS_64BIT);
+	entry->msi_attrib.is_virtual    = 0;
 	entry->msi_attrib.entry_nr	= 0;
 	entry->msi_attrib.maskbit	= !!(control & PCI_MSI_FLAGS_MASKBIT);
 	entry->msi_attrib.default_irq	= dev->irq;	/* Save IOAPIC IRQ */
@@ -674,6 +697,7 @@ static int msix_setup_entries(struct pci_dev *dev, void __iomem *base,
 	struct irq_affinity_desc *curmsk, *masks = NULL;
 	struct msi_desc *entry;
 	int ret, i;
+	int vec_count = pci_msix_vec_count(dev);
 
 	if (affd)
 		masks = irq_create_affinity_masks(nvec, affd);
@@ -696,6 +720,10 @@ static int msix_setup_entries(struct pci_dev *dev, void __iomem *base,
 			entry->msi_attrib.entry_nr = entries[i].entry;
 		else
 			entry->msi_attrib.entry_nr = i;
+
+		entry->msi_attrib.is_virtual =
+			entry->msi_attrib.entry_nr >= vec_count;
+
 		entry->msi_attrib.default_irq	= dev->irq;
 		entry->mask_base		= base;
 
@@ -714,12 +742,19 @@ static void msix_program_entries(struct pci_dev *dev,
 {
 	struct msi_desc *entry;
 	int i = 0;
+	void __iomem *desc_addr;
 
 	for_each_pci_msi_entry(entry, dev) {
 		if (entries)
 			entries[i++].vector = entry->irq;
-		entry->masked = readl(pci_msix_desc_addr(entry) +
-				PCI_MSIX_ENTRY_VECTOR_CTRL);
+
+		desc_addr = pci_msix_desc_addr(entry);
+		if (desc_addr)
+			entry->masked = readl(desc_addr +
+					      PCI_MSIX_ENTRY_VECTOR_CTRL);
+		else
+			entry->masked = 0;
+
 		msix_mask_irq(entry, 1);
 	}
 }
@@ -932,7 +967,7 @@ int pci_msix_vec_count(struct pci_dev *dev)
 EXPORT_SYMBOL(pci_msix_vec_count);
 
 static int __pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries,
-			     int nvec, struct irq_affinity *affd)
+			     int nvec, struct irq_affinity *affd, int flags)
 {
 	int nr_entries;
 	int i, j;
@@ -943,7 +978,7 @@ static int __pci_enable_msix(struct pci_dev *dev, struct msix_entry *entries,
 	nr_entries = pci_msix_vec_count(dev);
 	if (nr_entries < 0)
 		return nr_entries;
-	if (nvec > nr_entries)
+	if (nvec > nr_entries && !(flags & PCI_IRQ_VIRTUAL))
 		return nr_entries;
 
 	if (entries) {
@@ -1079,7 +1114,8 @@ EXPORT_SYMBOL(pci_enable_msi);
 
 static int __pci_enable_msix_range(struct pci_dev *dev,
 				   struct msix_entry *entries, int minvec,
-				   int maxvec, struct irq_affinity *affd)
+				   int maxvec, struct irq_affinity *affd,
+				   int flags)
 {
 	int rc, nvec = maxvec;
 
@@ -1096,7 +1132,7 @@ static int __pci_enable_msix_range(struct pci_dev *dev,
 				return -ENOSPC;
 		}
 
-		rc = __pci_enable_msix(dev, entries, nvec, affd);
+		rc = __pci_enable_msix(dev, entries, nvec, affd, flags);
 		if (rc == 0)
 			return nvec;
 
@@ -1127,7 +1163,7 @@ static int __pci_enable_msix_range(struct pci_dev *dev,
 int pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries,
 		int minvec, int maxvec)
 {
-	return __pci_enable_msix_range(dev, entries, minvec, maxvec, NULL);
+	return __pci_enable_msix_range(dev, entries, minvec, maxvec, NULL, 0);
 }
 EXPORT_SYMBOL(pci_enable_msix_range);
 
@@ -1167,7 +1203,7 @@ int pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs,
 
 	if (flags & PCI_IRQ_MSIX) {
 		msix_vecs = __pci_enable_msix_range(dev, NULL, min_vecs,
-						    max_vecs, affd);
+						    max_vecs, affd, flags);
 		if (msix_vecs > 0)
 			return msix_vecs;
 	}
diff --git a/include/linux/msi.h b/include/linux/msi.h
index 7e9b81c3b50d..c278ae8760df 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -56,6 +56,10 @@ struct fsl_mc_msi_desc {
  * @msg:	The last set MSI message cached for reuse
  * @affinity:	Optional pointer to a cpu affinity mask for this descriptor
  *
+ * @write_msi_msg:	Callback that may be called when the MSI message
+ *			address or data changes
+ * @write_msi_msg_data:	Data parameter for the callback.
+ *
  * @masked:	[PCI MSI/X] Mask bits
  * @is_msix:	[PCI MSI/X] True if MSI-X
  * @multiple:	[PCI MSI/X] log2 num of messages allocated
@@ -78,6 +82,9 @@ struct msi_desc {
 	struct msi_msg			msg;
 	struct irq_affinity_desc	*affinity;
 
+	void (*write_msi_msg)(struct msi_desc *entry, void *data);
+	void *write_msi_msg_data;
+
 	union {
 		/* PCI MSI/X specific data */
 		struct {
@@ -88,6 +95,7 @@ struct msi_desc {
 				u8	multi_cap	: 3;
 				u8	maskbit		: 1;
 				u8	is_64		: 1;
+				u8	is_virtual	: 1;
 				u16	entry_nr;
 				unsigned default_irq;
 			} msi_attrib;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 77448215ef5b..c482aaa8e970 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1355,6 +1355,15 @@ int pci_set_vga_state(struct pci_dev *pdev, bool decode,
 #define PCI_IRQ_MSI		(1 << 1) /* Allow MSI interrupts */
 #define PCI_IRQ_MSIX		(1 << 2) /* Allow MSI-X interrupts */
 #define PCI_IRQ_AFFINITY	(1 << 3) /* Auto-assign affinity */
+
+/*
+ * Virtual interrupts allow for more interrupts to be allocated
+ * than the device has interrupts for. These are not programmed
+ * into the device's MSI-X table and must be handled by some
+ * other driver means.
+ */
+#define PCI_IRQ_VIRTUAL		(1 << 4)
+
 #define PCI_IRQ_ALL_TYPES \
 	(PCI_IRQ_LEGACY | PCI_IRQ_MSI | PCI_IRQ_MSIX)
 
-- 
2.20.1

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 13+ messages in thread

* [PATCH v5 02/10] PCI/switchtec: Add module parameter to request more interrupts
  2019-05-23 22:30 [PATCH v5 00/10] Support using MSI interrupts in ntb_transport Logan Gunthorpe
  2019-05-23 22:30 ` [PATCH v5 01/10] PCI/MSI: Support allocating virtual MSI interrupts Logan Gunthorpe
@ 2019-05-23 22:30 ` Logan Gunthorpe
  2019-05-23 22:30 ` [PATCH v5 03/10] NTB: Introduce helper functions to calculate logical port number Logan Gunthorpe
                   ` (8 subsequent siblings)
  10 siblings, 0 replies; 13+ messages in thread
From: Logan Gunthorpe @ 2019-05-23 22:30 UTC (permalink / raw)
  To: linux-kernel, linux-ntb, linux-pci, iommu, linux-kselftest,
	Jon Mason, Joerg Roedel
  Cc: Allen Hubbe, Dave Jiang, Serge Semin, Eric Pilmore,
	Bjorn Helgaas, Logan Gunthorpe

Seeing the we want to use more interrupts in the NTB MSI code
we need to be able allocate more (sometimes virtual) interrupts
in the switchtec driver. Therefore add a module parameter to
request to allocate additional interrupts.

This puts virtually no limit on the number of MSI interrupts available
to NTB clients.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/pci/switch/switchtec.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c
index e22766c79fe9..8b1db78197d9 100644
--- a/drivers/pci/switch/switchtec.c
+++ b/drivers/pci/switch/switchtec.c
@@ -30,6 +30,10 @@ module_param(use_dma_mrpc, bool, 0644);
 MODULE_PARM_DESC(use_dma_mrpc,
 		 "Enable the use of the DMA MRPC feature");
 
+static int nirqs = 32;
+module_param(nirqs, int, 0644);
+MODULE_PARM_DESC(nirqs, "number of interrupts to allocate (more may be useful for NTB applications)");
+
 static dev_t switchtec_devt;
 static DEFINE_IDA(switchtec_minor_ida);
 
@@ -1247,8 +1251,12 @@ static int switchtec_init_isr(struct switchtec_dev *stdev)
 	int dma_mrpc_irq;
 	int rc;
 
-	nvecs = pci_alloc_irq_vectors(stdev->pdev, 1, 4,
-				      PCI_IRQ_MSIX | PCI_IRQ_MSI);
+	if (nirqs < 4)
+		nirqs = 4;
+
+	nvecs = pci_alloc_irq_vectors(stdev->pdev, 1, nirqs,
+				      PCI_IRQ_MSIX | PCI_IRQ_MSI |
+				      PCI_IRQ_VIRTUAL);
 	if (nvecs < 0)
 		return nvecs;
 
-- 
2.20.1

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 13+ messages in thread

* [PATCH v5 03/10] NTB: Introduce helper functions to calculate logical port number
  2019-05-23 22:30 [PATCH v5 00/10] Support using MSI interrupts in ntb_transport Logan Gunthorpe
  2019-05-23 22:30 ` [PATCH v5 01/10] PCI/MSI: Support allocating virtual MSI interrupts Logan Gunthorpe
  2019-05-23 22:30 ` [PATCH v5 02/10] PCI/switchtec: Add module parameter to request more interrupts Logan Gunthorpe
@ 2019-05-23 22:30 ` Logan Gunthorpe
  2019-05-23 22:30 ` [PATCH v5 04/10] NTB: Introduce functions to calculate multi-port resource index Logan Gunthorpe
                   ` (7 subsequent siblings)
  10 siblings, 0 replies; 13+ messages in thread
From: Logan Gunthorpe @ 2019-05-23 22:30 UTC (permalink / raw)
  To: linux-kernel, linux-ntb, linux-pci, iommu, linux-kselftest,
	Jon Mason, Joerg Roedel
  Cc: Allen Hubbe, Dave Jiang, Serge Semin, Eric Pilmore,
	Bjorn Helgaas, Logan Gunthorpe

This patch introduces the "Logical Port Number" which is similar to the
"Port Number" in that it enumerates the ports in the system.

The original (or Physical) "Port Number" can be any number used by the
hardware to uniquely identify a port in the system. The "Logical Port
Number" enumerates all ports in the system from 0 to the number of
ports minus one.

For example a system with 5 ports might have the following port numbers
which would be enumerated thusly:

Port Number:           1  2  5  7  116
Logical Port Number:   0  1  2  3  4

The logical port number is useful when calculating which resources
to use for which peers. So we thus define two helper functions:
ntb_logical_port_number() and ntb_peer_logical_port_number() which
provide the "Logical Port Number" for the local port and any peer
respectively.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Jon Mason <jdmason@kudzu.us>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Allen Hubbe <allenbh@gmail.com>
Cc: Serge Semin <fancer.lancer@gmail.com>
---
 include/linux/ntb.h | 53 ++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 52 insertions(+), 1 deletion(-)

diff --git a/include/linux/ntb.h b/include/linux/ntb.h
index 56a92e3ae3ae..91cf492b16a0 100644
--- a/include/linux/ntb.h
+++ b/include/linux/ntb.h
@@ -616,7 +616,6 @@ static inline int ntb_port_number(struct ntb_dev *ntb)
 
 	return ntb->ops->port_number(ntb);
 }
-
 /**
  * ntb_peer_port_count() - get the number of peer device ports
  * @ntb:	NTB device context.
@@ -653,6 +652,58 @@ static inline int ntb_peer_port_number(struct ntb_dev *ntb, int pidx)
 	return ntb->ops->peer_port_number(ntb, pidx);
 }
 
+/**
+ * ntb_logical_port_number() - get the logical port number of the local port
+ * @ntb:	NTB device context.
+ *
+ * The Logical Port Number is defined to be a unique number for each
+ * port starting from zero through to the number of ports minus one.
+ * This is in contrast to the Port Number where each port can be assigned
+ * any unique physical number by the hardware.
+ *
+ * The logical port number is useful for calculating the resource indexes
+ * used by peers.
+ *
+ * Return: the logical port number or negative value indicating an error
+ */
+static inline int ntb_logical_port_number(struct ntb_dev *ntb)
+{
+	int lport = ntb_port_number(ntb);
+	int pidx;
+
+	if (lport < 0)
+		return lport;
+
+	for (pidx = 0; pidx < ntb_peer_port_count(ntb); pidx++)
+		if (lport <= ntb_peer_port_number(ntb, pidx))
+			return pidx;
+
+	return pidx;
+}
+
+/**
+ * ntb_peer_logical_port_number() - get the logical peer port by given index
+ * @ntb:	NTB device context.
+ * @pidx:	Peer port index.
+ *
+ * The Logical Port Number is defined to be a unique number for each
+ * port starting from zero through to the number of ports minus one.
+ * This is in contrast to the Port Number where each port can be assigned
+ * any unique physical number by the hardware.
+ *
+ * The logical port number is useful for calculating the resource indexes
+ * used by peers.
+ *
+ * Return: the peer's logical port number or negative value indicating an error
+ */
+static inline int ntb_peer_logical_port_number(struct ntb_dev *ntb, int pidx)
+{
+	if (ntb_peer_port_number(ntb, pidx) < ntb_port_number(ntb))
+		return pidx;
+	else
+		return pidx + 1;
+}
+
 /**
  * ntb_peer_port_idx() - get the peer device port index by given port number
  * @ntb:	NTB device context.
-- 
2.20.1

_______________________________________________
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https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 13+ messages in thread

* [PATCH v5 04/10] NTB: Introduce functions to calculate multi-port resource index
  2019-05-23 22:30 [PATCH v5 00/10] Support using MSI interrupts in ntb_transport Logan Gunthorpe
                   ` (2 preceding siblings ...)
  2019-05-23 22:30 ` [PATCH v5 03/10] NTB: Introduce helper functions to calculate logical port number Logan Gunthorpe
@ 2019-05-23 22:30 ` Logan Gunthorpe
  2019-05-23 22:30 ` [PATCH v5 05/10] NTB: Rename ntb.c to support multiple source files in the module Logan Gunthorpe
                   ` (6 subsequent siblings)
  10 siblings, 0 replies; 13+ messages in thread
From: Logan Gunthorpe @ 2019-05-23 22:30 UTC (permalink / raw)
  To: linux-kernel, linux-ntb, linux-pci, iommu, linux-kselftest,
	Jon Mason, Joerg Roedel
  Cc: Allen Hubbe, Dave Jiang, Serge Semin, Eric Pilmore,
	Bjorn Helgaas, Logan Gunthorpe

When using multi-ports each port uses resources (dbs, msgs, mws, etc)
on every other port. Creating a mapping for these resources such that
each port has a corresponding resource on every other port is a bit
tricky.

Introduce the ntb_peer_resource_idx() function for this purpose.
It returns the peer resource number that will correspond with the
local peer index on the remote peer.

Also, introduce ntb_peer_highest_mw_idx() which will use
ntb_peer_resource_idx() but return the MW index starting with the
highest index and working down.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Jon Mason <jdmason@kudzu.us>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Allen Hubbe <allenbh@gmail.com>
---
 include/linux/ntb.h | 70 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)

diff --git a/include/linux/ntb.h b/include/linux/ntb.h
index 91cf492b16a0..66552830544b 100644
--- a/include/linux/ntb.h
+++ b/include/linux/ntb.h
@@ -1557,4 +1557,74 @@ static inline int ntb_peer_msg_write(struct ntb_dev *ntb, int pidx, int midx,
 	return ntb->ops->peer_msg_write(ntb, pidx, midx, msg);
 }
 
+/**
+ * ntb_peer_resource_idx() - get a resource index for a given peer idx
+ * @ntb:	NTB device context.
+ * @pidx:	Peer port index.
+ *
+ * When constructing a graph of peers, each remote peer must use a different
+ * resource index (mw, doorbell, etc) to communicate with each other
+ * peer.
+ *
+ * In a two peer system, this function should always return 0 such that
+ * resource 0 points to the remote peer on both ports.
+ *
+ * In a 5 peer system, this function will return the following matrix
+ *
+ * pidx \ port    0    1    2    3    4
+ * 0              0    0    1    2    3
+ * 1              0    1    1    2    3
+ * 2              0    1    2    2    3
+ * 3              0    1    2    3    3
+ *
+ * For example, if this function is used to program peer's memory
+ * windows, port 0 will program MW 0 on all it's peers to point to itself.
+ * port 1 will program MW 0 in port 0 to point to itself and MW 1 on all
+ * other ports. etc.
+ *
+ * For the legacy two host case, ntb_port_number() and ntb_peer_port_number()
+ * both return zero and therefore this function will always return zero.
+ * So MW 0 on each host would be programmed to point to the other host.
+ *
+ * Return: the resource index to use for that peer.
+ */
+static inline int ntb_peer_resource_idx(struct ntb_dev *ntb, int pidx)
+{
+	int local_port, peer_port;
+
+	if (pidx >= ntb_peer_port_count(ntb))
+		return -EINVAL;
+
+	local_port = ntb_logical_port_number(ntb);
+	peer_port = ntb_peer_logical_port_number(ntb, pidx);
+
+	if (peer_port < local_port)
+		return local_port - 1;
+	else
+		return local_port;
+}
+
+/**
+ * ntb_peer_highest_mw_idx() - get a memory window index for a given peer idx
+ *	using the highest index memory windows first
+ *
+ * @ntb:	NTB device context.
+ * @pidx:	Peer port index.
+ *
+ * Like ntb_peer_resource_idx(), except it returns indexes starting with
+ * last memory window index.
+ *
+ * Return: the resource index to use for that peer.
+ */
+static inline int ntb_peer_highest_mw_idx(struct ntb_dev *ntb, int pidx)
+{
+	int ret;
+
+	ret = ntb_peer_resource_idx(ntb, pidx);
+	if (ret < 0)
+		return ret;
+
+	return ntb_mw_count(ntb, pidx) - ret - 1;
+}
+
 #endif
-- 
2.20.1

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 13+ messages in thread

* [PATCH v5 05/10] NTB: Rename ntb.c to support multiple source files in the module
  2019-05-23 22:30 [PATCH v5 00/10] Support using MSI interrupts in ntb_transport Logan Gunthorpe
                   ` (3 preceding siblings ...)
  2019-05-23 22:30 ` [PATCH v5 04/10] NTB: Introduce functions to calculate multi-port resource index Logan Gunthorpe
@ 2019-05-23 22:30 ` Logan Gunthorpe
  2019-05-23 22:30 ` [PATCH v5 06/10] NTB: Introduce MSI library Logan Gunthorpe
                   ` (5 subsequent siblings)
  10 siblings, 0 replies; 13+ messages in thread
From: Logan Gunthorpe @ 2019-05-23 22:30 UTC (permalink / raw)
  To: linux-kernel, linux-ntb, linux-pci, iommu, linux-kselftest,
	Jon Mason, Joerg Roedel
  Cc: Allen Hubbe, Dave Jiang, Serge Semin, Eric Pilmore,
	Bjorn Helgaas, Logan Gunthorpe

The kbuild system does not support having multiple source files in
a module if one of those source files has the same name as the module.

Therefore, we must rename ntb.c to core.c, while the module remains
ntb.ko.

This is similar to the way the nvme modules are structured.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Jon Mason <jdmason@kudzu.us>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Allen Hubbe <allenbh@gmail.com>
---
 drivers/ntb/Makefile          | 2 ++
 drivers/ntb/{ntb.c => core.c} | 0
 2 files changed, 2 insertions(+)
 rename drivers/ntb/{ntb.c => core.c} (100%)

diff --git a/drivers/ntb/Makefile b/drivers/ntb/Makefile
index 1921dec1949d..537226f8e78d 100644
--- a/drivers/ntb/Makefile
+++ b/drivers/ntb/Makefile
@@ -1,2 +1,4 @@
 obj-$(CONFIG_NTB) += ntb.o hw/ test/
 obj-$(CONFIG_NTB_TRANSPORT) += ntb_transport.o
+
+ntb-y := core.o
diff --git a/drivers/ntb/ntb.c b/drivers/ntb/core.c
similarity index 100%
rename from drivers/ntb/ntb.c
rename to drivers/ntb/core.c
-- 
2.20.1

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 13+ messages in thread

* [PATCH v5 06/10] NTB: Introduce MSI library
  2019-05-23 22:30 [PATCH v5 00/10] Support using MSI interrupts in ntb_transport Logan Gunthorpe
                   ` (4 preceding siblings ...)
  2019-05-23 22:30 ` [PATCH v5 05/10] NTB: Rename ntb.c to support multiple source files in the module Logan Gunthorpe
@ 2019-05-23 22:30 ` Logan Gunthorpe
  2019-05-23 22:30 ` [PATCH v5 07/10] NTB: Introduce NTB MSI Test Client Logan Gunthorpe
                   ` (4 subsequent siblings)
  10 siblings, 0 replies; 13+ messages in thread
From: Logan Gunthorpe @ 2019-05-23 22:30 UTC (permalink / raw)
  To: linux-kernel, linux-ntb, linux-pci, iommu, linux-kselftest,
	Jon Mason, Joerg Roedel
  Cc: Allen Hubbe, Dave Jiang, Serge Semin, Eric Pilmore,
	Bjorn Helgaas, Logan Gunthorpe

The NTB MSI library allows passing MSI interrupts across a memory
window. This offers similar functionality to doorbells or messages
except will often have much better latency and the client can
potentially use significantly more remote interrupts than typical hardware
provides for doorbells. (Which can be important in high-multiport
setups.)

The library utilizes one memory window per peer and uses the highest
index memory windows. Before any ntb_msi function may be used, the user
must call ntb_msi_init(). It may then setup and tear down the memory
windows when the link state changes using ntb_msi_setup_mws() and
ntb_msi_clear_mws().

The peer which receives the interrupt must call ntb_msim_request_irq()
to assign the interrupt handler (this function is functionally
similar to devm_request_irq()) and the returned descriptor must be
transferred to the peer which can use it to trigger the interrupt.
The triggering peer, once having received the descriptor, can
trigger the interrupt by calling ntb_msi_peer_trigger().

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Jon Mason <jdmason@kudzu.us>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Allen Hubbe <allenbh@gmail.com>
---
 drivers/ntb/Kconfig  |  11 ++
 drivers/ntb/Makefile |   3 +-
 drivers/ntb/msi.c    | 415 +++++++++++++++++++++++++++++++++++++++++++
 include/linux/ntb.h  |  73 ++++++++
 4 files changed, 501 insertions(+), 1 deletion(-)
 create mode 100644 drivers/ntb/msi.c

diff --git a/drivers/ntb/Kconfig b/drivers/ntb/Kconfig
index 95944e52fa36..5760764052be 100644
--- a/drivers/ntb/Kconfig
+++ b/drivers/ntb/Kconfig
@@ -12,6 +12,17 @@ menuconfig NTB
 
 if NTB
 
+config NTB_MSI
+	bool "MSI Interrupt Support"
+	depends on PCI_MSI
+	help
+	 Support using MSI interrupt forwarding instead of (or in addition to)
+	 hardware doorbells. MSI interrupts typically offer lower latency
+	 than doorbells and more MSI interrupts can be made available to
+	 clients. However this requires an extra memory window and support
+	 in the hardware driver for creating the MSI interrupts.
+
+	 If unsure, say N.
 source "drivers/ntb/hw/Kconfig"
 
 source "drivers/ntb/test/Kconfig"
diff --git a/drivers/ntb/Makefile b/drivers/ntb/Makefile
index 537226f8e78d..cc27ad2ef150 100644
--- a/drivers/ntb/Makefile
+++ b/drivers/ntb/Makefile
@@ -1,4 +1,5 @@
 obj-$(CONFIG_NTB) += ntb.o hw/ test/
 obj-$(CONFIG_NTB_TRANSPORT) += ntb_transport.o
 
-ntb-y := core.o
+ntb-y			:= core.o
+ntb-$(CONFIG_NTB_MSI)	+= msi.o
diff --git a/drivers/ntb/msi.c b/drivers/ntb/msi.c
new file mode 100644
index 000000000000..9dddf133658f
--- /dev/null
+++ b/drivers/ntb/msi.c
@@ -0,0 +1,415 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/ntb.h>
+#include <linux/msi.h>
+#include <linux/pci.h>
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_VERSION("0.1");
+MODULE_AUTHOR("Logan Gunthorpe <logang@deltatee.com>");
+MODULE_DESCRIPTION("NTB MSI Interrupt Library");
+
+struct ntb_msi {
+	u64 base_addr;
+	u64 end_addr;
+
+	void (*desc_changed)(void *ctx);
+
+	u32 __iomem *peer_mws[];
+};
+
+/**
+ * ntb_msi_init() - Initialize the MSI context
+ * @ntb:	NTB device context
+ *
+ * This function must be called before any other ntb_msi function.
+ * It initializes the context for MSI operations and maps
+ * the peer memory windows.
+ *
+ * This function reserves the last N outbound memory windows (where N
+ * is the number of peers).
+ *
+ * Return: Zero on success, otherwise a negative error number.
+ */
+int ntb_msi_init(struct ntb_dev *ntb,
+		 void (*desc_changed)(void *ctx))
+{
+	phys_addr_t mw_phys_addr;
+	resource_size_t mw_size;
+	size_t struct_size;
+	int peer_widx;
+	int peers;
+	int ret;
+	int i;
+
+	peers = ntb_peer_port_count(ntb);
+	if (peers <= 0)
+		return -EINVAL;
+
+	struct_size = sizeof(*ntb->msi) + sizeof(*ntb->msi->peer_mws) * peers;
+
+	ntb->msi = devm_kzalloc(&ntb->dev, struct_size, GFP_KERNEL);
+	if (!ntb->msi)
+		return -ENOMEM;
+
+	ntb->msi->desc_changed = desc_changed;
+
+	for (i = 0; i < peers; i++) {
+		peer_widx = ntb_peer_mw_count(ntb) - 1 - i;
+
+		ret = ntb_peer_mw_get_addr(ntb, peer_widx, &mw_phys_addr,
+					   &mw_size);
+		if (ret)
+			goto unroll;
+
+		ntb->msi->peer_mws[i] = devm_ioremap(&ntb->dev, mw_phys_addr,
+						     mw_size);
+		if (!ntb->msi->peer_mws[i]) {
+			ret = -EFAULT;
+			goto unroll;
+		}
+	}
+
+	return 0;
+
+unroll:
+	for (i = 0; i < peers; i++)
+		if (ntb->msi->peer_mws[i])
+			devm_iounmap(&ntb->dev, ntb->msi->peer_mws[i]);
+
+	devm_kfree(&ntb->dev, ntb->msi);
+	ntb->msi = NULL;
+	return ret;
+}
+EXPORT_SYMBOL(ntb_msi_init);
+
+/**
+ * ntb_msi_setup_mws() - Initialize the MSI inbound memory windows
+ * @ntb:	NTB device context
+ *
+ * This function sets up the required inbound memory windows. It should be
+ * called from a work function after a link up event.
+ *
+ * Over the entire network, this function will reserves the last N
+ * inbound memory windows for each peer (where N is the number of peers).
+ *
+ * ntb_msi_init() must be called before this function.
+ *
+ * Return: Zero on success, otherwise a negative error number.
+ */
+int ntb_msi_setup_mws(struct ntb_dev *ntb)
+{
+	struct msi_desc *desc;
+	u64 addr;
+	int peer, peer_widx;
+	resource_size_t addr_align, size_align, size_max;
+	resource_size_t mw_size = SZ_32K;
+	resource_size_t mw_min_size = mw_size;
+	int i;
+	int ret;
+
+	if (!ntb->msi)
+		return -EINVAL;
+
+	desc = first_msi_entry(&ntb->pdev->dev);
+	addr = desc->msg.address_lo + ((uint64_t)desc->msg.address_hi << 32);
+
+	for (peer = 0; peer < ntb_peer_port_count(ntb); peer++) {
+		peer_widx = ntb_peer_highest_mw_idx(ntb, peer);
+		if (peer_widx < 0)
+			return peer_widx;
+
+		ret = ntb_mw_get_align(ntb, peer, peer_widx, &addr_align,
+				       NULL, NULL);
+		if (ret)
+			return ret;
+
+		addr &= ~(addr_align - 1);
+	}
+
+	for (peer = 0; peer < ntb_peer_port_count(ntb); peer++) {
+		peer_widx = ntb_peer_highest_mw_idx(ntb, peer);
+		if (peer_widx < 0) {
+			ret = peer_widx;
+			goto error_out;
+		}
+
+		ret = ntb_mw_get_align(ntb, peer, peer_widx, NULL,
+				       &size_align, &size_max);
+		if (ret)
+			goto error_out;
+
+		mw_size = round_up(mw_size, size_align);
+		mw_size = max(mw_size, size_max);
+		if (mw_size < mw_min_size)
+			mw_min_size = mw_size;
+
+		ret = ntb_mw_set_trans(ntb, peer, peer_widx,
+				       addr, mw_size);
+		if (ret)
+			goto error_out;
+	}
+
+	ntb->msi->base_addr = addr;
+	ntb->msi->end_addr = addr + mw_min_size;
+
+	return 0;
+
+error_out:
+	for (i = 0; i < peer; i++) {
+		peer_widx = ntb_peer_highest_mw_idx(ntb, peer);
+		if (peer_widx < 0)
+			continue;
+
+		ntb_mw_clear_trans(ntb, i, peer_widx);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(ntb_msi_setup_mws);
+
+/**
+ * ntb_msi_clear_mws() - Clear all inbound memory windows
+ * @ntb:	NTB device context
+ *
+ * This function tears down the resources used by ntb_msi_setup_mws().
+ */
+void ntb_msi_clear_mws(struct ntb_dev *ntb)
+{
+	int peer;
+	int peer_widx;
+
+	for (peer = 0; peer < ntb_peer_port_count(ntb); peer++) {
+		peer_widx = ntb_peer_highest_mw_idx(ntb, peer);
+		if (peer_widx < 0)
+			continue;
+
+		ntb_mw_clear_trans(ntb, peer, peer_widx);
+	}
+}
+EXPORT_SYMBOL(ntb_msi_clear_mws);
+
+struct ntb_msi_devres {
+	struct ntb_dev *ntb;
+	struct msi_desc *entry;
+	struct ntb_msi_desc *msi_desc;
+};
+
+static int ntb_msi_set_desc(struct ntb_dev *ntb, struct msi_desc *entry,
+			    struct ntb_msi_desc *msi_desc)
+{
+	u64 addr;
+
+	addr = entry->msg.address_lo +
+		((uint64_t)entry->msg.address_hi << 32);
+
+	if (addr < ntb->msi->base_addr || addr >= ntb->msi->end_addr) {
+		dev_warn_once(&ntb->dev,
+			      "IRQ %d: MSI Address not within the memory window (%llx, [%llx %llx])\n",
+			      entry->irq, addr, ntb->msi->base_addr,
+			      ntb->msi->end_addr);
+		return -EFAULT;
+	}
+
+	msi_desc->addr_offset = addr - ntb->msi->base_addr;
+	msi_desc->data = entry->msg.data;
+
+	return 0;
+}
+
+static void ntb_msi_write_msg(struct msi_desc *entry, void *data)
+{
+	struct ntb_msi_devres *dr = data;
+
+	WARN_ON(ntb_msi_set_desc(dr->ntb, entry, dr->msi_desc));
+
+	if (dr->ntb->msi->desc_changed)
+		dr->ntb->msi->desc_changed(dr->ntb->ctx);
+}
+
+static void ntbm_msi_callback_release(struct device *dev, void *res)
+{
+	struct ntb_msi_devres *dr = res;
+
+	dr->entry->write_msi_msg = NULL;
+	dr->entry->write_msi_msg_data = NULL;
+}
+
+static int ntbm_msi_setup_callback(struct ntb_dev *ntb, struct msi_desc *entry,
+				   struct ntb_msi_desc *msi_desc)
+{
+	struct ntb_msi_devres *dr;
+
+	dr = devres_alloc(ntbm_msi_callback_release,
+			  sizeof(struct ntb_msi_devres), GFP_KERNEL);
+	if (!dr)
+		return -ENOMEM;
+
+	dr->ntb = ntb;
+	dr->entry = entry;
+	dr->msi_desc = msi_desc;
+
+	devres_add(&ntb->dev, dr);
+
+	dr->entry->write_msi_msg = ntb_msi_write_msg;
+	dr->entry->write_msi_msg_data = dr;
+
+	return 0;
+}
+
+/**
+ * ntbm_msi_request_threaded_irq() - allocate an MSI interrupt
+ * @ntb:	NTB device context
+ * @handler:	Function to be called when the IRQ occurs
+ * @thread_fn:  Function to be called in a threaded interrupt context. NULL
+ *              for clients which handle everything in @handler
+ * @devname:    An ascii name for the claiming device, dev_name(dev) if NULL
+ * @dev_id:     A cookie passed back to the handler function
+ *
+ * This function assigns an interrupt handler to an unused
+ * MSI interrupt and returns the descriptor used to trigger
+ * it. The descriptor can then be sent to a peer to trigger
+ * the interrupt.
+ *
+ * The interrupt resource is managed with devres so it will
+ * be automatically freed when the NTB device is torn down.
+ *
+ * If an IRQ allocated with this function needs to be freed
+ * separately, ntbm_free_irq() must be used.
+ *
+ * Return: IRQ number assigned on success, otherwise a negative error number.
+ */
+int ntbm_msi_request_threaded_irq(struct ntb_dev *ntb, irq_handler_t handler,
+				  irq_handler_t thread_fn,
+				  const char *name, void *dev_id,
+				  struct ntb_msi_desc *msi_desc)
+{
+	struct msi_desc *entry;
+	struct irq_desc *desc;
+	int ret;
+
+	if (!ntb->msi)
+		return -EINVAL;
+
+	for_each_pci_msi_entry(entry, ntb->pdev) {
+		desc = irq_to_desc(entry->irq);
+		if (desc->action)
+			continue;
+
+		ret = devm_request_threaded_irq(&ntb->dev, entry->irq, handler,
+						thread_fn, 0, name, dev_id);
+		if (ret)
+			continue;
+
+		if (ntb_msi_set_desc(ntb, entry, msi_desc)) {
+			devm_free_irq(&ntb->dev, entry->irq, dev_id);
+			continue;
+		}
+
+		ret = ntbm_msi_setup_callback(ntb, entry, msi_desc);
+		if (ret) {
+			devm_free_irq(&ntb->dev, entry->irq, dev_id);
+			return ret;
+		}
+
+
+		return entry->irq;
+	}
+
+	return -ENODEV;
+}
+EXPORT_SYMBOL(ntbm_msi_request_threaded_irq);
+
+static int ntbm_msi_callback_match(struct device *dev, void *res, void *data)
+{
+	struct ntb_dev *ntb = dev_ntb(dev);
+	struct ntb_msi_devres *dr = res;
+
+	return dr->ntb == ntb && dr->entry == data;
+}
+
+/**
+ * ntbm_msi_free_irq() - free an interrupt
+ * @ntb:	NTB device context
+ * @irq:	Interrupt line to free
+ * @dev_id:	Device identity to free
+ *
+ * This function should be used to manually free IRQs allocated with
+ * ntbm_request_[threaded_]irq().
+ */
+void ntbm_msi_free_irq(struct ntb_dev *ntb, unsigned int irq, void *dev_id)
+{
+	struct msi_desc *entry = irq_get_msi_desc(irq);
+
+	entry->write_msi_msg = NULL;
+	entry->write_msi_msg_data = NULL;
+
+	WARN_ON(devres_destroy(&ntb->dev, ntbm_msi_callback_release,
+			       ntbm_msi_callback_match, entry));
+
+	devm_free_irq(&ntb->dev, irq, dev_id);
+}
+EXPORT_SYMBOL(ntbm_msi_free_irq);
+
+/**
+ * ntb_msi_peer_trigger() - Trigger an interrupt handler on a peer
+ * @ntb:	NTB device context
+ * @peer:	Peer index
+ * @desc:	MSI descriptor data which triggers the interrupt
+ *
+ * This function triggers an interrupt on a peer. It requires
+ * the descriptor structure to have been passed from that peer
+ * by some other means.
+ *
+ * Return: Zero on success, otherwise a negative error number.
+ */
+int ntb_msi_peer_trigger(struct ntb_dev *ntb, int peer,
+			 struct ntb_msi_desc *desc)
+{
+	int idx;
+
+	if (!ntb->msi)
+		return -EINVAL;
+
+	idx = desc->addr_offset / sizeof(*ntb->msi->peer_mws[peer]);
+
+	iowrite32(desc->data, &ntb->msi->peer_mws[peer][idx]);
+
+	return 0;
+}
+EXPORT_SYMBOL(ntb_msi_peer_trigger);
+
+/**
+ * ntb_msi_peer_addr() - Get the DMA address to trigger a peer's MSI interrupt
+ * @ntb:	NTB device context
+ * @peer:	Peer index
+ * @desc:	MSI descriptor data which triggers the interrupt
+ * @msi_addr:   Physical address to trigger the interrupt
+ *
+ * This function allows using DMA engines to trigger an interrupt
+ * (for example, trigger an interrupt to process the data after
+ * sending it). To trigger the interrupt, write @desc.data to the address
+ * returned in @msi_addr
+ *
+ * Return: Zero on success, otherwise a negative error number.
+ */
+int ntb_msi_peer_addr(struct ntb_dev *ntb, int peer,
+		      struct ntb_msi_desc *desc,
+		      phys_addr_t *msi_addr)
+{
+	int peer_widx = ntb_peer_mw_count(ntb) - 1 - peer;
+	phys_addr_t mw_phys_addr;
+	int ret;
+
+	ret = ntb_peer_mw_get_addr(ntb, peer_widx, &mw_phys_addr, NULL);
+	if (ret)
+		return ret;
+
+	if (msi_addr)
+		*msi_addr = mw_phys_addr + desc->addr_offset;
+
+	return 0;
+}
+EXPORT_SYMBOL(ntb_msi_peer_addr);
diff --git a/include/linux/ntb.h b/include/linux/ntb.h
index 66552830544b..2abf30caf4a7 100644
--- a/include/linux/ntb.h
+++ b/include/linux/ntb.h
@@ -58,9 +58,11 @@
 
 #include <linux/completion.h>
 #include <linux/device.h>
+#include <linux/interrupt.h>
 
 struct ntb_client;
 struct ntb_dev;
+struct ntb_msi;
 struct pci_dev;
 
 /**
@@ -426,6 +428,10 @@ struct ntb_dev {
 	spinlock_t			ctx_lock;
 	/* block unregister until device is fully released */
 	struct completion		released;
+
+#ifdef CONFIG_NTB_MSI
+	struct ntb_msi *msi;
+#endif
 };
 #define dev_ntb(__dev) container_of((__dev), struct ntb_dev, dev)
 
@@ -1627,4 +1633,71 @@ static inline int ntb_peer_highest_mw_idx(struct ntb_dev *ntb, int pidx)
 	return ntb_mw_count(ntb, pidx) - ret - 1;
 }
 
+struct ntb_msi_desc {
+	u32 addr_offset;
+	u32 data;
+};
+
+#ifdef CONFIG_NTB_MSI
+
+int ntb_msi_init(struct ntb_dev *ntb, void (*desc_changed)(void *ctx));
+int ntb_msi_setup_mws(struct ntb_dev *ntb);
+void ntb_msi_clear_mws(struct ntb_dev *ntb);
+int ntbm_msi_request_threaded_irq(struct ntb_dev *ntb, irq_handler_t handler,
+				  irq_handler_t thread_fn,
+				  const char *name, void *dev_id,
+				  struct ntb_msi_desc *msi_desc);
+void ntbm_msi_free_irq(struct ntb_dev *ntb, unsigned int irq, void *dev_id);
+int ntb_msi_peer_trigger(struct ntb_dev *ntb, int peer,
+			 struct ntb_msi_desc *desc);
+int ntb_msi_peer_addr(struct ntb_dev *ntb, int peer,
+		      struct ntb_msi_desc *desc,
+		      phys_addr_t *msi_addr);
+
+#else /* not CONFIG_NTB_MSI */
+
+static inline int ntb_msi_init(struct ntb_dev *ntb,
+			       void (*desc_changed)(void *ctx))
+{
+	return -EOPNOTSUPP;
+}
+static inline int ntb_msi_setup_mws(struct ntb_dev *ntb)
+{
+	return -EOPNOTSUPP;
+}
+static inline void ntb_msi_clear_mws(struct ntb_dev *ntb) {}
+static inline int ntbm_msi_request_threaded_irq(struct ntb_dev *ntb,
+						irq_handler_t handler,
+						irq_handler_t thread_fn,
+						const char *name, void *dev_id,
+						struct ntb_msi_desc *msi_desc)
+{
+	return -EOPNOTSUPP;
+}
+static inline void ntbm_msi_free_irq(struct ntb_dev *ntb, unsigned int irq,
+				     void *dev_id) {}
+static inline int ntb_msi_peer_trigger(struct ntb_dev *ntb, int peer,
+				       struct ntb_msi_desc *desc)
+{
+	return -EOPNOTSUPP;
+}
+static inline int ntb_msi_peer_addr(struct ntb_dev *ntb, int peer,
+				    struct ntb_msi_desc *desc,
+				    phys_addr_t *msi_addr)
+{
+	return -EOPNOTSUPP;
+
+}
+
+#endif /* CONFIG_NTB_MSI */
+
+static inline int ntbm_msi_request_irq(struct ntb_dev *ntb,
+				       irq_handler_t handler,
+				       const char *name, void *dev_id,
+				       struct ntb_msi_desc *msi_desc)
+{
+	return ntbm_msi_request_threaded_irq(ntb, handler, NULL, name,
+					     dev_id, msi_desc);
+}
+
 #endif
-- 
2.20.1

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^ permalink raw reply	[flat|nested] 13+ messages in thread

* [PATCH v5 07/10] NTB: Introduce NTB MSI Test Client
  2019-05-23 22:30 [PATCH v5 00/10] Support using MSI interrupts in ntb_transport Logan Gunthorpe
                   ` (5 preceding siblings ...)
  2019-05-23 22:30 ` [PATCH v5 06/10] NTB: Introduce MSI library Logan Gunthorpe
@ 2019-05-23 22:30 ` Logan Gunthorpe
  2019-05-23 22:30 ` [PATCH v5 08/10] NTB: Add ntb_msi_test support to ntb_test Logan Gunthorpe
                   ` (3 subsequent siblings)
  10 siblings, 0 replies; 13+ messages in thread
From: Logan Gunthorpe @ 2019-05-23 22:30 UTC (permalink / raw)
  To: linux-kernel, linux-ntb, linux-pci, iommu, linux-kselftest,
	Jon Mason, Joerg Roedel
  Cc: Allen Hubbe, Dave Jiang, Serge Semin, Eric Pilmore,
	Bjorn Helgaas, Logan Gunthorpe

Introduce a tool to test NTB MSI interrupts similar to the other
NTB test tools. This tool creates a debugfs directory for each
NTB device with the following files:

port
irqX_occurrences
peerX/port
peerX/count
peerX/trigger

The 'port' file tells the user the local port number and the
'occurrences' files tell the number of local interrupts that
have been received for each interrupt.

For each peer, the 'port' file and the 'count' file tell you the
peer's port number and number of interrupts respectively. Writing
the interrupt number to the 'trigger' file triggers the interrupt
handler for the peer which should increment their corresponding
'occurrences' file. The 'ready' file indicates if a peer is ready,
writing to this file blocks until it is ready.

The module parameter num_irqs can be used to set the number of
local interrupts. By default this is 4. This is only limited by
the number of unused MSI interrupts registered by the hardware
(this will require support of the hardware driver) and there must
be at least 2*num_irqs + 1 spads registers available.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Jon Mason <jdmason@kudzu.us>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Allen Hubbe <allenbh@gmail.com>
---
 drivers/ntb/test/Kconfig        |   9 +
 drivers/ntb/test/Makefile       |   1 +
 drivers/ntb/test/ntb_msi_test.c | 433 ++++++++++++++++++++++++++++++++
 3 files changed, 443 insertions(+)
 create mode 100644 drivers/ntb/test/ntb_msi_test.c

diff --git a/drivers/ntb/test/Kconfig b/drivers/ntb/test/Kconfig
index a5d0eda44438..a3f3e2638935 100644
--- a/drivers/ntb/test/Kconfig
+++ b/drivers/ntb/test/Kconfig
@@ -25,3 +25,12 @@ config NTB_PERF
 	 to and from the window without additional software interaction.
 
 	 If unsure, say N.
+
+config NTB_MSI_TEST
+	tristate "NTB MSI Test Client"
+	depends on NTB_MSI
+	help
+	  This tool demonstrates the use of the NTB MSI library to
+	  send MSI interrupts between peers.
+
+	  If unsure, say N.
diff --git a/drivers/ntb/test/Makefile b/drivers/ntb/test/Makefile
index 9e77e0b761c2..d2895ca995e4 100644
--- a/drivers/ntb/test/Makefile
+++ b/drivers/ntb/test/Makefile
@@ -1,3 +1,4 @@
 obj-$(CONFIG_NTB_PINGPONG) += ntb_pingpong.o
 obj-$(CONFIG_NTB_TOOL) += ntb_tool.o
 obj-$(CONFIG_NTB_PERF) += ntb_perf.o
+obj-$(CONFIG_NTB_MSI_TEST) += ntb_msi_test.o
diff --git a/drivers/ntb/test/ntb_msi_test.c b/drivers/ntb/test/ntb_msi_test.c
new file mode 100644
index 000000000000..99d826ed9c34
--- /dev/null
+++ b/drivers/ntb/test/ntb_msi_test.c
@@ -0,0 +1,433 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+
+#include <linux/module.h>
+#include <linux/debugfs.h>
+#include <linux/ntb.h>
+#include <linux/pci.h>
+#include <linux/radix-tree.h>
+#include <linux/workqueue.h>
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_VERSION("0.1");
+MODULE_AUTHOR("Logan Gunthorpe <logang@deltatee.com>");
+MODULE_DESCRIPTION("Test for sending MSI interrupts over an NTB memory window");
+
+static int num_irqs = 4;
+module_param(num_irqs, int, 0644);
+MODULE_PARM_DESC(num_irqs, "number of irqs to use");
+
+struct ntb_msit_ctx {
+	struct ntb_dev *ntb;
+	struct dentry *dbgfs_dir;
+	struct work_struct setup_work;
+
+	struct ntb_msit_isr_ctx {
+		int irq_idx;
+		int irq_num;
+		int occurrences;
+		struct ntb_msit_ctx *nm;
+		struct ntb_msi_desc desc;
+	} *isr_ctx;
+
+	struct ntb_msit_peer {
+		struct ntb_msit_ctx *nm;
+		int pidx;
+		int num_irqs;
+		struct completion init_comp;
+		struct ntb_msi_desc *msi_desc;
+	} peers[];
+};
+
+static struct dentry *ntb_msit_dbgfs_topdir;
+
+static irqreturn_t ntb_msit_isr(int irq, void *dev)
+{
+	struct ntb_msit_isr_ctx *isr_ctx = dev;
+	struct ntb_msit_ctx *nm = isr_ctx->nm;
+
+	dev_dbg(&nm->ntb->dev, "Interrupt Occurred: %d",
+		isr_ctx->irq_idx);
+
+	isr_ctx->occurrences++;
+
+	return IRQ_HANDLED;
+}
+
+static void ntb_msit_setup_work(struct work_struct *work)
+{
+	struct ntb_msit_ctx *nm = container_of(work, struct ntb_msit_ctx,
+					       setup_work);
+	int irq_count = 0;
+	int irq;
+	int ret;
+	uintptr_t i;
+
+	ret = ntb_msi_setup_mws(nm->ntb);
+	if (ret) {
+		dev_err(&nm->ntb->dev, "Unable to setup MSI windows: %d\n",
+			ret);
+		return;
+	}
+
+	for (i = 0; i < num_irqs; i++) {
+		nm->isr_ctx[i].irq_idx = i;
+		nm->isr_ctx[i].nm = nm;
+
+		if (!nm->isr_ctx[i].irq_num) {
+			irq = ntbm_msi_request_irq(nm->ntb, ntb_msit_isr,
+						   KBUILD_MODNAME,
+						   &nm->isr_ctx[i],
+						   &nm->isr_ctx[i].desc);
+			if (irq < 0)
+				break;
+
+			nm->isr_ctx[i].irq_num = irq;
+		}
+
+		ret = ntb_spad_write(nm->ntb, 2 * i + 1,
+				     nm->isr_ctx[i].desc.addr_offset);
+		if (ret)
+			break;
+
+		ret = ntb_spad_write(nm->ntb, 2 * i + 2,
+				     nm->isr_ctx[i].desc.data);
+		if (ret)
+			break;
+
+		irq_count++;
+	}
+
+	ntb_spad_write(nm->ntb, 0, irq_count);
+	ntb_peer_db_set(nm->ntb, BIT(ntb_port_number(nm->ntb)));
+}
+
+static void ntb_msit_desc_changed(void *ctx)
+{
+	struct ntb_msit_ctx *nm = ctx;
+	int i;
+
+	dev_dbg(&nm->ntb->dev, "MSI Descriptors Changed\n");
+
+	for (i = 0; i < num_irqs; i++) {
+		ntb_spad_write(nm->ntb, 2 * i + 1,
+			       nm->isr_ctx[i].desc.addr_offset);
+		ntb_spad_write(nm->ntb, 2 * i + 2,
+			       nm->isr_ctx[i].desc.data);
+	}
+
+	ntb_peer_db_set(nm->ntb, BIT(ntb_port_number(nm->ntb)));
+}
+
+static void ntb_msit_link_event(void *ctx)
+{
+	struct ntb_msit_ctx *nm = ctx;
+
+	if (!ntb_link_is_up(nm->ntb, NULL, NULL))
+		return;
+
+	schedule_work(&nm->setup_work);
+}
+
+static void ntb_msit_copy_peer_desc(struct ntb_msit_ctx *nm, int peer)
+{
+	int i;
+	struct ntb_msi_desc *desc = nm->peers[peer].msi_desc;
+	int irq_count = nm->peers[peer].num_irqs;
+
+	for (i = 0; i < irq_count; i++) {
+		desc[i].addr_offset = ntb_peer_spad_read(nm->ntb, peer,
+							 2 * i + 1);
+		desc[i].data = ntb_peer_spad_read(nm->ntb, peer, 2 * i + 2);
+	}
+
+	dev_info(&nm->ntb->dev, "Found %d interrupts on peer %d\n",
+		 irq_count, peer);
+
+	complete_all(&nm->peers[peer].init_comp);
+}
+
+static void ntb_msit_db_event(void *ctx, int vec)
+{
+	struct ntb_msit_ctx *nm = ctx;
+	struct ntb_msi_desc *desc;
+	u64 peer_mask = ntb_db_read(nm->ntb);
+	u32 irq_count;
+	int peer;
+
+	ntb_db_clear(nm->ntb, peer_mask);
+
+	for (peer = 0; peer < sizeof(peer_mask) * 8; peer++) {
+		if (!(peer_mask & BIT(peer)))
+			continue;
+
+		irq_count = ntb_peer_spad_read(nm->ntb, peer, 0);
+		if (irq_count == -1)
+			continue;
+
+		desc = kcalloc(irq_count, sizeof(*desc), GFP_ATOMIC);
+		if (!desc)
+			continue;
+
+		kfree(nm->peers[peer].msi_desc);
+		nm->peers[peer].msi_desc = desc;
+		nm->peers[peer].num_irqs = irq_count;
+
+		ntb_msit_copy_peer_desc(nm, peer);
+	}
+}
+
+static const struct ntb_ctx_ops ntb_msit_ops = {
+	.link_event = ntb_msit_link_event,
+	.db_event = ntb_msit_db_event,
+};
+
+static int ntb_msit_dbgfs_trigger(void *data, u64 idx)
+{
+	struct ntb_msit_peer *peer = data;
+
+	if (idx >= peer->num_irqs)
+		return -EINVAL;
+
+	dev_dbg(&peer->nm->ntb->dev, "trigger irq %llu on peer %u\n",
+		idx, peer->pidx);
+
+	return ntb_msi_peer_trigger(peer->nm->ntb, peer->pidx,
+				    &peer->msi_desc[idx]);
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(ntb_msit_trigger_fops, NULL,
+			 ntb_msit_dbgfs_trigger, "%llu\n");
+
+static int ntb_msit_dbgfs_port_get(void *data, u64 *port)
+{
+	struct ntb_msit_peer *peer = data;
+
+	*port = ntb_peer_port_number(peer->nm->ntb, peer->pidx);
+
+	return 0;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(ntb_msit_port_fops, ntb_msit_dbgfs_port_get,
+			 NULL, "%llu\n");
+
+static int ntb_msit_dbgfs_count_get(void *data, u64 *count)
+{
+	struct ntb_msit_peer *peer = data;
+
+	*count = peer->num_irqs;
+
+	return 0;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(ntb_msit_count_fops, ntb_msit_dbgfs_count_get,
+			 NULL, "%llu\n");
+
+static int ntb_msit_dbgfs_ready_get(void *data, u64 *ready)
+{
+	struct ntb_msit_peer *peer = data;
+
+	*ready = try_wait_for_completion(&peer->init_comp);
+
+	return 0;
+}
+
+static int ntb_msit_dbgfs_ready_set(void *data, u64 ready)
+{
+	struct ntb_msit_peer *peer = data;
+
+	return wait_for_completion_interruptible(&peer->init_comp);
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(ntb_msit_ready_fops, ntb_msit_dbgfs_ready_get,
+			 ntb_msit_dbgfs_ready_set, "%llu\n");
+
+static int ntb_msit_dbgfs_occurrences_get(void *data, u64 *occurrences)
+{
+	struct ntb_msit_isr_ctx *isr_ctx = data;
+
+	*occurrences = isr_ctx->occurrences;
+
+	return 0;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(ntb_msit_occurrences_fops,
+			 ntb_msit_dbgfs_occurrences_get,
+			 NULL, "%llu\n");
+
+static int ntb_msit_dbgfs_local_port_get(void *data, u64 *port)
+{
+	struct ntb_msit_ctx *nm = data;
+
+	*port = ntb_port_number(nm->ntb);
+
+	return 0;
+}
+
+DEFINE_DEBUGFS_ATTRIBUTE(ntb_msit_local_port_fops,
+			 ntb_msit_dbgfs_local_port_get,
+			 NULL, "%llu\n");
+
+static void ntb_msit_create_dbgfs(struct ntb_msit_ctx *nm)
+{
+	struct pci_dev *pdev = nm->ntb->pdev;
+	char buf[32];
+	int i;
+	struct dentry *peer_dir;
+
+	nm->dbgfs_dir = debugfs_create_dir(pci_name(pdev),
+					   ntb_msit_dbgfs_topdir);
+	debugfs_create_file("port", 0400, nm->dbgfs_dir, nm,
+			    &ntb_msit_local_port_fops);
+
+	for (i = 0; i < ntb_peer_port_count(nm->ntb); i++) {
+		nm->peers[i].pidx = i;
+		nm->peers[i].nm = nm;
+		init_completion(&nm->peers[i].init_comp);
+
+		snprintf(buf, sizeof(buf), "peer%d", i);
+		peer_dir = debugfs_create_dir(buf, nm->dbgfs_dir);
+
+		debugfs_create_file_unsafe("trigger", 0200, peer_dir,
+					   &nm->peers[i],
+					   &ntb_msit_trigger_fops);
+
+		debugfs_create_file_unsafe("port", 0400, peer_dir,
+					   &nm->peers[i], &ntb_msit_port_fops);
+
+		debugfs_create_file_unsafe("count", 0400, peer_dir,
+					   &nm->peers[i],
+					   &ntb_msit_count_fops);
+
+		debugfs_create_file_unsafe("ready", 0600, peer_dir,
+					   &nm->peers[i],
+					   &ntb_msit_ready_fops);
+	}
+
+	for (i = 0; i < num_irqs; i++) {
+		snprintf(buf, sizeof(buf), "irq%d_occurrences", i);
+		debugfs_create_file_unsafe(buf, 0400, nm->dbgfs_dir,
+					   &nm->isr_ctx[i],
+					   &ntb_msit_occurrences_fops);
+	}
+}
+
+static void ntb_msit_remove_dbgfs(struct ntb_msit_ctx *nm)
+{
+	debugfs_remove_recursive(nm->dbgfs_dir);
+}
+
+static int ntb_msit_probe(struct ntb_client *client, struct ntb_dev *ntb)
+{
+	struct ntb_msit_ctx *nm;
+	size_t struct_size;
+	int peers;
+	int ret;
+
+	peers = ntb_peer_port_count(ntb);
+	if (peers <= 0)
+		return -EINVAL;
+
+	if (ntb_spad_is_unsafe(ntb) || ntb_spad_count(ntb) < 2 * num_irqs + 1) {
+		dev_err(&ntb->dev, "NTB MSI test requires at least %d spads for %d irqs\n",
+			2 * num_irqs + 1, num_irqs);
+		return -EFAULT;
+	}
+
+	ret = ntb_spad_write(ntb, 0, -1);
+	if (ret) {
+		dev_err(&ntb->dev, "Unable to write spads: %d\n", ret);
+		return ret;
+	}
+
+	ret = ntb_db_clear_mask(ntb, GENMASK(peers - 1, 0));
+	if (ret) {
+		dev_err(&ntb->dev, "Unable to clear doorbell mask: %d\n", ret);
+		return ret;
+	}
+
+	ret = ntb_msi_init(ntb, ntb_msit_desc_changed);
+	if (ret) {
+		dev_err(&ntb->dev, "Unable to initialize MSI library: %d\n",
+			ret);
+		return ret;
+	}
+
+	struct_size = sizeof(*nm) + sizeof(*nm->peers) * peers;
+
+	nm = devm_kzalloc(&ntb->dev, struct_size, GFP_KERNEL);
+	if (!nm)
+		return -ENOMEM;
+
+	nm->isr_ctx = devm_kcalloc(&ntb->dev, num_irqs, sizeof(*nm->isr_ctx),
+				   GFP_KERNEL);
+	if (!nm->isr_ctx)
+		return -ENOMEM;
+
+	INIT_WORK(&nm->setup_work, ntb_msit_setup_work);
+	nm->ntb = ntb;
+
+	ntb_msit_create_dbgfs(nm);
+
+	ret = ntb_set_ctx(ntb, nm, &ntb_msit_ops);
+	if (ret)
+		goto remove_dbgfs;
+
+	if (!nm->isr_ctx)
+		goto remove_dbgfs;
+
+	ntb_link_enable(ntb, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
+
+	return 0;
+
+remove_dbgfs:
+	ntb_msit_remove_dbgfs(nm);
+	devm_kfree(&ntb->dev, nm->isr_ctx);
+	devm_kfree(&ntb->dev, nm);
+	return ret;
+}
+
+static void ntb_msit_remove(struct ntb_client *client, struct ntb_dev *ntb)
+{
+	struct ntb_msit_ctx *nm = ntb->ctx;
+	int i;
+
+	ntb_link_disable(ntb);
+	ntb_db_set_mask(ntb, ntb_db_valid_mask(ntb));
+	ntb_msi_clear_mws(ntb);
+
+	for (i = 0; i < ntb_peer_port_count(ntb); i++)
+		kfree(nm->peers[i].msi_desc);
+
+	ntb_clear_ctx(ntb);
+	ntb_msit_remove_dbgfs(nm);
+}
+
+static struct ntb_client ntb_msit_client = {
+	.ops = {
+		.probe = ntb_msit_probe,
+		.remove = ntb_msit_remove
+	}
+};
+
+static int __init ntb_msit_init(void)
+{
+	int ret;
+
+	if (debugfs_initialized())
+		ntb_msit_dbgfs_topdir = debugfs_create_dir(KBUILD_MODNAME,
+							   NULL);
+
+	ret = ntb_register_client(&ntb_msit_client);
+	if (ret)
+		debugfs_remove_recursive(ntb_msit_dbgfs_topdir);
+
+	return ret;
+}
+module_init(ntb_msit_init);
+
+static void __exit ntb_msit_exit(void)
+{
+	ntb_unregister_client(&ntb_msit_client);
+	debugfs_remove_recursive(ntb_msit_dbgfs_topdir);
+}
+module_exit(ntb_msit_exit);
-- 
2.20.1

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 13+ messages in thread

* [PATCH v5 08/10] NTB: Add ntb_msi_test support to ntb_test
  2019-05-23 22:30 [PATCH v5 00/10] Support using MSI interrupts in ntb_transport Logan Gunthorpe
                   ` (6 preceding siblings ...)
  2019-05-23 22:30 ` [PATCH v5 07/10] NTB: Introduce NTB MSI Test Client Logan Gunthorpe
@ 2019-05-23 22:30 ` Logan Gunthorpe
  2019-05-23 22:30 ` [PATCH v5 09/10] NTB: Add MSI interrupt support to ntb_transport Logan Gunthorpe
                   ` (2 subsequent siblings)
  10 siblings, 0 replies; 13+ messages in thread
From: Logan Gunthorpe @ 2019-05-23 22:30 UTC (permalink / raw)
  To: linux-kernel, linux-ntb, linux-pci, iommu, linux-kselftest,
	Jon Mason, Joerg Roedel
  Cc: Allen Hubbe, Dave Jiang, Serge Semin, Eric Pilmore,
	Bjorn Helgaas, Logan Gunthorpe

When the ntb_msi_test module is available, the test code will trigger
each of the interrupts and ensure the corresponding occurrences files
gets incremented.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Jon Mason <jdmason@kudzu.us>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Allen Hubbe <allenbh@gmail.com>
---
 tools/testing/selftests/ntb/ntb_test.sh | 54 ++++++++++++++++++++++++-
 1 file changed, 52 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/ntb/ntb_test.sh b/tools/testing/selftests/ntb/ntb_test.sh
index 17ca36403d04..1a10b8f67727 100755
--- a/tools/testing/selftests/ntb/ntb_test.sh
+++ b/tools/testing/selftests/ntb/ntb_test.sh
@@ -87,10 +87,10 @@ set -e
 
 function _modprobe()
 {
-	modprobe "$@"
+	modprobe "$@" || return 1
 
 	if [[ "$REMOTE_HOST" != "" ]]; then
-		ssh "$REMOTE_HOST" modprobe "$@"
+		ssh "$REMOTE_HOST" modprobe "$@" || return 1
 	fi
 }
 
@@ -451,6 +451,30 @@ function pingpong_test()
 	echo "  Passed"
 }
 
+function msi_test()
+{
+	LOC=$1
+	REM=$2
+
+	write_file 1 $LOC/ready
+
+	echo "Running MSI interrupt tests on: $(subdirname $LOC) / $(subdirname $REM)"
+
+	CNT=$(read_file "$LOC/count")
+	for ((i = 0; i < $CNT; i++)); do
+		START=$(read_file $REM/../irq${i}_occurrences)
+		write_file $i $LOC/trigger
+		END=$(read_file $REM/../irq${i}_occurrences)
+
+		if [[ $(($END - $START)) != 1 ]]; then
+			echo "MSI did not trigger the interrupt on the remote side!" >&2
+			exit 1
+		fi
+	done
+
+	echo "  Passed"
+}
+
 function perf_test()
 {
 	USE_DMA=$1
@@ -529,6 +553,29 @@ function ntb_pingpong_tests()
 	_modprobe -r ntb_pingpong
 }
 
+function ntb_msi_tests()
+{
+	LOCAL_MSI="$DEBUGFS/ntb_msi_test/$LOCAL_DEV"
+	REMOTE_MSI="$REMOTE_HOST:$DEBUGFS/ntb_msi_test/$REMOTE_DEV"
+
+	echo "Starting ntb_msi_test tests..."
+
+	if ! _modprobe ntb_msi_test 2> /dev/null; then
+		echo "  Not doing MSI tests seeing the module is not available."
+		return
+	fi
+
+	port_test $LOCAL_MSI $REMOTE_MSI
+
+	LOCAL_PEER="$LOCAL_MSI/peer$LOCAL_PIDX"
+	REMOTE_PEER="$REMOTE_MSI/peer$REMOTE_PIDX"
+
+	msi_test $LOCAL_PEER $REMOTE_PEER
+	msi_test $REMOTE_PEER $LOCAL_PEER
+
+	_modprobe -r ntb_msi_test
+}
+
 function ntb_perf_tests()
 {
 	LOCAL_PERF="$DEBUGFS/ntb_perf/$LOCAL_DEV"
@@ -550,6 +597,7 @@ function cleanup()
 	_modprobe -r ntb_perf 2> /dev/null
 	_modprobe -r ntb_pingpong 2> /dev/null
 	_modprobe -r ntb_transport 2> /dev/null
+	_modprobe -r ntb_msi_test 2> /dev/null
 	set -e
 }
 
@@ -586,5 +634,7 @@ ntb_tool_tests
 echo
 ntb_pingpong_tests
 echo
+ntb_msi_tests
+echo
 ntb_perf_tests
 echo
-- 
2.20.1

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 13+ messages in thread

* [PATCH v5 09/10] NTB: Add MSI interrupt support to ntb_transport
  2019-05-23 22:30 [PATCH v5 00/10] Support using MSI interrupts in ntb_transport Logan Gunthorpe
                   ` (7 preceding siblings ...)
  2019-05-23 22:30 ` [PATCH v5 08/10] NTB: Add ntb_msi_test support to ntb_test Logan Gunthorpe
@ 2019-05-23 22:30 ` Logan Gunthorpe
  2019-05-23 22:31 ` [PATCH v5 10/10] NTB: Describe the ntb_msi_test client in the documentation Logan Gunthorpe
  2019-06-13 13:30 ` [PATCH v5 00/10] Support using MSI interrupts in ntb_transport Jon Mason
  10 siblings, 0 replies; 13+ messages in thread
From: Logan Gunthorpe @ 2019-05-23 22:30 UTC (permalink / raw)
  To: linux-kernel, linux-ntb, linux-pci, iommu, linux-kselftest,
	Jon Mason, Joerg Roedel
  Cc: Allen Hubbe, Dave Jiang, Serge Semin, Eric Pilmore,
	Bjorn Helgaas, Logan Gunthorpe

Introduce the module parameter 'use_msi' which, when set, uses
MSI interrupts instead of doorbells for each queue pair (QP). The
parameter is only available if NTB MSI support is configured into
the kernel. We also require there to be more than one memory window
(MW) so that an extra one is available to forward the APIC region.

To use MSIs, we request one interrupt per QP and forward the MSI address
and data to the peer using scratch pad registers (SPADS) above the MW
SPADS. (If there are not enough SPADS the MSI interrupt will not be used.)

Once registered, we simply use ntb_msi_peer_trigger and the receiving
ISR simply queues up the rxc_db_work for the queue.

This addition can significantly improve performance of ntb_transport.
In a simple, untuned, apples-to-apples comparision using ntb_netdev
and iperf with switchtec hardware, I see 3.88Gb/s without MSI
interrupts and 14.1Gb/s wit MSI, which is a more than 3x improvement.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Jon Mason <jdmason@kudzu.us>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Allen Hubbe <allenbh@gmail.com>
---
 drivers/ntb/ntb_transport.c | 169 +++++++++++++++++++++++++++++++++++-
 1 file changed, 168 insertions(+), 1 deletion(-)

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index d4f39ba1d976..f1cf0942cb99 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -93,6 +93,12 @@ static bool use_dma;
 module_param(use_dma, bool, 0644);
 MODULE_PARM_DESC(use_dma, "Use DMA engine to perform large data copy");
 
+static bool use_msi;
+#ifdef CONFIG_NTB_MSI
+module_param(use_msi, bool, 0644);
+MODULE_PARM_DESC(use_msi, "Use MSI interrupts instead of doorbells");
+#endif
+
 static struct dentry *nt_debugfs_dir;
 
 /* Only two-ports NTB devices are supported */
@@ -188,6 +194,11 @@ struct ntb_transport_qp {
 	u64 tx_err_no_buf;
 	u64 tx_memcpy;
 	u64 tx_async;
+
+	bool use_msi;
+	int msi_irq;
+	struct ntb_msi_desc msi_desc;
+	struct ntb_msi_desc peer_msi_desc;
 };
 
 struct ntb_transport_mw {
@@ -221,6 +232,10 @@ struct ntb_transport_ctx {
 	u64 qp_bitmap;
 	u64 qp_bitmap_free;
 
+	bool use_msi;
+	unsigned int msi_spad_offset;
+	u64 msi_db_mask;
+
 	bool link_is_up;
 	struct delayed_work link_work;
 	struct work_struct link_cleanup;
@@ -667,6 +682,114 @@ static int ntb_transport_setup_qp_mw(struct ntb_transport_ctx *nt,
 	return 0;
 }
 
+static irqreturn_t ntb_transport_isr(int irq, void *dev)
+{
+	struct ntb_transport_qp *qp = dev;
+
+	tasklet_schedule(&qp->rxc_db_work);
+
+	return IRQ_HANDLED;
+}
+
+static void ntb_transport_setup_qp_peer_msi(struct ntb_transport_ctx *nt,
+					    unsigned int qp_num)
+{
+	struct ntb_transport_qp *qp = &nt->qp_vec[qp_num];
+	int spad = qp_num * 2 + nt->msi_spad_offset;
+
+	if (!nt->use_msi)
+		return;
+
+	if (spad >= ntb_spad_count(nt->ndev))
+		return;
+
+	qp->peer_msi_desc.addr_offset =
+		ntb_peer_spad_read(qp->ndev, PIDX, spad);
+	qp->peer_msi_desc.data =
+		ntb_peer_spad_read(qp->ndev, PIDX, spad + 1);
+
+	dev_dbg(&qp->ndev->pdev->dev, "QP%d Peer MSI addr=%x data=%x\n",
+		qp_num, qp->peer_msi_desc.addr_offset, qp->peer_msi_desc.data);
+
+	if (qp->peer_msi_desc.addr_offset) {
+		qp->use_msi = true;
+		dev_info(&qp->ndev->pdev->dev,
+			 "Using MSI interrupts for QP%d\n", qp_num);
+	}
+}
+
+static void ntb_transport_setup_qp_msi(struct ntb_transport_ctx *nt,
+				       unsigned int qp_num)
+{
+	struct ntb_transport_qp *qp = &nt->qp_vec[qp_num];
+	int spad = qp_num * 2 + nt->msi_spad_offset;
+	int rc;
+
+	if (!nt->use_msi)
+		return;
+
+	if (spad >= ntb_spad_count(nt->ndev)) {
+		dev_warn_once(&qp->ndev->pdev->dev,
+			      "Not enough SPADS to use MSI interrupts\n");
+		return;
+	}
+
+	ntb_spad_write(qp->ndev, spad, 0);
+	ntb_spad_write(qp->ndev, spad + 1, 0);
+
+	if (!qp->msi_irq) {
+		qp->msi_irq = ntbm_msi_request_irq(qp->ndev, ntb_transport_isr,
+						   KBUILD_MODNAME, qp,
+						   &qp->msi_desc);
+		if (qp->msi_irq < 0) {
+			dev_warn(&qp->ndev->pdev->dev,
+				 "Unable to allocate MSI interrupt for qp%d\n",
+				 qp_num);
+			return;
+		}
+	}
+
+	rc = ntb_spad_write(qp->ndev, spad, qp->msi_desc.addr_offset);
+	if (rc)
+		goto err_free_interrupt;
+
+	rc = ntb_spad_write(qp->ndev, spad + 1, qp->msi_desc.data);
+	if (rc)
+		goto err_free_interrupt;
+
+	dev_dbg(&qp->ndev->pdev->dev, "QP%d MSI %d addr=%x data=%x\n",
+		qp_num, qp->msi_irq, qp->msi_desc.addr_offset,
+		qp->msi_desc.data);
+
+	return;
+
+err_free_interrupt:
+	devm_free_irq(&nt->ndev->dev, qp->msi_irq, qp);
+}
+
+static void ntb_transport_msi_peer_desc_changed(struct ntb_transport_ctx *nt)
+{
+	int i;
+
+	dev_dbg(&nt->ndev->pdev->dev, "Peer MSI descriptors changed");
+
+	for (i = 0; i < nt->qp_count; i++)
+		ntb_transport_setup_qp_peer_msi(nt, i);
+}
+
+static void ntb_transport_msi_desc_changed(void *data)
+{
+	struct ntb_transport_ctx *nt = data;
+	int i;
+
+	dev_dbg(&nt->ndev->pdev->dev, "MSI descriptors changed");
+
+	for (i = 0; i < nt->qp_count; i++)
+		ntb_transport_setup_qp_msi(nt, i);
+
+	ntb_peer_db_set(nt->ndev, nt->msi_db_mask);
+}
+
 static void ntb_free_mw(struct ntb_transport_ctx *nt, int num_mw)
 {
 	struct ntb_transport_mw *mw = &nt->mw_vec[num_mw];
@@ -905,6 +1028,20 @@ static void ntb_transport_link_work(struct work_struct *work)
 	int rc = 0, i, spad;
 
 	/* send the local info, in the opposite order of the way we read it */
+
+	if (nt->use_msi) {
+		rc = ntb_msi_setup_mws(ndev);
+		if (rc) {
+			dev_warn(&pdev->dev,
+				 "Failed to register MSI memory window: %d\n",
+				 rc);
+			nt->use_msi = false;
+		}
+	}
+
+	for (i = 0; i < nt->qp_count; i++)
+		ntb_transport_setup_qp_msi(nt, i);
+
 	for (i = 0; i < nt->mw_count; i++) {
 		size = nt->mw_vec[i].phys_size;
 
@@ -962,6 +1099,7 @@ static void ntb_transport_link_work(struct work_struct *work)
 		struct ntb_transport_qp *qp = &nt->qp_vec[i];
 
 		ntb_transport_setup_qp_mw(nt, i);
+		ntb_transport_setup_qp_peer_msi(nt, i);
 
 		if (qp->client_ready)
 			schedule_delayed_work(&qp->link_work, 0);
@@ -1135,6 +1273,19 @@ static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
 		return -ENOMEM;
 
 	nt->ndev = ndev;
+
+	/*
+	 * If we are using MSI, and have at least one extra memory window,
+	 * we will reserve the last MW for the MSI window.
+	 */
+	if (use_msi && mw_count > 1) {
+		rc = ntb_msi_init(ndev, ntb_transport_msi_desc_changed);
+		if (!rc) {
+			mw_count -= 1;
+			nt->use_msi = true;
+		}
+	}
+
 	spad_count = ntb_spad_count(ndev);
 
 	/* Limit the MW's based on the availability of scratchpads */
@@ -1148,6 +1299,8 @@ static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
 	max_mw_count_for_spads = (spad_count - MW0_SZ_HIGH) / 2;
 	nt->mw_count = min(mw_count, max_mw_count_for_spads);
 
+	nt->msi_spad_offset = nt->mw_count * 2 + MW0_SZ_HIGH;
+
 	nt->mw_vec = kcalloc_node(mw_count, sizeof(*nt->mw_vec),
 				  GFP_KERNEL, node);
 	if (!nt->mw_vec) {
@@ -1178,6 +1331,12 @@ static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
 	qp_bitmap = ntb_db_valid_mask(ndev);
 
 	qp_count = ilog2(qp_bitmap);
+	if (nt->use_msi) {
+		qp_count -= 1;
+		nt->msi_db_mask = 1 << qp_count;
+		ntb_db_clear_mask(ndev, nt->msi_db_mask);
+	}
+
 	if (max_num_clients && max_num_clients < qp_count)
 		qp_count = max_num_clients;
 	else if (nt->mw_count < qp_count)
@@ -1601,7 +1760,10 @@ static void ntb_tx_copy_callback(void *data,
 
 	iowrite32(entry->flags | DESC_DONE_FLAG, &hdr->flags);
 
-	ntb_peer_db_set(qp->ndev, BIT_ULL(qp->qp_num));
+	if (qp->use_msi)
+		ntb_msi_peer_trigger(qp->ndev, PIDX, &qp->peer_msi_desc);
+	else
+		ntb_peer_db_set(qp->ndev, BIT_ULL(qp->qp_num));
 
 	/* The entry length can only be zero if the packet is intended to be a
 	 * "link down" or similar.  Since no payload is being sent in these
@@ -2268,6 +2430,11 @@ static void ntb_transport_doorbell_callback(void *data, int vector)
 	u64 db_bits;
 	unsigned int qp_num;
 
+	if (ntb_db_read(nt->ndev) & nt->msi_db_mask) {
+		ntb_transport_msi_peer_desc_changed(nt);
+		ntb_db_clear(nt->ndev, nt->msi_db_mask);
+	}
+
 	db_bits = (nt->qp_bitmap & ~nt->qp_bitmap_free &
 		   ntb_db_vector_mask(nt->ndev, vector));
 
-- 
2.20.1

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 13+ messages in thread

* [PATCH v5 10/10] NTB: Describe the ntb_msi_test client in the documentation.
  2019-05-23 22:30 [PATCH v5 00/10] Support using MSI interrupts in ntb_transport Logan Gunthorpe
                   ` (8 preceding siblings ...)
  2019-05-23 22:30 ` [PATCH v5 09/10] NTB: Add MSI interrupt support to ntb_transport Logan Gunthorpe
@ 2019-05-23 22:31 ` Logan Gunthorpe
  2019-06-13 13:30 ` [PATCH v5 00/10] Support using MSI interrupts in ntb_transport Jon Mason
  10 siblings, 0 replies; 13+ messages in thread
From: Logan Gunthorpe @ 2019-05-23 22:31 UTC (permalink / raw)
  To: linux-kernel, linux-ntb, linux-pci, iommu, linux-kselftest,
	Jon Mason, Joerg Roedel
  Cc: Allen Hubbe, Dave Jiang, Serge Semin, Eric Pilmore,
	Bjorn Helgaas, Logan Gunthorpe

Add a blurb in Documentation/ntb.txt to describe the ntb_msi_test tool's
debugfs interface. Similar to the (out of date) ntb_tool description.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
---
 Documentation/ntb.txt | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/Documentation/ntb.txt b/Documentation/ntb.txt
index a043854d28df..802a539f1592 100644
--- a/Documentation/ntb.txt
+++ b/Documentation/ntb.txt
@@ -194,6 +194,33 @@ Debugfs Files:
 	This file is used to read and write peer scratchpads.  See
 	*spad* for details.
 
+NTB MSI Test Client (ntb\_msi\_test)
+------------------------------------
+
+The MSI test client serves to test and debug the MSI library which
+allows for passing MSI interrupts across NTB memory windows. The
+test client is interacted with through the debugfs filesystem:
+
+* *debugfs*/ntb\_tool/*hw*/
+	A directory in debugfs will be created for each
+	NTB device probed by the tool.  This directory is shortened to *hw*
+	below.
+* *hw*/port
+	This file describes the local port number
+* *hw*/irq*_occurrences
+	One occurrences file exists for each interrupt and, when read,
+	returns the number of times the interrupt has been triggered.
+* *hw*/peer*/port
+	This file describes the port number for each peer
+* *hw*/peer*/count
+	This file describes the number of interrupts that can be
+	triggered on each peer
+* *hw*/peer*/trigger
+	Writing an interrupt number (any number less than the value
+	specified in count) will trigger the interrupt on the
+	specified peer. That peer's interrupt's occurrence file
+	should be incremented.
+
 NTB Hardware Drivers
 ====================
 
-- 
2.20.1

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH v5 00/10]  Support using MSI interrupts in ntb_transport
  2019-05-23 22:30 [PATCH v5 00/10] Support using MSI interrupts in ntb_transport Logan Gunthorpe
                   ` (9 preceding siblings ...)
  2019-05-23 22:31 ` [PATCH v5 10/10] NTB: Describe the ntb_msi_test client in the documentation Logan Gunthorpe
@ 2019-06-13 13:30 ` Jon Mason
  2019-06-13 15:46   ` Logan Gunthorpe
  10 siblings, 1 reply; 13+ messages in thread
From: Jon Mason @ 2019-06-13 13:30 UTC (permalink / raw)
  To: Logan Gunthorpe
  Cc: Allen Hubbe, Dave Jiang, linux-pci, linux-kernel, Serge Semin,
	Eric Pilmore, iommu, linux-kselftest, Bjorn Helgaas, linux-ntb

On Thu, May 23, 2019 at 04:30:50PM -0600, Logan Gunthorpe wrote:
> This is another resend as there has been no feedback since v4.
> Seems Jon has been MIA this past cycle so hopefully he appears on the
> list soon.
> 
> I've addressed the feedback so far and rebased on the latest kernel
> and would like this to be considered for merging this cycle.
> 
> The only outstanding issue I know of is that it still will not work
> with IDT hardware, but ntb_transport doesn't work with IDT hardware
> and there is still no sensible common infrastructure to support
> ntb_peer_mw_set_trans(). Thus, I decline to consider that complication
> in this patchset. However, I'll be happy to review work that adds this
> feature in the future.
> 
> Also, as the port number and resource index stuff is a bit complicated,
> I made a quick out of tree test fixture to ensure it's correct[1]. As
> an excerise I also wrote some test code[2] using the upcomming KUnit
> feature.

Sorry for the delay.  The patch is now in the ntb-next branch.  We've
missed window for 5.2, but it will be in the 5.3 pull request (barring
last minute comments).

Thanks,
Jon

> 
> Logan
> 
> [1] https://repl.it/repls/ExcitingPresentFile
> [2] https://github.com/sbates130272/linux-p2pmem/commits/ntb_kunit
> 
> --
> 
> Changes in v5:
> 
> * Rebased onto v5.2-rc1 (plus the patches in ntb-next)
> 
> --
> 
> Changes in v4:
> 
> * Rebased onto v5.1-rc6 (No changes)
> 
> * Numerous grammar and spelling mistakes spotted by Bjorn
> 
> --
> 
> Changes in v3:
> 
> * Rebased onto v5.1-rc1 (Dropped the first two patches as they have
>   been merged, and cleaned up some minor conflicts in the PCI tree)
> 
> * Added a new patch (#3) to calculate logical port numbers that
>   are port numbers from 0 to (number of ports - 1). This is
>   then used in ntb_peer_resource_idx() to fix the issues brought
>   up by Serge.
> 
> * Fixed missing __iomem and iowrite calls (as noticed by Serge)
> 
> * Added patch 10 which describes ntb_msi_test in the documentation
>   file (as requested by Serge)
> 
> * A couple other minor nits and documentation fixes
> 
> --
> 
> Changes in v2:
> 
> * Cleaned up the changes in intel_irq_remapping.c to make them
>   less confusing and add a comment. (Per discussion with Jacob and
>   Joerg)
> 
> * Fixed a nit from Bjorn and collected his Ack
> 
> * Added a Kconfig dependancy on CONFIG_PCI_MSI for CONFIG_NTB_MSI
>   as the Kbuild robot hit a random config that didn't build
>   without it.
> 
> * Worked in a callback for when the MSI descriptor changes so that
>   the clients can resend the new address and data values to the peer.
>   On my test system this was never necessary, but there may be
>   other platforms where this can occur. I tested this by hacking
>   in a path to rewrite the MSI descriptor when I change the cpu
>   affinity of an IRQ. There's a bit of uncertainty over the latency
>   of the change, but without hardware this can acctually occur on
>   we can't test this. This was the result of a discussion with Dave.
> 
> --
> 
> This patch series adds optional support for using MSI interrupts instead
> of NTB doorbells in ntb_transport. This is desirable seeing doorbells on
> current hardware are quite slow and therefore switching to MSI interrupts
> provides a significant performance gain. On switchtec hardware, a simple
> apples-to-apples comparison shows ntb_netdev/iperf numbers going from
> 3.88Gb/s to 14.1Gb/s when switching to MSI interrupts.
> 
> To do this, a couple changes are required outside of the NTB tree:
> 
> 1) The IOMMU must know to accept MSI requests from aliased bused numbers
> seeing NTB hardware typically sends proxied request IDs through
> additional requester IDs. The first patch in this series adds support
> for the Intel IOMMU. A quirk to add these aliases for switchtec hardware
> was already accepted. See commit ad281ecf1c7d ("PCI: Add DMA alias quirk
> for Microsemi Switchtec NTB") for a description of NTB proxy IDs and why
> this is necessary.
> 
> 2) NTB transport (and other clients) may often need more MSI interrupts
> than the NTB hardware actually advertises support for. However, seeing
> these interrupts will not be triggered by the hardware but through an
> NTB memory window, the hardware does not actually need support or need
> to know about them. Therefore we add the concept of Virtual MSI
> interrupts which are allocated just like any other MSI interrupt but
> are not programmed into the hardware's MSI table. This is done in
> Patch 2 and then made use of in Patch 3.
> 
> The remaining patches in this series add a library for dealing with MSI
> interrupts, a test client and finally support in ntb_transport.
> 
> The series is based off of v5.1-rc6 plus the patches in ntb-next.
> A git repo is available here:
> 
> https://github.com/sbates130272/linux-p2pmem/ ntb_transport_msi_v4
> 
> Thanks,
> 
> Logan
> 
> --
> 
> Logan Gunthorpe (10):
>   PCI/MSI: Support allocating virtual MSI interrupts
>   PCI/switchtec: Add module parameter to request more interrupts
>   NTB: Introduce helper functions to calculate logical port number
>   NTB: Introduce functions to calculate multi-port resource index
>   NTB: Rename ntb.c to support multiple source files in the module
>   NTB: Introduce MSI library
>   NTB: Introduce NTB MSI Test Client
>   NTB: Add ntb_msi_test support to ntb_test
>   NTB: Add MSI interrupt support to ntb_transport
>   NTB: Describe the ntb_msi_test client in the documentation.
> 
>  Documentation/ntb.txt                   |  27 ++
>  drivers/ntb/Kconfig                     |  11 +
>  drivers/ntb/Makefile                    |   3 +
>  drivers/ntb/{ntb.c => core.c}           |   0
>  drivers/ntb/msi.c                       | 415 +++++++++++++++++++++++
>  drivers/ntb/ntb_transport.c             | 169 ++++++++-
>  drivers/ntb/test/Kconfig                |   9 +
>  drivers/ntb/test/Makefile               |   1 +
>  drivers/ntb/test/ntb_msi_test.c         | 433 ++++++++++++++++++++++++
>  drivers/pci/msi.c                       |  54 ++-
>  drivers/pci/switch/switchtec.c          |  12 +-
>  include/linux/msi.h                     |   8 +
>  include/linux/ntb.h                     | 196 ++++++++++-
>  include/linux/pci.h                     |   9 +
>  tools/testing/selftests/ntb/ntb_test.sh |  54 ++-
>  15 files changed, 1386 insertions(+), 15 deletions(-)
>  rename drivers/ntb/{ntb.c => core.c} (100%)
>  create mode 100644 drivers/ntb/msi.c
>  create mode 100644 drivers/ntb/test/ntb_msi_test.c
> 
> --
> 2.20.1
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^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [PATCH v5 00/10] Support using MSI interrupts in ntb_transport
  2019-06-13 13:30 ` [PATCH v5 00/10] Support using MSI interrupts in ntb_transport Jon Mason
@ 2019-06-13 15:46   ` Logan Gunthorpe
  0 siblings, 0 replies; 13+ messages in thread
From: Logan Gunthorpe @ 2019-06-13 15:46 UTC (permalink / raw)
  To: Jon Mason
  Cc: Allen Hubbe, Dave Jiang, linux-pci, linux-kernel, Serge Semin,
	Eric Pilmore, iommu, linux-kselftest, Bjorn Helgaas, linux-ntb



On 2019-06-13 7:30 a.m., Jon Mason wrote:
> On Thu, May 23, 2019 at 04:30:50PM -0600, Logan Gunthorpe wrote:
>> This is another resend as there has been no feedback since v4.
>> Seems Jon has been MIA this past cycle so hopefully he appears on the
>> list soon.
>>
>> I've addressed the feedback so far and rebased on the latest kernel
>> and would like this to be considered for merging this cycle.
>>
>> The only outstanding issue I know of is that it still will not work
>> with IDT hardware, but ntb_transport doesn't work with IDT hardware
>> and there is still no sensible common infrastructure to support
>> ntb_peer_mw_set_trans(). Thus, I decline to consider that complication
>> in this patchset. However, I'll be happy to review work that adds this
>> feature in the future.
>>
>> Also, as the port number and resource index stuff is a bit complicated,
>> I made a quick out of tree test fixture to ensure it's correct[1]. As
>> an excerise I also wrote some test code[2] using the upcomming KUnit
>> feature.
> 
> Sorry for the delay.  The patch is now in the ntb-next branch.  We've
> missed window for 5.2, but it will be in the 5.3 pull request (barring
> last minute comments).

Thanks Jon!

Logan
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^ permalink raw reply	[flat|nested] 13+ messages in thread

end of thread, back to index

Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-05-23 22:30 [PATCH v5 00/10] Support using MSI interrupts in ntb_transport Logan Gunthorpe
2019-05-23 22:30 ` [PATCH v5 01/10] PCI/MSI: Support allocating virtual MSI interrupts Logan Gunthorpe
2019-05-23 22:30 ` [PATCH v5 02/10] PCI/switchtec: Add module parameter to request more interrupts Logan Gunthorpe
2019-05-23 22:30 ` [PATCH v5 03/10] NTB: Introduce helper functions to calculate logical port number Logan Gunthorpe
2019-05-23 22:30 ` [PATCH v5 04/10] NTB: Introduce functions to calculate multi-port resource index Logan Gunthorpe
2019-05-23 22:30 ` [PATCH v5 05/10] NTB: Rename ntb.c to support multiple source files in the module Logan Gunthorpe
2019-05-23 22:30 ` [PATCH v5 06/10] NTB: Introduce MSI library Logan Gunthorpe
2019-05-23 22:30 ` [PATCH v5 07/10] NTB: Introduce NTB MSI Test Client Logan Gunthorpe
2019-05-23 22:30 ` [PATCH v5 08/10] NTB: Add ntb_msi_test support to ntb_test Logan Gunthorpe
2019-05-23 22:30 ` [PATCH v5 09/10] NTB: Add MSI interrupt support to ntb_transport Logan Gunthorpe
2019-05-23 22:31 ` [PATCH v5 10/10] NTB: Describe the ntb_msi_test client in the documentation Logan Gunthorpe
2019-06-13 13:30 ` [PATCH v5 00/10] Support using MSI interrupts in ntb_transport Jon Mason
2019-06-13 15:46   ` Logan Gunthorpe

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