[dpdk-dev] [PATCH V4 0/9] hot plug failure handle mechanism

[dpdk-dev] [PATCH V4 0/9] hot plug failure handle mechanism

[Jeff Guo]

As we know, hot plug is an importance feature, either use for the datacenter
device’s fail-safe, or use for SRIOV Live Migration in SDN/NFV. It could bring
the higher flexibility and continuality to the networking services in multiple
use cases in industry. So let we see, dpdk as an importance networking
framework, what can it help to implement hot plug solution for users.

We already have a general device event detect mechanism, failsafe driver,
bonding driver and hot plug/unplug api in framework, app could use these to
develop their hot plug solution.

let’s see the case of hot unplug, it can happen when a hardware device is
be removed physically, or when the software disables it.  App need to call
ether dev API to detach the device, to unplug the device at the bus level and
make access to the device invalid. But the problem is that, the removal of the
device from the software lists is not going to be instantaneous, at this time
if the data(fast) path still read/write the device, it will cause MMIO error
and result of the app crash out.

Seems that we have got fail-safe driver(or app) + RTE_ETH_EVENT_INTR_RMV +
kernel core driver solution to handle it, but still not have failsafe driver
(or app) + RTE_DEV_EVENT_REMOVE + PCIe pmd driver failure handle solution. So
there is an absence in dpdk hot plug solution right now.

Also, we know that kernel only guaranty hot plug on the kernel side, but not for
the user mode side. Firstly we can hardly have a gatekeeper for any MMIO for
multiple PMD driver. Secondly, no more specific 3rd tools such as udev/driverctl
have especially cover these hot plug failure processing. Third, the feasibility
of app’s implement for multiple user mode PMD driver is still a problem. Here,
a general hot plug failure handle mechanism in dpdk framework would be proposed,
it aim to guaranty that, when hot unplug occur, the system will not crash and
app will not be break out, and user space can normally stop and release any
relevant resources, then unplug of the device at the bus level cleanly.

The mechanism should be come across as bellow:

Firstly, app enabled the device event monitor and register the hot plug event’s
callback before running data path. Once the hot unplug behave occur, the
mechanism will detect the removal event and then accordingly do the failure
handle. In order to do that, below functional will be bring in.
 - Add a new bus ops “handle_hot_unplug” to handle bus read/write error, it is
   bus-specific and each kind of bus can implement its own logic.
 - Implement pci bus specific ops “pci_handle_hot_unplug”. It will base on the
   failure address to remap memory for the corresponding device that unplugged.

For the data path or other unexpected control from the control path when hot
unplug occur.
 - Implement a new sigbus handler, it is registered when start device even
   monitoring. The handler is per process. Base on the signal event principle,
   control path thread and data path thread will randomly receive the sigbus
   error, but will go to the common sigbus handler. Once the MMIO sigbus error
   exposure, it will trigger the above hot unplug operation. The sigbus will be
   check if it is cause of the hot unplug or not, if not will info exception as
   the original sigbus handler. If yes, will do memory remapping.

For the control path and the igb uio release:
 - When hot unplug device, the kernel will release the device resource in the
   kernel side, such as the fd sys file will disappear, and the irq will be
   released. At this time, if igb uio driver still try to release this resource,
   it will cause kernel crash.
   On the other hand, something like interrupt disable do not automatically
   process in kernel side. If not handler it, this redundancy and dirty thing
   will affect the interrupt resource be used by other device.
   So the igb_uio driver have to check the hot plug status and corresponding
   process should be taken in igb uio deriver.
   This patch propose to add structure of rte_udev_state into rte_uio_pci_dev
   of igb_uio kernel driver, which will record the state of uio device, such as
   probed/opened/released/removed/unplug. When detect the unexpected removal
   which cause of hot unplug behavior, it will corresponding disable interrupt
   resource, while for the part of releasement which kernel have already handle,
   just skip it to avoid double free or null pointer kernel crash issue.

The mechanism could be use for fail-safe driver and app which want to use hot
plug solution. At this stage, will only use testpmd as reference to show how to
use the mechanism.
 - Enable device event monitor->device unplug->failure handle->stop forwarding->
   stop port->close port->detach port.

This process will not breaking the app/fail-safe running, and will not break
other irrelevance device. And app could plug in the device and restart the date
path again by below.
 - Device plug in->bind igb_uio driver ->attached device->start port->
   start forwarding.

patchset history:
v4->v3:
split patches to be small and clear
change to use new parameter "--hotplug-mode" in testpmd
to identify the eal hotplug and ethdev hotplug

v3->v2:
change bus ops name to bus_hotplug_handler.
add new API and bus ops of bus_signal_handler
distingush handle generic sigbus and hotplug sigbus

v2->v1(v21):
refine some doc and commit log
fix igb uio kernel issue for control path failure
rebase testpmd code

Since the hot plug solution be discussed serval around in the public, the
scope be changed and the patch set be split into many times. Coming to the
recently RFC and feature design, it just focus on the hot unplug failure
handler at this patch set, so in order let this topic more clear and focus,
summarize privours patch set in history “v1(v21)”, the v2 here go ahead
for further track.

"v1(21)" == v21 as below:
v21->v20:
split function in hot unplug ops
sync failure hanlde to fix multiple process issue fix attach port issue for multiple devices case.
combind rmv callback function to be only one.

v20->v19:
clean the code
refine the remap logic for multiple device.
remove the auto binding

v19->18:
note for limitation of multiple hotplug,fix some typo, sqeeze patch.

v18->v15:
add document, add signal bus handler, refine the code to be more clear.

the prior patch history please check the patch set "add device event monitor framework"

Jeff Guo (9):
  bus: introduce hotplug failure handler
  bus/pci: implement hotplug handler operation
  bus: introduce sigbus handler
  bus/pci: implement sigbus handler operation
  bus: add helper to handle sigbus
  eal: add failure handle mechanism for hot plug
  igb_uio: fix uio release issue when hot unplug
  app/testpmd: show example to handle hot unplug
  app/testpmd: enable device hotplug monitoring

 app/test-pmd/parameters.c               | 20 ++++++--
 app/test-pmd/testpmd.c                  | 31 +++++++-----
 app/test-pmd/testpmd.h                  |  8 ++-
 doc/guides/testpmd_app_ug/run_app.rst   | 10 +++-
 drivers/bus/pci/pci_common.c            | 78 +++++++++++++++++++++++++++++
 drivers/bus/pci/pci_common_uio.c        | 33 +++++++++++++
 drivers/bus/pci/private.h               | 12 +++++
 kernel/linux/igb_uio/igb_uio.c          | 50 +++++++++++++++++--
 lib/librte_eal/common/eal_common_bus.c  | 34 ++++++++++++-
 lib/librte_eal/common/eal_private.h     | 11 +++++
 lib/librte_eal/common/include/rte_bus.h | 31 ++++++++++++
 lib/librte_eal/linuxapp/eal/eal_dev.c   | 88 ++++++++++++++++++++++++++++++++-
 12 files changed, 381 insertions(+), 25 deletions(-)

-- 
2.7.4

[dpdk-dev] [PATCH V4 1/9] bus: introduce hotplug failure handler

[Jeff Guo]

When a hardware device is removed physically or the software disables
it, the hotplug occur. App need to call ether dev API to detach the device,
to unplug the device at the bus level and make access to the device
invalid. But the removal of the device from the software lists is not going
to be instantaneous, at this time if the data path still read/write the
device, it will cause MMIO error and result of the app crash out. So a
hotplug failure handle mechanism need to be used to guaranty app will not
crash out when hot unplug device.

To handle device hot plug failure is a bus-specific behavior, this patch
introduces a bus ops so that each kind of bus can implement its own logic.

Signed-off-by: Jeff Guo <jia.guo@intel.com>
---
v4->v3:
split patches to be small and clear.
---
 lib/librte_eal/common/include/rte_bus.h | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/lib/librte_eal/common/include/rte_bus.h b/lib/librte_eal/common/include/rte_bus.h
index eb9eded..3642aeb 100644
--- a/lib/librte_eal/common/include/rte_bus.h
+++ b/lib/librte_eal/common/include/rte_bus.h
@@ -168,6 +168,19 @@ typedef int (*rte_bus_unplug_t)(struct rte_device *dev);
 typedef int (*rte_bus_parse_t)(const char *name, void *addr);
 
 /**
+ * Implementation a specific hot plug handler, which is responsible
+ * for handle the failure when hot remove the device, guaranty the system
+ * would not crash in the case.
+ * @param dev
+ *	Pointer of the device structure.
+ *
+ * @return
+ *	0 on success.
+ *	!0 on error.
+ */
+typedef int (*rte_bus_hotplug_handler_t)(struct rte_device *dev);
+
+/**
  * Bus scan policies
  */
 enum rte_bus_scan_mode {
@@ -211,6 +224,8 @@ struct rte_bus {
 	rte_bus_parse_t parse;       /**< Parse a device name */
 	struct rte_bus_conf conf;    /**< Bus configuration */
 	rte_bus_get_iommu_class_t get_iommu_class; /**< Get iommu class */
+	rte_bus_hotplug_handler_t hotplug_handler;
+						/**< handle hot plug on bus */
 };
 
 /**
-- 
2.7.4

[dpdk-dev] [PATCH V4 2/9] bus/pci: implement hotplug handler operation

[Jeff Guo]

This patch implements the ops of hotplug handler for PCI bus, it is
functional to remap a new dummy memory which overlap to the failure
memory to avoid MMIO read/write error.

Signed-off-by: Jeff Guo <jia.guo@intel.com>
---
v4->v3:
split patches to be small and clear.
---
 drivers/bus/pci/pci_common.c     | 28 ++++++++++++++++++++++++++++
 drivers/bus/pci/pci_common_uio.c | 33 +++++++++++++++++++++++++++++++++
 drivers/bus/pci/private.h        | 12 ++++++++++++
 3 files changed, 73 insertions(+)

diff --git a/drivers/bus/pci/pci_common.c b/drivers/bus/pci/pci_common.c
index d8151b0..095cd4e 100644
--- a/drivers/bus/pci/pci_common.c
+++ b/drivers/bus/pci/pci_common.c
@@ -401,6 +401,33 @@ pci_find_device(const struct rte_device *start, rte_dev_cmp_t cmp,
 }
 
 static int
+pci_hotplug_handler(struct rte_device *dev)
+{
+	struct rte_pci_device *pdev = NULL;
+	int ret = 0;
+
+	pdev = RTE_DEV_TO_PCI(dev);
+	if (!pdev)
+		return -1;
+
+	switch (pdev->kdrv) {
+	case RTE_KDRV_IGB_UIO:
+	case RTE_KDRV_UIO_GENERIC:
+	case RTE_KDRV_NIC_UIO:
+		/* mmio resources is invalid, remap it to be safe. */
+		ret = pci_uio_remap_resource(pdev);
+		break;
+	default:
+		RTE_LOG(DEBUG, EAL,
+			"Not managed by a supported kernel driver, skipped\n");
+		ret = -1;
+		break;
+	}
+
+	return ret;
+}
+
+static int
 pci_plug(struct rte_device *dev)
 {
 	return pci_probe_all_drivers(RTE_DEV_TO_PCI(dev));
@@ -430,6 +457,7 @@ struct rte_pci_bus rte_pci_bus = {
 		.unplug = pci_unplug,
 		.parse = pci_parse,
 		.get_iommu_class = rte_pci_get_iommu_class,
+		.hotplug_handler = pci_hotplug_handler,
 	},
 	.device_list = TAILQ_HEAD_INITIALIZER(rte_pci_bus.device_list),
 	.driver_list = TAILQ_HEAD_INITIALIZER(rte_pci_bus.driver_list),
diff --git a/drivers/bus/pci/pci_common_uio.c b/drivers/bus/pci/pci_common_uio.c
index 54bc20b..7ea73db 100644
--- a/drivers/bus/pci/pci_common_uio.c
+++ b/drivers/bus/pci/pci_common_uio.c
@@ -146,6 +146,39 @@ pci_uio_unmap(struct mapped_pci_resource *uio_res)
 	}
 }
 
+/* remap the PCI resource of a PCI device in anonymous virtual memory */
+int
+pci_uio_remap_resource(struct rte_pci_device *dev)
+{
+	int i;
+	void *map_address;
+
+	if (dev == NULL)
+		return -1;
+
+	/* Remap all BARs */
+	for (i = 0; i != PCI_MAX_RESOURCE; i++) {
+		/* skip empty BAR */
+		if (dev->mem_resource[i].phys_addr == 0)
+			continue;
+		map_address = mmap(dev->mem_resource[i].addr,
+				(size_t)dev->mem_resource[i].len,
+				PROT_READ | PROT_WRITE,
+				MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
+		if (map_address == MAP_FAILED) {
+			RTE_LOG(ERR, EAL,
+				"Cannot remap resource for device %s\n",
+				dev->name);
+			return -1;
+		}
+		RTE_LOG(INFO, EAL,
+			"Successful remap resource for device %s\n",
+			dev->name);
+	}
+
+	return 0;
+}
+
 static struct mapped_pci_resource *
 pci_uio_find_resource(struct rte_pci_device *dev)
 {
diff --git a/drivers/bus/pci/private.h b/drivers/bus/pci/private.h
index 8ddd03e..6b312e5 100644
--- a/drivers/bus/pci/private.h
+++ b/drivers/bus/pci/private.h
@@ -123,6 +123,18 @@ void pci_uio_free_resource(struct rte_pci_device *dev,
 		struct mapped_pci_resource *uio_res);
 
 /**
+ * Remap the PCI resource of a PCI device in anonymous virtual memory.
+ *
+ * @param dev
+ *   Point to the struct rte pci device.
+ * @return
+ *   - On success, zero.
+ *   - On failure, a negative value.
+ */
+int
+pci_uio_remap_resource(struct rte_pci_device *dev);
+
+/**
  * Map device memory to uio resource
  *
  * This function is private to EAL.
-- 
2.7.4

[dpdk-dev] [PATCH V4 3/9] bus: introduce sigbus handler

[Jeff Guo]

When device be hotplug, if data path still read/write device, the sigbus
error will occur, this error need to be handled. So a handler need to be
here to capture the signal and handle it correspondingly.

To handle sigbus error is a bus-specific behavior, this patch introduces
a bus ops so that each kind of bus can implement its own logic.

Signed-off-by: Jeff Guo <jia.guo@intel.com>
---
v4->v3:
split patches to be small and clear.
---
 lib/librte_eal/common/include/rte_bus.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/lib/librte_eal/common/include/rte_bus.h b/lib/librte_eal/common/include/rte_bus.h
index 3642aeb..231bd3d 100644
--- a/lib/librte_eal/common/include/rte_bus.h
+++ b/lib/librte_eal/common/include/rte_bus.h
@@ -181,6 +181,20 @@ typedef int (*rte_bus_parse_t)(const char *name, void *addr);
 typedef int (*rte_bus_hotplug_handler_t)(struct rte_device *dev);
 
 /**
+ * Implementation a specific sigbus handler, which is responsible
+ * for handle the sigbus error which is original memory error, or specific
+ * memory error that caused of hot unplug.
+ * @param failure_addr
+ *	Pointer of the fault address of the sigbus error.
+ *
+ * @return
+ *	0 for success handle the sigbus.
+ *	1 for no handle the sigbus.
+ *	-1 for failed to handle the sigbus
+ */
+typedef int (*rte_bus_sigbus_handler_t)(const void *failure_addr);
+
+/**
  * Bus scan policies
  */
 enum rte_bus_scan_mode {
@@ -226,6 +240,8 @@ struct rte_bus {
 	rte_bus_get_iommu_class_t get_iommu_class; /**< Get iommu class */
 	rte_bus_hotplug_handler_t hotplug_handler;
 						/**< handle hot plug on bus */
+	rte_bus_sigbus_handler_t sigbus_handler; /**< handle sigbus error */
+
 };
 
 /**
-- 
2.7.4

[dpdk-dev] [PATCH V4 4/9] bus/pci: implement sigbus handler operation

[Jeff Guo]

This patch implements the ops of sigbus handler for PCI bus, it is
functional to find the corresponding pci device which is be hot removal.
and then handle the hot plug failure for this device.

Signed-off-by: Jeff Guo <jia.guo@intel.com>
---
v4->v3:
split patches to be small and clear.
---
 drivers/bus/pci/pci_common.c | 50 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/drivers/bus/pci/pci_common.c b/drivers/bus/pci/pci_common.c
index 095cd4e..0f5b4af 100644
--- a/drivers/bus/pci/pci_common.c
+++ b/drivers/bus/pci/pci_common.c
@@ -400,6 +400,32 @@ pci_find_device(const struct rte_device *start, rte_dev_cmp_t cmp,
 	return NULL;
 }
 
+/* check the failure address belongs to which device. */
+static struct rte_pci_device *
+pci_find_device_by_addr(const void *failure_addr)
+{
+	struct rte_pci_device *pdev = NULL;
+	int i;
+
+	FOREACH_DEVICE_ON_PCIBUS(pdev) {
+		for (i = 0; i != RTE_DIM(pdev->mem_resource); i++) {
+			if ((uint64_t)(uintptr_t)failure_addr >=
+			    (uint64_t)(uintptr_t)pdev->mem_resource[i].addr &&
+			    (uint64_t)(uintptr_t)failure_addr <
+			    (uint64_t)(uintptr_t)pdev->mem_resource[i].addr +
+			    pdev->mem_resource[i].len) {
+				RTE_LOG(INFO, EAL, "Failure address "
+					"%16.16"PRIx64" belongs to "
+					"device %s!\n",
+					(uint64_t)(uintptr_t)failure_addr,
+					pdev->device.name);
+				return pdev;
+			}
+		}
+	}
+	return NULL;
+}
+
 static int
 pci_hotplug_handler(struct rte_device *dev)
 {
@@ -428,6 +454,29 @@ pci_hotplug_handler(struct rte_device *dev)
 }
 
 static int
+pci_sigbus_handler(const void *failure_addr)
+{
+	struct rte_pci_device *pdev = NULL;
+	int ret = 0;
+
+	pdev = pci_find_device_by_addr(failure_addr);
+	if (!pdev) {
+		/* It is a generic sigbus error. */
+		ret = 1;
+	} else {
+		/* The sigbus error is caused of hot removal. */
+		ret = pci_hotplug_handler(&pdev->device);
+		if (ret) {
+			RTE_LOG(ERR, EAL, "Failed to handle hot plug for "
+				"device %s", pdev->name);
+			ret = -1;
+			rte_errno = -1;
+		}
+	}
+	return ret;
+}
+
+static int
 pci_plug(struct rte_device *dev)
 {
 	return pci_probe_all_drivers(RTE_DEV_TO_PCI(dev));
@@ -458,6 +507,7 @@ struct rte_pci_bus rte_pci_bus = {
 		.parse = pci_parse,
 		.get_iommu_class = rte_pci_get_iommu_class,
 		.hotplug_handler = pci_hotplug_handler,
+		.sigbus_handler = pci_sigbus_handler,
 	},
 	.device_list = TAILQ_HEAD_INITIALIZER(rte_pci_bus.device_list),
 	.driver_list = TAILQ_HEAD_INITIALIZER(rte_pci_bus.driver_list),
-- 
2.7.4

[dpdk-dev] [PATCH V4 5/9] bus: add helper to handle sigbus

[Jeff Guo]

This patch aim to add a helper to iterate all buses to find the
corresponding bus to handle the sigbus error.

Signed-off-by: Jeff Guo <jia.guo@intel.com>
---
v4->v3:
split patches to be small and clear.
---
 lib/librte_eal/common/eal_common_bus.c | 34 +++++++++++++++++++++++++++++++++-
 lib/librte_eal/common/eal_private.h    | 11 +++++++++++
 2 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/lib/librte_eal/common/eal_common_bus.c b/lib/librte_eal/common/eal_common_bus.c
index 0943851..34c4f2d 100644
--- a/lib/librte_eal/common/eal_common_bus.c
+++ b/lib/librte_eal/common/eal_common_bus.c
@@ -37,6 +37,7 @@
 #include <rte_bus.h>
 #include <rte_debug.h>
 #include <rte_string_fns.h>
+#include <rte_errno.h>
 
 #include "eal_private.h"
 
@@ -220,7 +221,6 @@ rte_bus_find_by_device_name(const char *str)
 	return rte_bus_find(NULL, bus_can_parse, name);
 }
 
-
 /*
  * Get iommu class of devices on the bus.
  */
@@ -242,3 +242,35 @@ rte_bus_get_iommu_class(void)
 	}
 	return mode;
 }
+
+static int
+bus_handle_sigbus(const struct rte_bus *bus,
+			const void *failure_addr)
+{
+	return !(bus->sigbus_handler && bus->sigbus_handler(failure_addr) <= 0);
+}
+
+int
+rte_bus_sigbus_handler(const void *failure_addr)
+{
+	struct rte_bus *bus;
+	int old_errno = rte_errno;
+	int ret = 0;
+
+	rte_errno = 0;
+
+	bus = rte_bus_find(NULL, bus_handle_sigbus, failure_addr);
+	if (bus == NULL) {
+		RTE_LOG(ERR, EAL, "No bus can handle the sigbus error!");
+		ret = -1;
+	} else if (rte_errno != 0) {
+		RTE_LOG(ERR, EAL, "Failed to handle the sigbus error!");
+		ret = -1;
+	}
+
+	/* if sigbus not be handled, return back old errno. */
+	if (ret)
+		rte_errno = old_errno;
+
+	return ret;
+}
diff --git a/lib/librte_eal/common/eal_private.h b/lib/librte_eal/common/eal_private.h
index bdadc4d..9517f2b 100644
--- a/lib/librte_eal/common/eal_private.h
+++ b/lib/librte_eal/common/eal_private.h
@@ -258,4 +258,15 @@ int rte_mp_channel_init(void);
  */
 void dev_callback_process(char *device_name, enum rte_dev_event_type event);
 
+
+/**
+ * Iterate all buses to find the corresponding bus, to handle the sigbus error.
+ * @param failure_addr
+ *	Pointer of the fault address of the sigbus error.
+ *
+ * @return
+ *	 0 on success.
+ *	-1 on error
+ */
+int rte_bus_sigbus_handler(const void *failure_addr);
 #endif /* _EAL_PRIVATE_H_ */
-- 
2.7.4

[dpdk-dev] [PATCH V4 6/9] eal: add failure handle mechanism for hot plug

[Jeff Guo]

This patch introduces a failure handler mechanism to handle device
hot plug removal event.

First register sigbus handler, once sigbus error be captured, will
check the failure address and accordingly remap the invalid memory
for the corresponding device. Bese on this mechanism, it could
guaranty the application not to be crash when hot unplug devices.

Signed-off-by: Jeff Guo <jia.guo@intel.com>
---
v4->v3:
split patches to be small and clear.
---
 lib/librte_eal/linuxapp/eal/eal_dev.c | 88 ++++++++++++++++++++++++++++++++++-
 1 file changed, 87 insertions(+), 1 deletion(-)

diff --git a/lib/librte_eal/linuxapp/eal/eal_dev.c b/lib/librte_eal/linuxapp/eal/eal_dev.c
index 1cf6aeb..c9dddab 100644
--- a/lib/librte_eal/linuxapp/eal/eal_dev.c
+++ b/lib/librte_eal/linuxapp/eal/eal_dev.c
@@ -4,6 +4,8 @@
 
 #include <string.h>
 #include <unistd.h>
+#include <fcntl.h>
+#include <signal.h>
 #include <sys/socket.h>
 #include <linux/netlink.h>
 
@@ -14,15 +16,24 @@
 #include <rte_malloc.h>
 #include <rte_interrupts.h>
 #include <rte_alarm.h>
+#include <rte_bus.h>
+#include <rte_eal.h>
+#include <rte_spinlock.h>
+#include <rte_errno.h>
 
 #include "eal_private.h"
 
 static struct rte_intr_handle intr_handle = {.fd = -1 };
 static bool monitor_started;
 
+extern struct rte_bus_list rte_bus_list;
+
 #define EAL_UEV_MSG_LEN 4096
 #define EAL_UEV_MSG_ELEM_LEN 128
 
+/* spinlock for device failure process */
+static rte_spinlock_t dev_failure_lock = RTE_SPINLOCK_INITIALIZER;
+
 static void dev_uev_handler(__rte_unused void *param);
 
 /* identify the system layer which reports this event. */
@@ -33,6 +44,34 @@ enum eal_dev_event_subsystem {
 	EAL_DEV_EVENT_SUBSYSTEM_MAX
 };
 
+static void sigbus_handler(int signum __rte_unused, siginfo_t *info,
+				void *ctx __rte_unused)
+{
+	int ret;
+
+	RTE_LOG(DEBUG, EAL, "Thread[%d] catch SIGBUS, fault address:%p\n",
+		(int)pthread_self(), info->si_addr);
+
+	rte_spinlock_lock(&dev_failure_lock);
+	ret = rte_bus_sigbus_handler(info->si_addr);
+	rte_spinlock_unlock(&dev_failure_lock);
+	if (!ret)
+		RTE_LOG(INFO, EAL,
+			"Success to handle SIGBUS error for hotplug!\n");
+	else
+		rte_exit(EXIT_FAILURE,
+			 "A generic SIGBUS error, (rte_errno: %s)!",
+			 strerror(rte_errno));
+}
+
+static int cmp_dev_name(const struct rte_device *dev,
+	const void *_name)
+{
+	const char *name = _name;
+
+	return strcmp(dev->name, name);
+}
+
 static int
 dev_uev_socket_fd_create(void)
 {
@@ -147,6 +186,9 @@ dev_uev_handler(__rte_unused void *param)
 	struct rte_dev_event uevent;
 	int ret;
 	char buf[EAL_UEV_MSG_LEN];
+	struct rte_bus *bus;
+	struct rte_device *dev;
+	const char *busname;
 
 	memset(&uevent, 0, sizeof(struct rte_dev_event));
 	memset(buf, 0, EAL_UEV_MSG_LEN);
@@ -171,13 +213,48 @@ dev_uev_handler(__rte_unused void *param)
 	RTE_LOG(DEBUG, EAL, "receive uevent(name:%s, type:%d, subsystem:%d)\n",
 		uevent.devname, uevent.type, uevent.subsystem);
 
-	if (uevent.devname)
+	switch (uevent.subsystem) {
+	case EAL_DEV_EVENT_SUBSYSTEM_PCI:
+	case EAL_DEV_EVENT_SUBSYSTEM_UIO:
+		busname = "pci";
+		break;
+	default:
+		break;
+	}
+
+	if (uevent.devname) {
+		if (uevent.type == RTE_DEV_EVENT_REMOVE) {
+			bus = rte_bus_find_by_name(busname);
+			if (bus == NULL) {
+				RTE_LOG(ERR, EAL, "Cannot find bus (%s)\n",
+					busname);
+				return;
+			}
+			dev = bus->find_device(NULL, cmp_dev_name,
+					       uevent.devname);
+			if (dev == NULL) {
+				RTE_LOG(ERR, EAL, "Cannot find device (%s) on "
+					"bus (%s)\n", uevent.devname, busname);
+				return;
+			}
+			rte_spinlock_lock(&dev_failure_lock);
+			ret = bus->hotplug_handler(dev);
+			rte_spinlock_unlock(&dev_failure_lock);
+			if (ret) {
+				RTE_LOG(ERR, EAL, "Can not handle hotplug for "
+					"device (%s)\n", dev->name);
+				return;
+			}
+		}
 		dev_callback_process(uevent.devname, uevent.type);
+	}
 }
 
 int __rte_experimental
 rte_dev_event_monitor_start(void)
 {
+	sigset_t mask;
+	struct sigaction action;
 	int ret;
 
 	if (monitor_started)
@@ -197,6 +274,14 @@ rte_dev_event_monitor_start(void)
 		return -1;
 	}
 
+	/* register sigbus handler */
+	sigemptyset(&mask);
+	sigaddset(&mask, SIGBUS);
+	action.sa_flags = SA_SIGINFO;
+	action.sa_mask = mask;
+	action.sa_sigaction = sigbus_handler;
+	sigaction(SIGBUS, &action, NULL);
+
 	monitor_started = true;
 
 	return 0;
@@ -220,5 +305,6 @@ rte_dev_event_monitor_stop(void)
 	close(intr_handle.fd);
 	intr_handle.fd = -1;
 	monitor_started = false;
+
 	return 0;
 }
-- 
2.7.4

[dpdk-dev] [PATCH V4 7/9] igb_uio: fix uio release issue when hot unplug

[Jeff Guo]

When hot unplug device, the kernel will release the device resource in the
kernel side, such as the fd sys file will disappear, and the irq will be
released. At this time, if igb uio driver still try to release this
resource, it will cause kernel crash. On the other hand, something like
interrupt disabling do not automatically process in kernel side. If not
handler it, this redundancy and dirty thing will affect the interrupt
resource be used by other device. So the igb_uio driver have to check the
hot plug status, and the corresponding process should be taken in igb uio
driver.

This patch propose to add structure of rte_udev_state into rte_uio_pci_dev
of igb_uio kernel driver, which will record the state of uio device, such
as probed/opened/released/removed/unplug. When detect the unexpected
removal which cause of hot unplug behavior, it will corresponding disable
interrupt resource, while for the part of releasement which kernel have
already handle, just skip it to avoid double free or null pointer kernel
crash issue.

Signed-off-by: Jeff Guo <jia.guo@intel.com>
---
v4->v3:
no change
---
 kernel/linux/igb_uio/igb_uio.c | 50 +++++++++++++++++++++++++++++++++++++-----
 1 file changed, 45 insertions(+), 5 deletions(-)

diff --git a/kernel/linux/igb_uio/igb_uio.c b/kernel/linux/igb_uio/igb_uio.c
index b3233f1..d301302 100644
--- a/kernel/linux/igb_uio/igb_uio.c
+++ b/kernel/linux/igb_uio/igb_uio.c
@@ -19,6 +19,15 @@
 
 #include "compat.h"
 
+/* uio pci device state */
+enum rte_udev_state {
+	RTE_UDEV_PROBED,
+	RTE_UDEV_OPENNED,
+	RTE_UDEV_RELEASED,
+	RTE_UDEV_REMOVED,
+	RTE_UDEV_UNPLUG
+};
+
 /**
  * A structure describing the private information for a uio device.
  */
@@ -28,6 +37,7 @@ struct rte_uio_pci_dev {
 	enum rte_intr_mode mode;
 	struct mutex lock;
 	int refcnt;
+	enum rte_udev_state state;
 };
 
 static char *intr_mode;
@@ -194,12 +204,20 @@ igbuio_pci_irqhandler(int irq, void *dev_id)
 {
 	struct rte_uio_pci_dev *udev = (struct rte_uio_pci_dev *)dev_id;
 	struct uio_info *info = &udev->info;
+	struct pci_dev *pdev = udev->pdev;
 
 	/* Legacy mode need to mask in hardware */
 	if (udev->mode == RTE_INTR_MODE_LEGACY &&
 	    !pci_check_and_mask_intx(udev->pdev))
 		return IRQ_NONE;
 
+	/* check the uevent of the kobj */
+	if ((&pdev->dev.kobj)->state_remove_uevent_sent == 1) {
+		dev_notice(&pdev->dev, "device:%s, sent remove uevent!\n",
+			   (&pdev->dev.kobj)->name);
+		udev->state = RTE_UDEV_UNPLUG;
+	}
+
 	uio_event_notify(info);
 
 	/* Message signal mode, no share IRQ and automasked */
@@ -308,7 +326,6 @@ igbuio_pci_disable_interrupts(struct rte_uio_pci_dev *udev)
 #endif
 }
 
-
 /**
  * This gets called while opening uio device file.
  */
@@ -330,24 +347,33 @@ igbuio_pci_open(struct uio_info *info, struct inode *inode)
 
 	/* enable interrupts */
 	err = igbuio_pci_enable_interrupts(udev);
-	mutex_unlock(&udev->lock);
 	if (err) {
 		dev_err(&dev->dev, "Enable interrupt fails\n");
+		pci_clear_master(dev);
 		return err;
 	}
+	udev->state = RTE_UDEV_OPENNED;
+	mutex_unlock(&udev->lock);
 	return 0;
 }
 
+/**
+ * This gets called while closing uio device file.
+ */
 static int
 igbuio_pci_release(struct uio_info *info, struct inode *inode)
 {
+
 	struct rte_uio_pci_dev *udev = info->priv;
 	struct pci_dev *dev = udev->pdev;
 
+	if (udev->state == RTE_UDEV_REMOVED)
+		return 0;
+
 	mutex_lock(&udev->lock);
 	if (--udev->refcnt > 0) {
 		mutex_unlock(&udev->lock);
-		return 0;
+		return -1;
 	}
 
 	/* disable interrupts */
@@ -355,7 +381,7 @@ igbuio_pci_release(struct uio_info *info, struct inode *inode)
 
 	/* stop the device from further DMA */
 	pci_clear_master(dev);
-
+	udev->state = RTE_UDEV_RELEASED;
 	mutex_unlock(&udev->lock);
 	return 0;
 }
@@ -557,6 +583,7 @@ igbuio_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 			 (unsigned long long)map_dma_addr, map_addr);
 	}
 
+	udev->state = RTE_UDEV_PROBED;
 	return 0;
 
 fail_remove_group:
@@ -573,11 +600,24 @@ igbuio_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 static void
 igbuio_pci_remove(struct pci_dev *dev)
 {
+
 	struct rte_uio_pci_dev *udev = pci_get_drvdata(dev);
+	int ret;
+
+	/* handler hot unplug */
+	if (udev->state == RTE_UDEV_OPENNED ||
+		udev->state == RTE_UDEV_UNPLUG) {
+		dev_notice(&dev->dev, "Unexpected removal!\n");
+		ret = igbuio_pci_release(&udev->info, NULL);
+		if (ret)
+			return;
+		udev->state = RTE_UDEV_REMOVED;
+		return;
+	}
 
 	mutex_destroy(&udev->lock);
-	sysfs_remove_group(&dev->dev.kobj, &dev_attr_grp);
 	uio_unregister_device(&udev->info);
+	sysfs_remove_group(&dev->dev.kobj, &dev_attr_grp);
 	igbuio_pci_release_iomem(&udev->info);
 	pci_disable_device(dev);
 	pci_set_drvdata(dev, NULL);
-- 
2.7.4

[dpdk-dev] [PATCH V4 8/9] app/testpmd: show example to handle hot unplug

[Jeff Guo]

Use testpmd for example, to show how an application smoothly handle
failure when device being hot unplug. If app have enabled the device event
monitor and register the hot plug event’s callback before running, once
app detect the removal event, the callback would be called. It will first
stop the packet forwarding, then stop the port, close the port, and finally
detach the port to remove the device out from the device lists.

Signed-off-by: Jeff Guo <jia.guo@intel.com>
---
v4->v3:
remove some unused code
---
 app/test-pmd/testpmd.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c
index 24c1998..42ed196 100644
--- a/app/test-pmd/testpmd.c
+++ b/app/test-pmd/testpmd.c
@@ -2196,6 +2196,9 @@ static void
 eth_dev_event_callback(char *device_name, enum rte_dev_event_type type,
 			     __rte_unused void *arg)
 {
+	uint16_t port_id;
+	int ret;
+
 	if (type >= RTE_DEV_EVENT_MAX) {
 		fprintf(stderr, "%s called upon invalid event %d\n",
 			__func__, type);
@@ -2206,9 +2209,12 @@ eth_dev_event_callback(char *device_name, enum rte_dev_event_type type,
 	case RTE_DEV_EVENT_REMOVE:
 		RTE_LOG(ERR, EAL, "The device: %s has been removed!\n",
 			device_name);
-		/* TODO: After finish failure handle, begin to stop
-		 * packet forward, stop port, close port, detach port.
-		 */
+		ret = rte_eth_dev_get_port_by_name(device_name, &port_id);
+		if (ret) {
+			printf("can not get port by device %s!\n", device_name);
+			return;
+		}
+		rmv_event_callback((void *)(intptr_t)port_id);
 		break;
 	case RTE_DEV_EVENT_ADD:
 		RTE_LOG(ERR, EAL, "The device: %s has been added!\n",
@@ -2736,7 +2742,6 @@ main(int argc, char** argv)
 			return -1;
 		}
 		eth_dev_event_callback_register();
-
 	}
 
 	if (start_port(RTE_PORT_ALL) != 0)
-- 
2.7.4

[dpdk-dev] [PATCH V4 9/9] app/testpmd: enable device hotplug monitoring

[Jeff Guo]

As we know, there 2 different hotplug mechanisms in dpdk, the one is
ethdev event + kernel driver hotplug solution, while the other one is
eal device event + pci uio driver hotplug solution, each of them have
different configure and callback process in testpmd. In oder to avoid
the race between them, this patch aim to use a new parameter
"--hotplug-mode" to replace the previous "--hot-plug" command parameter,
to identify these different mode.

There are 3 modes on hotplug mode: disable, eal, or ethdev(default).

If user want to use eal device event monitor mode, could use below
command when start testpmd. If not set this parameter, ethdev hotplug
mode is default to be used.

E.g. ./build/app/testpmd -c 0x3 --n 4 -- -i --hotplug-mode=eal

Signed-off-by: Jeff Guo <jia.guo@intel.com>
---
v4->v3:
change to use new parameter "--hotplug-mode" in testpmd
to identify the eal hotplug and ethdev hotplug
---
 app/test-pmd/parameters.c             | 20 ++++++++++++++++----
 app/test-pmd/testpmd.c                | 18 +++++++++++-------
 app/test-pmd/testpmd.h                |  8 +++++++-
 doc/guides/testpmd_app_ug/run_app.rst | 10 ++++++++--
 4 files changed, 42 insertions(+), 14 deletions(-)

diff --git a/app/test-pmd/parameters.c b/app/test-pmd/parameters.c
index 7580762..601e13e 100644
--- a/app/test-pmd/parameters.c
+++ b/app/test-pmd/parameters.c
@@ -186,7 +186,8 @@ usage(char* progname)
 	printf("  --flow-isolate-all: "
 	       "requests flow API isolated mode on all ports at initialization time.\n");
 	printf("  --tx-offloads=0xXXXXXXXX: hexadecimal bitmask of TX queue offloads\n");
-	printf("  --hot-plug: enable hot plug for device.\n");
+	printf("  --hotplug-mode=N: set hotplug mode for device "
+	       "(N: disable (default) or eal or ethdev.\n");
 	printf("  --vxlan-gpe-port=N: UPD port of tunnel VXLAN-GPE\n");
 	printf("  --mlockall: lock all memory\n");
 	printf("  --no-mlockall: do not lock all memory\n");
@@ -621,7 +622,7 @@ launch_args_parse(int argc, char** argv)
 		{ "print-event",		1, 0, 0 },
 		{ "mask-event",			1, 0, 0 },
 		{ "tx-offloads",		1, 0, 0 },
-		{ "hot-plug",			0, 0, 0 },
+		{ "hotplug-mode",		1, 0, 0 },
 		{ "vxlan-gpe-port",		1, 0, 0 },
 		{ "mlockall",			0, 0, 0 },
 		{ "no-mlockall",		0, 0, 0 },
@@ -1139,8 +1140,19 @@ launch_args_parse(int argc, char** argv)
 					rte_exit(EXIT_FAILURE,
 						 "invalid mask-event argument\n");
 				}
-			if (!strcmp(lgopts[opt_idx].name, "hot-plug"))
-				hot_plug = 1;
+			if (!strcmp(lgopts[opt_idx].name, "hotplug-mode")) {
+				if (!strcmp(optarg, "disable"))
+					hotplug_mode = HOTPLUG_MODE_DISABLE;
+				else if (!strcmp(optarg, "eal"))
+					hotplug_mode = HOTPLUG_MODE_EAL;
+				else if (!strcmp(optarg, "ethdev"))
+					hotplug_mode = HOTPLUG_MODE_ETHDEV;
+				else
+					rte_exit(EXIT_FAILURE,
+						 "hotplug-mode %s invalid - must be: "
+						 "disable, eal, ethdev.\n",
+						 optarg);
+			}
 			if (!strcmp(lgopts[opt_idx].name, "mlockall"))
 				do_mlockall = 1;
 			if (!strcmp(lgopts[opt_idx].name, "no-mlockall"))
diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c
index 42ed196..9269400 100644
--- a/app/test-pmd/testpmd.c
+++ b/app/test-pmd/testpmd.c
@@ -286,7 +286,7 @@ uint8_t lsc_interrupt = 1; /* enabled by default */
  */
 uint8_t rmv_interrupt = 1; /* enabled by default */
 
-uint8_t hot_plug = 0; /**< hotplug disabled by default. */
+uint8_t hotplug_mode = HOTPLUG_MODE_ETHDEV; /**< hotplug disabled by default. */
 
 /*
  * Display or mask ether events
@@ -2043,7 +2043,7 @@ pmd_test_exit(void)
 		}
 	}
 
-	if (hot_plug) {
+	if (hotplug_mode == HOTPLUG_MODE_EAL) {
 		ret = rte_dev_event_monitor_stop();
 		if (ret)
 			RTE_LOG(ERR, EAL,
@@ -2181,9 +2181,13 @@ eth_event_callback(portid_t port_id, enum rte_eth_event_type type, void *param,
 
 	switch (type) {
 	case RTE_ETH_EVENT_INTR_RMV:
-		if (rte_eal_alarm_set(100000,
-				rmv_event_callback, (void *)(intptr_t)port_id))
-			fprintf(stderr, "Could not set up deferred device removal\n");
+		if (hotplug_mode == HOTPLUG_MODE_ETHDEV) {
+			if (rte_eal_alarm_set(100000,
+					rmv_event_callback,
+					(void *)(intptr_t)port_id))
+				fprintf(stderr, "Could not set up deferred "
+					"device removal\n");
+		}
 		break;
 	default:
 		break;
@@ -2734,8 +2738,8 @@ main(int argc, char** argv)
 
 	init_config();
 
-	if (hot_plug) {
-		/* enable hot plug monitoring */
+	if (hotplug_mode == HOTPLUG_MODE_EAL) {
+		/* enable hotplug event monitoring */
 		ret = rte_dev_event_monitor_start();
 		if (ret) {
 			rte_errno = EINVAL;
diff --git a/app/test-pmd/testpmd.h b/app/test-pmd/testpmd.h
index f51cd9d..e29ee2a 100644
--- a/app/test-pmd/testpmd.h
+++ b/app/test-pmd/testpmd.h
@@ -69,6 +69,12 @@ enum {
 	PORT_TOPOLOGY_LOOP,
 };
 
+enum {
+	HOTPLUG_MODE_DISABLE,
+	HOTPLUG_MODE_EAL,
+	HOTPLUG_MODE_ETHDEV,
+};
+
 #ifdef RTE_TEST_PMD_RECORD_BURST_STATS
 /**
  * The data structure associated with RX and TX packet burst statistics
@@ -335,7 +341,7 @@ extern uint8_t lsc_interrupt; /**< disabled by "--no-lsc-interrupt" parameter */
 extern uint8_t rmv_interrupt; /**< disabled by "--no-rmv-interrupt" parameter */
 extern uint32_t event_print_mask;
 /**< set by "--print-event xxxx" and "--mask-event xxxx parameters */
-extern uint8_t hot_plug; /**< enable by "--hot-plug" parameter */
+extern uint8_t hotplug_mode; /**< set by "--hotplug-mode" parameter */
 extern int do_mlockall; /**< set by "--mlockall" or "--no-mlockall" parameter */
 
 #ifdef RTE_LIBRTE_IXGBE_BYPASS
diff --git a/doc/guides/testpmd_app_ug/run_app.rst b/doc/guides/testpmd_app_ug/run_app.rst
index f301c2b..09e2716 100644
--- a/doc/guides/testpmd_app_ug/run_app.rst
+++ b/doc/guides/testpmd_app_ug/run_app.rst
@@ -482,9 +482,15 @@ The commandline options are:
     Set the hexadecimal bitmask of TX queue offloads.
     The default value is 0.
 
-*   ``--hot-plug``
+*   ``--hotplug-mode``
 
-    Enable device event monitor machenism for hotplug.
+    Set the hotplug handle mode, that is ``disable`` or ``eal`` or ``ethdev`` (the default).
+
+    In ``disable`` mode, it will not handle the hotplug for device.
+
+    In ``eal`` mode, it will start device event monitor and register eth_dev_event_callback for hotplug process.
+
+    In ``ethdev`` mode, it will process RTE_ETH_EVENT_INTR_RMV event which is detected from ethdev.
 
 *   ``--vxlan-gpe-port=N``
 
-- 
2.7.4

Re: [dpdk-dev] [PATCH V4 3/9] bus: introduce sigbus handler

[Jeff Guo]

On 7/11/2018 5:55 AM, Stephen Hemminger wrote:
> On Fri, 29 Jun 2018 18:30:42 +0800
> Jeff Guo <jia.guo@intel.com> wrote:
>
>> When device be hotplug, if data path still read/write device, the sigbus
>> error will occur, this error need to be handled. So a handler need to be
>> here to capture the signal and handle it correspondingly.
>>
>> To handle sigbus error is a bus-specific behavior, this patch introduces
>> a bus ops so that each kind of bus can implement its own logic.
>>
>> Signed-off-by: Jeff Guo <jia.guo@intel.com>
>> ---
>> v4->v3:
>> split patches to be small and clear.
>> ---
>>   lib/librte_eal/common/include/rte_bus.h | 16 ++++++++++++++++
>>   1 file changed, 16 insertions(+)
>>
>> diff --git a/lib/librte_eal/common/include/rte_bus.h b/lib/librte_eal/common/include/rte_bus.h
>> index 3642aeb..231bd3d 100644
>> --- a/lib/librte_eal/common/include/rte_bus.h
>> +++ b/lib/librte_eal/common/include/rte_bus.h
>> @@ -181,6 +181,20 @@ typedef int (*rte_bus_parse_t)(const char *name, void *addr);
>>   typedef int (*rte_bus_hotplug_handler_t)(struct rte_device *dev);
>>   
>>   /**
>> + * Implementation a specific sigbus handler, which is responsible
>> + * for handle the sigbus error which is original memory error, or specific
>> + * memory error that caused of hot unplug.
>> + * @param failure_addr
>> + *	Pointer of the fault address of the sigbus error.
>> + *
>> + * @return
>> + *	0 for success handle the sigbus.
>> + *	1 for no handle the sigbus.
>> + *	-1 for failed to handle the sigbus
>> + */
>> +typedef int (*rte_bus_sigbus_handler_t)(const void *failure_addr);
>> +
>> +/**
>>    * Bus scan policies
>>    */
>>   enum rte_bus_scan_mode {
>> @@ -226,6 +240,8 @@ struct rte_bus {
>>   	rte_bus_get_iommu_class_t get_iommu_class; /**< Get iommu class */
>>   	rte_bus_hotplug_handler_t hotplug_handler;
>>   						/**< handle hot plug on bus */
>> +	rte_bus_sigbus_handler_t sigbus_handler; /**< handle sigbus error */
>> +
>>   };
>>   
>>   /**
> One issue with handling sigbus is that you are going to trap program errors
> as well as hotplug. How can you distinguish between removed device and a
> buggy userspace program (or worse comprimised program)?
That is a problem which i have been considerate in this mechanism and do 
it in other patch, the way is that first check if the error domain is 
belong to the mmio device resource or not,
if it is will do new sigbus handler for hotplug, if not will mean that 
it is buggy user space program, will use generic sigbus handler to 
handler it.

Re: [dpdk-dev] [PATCH V4 3/9] bus: introduce sigbus handler

[Stephen Hemminger]

On Fri, 29 Jun 2018 18:30:42 +0800
Jeff Guo <jia.guo@intel.com> wrote:

> When device be hotplug, if data path still read/write device, the sigbus
> error will occur, this error need to be handled. So a handler need to be
> here to capture the signal and handle it correspondingly.
> 
> To handle sigbus error is a bus-specific behavior, this patch introduces
> a bus ops so that each kind of bus can implement its own logic.
> 
> Signed-off-by: Jeff Guo <jia.guo@intel.com>
> ---
> v4->v3:
> split patches to be small and clear.
> ---
>  lib/librte_eal/common/include/rte_bus.h | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/lib/librte_eal/common/include/rte_bus.h b/lib/librte_eal/common/include/rte_bus.h
> index 3642aeb..231bd3d 100644
> --- a/lib/librte_eal/common/include/rte_bus.h
> +++ b/lib/librte_eal/common/include/rte_bus.h
> @@ -181,6 +181,20 @@ typedef int (*rte_bus_parse_t)(const char *name, void *addr);
>  typedef int (*rte_bus_hotplug_handler_t)(struct rte_device *dev);
>  
>  /**
> + * Implementation a specific sigbus handler, which is responsible
> + * for handle the sigbus error which is original memory error, or specific
> + * memory error that caused of hot unplug.
> + * @param failure_addr
> + *	Pointer of the fault address of the sigbus error.
> + *
> + * @return
> + *	0 for success handle the sigbus.
> + *	1 for no handle the sigbus.
> + *	-1 for failed to handle the sigbus
> + */
> +typedef int (*rte_bus_sigbus_handler_t)(const void *failure_addr);
> +
> +/**
>   * Bus scan policies
>   */
>  enum rte_bus_scan_mode {
> @@ -226,6 +240,8 @@ struct rte_bus {
>  	rte_bus_get_iommu_class_t get_iommu_class; /**< Get iommu class */
>  	rte_bus_hotplug_handler_t hotplug_handler;
>  						/**< handle hot plug on bus */
> +	rte_bus_sigbus_handler_t sigbus_handler; /**< handle sigbus error */
> +
>  };
>  
>  /**

One issue with handling sigbus is that you are going to trap program errors
as well as hotplug. How can you distinguish between removed device and a
buggy userspace program (or worse comprimised program)?

[dpdk-dev] [PATCH V4 3/9] bus: introduce sigbus handler

[Jeff Guo]

When device be hotplug, if data path still read/write device, the sigbus
error will occur, this error need to be handled. So a handler need to be
here to capture the signal and handle it correspondingly.

To handle sigbus error is a bus-specific behavior, this patch introduces
a bus ops so that each kind of bus can implement its own logic.

Signed-off-by: Jeff Guo <jia.guo@intel.com>
---
v4->v3:
split patches to be small and clear.
---
 lib/librte_eal/common/include/rte_bus.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/lib/librte_eal/common/include/rte_bus.h b/lib/librte_eal/common/include/rte_bus.h
index 3642aeb..231bd3d 100644
--- a/lib/librte_eal/common/include/rte_bus.h
+++ b/lib/librte_eal/common/include/rte_bus.h
@@ -181,6 +181,20 @@ typedef int (*rte_bus_parse_t)(const char *name, void *addr);
 typedef int (*rte_bus_hotplug_handler_t)(struct rte_device *dev);
 
 /**
+ * Implementation a specific sigbus handler, which is responsible
+ * for handle the sigbus error which is original memory error, or specific
+ * memory error that caused of hot unplug.
+ * @param failure_addr
+ *	Pointer of the fault address of the sigbus error.
+ *
+ * @return
+ *	0 for success handle the sigbus.
+ *	1 for no handle the sigbus.
+ *	-1 for failed to handle the sigbus
+ */
+typedef int (*rte_bus_sigbus_handler_t)(const void *failure_addr);
+
+/**
  * Bus scan policies
  */
 enum rte_bus_scan_mode {
@@ -226,6 +240,8 @@ struct rte_bus {
 	rte_bus_get_iommu_class_t get_iommu_class; /**< Get iommu class */
 	rte_bus_hotplug_handler_t hotplug_handler;
 						/**< handle hot plug on bus */
+	rte_bus_sigbus_handler_t sigbus_handler; /**< handle sigbus error */
+
 };
 
 /**
-- 
2.7.4