Commit 244009b0 authored by Dave Jiang's avatar Dave Jiang Committed by Vinod Koul
Browse files

dmaengine: idxd: expose fault counters to sysfs 



Expose cr_faults and cr_fault_failures counters to the user space. This
allows a user app to keep track of how many fault the application is
causing with the completion record (CR) and also the number of failures
of the CR writeback. Having a high number of cr_fault_failures is bad as
the app is submitting descriptors with the CR addresses that are bad. User
monitoring daemon may want to consider killing the application as it may be
malicious and attempting to flood the device event log.

Tested-by: default avatarTony Zhu <tony.zhu@intel.com>
Signed-off-by: default avatarDave Jiang <dave.jiang@intel.com>
Co-developed-by: default avatarFenghua Yu <fenghua.yu@intel.com>
Signed-off-by: default avatarFenghua Yu <fenghua.yu@intel.com>
Link: https://lore.kernel.org/r/20230407203143.2189681-15-fenghua.yu@intel.com


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent e6fd6d7e

Documentation/ABI/stable/sysfs-driver-dma-idxd

+17 −0
Original line number Diff line number Diff line
@@ -318,3 +318,20 @@ Description: Allows control of the number of batch descriptors that can be 
		1 (1/2 of max value), 2 (1/4 of the max value), and 3 (1/8 of

		the max value). It's visible only on platforms that support

		the capability.



What:		/sys/bus/dsa/devices/wq<m>.<n>/dsa<x>\!wq<m>.<n>/file<y>/cr_faults

Date:		Sept 14, 2022

KernelVersion:	6.4.0

Contact:	dmaengine@vger.kernel.org

Description:	Show the number of Completion Record (CR) faults this application

		has caused.



What:		/sys/bus/dsa/devices/wq<m>.<n>/dsa<x>\!wq<m>.<n>/file<y>/cr_fault_failures

Date:		Sept 14, 2022

KernelVersion:	6.4.0

Contact:	dmaengine@vger.kernel.org

Description:	Show the number of Completion Record (CR) faults failures that this

		application has caused. The failure counter is incremented when the

		driver cannot fault in the address for the CR. Typically this is caused

		by a bad address programmed in the submitted descriptor or a malicious

		submitter is using bad CR address on purpose.

drivers/dma/idxd/cdev.c

+46 −0
Original line number Diff line number Diff line
@@ -61,6 +61,51 @@ static inline struct idxd_user_context *dev_to_uctx(struct device *dev) 
	return container_of(idxd_dev, struct idxd_user_context, idxd_dev);

}



static ssize_t cr_faults_show(struct device *dev, struct device_attribute *attr, char *buf)

{

	struct idxd_user_context *ctx = dev_to_uctx(dev);



	return sysfs_emit(buf, "%llu\n", ctx->counters[COUNTER_FAULTS]);

}

static DEVICE_ATTR_RO(cr_faults);



static ssize_t cr_fault_failures_show(struct device *dev,

				      struct device_attribute *attr, char *buf)

{

	struct idxd_user_context *ctx = dev_to_uctx(dev);



	return sysfs_emit(buf, "%llu\n", ctx->counters[COUNTER_FAULT_FAILS]);

}

static DEVICE_ATTR_RO(cr_fault_failures);



static struct attribute *cdev_file_attributes[] = {

	&dev_attr_cr_faults.attr,

	&dev_attr_cr_fault_failures.attr,

	NULL

};



static umode_t cdev_file_attr_visible(struct kobject *kobj, struct attribute *a, int n)

{

	struct device *dev = container_of(kobj, typeof(*dev), kobj);

	struct idxd_user_context *ctx = dev_to_uctx(dev);

	struct idxd_wq *wq = ctx->wq;



	if (!wq_pasid_enabled(wq))

		return 0;



	return a->mode;

}



static const struct attribute_group cdev_file_attribute_group = {

	.attrs = cdev_file_attributes,

	.is_visible = cdev_file_attr_visible,

};



static const struct attribute_group *cdev_file_attribute_groups[] = {

	&cdev_file_attribute_group,

	NULL

};



static void idxd_file_dev_release(struct device *dev)

{

	struct idxd_user_context *ctx = dev_to_uctx(dev);
@@ -100,6 +145,7 @@ static void idxd_file_dev_release(struct device *dev) 
static struct device_type idxd_cdev_file_type = {

	.name = "idxd_file",

	.release = idxd_file_dev_release,

	.groups = cdev_file_attribute_groups,

};



static void idxd_cdev_dev_release(struct device *dev)