[PATCH 2/3] drivers: hv: vmbus: add fuzz test attributes to sysfs

[Branden Bonaby <brandonbonaby94@gmail.com>]

Expose the test parameters as part of the sysfs channel attributes.
We will control the testing state via these attributes.

Signed-off-by: Branden Bonaby <brandonbonaby94@gmail.com>
---
 Documentation/ABI/stable/sysfs-bus-vmbus | 22 ++++++
 drivers/hv/vmbus_drv.c                   | 97 +++++++++++++++++++++++-
 2 files changed, 118 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/stable/sysfs-bus-vmbus b/Documentation/ABI/stable/sysfs-bus-vmbus
index 8e8d167eca31..239fcb6fdc75 100644
--- a/Documentation/ABI/stable/sysfs-bus-vmbus
+++ b/Documentation/ABI/stable/sysfs-bus-vmbus
@@ -185,3 +185,25 @@ Contact:        Michael Kelley <mikelley@microsoft.com>
 Description:    Total number of write operations that encountered an outbound
 		ring buffer full condition
 Users:          Debugging tools
+
+What:           /sys/bus/vmbus/devices/<UUID>/fuzz_test_state
+Date:           July 2019
+KernelVersion:  5.2
+Contact:        Branden Bonaby <brandonbonaby94@gmail.com>
+Description:    Fuzz testing status of a vmbus device, whether its in an ON
+		 state or a OFF state
+Users:          Debugging tools
+
+What:           /sys/bus/vmbus/devices/<UUID>/fuzz_test_buffer_delay
+Date:           July 2019
+KernelVersion:  5.2
+Contact:        Branden Bonaby <brandonbonaby94@gmail.com>
+Description:    Fuzz testing buffer delay value between 0 - 1000
+Users:          Debugging tools
+
+What:           /sys/bus/vmbus/devices/<UUID>/fuzz_test_message_delay
+Date:           July 2019
+KernelVersion:  5.2
+Contact:        Branden Bonaby <brandonbonaby94@gmail.com>
+Description:    Fuzz testing message delay value between 0 - 1000
+Users:          Debugging tools
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 92b1874b3eb3..0c71fd66ef81 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -22,7 +22,7 @@
 #include <linux/clockchips.h>
 #include <linux/cpu.h>
 #include <linux/sched/task_stack.h>
-
+#include <linux/kernel.h>
 #include <asm/mshyperv.h>
 #include <linux/notifier.h>
 #include <linux/ptrace.h>
@@ -584,6 +584,98 @@ static ssize_t driver_override_show(struct device *dev,
 }
 static DEVICE_ATTR_RW(driver_override);
 
+static ssize_t fuzz_test_state_store(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t count)
+{
+	struct hv_device *hv_dev = device_to_hv_device(dev);
+	struct vmbus_channel *channel = hv_dev->channel;
+	int state;
+	int delay = kstrtoint(buf, 0, &state);
+
+	if (delay)
+		return count;
+	if (state)
+		channel->fuzz_testing_state = 1;
+	else
+		channel->fuzz_testing_state = 0;
+	return count;
+}
+
+static ssize_t fuzz_test_state_show(struct device *dev,
+				    struct device_attribute *dev_attr,
+				    char *buf)
+{
+	struct hv_device *hv_dev = device_to_hv_device(dev);
+	struct vmbus_channel *channel = hv_dev->channel;
+
+	return sprintf(buf, "%u\n", channel->fuzz_testing_state);
+}
+static DEVICE_ATTR_RW(fuzz_test_state);
+
+static ssize_t fuzz_test_buffer_delay_store(struct device *dev,
+					    struct device_attribute *attr,
+					    const char *buf, size_t count)
+{
+	struct hv_device *hv_dev = device_to_hv_device(dev);
+	struct vmbus_channel *channel = hv_dev->channel;
+	int val;
+	int delay = kstrtoint(buf, 0, &val);
+
+	if (delay)
+		return count;
+	if (val >= 1 && val <= 1000)
+		channel->fuzz_testing_buffer_delay = val;
+	/*Best to not use else statement here since we want
+	 *the buffer delay to remain the same if val > 1000
+	 */
+	else if (val <= 0)
+		channel->fuzz_testing_buffer_delay = 0;
+	return count;
+}
+
+static ssize_t fuzz_test_buffer_delay_show(struct device *dev,
+					   struct device_attribute *dev_attr,
+					   char *buf)
+{
+	struct hv_device *hv_dev = device_to_hv_device(dev);
+	struct vmbus_channel *channel = hv_dev->channel;
+
+	return sprintf(buf, "%u\n", channel->fuzz_testing_buffer_delay);
+}
+static DEVICE_ATTR_RW(fuzz_test_buffer_delay);
+
+static ssize_t fuzz_test_message_delay_store(struct device *dev,
+					     struct device_attribute *attr,
+					     const char *buf, size_t count)
+{
+	struct hv_device *hv_dev = device_to_hv_device(dev);
+	struct vmbus_channel *channel = hv_dev->channel;
+	int val;
+	int delay = kstrtoint(buf, 0, &val);
+
+	if (delay)
+		return count;
+	if (val >= 1 && val <= 1000)
+		channel->fuzz_testing_message_delay = val;
+	/*Best to not use else statement here since we want
+	 *the message delay to remain the same if val > 1000
+	 */
+	else if (val <= 0)
+		channel->fuzz_testing_message_delay = 0;
+	return count;
+}
+
+static ssize_t fuzz_test_message_delay_show(struct device *dev,
+					    struct device_attribute *dev_attr,
+					    char *buf)
+{
+	struct hv_device *hv_dev = device_to_hv_device(dev);
+	struct vmbus_channel *channel = hv_dev->channel;
+
+	return sprintf(buf, "%u\n", channel->fuzz_testing_message_delay);
+}
+static DEVICE_ATTR_RW(fuzz_test_message_delay);
 /* Set up per device attributes in /sys/bus/vmbus/devices/<bus device> */
 static struct attribute *vmbus_dev_attrs[] = {
 	&dev_attr_id.attr,
@@ -615,6 +707,9 @@ static struct attribute *vmbus_dev_attrs[] = {
 	&dev_attr_vendor.attr,
 	&dev_attr_device.attr,
 	&dev_attr_driver_override.attr,
+	&dev_attr_fuzz_test_state.attr,
+	&dev_attr_fuzz_test_buffer_delay.attr,
+	&dev_attr_fuzz_test_message_delay.attr,
 	NULL,
 };
 
-- 
2.17.1