scftorture: Count single_rpc offline failures in statistics outputgrafted

scf_torture_stats_print() aggregates each invoker thread's counters
into a local scf_statistics structure before printing, but the
n_single_rpc_ofl field is missing from the aggregation loop.  As a
result, the "single_rpc_ofl" value printed in the statistics line is
always zero, even when smp_call_function_single() invocations for the
RPC test have failed due to offline CPUs and been counted by the
invoker threads.

Add the missing accumulation so that the printed value reflects the
actual counts.

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

1 files changed, 181 insertions, 0 deletions

diff --git a/drivers/virt/vmgenid.c b/drivers/virt/vmgenid.c
new file mode 100644
index 000000000..66135eac3
--- /dev/null
+++ b/drivers/virt/vmgenid.c
@@ -0,0 +1,181 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2022 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ *
+ * The "Virtual Machine Generation ID" is exposed via ACPI or DT and changes when a
+ * virtual machine forks or is cloned. This driver exists for shepherding that
+ * information to random.c.
+ */
+
+#include <linux/acpi.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/random.h>
+
+ACPI_MODULE_NAME("vmgenid");
+
+enum { VMGENID_SIZE = 16 };
+
+struct vmgenid_state {
+	u8 *next_id;
+	u8 this_id[VMGENID_SIZE];
+};
+
+static void vmgenid_notify(struct device *device)
+{
+	struct vmgenid_state *state = device->driver_data;
+	u8 old_id[VMGENID_SIZE];
+
+	memcpy(old_id, state->this_id, sizeof(old_id));
+	memcpy(state->this_id, state->next_id, sizeof(state->this_id));
+	if (!memcmp(old_id, state->this_id, sizeof(old_id)))
+		return;
+	add_vmfork_randomness(state->this_id, sizeof(state->this_id));
+}
+
+static void setup_vmgenid_state(struct vmgenid_state *state, void *virt_addr)
+{
+	state->next_id = virt_addr;
+	memcpy(state->this_id, state->next_id, sizeof(state->this_id));
+	add_device_randomness(state->this_id, sizeof(state->this_id));
+}
+
+#ifdef CONFIG_ACPI
+static void vmgenid_acpi_handler(acpi_handle __always_unused handle,
+				 u32 __always_unused event, void *dev)
+{
+	vmgenid_notify(dev);
+}
+
+static int vmgenid_add_acpi(struct device *dev, struct vmgenid_state *state)
+{
+	struct acpi_device *device = ACPI_COMPANION(dev);
+	struct acpi_buffer parsed = { ACPI_ALLOCATE_BUFFER };
+	union acpi_object *obj;
+	phys_addr_t phys_addr;
+	acpi_status status;
+	void *virt_addr;
+	int ret = 0;
+
+	status = acpi_evaluate_object(device->handle, "ADDR", NULL, &parsed);
+	if (ACPI_FAILURE(status)) {
+		ACPI_EXCEPTION((AE_INFO, status, "Evaluating ADDR"));
+		return -ENODEV;
+	}
+	obj = parsed.pointer;
+	if (!obj || obj->type != ACPI_TYPE_PACKAGE || obj->package.count != 2 ||
+	    obj->package.elements[0].type != ACPI_TYPE_INTEGER ||
+	    obj->package.elements[1].type != ACPI_TYPE_INTEGER) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	phys_addr = (obj->package.elements[0].integer.value << 0) |
+		    (obj->package.elements[1].integer.value << 32);
+
+	virt_addr = devm_memremap(&device->dev, phys_addr, VMGENID_SIZE, MEMREMAP_WB);
+	if (IS_ERR(virt_addr)) {
+		ret = PTR_ERR(virt_addr);
+		goto out;
+	}
+	setup_vmgenid_state(state, virt_addr);
+
+	status = acpi_install_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
+					     vmgenid_acpi_handler, dev);
+	if (ACPI_FAILURE(status)) {
+		ret = -ENODEV;
+		goto out;
+	}
+
+	dev->driver_data = state;
+out:
+	ACPI_FREE(parsed.pointer);
+	return ret;
+}
+#else
+static int vmgenid_add_acpi(struct device *dev, struct vmgenid_state *state)
+{
+	return -EINVAL;
+}
+#endif
+
+static irqreturn_t vmgenid_of_irq_handler(int __always_unused irq, void *dev)
+{
+	vmgenid_notify(dev);
+	return IRQ_HANDLED;
+}
+
+static int vmgenid_add_of(struct platform_device *pdev,
+			  struct vmgenid_state *state)
+{
+	void *virt_addr;
+	int ret;
+
+	virt_addr = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
+	if (IS_ERR(virt_addr))
+		return PTR_ERR(virt_addr);
+
+	setup_vmgenid_state(state, virt_addr);
+
+	ret = platform_get_irq(pdev, 0);
+	if (ret < 0)
+		return ret;
+
+	ret = devm_request_irq(&pdev->dev, ret, vmgenid_of_irq_handler,
+			       IRQF_SHARED, "vmgenid", &pdev->dev);
+	if (ret < 0)
+		return ret;
+
+	pdev->dev.driver_data = state;
+	return 0;
+}
+
+static int vmgenid_add(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct vmgenid_state *state;
+	int ret;
+
+	state = devm_kmalloc(dev, sizeof(*state), GFP_KERNEL);
+	if (!state)
+		return -ENOMEM;
+
+	if (dev->of_node)
+		ret = vmgenid_add_of(pdev, state);
+	else
+		ret = vmgenid_add_acpi(dev, state);
+
+	if (ret < 0)
+		devm_kfree(dev, state);
+	return ret;
+}
+
+static const struct of_device_id vmgenid_of_ids[] = {
+	{ .compatible = "microsoft,vmgenid", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, vmgenid_of_ids);
+
+static const struct acpi_device_id vmgenid_acpi_ids[] = {
+	{ "VMGENCTR", 0 },
+	{ "VM_GEN_COUNTER", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, vmgenid_acpi_ids);
+
+static struct platform_driver vmgenid_plaform_driver = {
+	.probe      = vmgenid_add,
+	.driver     = {
+		.name   = "vmgenid",
+		.acpi_match_table = vmgenid_acpi_ids,
+		.of_match_table = vmgenid_of_ids,
+	},
+};
+
+module_platform_driver(vmgenid_plaform_driver)
+
+MODULE_DESCRIPTION("Virtual Machine Generation ID");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Jason A. Donenfeld <Jason@zx2c4.com>");