[PATCH v8] add support for pci in the pvpanic driver

[PATCH v8] add support for pci in the pvpanic driver

[Mihai Carabas]

This patchset adds support for PCI in the pvpanic driver. The device already
got in qemu [1].

v2:
- mmio -> MMIO, pci -> PCI suggested by Randy Dunlap.
- group pvpanic-common.c and mmio.c in the same module. The intention was to
  have only one module and the common code splitted up to be re-used by the
  pvpanic-pci module in the next patch.
- add a new patch where add the licenses for the new files (when I moved the
  code to mmio.c I preserved the original licenses there)
- properly clean-up PCI device when driver removed.

v3:
- drop patch 3 with licenses and add them when creating files
- create a new patch (2/3) which allowes multiple pvpanic instances

v4:
- fix Makefile in patch 1/3 and 3/3 for pvpanic.o as suggested by Arnd

v5:
- rebase on 5.12
- fix a warning caused by one of the patches

v6:
- remove pr_fmt as were not used
- "remove" functions of type void
- moved events/capability per-device structure

v7:
- rebased on char-misc-next

v8:
- fixed build error while compiling only the first patch (accept
  my apologizes Greg)
- build and tested pvpanic functionality after each applied patch

How to test:

Run a VM with latest qemu which has the pvpanic-pci device:
qemu-system-aarch64  -device pvpanic-pci

Generate a panic in the guest:
echo 1 > /proc/sys/kernel/sysrq
echo c > /proc/sysrq-trigger

Observe in the QMP console the panic events received by the device:

{"timestamp": {"seconds": 1613122186, "microseconds": 141729}, "event":
"GUEST_PANICKED", "data": {"action": "pause"}}

{"timestamp": {"seconds": 1613122186, "microseconds": 141833}, "event":
"GUEST_PANICKED", "data": {"action": "poweroff"}}

{"timestamp": {"seconds": 1613122186, "microseconds": 141896}, "event":
"SHUTDOWN", "data": {"guest": true, "reason": "guest-panic"}}


[1] https://github.com/qemu/qemu/commit/9df52f58e76e904fb141b10318362d718f470db2


Mihai Carabas (3):
  misc/pvpanic: split-up generic and platform dependent code
  misc/pvpanic: probe multiple instances
  misc/pvpanic: add PCI driver

 .../ABI/testing/sysfs-bus-pci-devices-pvpanic      |   4 +-
 drivers/misc/Kconfig                               |   9 +-
 drivers/misc/Makefile                              |   2 +-
 drivers/misc/pvpanic.c                             | 161 ---------------------
 drivers/misc/pvpanic/Kconfig                       |  27 ++++
 drivers/misc/pvpanic/Makefile                      |   8 +
 drivers/misc/pvpanic/pvpanic-mmio.c                | 144 ++++++++++++++++++
 drivers/misc/pvpanic/pvpanic-pci.c                 | 125 ++++++++++++++++
 drivers/misc/pvpanic/pvpanic.c                     | 113 +++++++++++++++
 drivers/misc/pvpanic/pvpanic.h                     |  21 +++
 10 files changed, 443 insertions(+), 171 deletions(-)
 delete mode 100644 drivers/misc/pvpanic.c
 create mode 100644 drivers/misc/pvpanic/Kconfig
 create mode 100644 drivers/misc/pvpanic/Makefile
 create mode 100644 drivers/misc/pvpanic/pvpanic-mmio.c
 create mode 100644 drivers/misc/pvpanic/pvpanic-pci.c
 create mode 100644 drivers/misc/pvpanic/pvpanic.c
 create mode 100644 drivers/misc/pvpanic/pvpanic.h

-- 
1.8.3.1

[PATCH v8 1/3] misc/pvpanic: split-up generic and platform dependent code

[Mihai Carabas]

Split-up generic and platform dependent code in order to be able to re-use
generic event handling code in pvpanic PCI device driver in the next patches.

The code from pvpanic.c was split in two new files:
- pvpanic.c: generic code that handles pvpanic events
- pvpanic-mmio.c: platform/bus dependent code

Signed-off-by: Mihai Carabas <mihai.carabas@oracle.com>
---
 drivers/misc/Kconfig                |   9 +-
 drivers/misc/Makefile               |   2 +-
 drivers/misc/pvpanic.c              | 161 ------------------------------------
 drivers/misc/pvpanic/Kconfig        |  19 +++++
 drivers/misc/pvpanic/Makefile       |   7 ++
 drivers/misc/pvpanic/pvpanic-mmio.c | 134 ++++++++++++++++++++++++++++++
 drivers/misc/pvpanic/pvpanic.c      |  81 ++++++++++++++++++
 drivers/misc/pvpanic/pvpanic.h      |  15 ++++
 8 files changed, 258 insertions(+), 170 deletions(-)
 delete mode 100644 drivers/misc/pvpanic.c
 create mode 100644 drivers/misc/pvpanic/Kconfig
 create mode 100644 drivers/misc/pvpanic/Makefile
 create mode 100644 drivers/misc/pvpanic/pvpanic-mmio.c
 create mode 100644 drivers/misc/pvpanic/pvpanic.c
 create mode 100644 drivers/misc/pvpanic/pvpanic.h

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index f532c59..c5f20e9 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -427,14 +427,6 @@ config MISC_RTSX
 	tristate
 	default MISC_RTSX_PCI || MISC_RTSX_USB
 
-config PVPANIC
-	tristate "pvpanic device support"
-	depends on HAS_IOMEM && (ACPI || OF)
-	help
-	  This driver provides support for the pvpanic device.  pvpanic is
-	  a paravirtualized device provided by QEMU; it lets a virtual machine
-	  (guest) communicate panic events to the host.
-
 config HISI_HIKEY_USB
 	tristate "USB GPIO Hub on HiSilicon Hikey 960/970 Platform"
 	depends on (OF && GPIOLIB) || COMPILE_TEST
@@ -461,4 +453,5 @@ source "drivers/misc/bcm-vk/Kconfig"
 source "drivers/misc/cardreader/Kconfig"
 source "drivers/misc/habanalabs/Kconfig"
 source "drivers/misc/uacce/Kconfig"
+source "drivers/misc/pvpanic/Kconfig"
 endmenu
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 99b6f15..fd5f87e 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -51,7 +51,7 @@ obj-$(CONFIG_PCI_ENDPOINT_TEST)	+= pci_endpoint_test.o
 obj-$(CONFIG_OCXL)		+= ocxl/
 obj-$(CONFIG_BCM_VK)		+= bcm-vk/
 obj-y				+= cardreader/
-obj-$(CONFIG_PVPANIC)   	+= pvpanic.o
+obj-$(CONFIG_PVPANIC)   	+= pvpanic/
 obj-$(CONFIG_HABANA_AI)		+= habanalabs/
 obj-$(CONFIG_UACCE)		+= uacce/
 obj-$(CONFIG_XILINX_SDFEC)	+= xilinx_sdfec.o
diff --git a/drivers/misc/pvpanic.c b/drivers/misc/pvpanic.c
deleted file mode 100644
index f1655f5..00000000
--- a/drivers/misc/pvpanic.c
+++ /dev/null
@@ -1,161 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0+
-/*
- *  Pvpanic Device Support
- *
- *  Copyright (C) 2013 Fujitsu.
- *  Copyright (C) 2018 ZTE.
- */
-
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
-#include <linux/io.h>
-#include <linux/kernel.h>
-#include <linux/kexec.h>
-#include <linux/mod_devicetable.h>
-#include <linux/module.h>
-#include <linux/platform_device.h>
-#include <linux/types.h>
-
-#include <uapi/misc/pvpanic.h>
-
-static void __iomem *base;
-static unsigned int capability = PVPANIC_PANICKED | PVPANIC_CRASH_LOADED;
-static unsigned int events;
-
-static ssize_t capability_show(struct device *dev,
-			       struct device_attribute *attr, char *buf)
-{
-	return sysfs_emit(buf, "%x\n", capability);
-}
-static DEVICE_ATTR_RO(capability);
-
-static ssize_t events_show(struct device *dev,  struct device_attribute *attr, char *buf)
-{
-	return sysfs_emit(buf, "%x\n", events);
-}
-
-static ssize_t events_store(struct device *dev,  struct device_attribute *attr,
-			    const char *buf, size_t count)
-{
-	unsigned int tmp;
-	int err;
-
-	err = kstrtouint(buf, 16, &tmp);
-	if (err)
-		return err;
-
-	if ((tmp & capability) != tmp)
-		return -EINVAL;
-
-	events = tmp;
-
-	return count;
-
-}
-static DEVICE_ATTR_RW(events);
-
-static struct attribute *pvpanic_dev_attrs[] = {
-	&dev_attr_capability.attr,
-	&dev_attr_events.attr,
-	NULL
-};
-ATTRIBUTE_GROUPS(pvpanic_dev);
-
-MODULE_AUTHOR("Hu Tao <hutao@cn.fujitsu.com>");
-MODULE_DESCRIPTION("pvpanic device driver");
-MODULE_LICENSE("GPL");
-
-static void
-pvpanic_send_event(unsigned int event)
-{
-	if (event & capability & events)
-		iowrite8(event, base);
-}
-
-static int
-pvpanic_panic_notify(struct notifier_block *nb, unsigned long code,
-		     void *unused)
-{
-	unsigned int event = PVPANIC_PANICKED;
-
-	if (kexec_crash_loaded())
-		event = PVPANIC_CRASH_LOADED;
-
-	pvpanic_send_event(event);
-
-	return NOTIFY_DONE;
-}
-
-static struct notifier_block pvpanic_panic_nb = {
-	.notifier_call = pvpanic_panic_notify,
-	.priority = 1, /* let this called before broken drm_fb_helper */
-};
-
-static int pvpanic_mmio_probe(struct platform_device *pdev)
-{
-	struct device *dev = &pdev->dev;
-	struct resource *res;
-
-	res = platform_get_mem_or_io(pdev, 0);
-	if (!res)
-		return -EINVAL;
-
-	switch (resource_type(res)) {
-	case IORESOURCE_IO:
-		base = devm_ioport_map(dev, res->start, resource_size(res));
-		if (!base)
-			return -ENOMEM;
-		break;
-	case IORESOURCE_MEM:
-		base = devm_ioremap_resource(dev, res);
-		if (IS_ERR(base))
-			return PTR_ERR(base);
-		break;
-	default:
-		return -EINVAL;
-	}
-
-	/* initlize capability by RDPT */
-	capability &= ioread8(base);
-	events = capability;
-
-	if (capability)
-		atomic_notifier_chain_register(&panic_notifier_list,
-					       &pvpanic_panic_nb);
-
-	return 0;
-}
-
-static int pvpanic_mmio_remove(struct platform_device *pdev)
-{
-
-	if (capability)
-		atomic_notifier_chain_unregister(&panic_notifier_list,
-						 &pvpanic_panic_nb);
-
-	return 0;
-}
-
-static const struct of_device_id pvpanic_mmio_match[] = {
-	{ .compatible = "qemu,pvpanic-mmio", },
-	{}
-};
-MODULE_DEVICE_TABLE(of, pvpanic_mmio_match);
-
-static const struct acpi_device_id pvpanic_device_ids[] = {
-	{ "QEMU0001", 0 },
-	{ "", 0 }
-};
-MODULE_DEVICE_TABLE(acpi, pvpanic_device_ids);
-
-static struct platform_driver pvpanic_mmio_driver = {
-	.driver = {
-		.name = "pvpanic-mmio",
-		.of_match_table = pvpanic_mmio_match,
-		.acpi_match_table = pvpanic_device_ids,
-		.dev_groups = pvpanic_dev_groups,
-	},
-	.probe = pvpanic_mmio_probe,
-	.remove = pvpanic_mmio_remove,
-};
-module_platform_driver(pvpanic_mmio_driver);
diff --git a/drivers/misc/pvpanic/Kconfig b/drivers/misc/pvpanic/Kconfig
new file mode 100644
index 00000000..454f1ee
--- /dev/null
+++ b/drivers/misc/pvpanic/Kconfig
@@ -0,0 +1,19 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Pvpanic Kconfig
+#
+# Copyright (C) 2021 Oracle.
+#
+
+config PVPANIC
+	bool "pvpanic device support"
+	help
+	  This option allows to select a specific pvpanic device driver.
+	  pvpanic is a paravirtualized device provided by QEMU; it lets
+	  a virtual machine (guest) communicate panic events to the host.
+
+config PVPANIC_MMIO
+	tristate "pvpanic MMIO device support"
+	depends on HAS_IOMEM && (ACPI || OF) && PVPANIC
+	help
+	  This driver provides support for the MMIO pvpanic device.
diff --git a/drivers/misc/pvpanic/Makefile b/drivers/misc/pvpanic/Makefile
new file mode 100644
index 00000000..e12a2dc
--- /dev/null
+++ b/drivers/misc/pvpanic/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Pvpanic Makefile
+#
+# Copyright (C) 2021 Oracle.
+#
+obj-$(CONFIG_PVPANIC_MMIO)	+= pvpanic.o pvpanic-mmio.o
diff --git a/drivers/misc/pvpanic/pvpanic-mmio.c b/drivers/misc/pvpanic/pvpanic-mmio.c
new file mode 100644
index 00000000..d7bf7db
--- /dev/null
+++ b/drivers/misc/pvpanic/pvpanic-mmio.c
@@ -0,0 +1,134 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *  Pvpanic MMIO Device Support
+ *
+ *  Copyright (C) 2013 Fujitsu.
+ *  Copyright (C) 2018 ZTE.
+ *  Copyright (C) 2021 Oracle.
+ */
+
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/kexec.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+
+#include <uapi/misc/pvpanic.h>
+
+#include "pvpanic.h"
+
+MODULE_AUTHOR("Hu Tao <hutao@cn.fujitsu.com>");
+MODULE_DESCRIPTION("pvpanic-mmio device driver");
+MODULE_LICENSE("GPL");
+
+static void __iomem *base;
+static unsigned int capability = PVPANIC_PANICKED | PVPANIC_CRASH_LOADED;
+static unsigned int events;
+
+static ssize_t capability_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%x\n", capability);
+}
+static DEVICE_ATTR_RO(capability);
+
+static ssize_t events_show(struct device *dev,  struct device_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%x\n", events);
+}
+
+static ssize_t events_store(struct device *dev,  struct device_attribute *attr,
+			    const char *buf, size_t count)
+{
+	unsigned int tmp;
+	int err;
+
+	err = kstrtouint(buf, 16, &tmp);
+	if (err)
+		return err;
+
+	if ((tmp & capability) != tmp)
+		return -EINVAL;
+
+	events = tmp;
+
+	pvpanic_set_events(events);
+
+	return count;
+
+}
+static DEVICE_ATTR_RW(events);
+
+static struct attribute *pvpanic_mmio_dev_attrs[] = {
+	&dev_attr_capability.attr,
+	&dev_attr_events.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(pvpanic_mmio_dev);
+
+static int pvpanic_mmio_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct resource *res;
+
+	res = platform_get_mem_or_io(pdev, 0);
+	if (!res)
+		return -EINVAL;
+
+	switch (resource_type(res)) {
+	case IORESOURCE_IO:
+		base = devm_ioport_map(dev, res->start, resource_size(res));
+		if (!base)
+			return -ENOMEM;
+		break;
+	case IORESOURCE_MEM:
+		base = devm_ioremap_resource(dev, res);
+		if (IS_ERR(base))
+			return PTR_ERR(base);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/* initlize capability by RDPT */
+	capability &= ioread8(base);
+	events = capability;
+
+	pvpanic_probe(base, capability);
+
+	return 0;
+}
+
+static int pvpanic_mmio_remove(struct platform_device *pdev)
+{
+
+	pvpanic_remove();
+
+	return 0;
+}
+
+static const struct of_device_id pvpanic_mmio_match[] = {
+	{ .compatible = "qemu,pvpanic-mmio", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, pvpanic_mmio_match);
+
+static const struct acpi_device_id pvpanic_device_ids[] = {
+	{ "QEMU0001", 0 },
+	{ "", 0 }
+};
+MODULE_DEVICE_TABLE(acpi, pvpanic_device_ids);
+
+static struct platform_driver pvpanic_mmio_driver = {
+	.driver = {
+		.name = "pvpanic-mmio",
+		.of_match_table = pvpanic_mmio_match,
+		.acpi_match_table = pvpanic_device_ids,
+		.dev_groups = pvpanic_mmio_dev_groups,
+	},
+	.probe = pvpanic_mmio_probe,
+	.remove = pvpanic_mmio_remove,
+};
+module_platform_driver(pvpanic_mmio_driver);
diff --git a/drivers/misc/pvpanic/pvpanic.c b/drivers/misc/pvpanic/pvpanic.c
new file mode 100644
index 00000000..a9605f9
--- /dev/null
+++ b/drivers/misc/pvpanic/pvpanic.c
@@ -0,0 +1,81 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *  Pvpanic Device Support
+ *
+ *  Copyright (C) 2013 Fujitsu.
+ *  Copyright (C) 2018 ZTE.
+ *  Copyright (C) 2021 Oracle.
+ */
+
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/kexec.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+
+#include <uapi/misc/pvpanic.h>
+
+#include "pvpanic.h"
+
+MODULE_AUTHOR("Mihai Carabas <mihai.carabas@oracle.com>");
+MODULE_DESCRIPTION("pvpanic device driver ");
+MODULE_LICENSE("GPL");
+
+static void __iomem *base;
+static unsigned int capability;
+static unsigned int events;
+
+static void
+pvpanic_send_event(unsigned int event)
+{
+	if (event & capability & events)
+		iowrite8(event, base);
+}
+
+static int
+pvpanic_panic_notify(struct notifier_block *nb, unsigned long code,
+		     void *unused)
+{
+	unsigned int event = PVPANIC_PANICKED;
+
+	if (kexec_crash_loaded())
+		event = PVPANIC_CRASH_LOADED;
+
+	pvpanic_send_event(event);
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block pvpanic_panic_nb = {
+	.notifier_call = pvpanic_panic_notify,
+	.priority = 1, /* let this called before broken drm_fb_helper */
+};
+
+void pvpanic_probe(void __iomem *pbase, unsigned int dev_cap)
+{
+	base = pbase;
+	capability = dev_cap;
+	events = capability;
+
+	if (capability)
+		atomic_notifier_chain_register(&panic_notifier_list,
+					       &pvpanic_panic_nb);
+}
+EXPORT_SYMBOL_GPL(pvpanic_probe);
+
+void pvpanic_remove(void)
+{
+	if (capability)
+		atomic_notifier_chain_unregister(&panic_notifier_list,
+						 &pvpanic_panic_nb);
+	base = NULL;
+}
+EXPORT_SYMBOL_GPL(pvpanic_remove);
+
+void pvpanic_set_events(unsigned int dev_events)
+{
+	events = dev_events;
+}
+EXPORT_SYMBOL_GPL(pvpanic_set_events);
diff --git a/drivers/misc/pvpanic/pvpanic.h b/drivers/misc/pvpanic/pvpanic.h
new file mode 100644
index 00000000..3abe15f
--- /dev/null
+++ b/drivers/misc/pvpanic/pvpanic.h
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *  Pvpanic Device Support
+ *
+ *  Copyright (C) 2021 Oracle.
+ */
+
+#ifndef PVPANIC_H_
+#define PVPANIC_H_
+
+void pvpanic_probe(void __iomem *base, unsigned int dev_cap);
+void pvpanic_remove(void);
+void pvpanic_set_events(unsigned int dev_events);
+
+#endif /* PVPANIC_H_ */
-- 
1.8.3.1

[PATCH v8 2/3] misc/pvpanic: probe multiple instances

[Mihai Carabas]

Create the mecahism that allows multiple pvpanic instances to call
pvpanic_probe and receive panic events. A global list will retain all the
mapped addresses where to write panic events.

Signed-off-by: Mihai Carabas <mihai.carabas@oracle.com>
---
 drivers/misc/pvpanic/pvpanic-mmio.c | 42 +++++++++++++---------
 drivers/misc/pvpanic/pvpanic.c      | 72 ++++++++++++++++++++++++++-----------
 drivers/misc/pvpanic/pvpanic.h      | 12 +++++--
 3 files changed, 87 insertions(+), 39 deletions(-)

diff --git a/drivers/misc/pvpanic/pvpanic-mmio.c b/drivers/misc/pvpanic/pvpanic-mmio.c
index d7bf7db..4c08417 100644
--- a/drivers/misc/pvpanic/pvpanic-mmio.c
+++ b/drivers/misc/pvpanic/pvpanic-mmio.c
@@ -14,6 +14,7 @@
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/types.h>
+#include <linux/slab.h>
 
 #include <uapi/misc/pvpanic.h>
 
@@ -23,25 +24,26 @@
 MODULE_DESCRIPTION("pvpanic-mmio device driver");
 MODULE_LICENSE("GPL");
 
-static void __iomem *base;
-static unsigned int capability = PVPANIC_PANICKED | PVPANIC_CRASH_LOADED;
-static unsigned int events;
-
 static ssize_t capability_show(struct device *dev,
 			       struct device_attribute *attr, char *buf)
 {
-	return sysfs_emit(buf, "%x\n", capability);
+	struct pvpanic_instance *pi = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%x\n", pi->capability);
 }
 static DEVICE_ATTR_RO(capability);
 
 static ssize_t events_show(struct device *dev,  struct device_attribute *attr, char *buf)
 {
-	return sysfs_emit(buf, "%x\n", events);
+	struct pvpanic_instance *pi = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%x\n", pi->events);
 }
 
 static ssize_t events_store(struct device *dev,  struct device_attribute *attr,
 			    const char *buf, size_t count)
 {
+	struct pvpanic_instance *pi = dev_get_drvdata(dev);
 	unsigned int tmp;
 	int err;
 
@@ -49,15 +51,12 @@ static ssize_t events_store(struct device *dev,  struct device_attribute *attr,
 	if (err)
 		return err;
 
-	if ((tmp & capability) != tmp)
+	if ((tmp & pi->capability) != tmp)
 		return -EINVAL;
 
-	events = tmp;
-
-	pvpanic_set_events(events);
+	pi->events = tmp;
 
 	return count;
-
 }
 static DEVICE_ATTR_RW(events);
 
@@ -71,7 +70,9 @@ static ssize_t events_store(struct device *dev,  struct device_attribute *attr,
 static int pvpanic_mmio_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
+	struct pvpanic_instance *pi;
 	struct resource *res;
+	void __iomem *base;
 
 	res = platform_get_mem_or_io(pdev, 0);
 	if (!res)
@@ -92,19 +93,28 @@ static int pvpanic_mmio_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
+	pi = kmalloc(sizeof(*pi), GFP_ATOMIC);
+	if (!pi)
+		return -ENOMEM;
+
+	pi->base = base;
+	pi->capability = PVPANIC_PANICKED | PVPANIC_CRASH_LOADED;
+
 	/* initlize capability by RDPT */
-	capability &= ioread8(base);
-	events = capability;
+	pi->capability &= ioread8(base);
+	pi->events = pi->capability;
 
-	pvpanic_probe(base, capability);
+	dev_set_drvdata(dev, pi);
 
-	return 0;
+	return pvpanic_probe(pi);
 }
 
 static int pvpanic_mmio_remove(struct platform_device *pdev)
 {
+	struct pvpanic_instance *pi = dev_get_drvdata(&pdev->dev);
 
-	pvpanic_remove();
+	pvpanic_remove(pi);
+	kfree(pi);
 
 	return 0;
 }
diff --git a/drivers/misc/pvpanic/pvpanic.c b/drivers/misc/pvpanic/pvpanic.c
index a9605f9..804099c 100644
--- a/drivers/misc/pvpanic/pvpanic.c
+++ b/drivers/misc/pvpanic/pvpanic.c
@@ -14,6 +14,8 @@
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/types.h>
+#include <linux/cdev.h>
+#include <linux/list.h>
 
 #include <uapi/misc/pvpanic.h>
 
@@ -23,15 +25,20 @@
 MODULE_DESCRIPTION("pvpanic device driver ");
 MODULE_LICENSE("GPL");
 
-static void __iomem *base;
-static unsigned int capability;
-static unsigned int events;
+struct list_head pvpanic_list;
+spinlock_t pvpanic_lock;
 
 static void
 pvpanic_send_event(unsigned int event)
 {
-	if (event & capability & events)
-		iowrite8(event, base);
+	struct pvpanic_instance *pi_cur;
+
+	spin_lock(&pvpanic_lock);
+	list_for_each_entry(pi_cur, &pvpanic_list, list) {
+		if (event & pi_cur->capability & pi_cur->events)
+			iowrite8(event, pi_cur->base);
+	}
+	spin_unlock(&pvpanic_lock);
 }
 
 static int
@@ -53,29 +60,54 @@
 	.priority = 1, /* let this called before broken drm_fb_helper */
 };
 
-void pvpanic_probe(void __iomem *pbase, unsigned int dev_cap)
+int pvpanic_probe(struct pvpanic_instance *pi)
 {
-	base = pbase;
-	capability = dev_cap;
-	events = capability;
+	if (!pi || !pi->base)
+		return -EINVAL;
+
+	spin_lock(&pvpanic_lock);
+	list_add(&pi->list, &pvpanic_list);
+	spin_unlock(&pvpanic_lock);
 
-	if (capability)
-		atomic_notifier_chain_register(&panic_notifier_list,
-					       &pvpanic_panic_nb);
+	return 0;
 }
 EXPORT_SYMBOL_GPL(pvpanic_probe);
 
-void pvpanic_remove(void)
+void pvpanic_remove(struct pvpanic_instance *pi)
 {
-	if (capability)
-		atomic_notifier_chain_unregister(&panic_notifier_list,
-						 &pvpanic_panic_nb);
-	base = NULL;
+	struct pvpanic_instance *pi_cur, *pi_next;
+
+	if (!pi)
+		return;
+
+	spin_lock(&pvpanic_lock);
+	list_for_each_entry_safe(pi_cur, pi_next, &pvpanic_list, list) {
+		if (pi_cur == pi) {
+			list_del(&pi_cur->list);
+			break;
+		}
+	}
+	spin_unlock(&pvpanic_lock);
 }
 EXPORT_SYMBOL_GPL(pvpanic_remove);
 
-void pvpanic_set_events(unsigned int dev_events)
+static int pvpanic_init(void)
 {
-	events = dev_events;
+	INIT_LIST_HEAD(&pvpanic_list);
+	spin_lock_init(&pvpanic_lock);
+
+	atomic_notifier_chain_register(&panic_notifier_list,
+				       &pvpanic_panic_nb);
+
+	return 0;
 }
-EXPORT_SYMBOL_GPL(pvpanic_set_events);
+
+static void pvpanic_exit(void)
+{
+	atomic_notifier_chain_unregister(&panic_notifier_list,
+					 &pvpanic_panic_nb);
+
+}
+
+module_init(pvpanic_init);
+module_exit(pvpanic_exit);
diff --git a/drivers/misc/pvpanic/pvpanic.h b/drivers/misc/pvpanic/pvpanic.h
index 3abe15f..1afccc2 100644
--- a/drivers/misc/pvpanic/pvpanic.h
+++ b/drivers/misc/pvpanic/pvpanic.h
@@ -8,8 +8,14 @@
 #ifndef PVPANIC_H_
 #define PVPANIC_H_
 
-void pvpanic_probe(void __iomem *base, unsigned int dev_cap);
-void pvpanic_remove(void);
-void pvpanic_set_events(unsigned int dev_events);
+struct pvpanic_instance {
+	void __iomem *base;
+	unsigned int capability;
+	unsigned int events;
+	struct list_head list;
+};
+
+int pvpanic_probe(struct pvpanic_instance *pi);
+void pvpanic_remove(struct pvpanic_instance *pi);
 
 #endif /* PVPANIC_H_ */
-- 
1.8.3.1

[PATCH v8 3/3] misc/pvpanic: add PCI driver

[Mihai Carabas]

Add support for pvpanic PCI device added in qemu [1]. At probe time, obtain the
address where to read/write pvpanic events and pass it to the generic handling
code. Will follow the same logic as pvpanic MMIO device driver. At remove time,
unmap base address and disable PCI device.

[1] https://github.com/qemu/qemu/commit/9df52f58e76e904fb141b10318362d718f470db2

Signed-off-by: Mihai Carabas <mihai.carabas@oracle.com>
---
 .../ABI/testing/sysfs-bus-pci-devices-pvpanic      |   4 +-
 drivers/misc/pvpanic/Kconfig                       |   8 ++
 drivers/misc/pvpanic/Makefile                      |   1 +
 drivers/misc/pvpanic/pvpanic-pci.c                 | 125 +++++++++++++++++++++
 4 files changed, 137 insertions(+), 1 deletion(-)
 create mode 100644 drivers/misc/pvpanic/pvpanic-pci.c

diff --git a/Documentation/ABI/testing/sysfs-bus-pci-devices-pvpanic b/Documentation/ABI/testing/sysfs-bus-pci-devices-pvpanic
index 1936f73..4ec03cd 100644
--- a/Documentation/ABI/testing/sysfs-bus-pci-devices-pvpanic
+++ b/Documentation/ABI/testing/sysfs-bus-pci-devices-pvpanic
@@ -1,4 +1,5 @@
-What:		/sys/devices/pci0000:00/*/QEMU0001:00/capability
+What:		/sys/devices/pci0000:00/*/QEMU0001:00/capability for MMIO
+		/sys/bus/pci/drivers/pvpanic-pci/0000:00:0*.0/capability for PCI
 Date:		Jan 2021
 Contact:	zhenwei pi <pizhenwei@bytedance.com>
 Description:
@@ -12,6 +13,7 @@ Description:
 		https://git.qemu.org/?p=qemu.git;a=blob_plain;f=docs/specs/pvpanic.txt
 
 What:		/sys/devices/pci0000:00/*/QEMU0001:00/events
+		/sys/bus/pci/drivers/pvpanic-pci/0000:00:0*.0/events for PCI
 Date:		Jan 2021
 Contact:	zhenwei pi <pizhenwei@bytedance.com>
 Description:
diff --git a/drivers/misc/pvpanic/Kconfig b/drivers/misc/pvpanic/Kconfig
index 454f1ee..12d40a2 100644
--- a/drivers/misc/pvpanic/Kconfig
+++ b/drivers/misc/pvpanic/Kconfig
@@ -17,3 +17,11 @@ config PVPANIC_MMIO
 	depends on HAS_IOMEM && (ACPI || OF) && PVPANIC
 	help
 	  This driver provides support for the MMIO pvpanic device.
+
+config PVPANIC_PCI
+	tristate "pvpanic PCI device support"
+	depends on PCI && PVPANIC
+	help
+	  This driver provides support for the PCI pvpanic device.
+	  pvpanic is a paravirtualized device provided by QEMU which
+	  forwards the panic events from the guest to the host.
diff --git a/drivers/misc/pvpanic/Makefile b/drivers/misc/pvpanic/Makefile
index e12a2dc..9471df7 100644
--- a/drivers/misc/pvpanic/Makefile
+++ b/drivers/misc/pvpanic/Makefile
@@ -5,3 +5,4 @@
 # Copyright (C) 2021 Oracle.
 #
 obj-$(CONFIG_PVPANIC_MMIO)	+= pvpanic.o pvpanic-mmio.o
+obj-$(CONFIG_PVPANIC_PCI)	+= pvpanic.o pvpanic-pci.o
diff --git a/drivers/misc/pvpanic/pvpanic-pci.c b/drivers/misc/pvpanic/pvpanic-pci.c
new file mode 100644
index 00000000..f38a80a
--- /dev/null
+++ b/drivers/misc/pvpanic/pvpanic-pci.c
@@ -0,0 +1,125 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ *  Pvpanic PCI Device Support
+ *
+ *  Copyright (C) 2021 Oracle.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+
+#include <uapi/misc/pvpanic.h>
+
+#include "pvpanic.h"
+
+#define PCI_VENDOR_ID_REDHAT             0x1b36
+#define PCI_DEVICE_ID_REDHAT_PVPANIC     0x0011
+
+MODULE_AUTHOR("Mihai Carabas <mihai.carabas@oracle.com>");
+MODULE_DESCRIPTION("pvpanic device driver ");
+MODULE_LICENSE("GPL");
+
+static const struct pci_device_id pvpanic_pci_id_tbl[]  = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_REDHAT, PCI_DEVICE_ID_REDHAT_PVPANIC)},
+	{}
+};
+
+static ssize_t capability_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	struct pvpanic_instance *pi = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%x\n", pi->capability);
+}
+static DEVICE_ATTR_RO(capability);
+
+static ssize_t events_show(struct device *dev,  struct device_attribute *attr, char *buf)
+{
+	struct pvpanic_instance *pi = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%x\n", pi->events);
+}
+
+static ssize_t events_store(struct device *dev,  struct device_attribute *attr,
+			    const char *buf, size_t count)
+{
+	struct pvpanic_instance *pi = dev_get_drvdata(dev);
+	unsigned int tmp;
+	int err;
+
+	err = kstrtouint(buf, 16, &tmp);
+	if (err)
+		return err;
+
+	if ((tmp & pi->capability) != tmp)
+		return -EINVAL;
+
+	pi->events = tmp;
+
+	return count;
+}
+static DEVICE_ATTR_RW(events);
+
+static struct attribute *pvpanic_pci_dev_attrs[] = {
+	&dev_attr_capability.attr,
+	&dev_attr_events.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(pvpanic_pci_dev);
+
+static int pvpanic_pci_probe(struct pci_dev *pdev,
+			     const struct pci_device_id *ent)
+{
+	struct device *dev = &pdev->dev;
+	struct pvpanic_instance *pi;
+	void __iomem *base;
+	int ret;
+
+	ret = pci_enable_device(pdev);
+	if (ret < 0)
+		return ret;
+
+	base = pci_iomap(pdev, 0, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	pi = kmalloc(sizeof(*pi), GFP_ATOMIC);
+	if (!pi)
+		return -ENOMEM;
+
+	pi->base = base;
+	pi->capability = PVPANIC_PANICKED | PVPANIC_CRASH_LOADED;
+
+	/* initlize capability by RDPT */
+	pi->capability &= ioread8(base);
+	pi->events = pi->capability;
+
+	dev_set_drvdata(dev, pi);
+
+	return pvpanic_probe(pi);
+}
+
+static void pvpanic_pci_remove(struct pci_dev *pdev)
+{
+	struct pvpanic_instance *pi = dev_get_drvdata(&pdev->dev);
+
+	pvpanic_remove(pi);
+	iounmap(pi->base);
+	kfree(pi);
+	pci_disable_device(pdev);
+}
+
+static struct pci_driver pvpanic_pci_driver = {
+	.name =         "pvpanic-pci",
+	.id_table =     pvpanic_pci_id_tbl,
+	.probe =        pvpanic_pci_probe,
+	.remove =       pvpanic_pci_remove,
+	.driver = {
+		.dev_groups = pvpanic_pci_dev_groups,
+	},
+};
+
+module_pci_driver(pvpanic_pci_driver);
-- 
1.8.3.1

Re: [PATCH v8] add support for pci in the pvpanic driver

[Greg KH]

On Wed, Mar 24, 2021 at 04:49:13PM +0200, Mihai Carabas wrote:
> This patchset adds support for PCI in the pvpanic driver. The device already
> got in qemu [1].
> 
> v2:
> - mmio -> MMIO, pci -> PCI suggested by Randy Dunlap.
> - group pvpanic-common.c and mmio.c in the same module. The intention was to
>   have only one module and the common code splitted up to be re-used by the
>   pvpanic-pci module in the next patch.
> - add a new patch where add the licenses for the new files (when I moved the
>   code to mmio.c I preserved the original licenses there)
> - properly clean-up PCI device when driver removed.
> 
> v3:
> - drop patch 3 with licenses and add them when creating files
> - create a new patch (2/3) which allowes multiple pvpanic instances
> 
> v4:
> - fix Makefile in patch 1/3 and 3/3 for pvpanic.o as suggested by Arnd
> 
> v5:
> - rebase on 5.12
> - fix a warning caused by one of the patches
> 
> v6:
> - remove pr_fmt as were not used
> - "remove" functions of type void
> - moved events/capability per-device structure
> 
> v7:
> - rebased on char-misc-next
> 
> v8:
> - fixed build error while compiling only the first patch (accept
>   my apologizes Greg)
> - build and tested pvpanic functionality after each applied patch

Much better, now queued up, thanks for sticking with it.

greg k-h