Commit db3a4f0a authored by Mihai Carabas's avatar Mihai Carabas Committed by Greg Kroah-Hartman
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misc/pvpanic: add PCI driver 

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: default avatarMihai Carabas <mihai.carabas@oracle.com>
Link: https://lore.kernel.org/r/1616597356-20696-4-git-send-email-mihai.carabas@oracle.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b3c0f877

Documentation/ABI/testing/sysfs-bus-pci-devices-pvpanic

+3 −1
Original line number Diff line number Diff line 
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:

drivers/misc/pvpanic/Kconfig

+8 −0
Original line number Diff line number Diff line
@@ -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.

drivers/misc/pvpanic/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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

drivers/misc/pvpanic/pvpanic-pci.c

0 → 100644
+125 −0
Original line number Diff line number Diff line 
// 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);