Re: [PATCH v18] pvpanic: pvpanic device driver

[Hu Tao <hutao@cn.fujitsu.com>]

On Tue, May 07, 2013 at 10:10:32AM +0200, Paolo Bonzini wrote:
> Il 07/05/2013 05:39, Hu Tao ha scritto:
> > pvpanic device is a qemu simulated device through which guest panic
> > event is sent to host.
> > 
> > Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
> > ---
> > 
> > v17 -> v18:  1. call acpi_walk_resources to get the port, and usb outb instead
> >                 of acpi_evaluate_oject in panic notifier callback
> >              2. reword help message
> > 
> >  drivers/platform/x86/Kconfig   |   8 +++
> >  drivers/platform/x86/Makefile  |   2 +
> >  drivers/platform/x86/pvpanic.c | 122 +++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 132 insertions(+)
> >  create mode 100644 drivers/platform/x86/pvpanic.c
> > 
> > diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> > index 3338437..8577261 100644
> > --- a/drivers/platform/x86/Kconfig
> > +++ b/drivers/platform/x86/Kconfig
> > @@ -781,4 +781,12 @@ config APPLE_GMUX
> >  	  graphics as well as the backlight. Currently only backlight
> >  	  control is supported by the driver.
> >  
> > +config PVPANIC
> > +	tristate "pvpanic device support"
> > +	depends on ACPI
> > +	---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.
> > +
> >  endif # X86_PLATFORM_DEVICES
> > diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
> > index ace2b38..ef0ec74 100644
> > --- a/drivers/platform/x86/Makefile
> > +++ b/drivers/platform/x86/Makefile
> > @@ -51,3 +51,5 @@ obj-$(CONFIG_INTEL_OAKTRAIL)	+= intel_oaktrail.o
> >  obj-$(CONFIG_SAMSUNG_Q10)	+= samsung-q10.o
> >  obj-$(CONFIG_APPLE_GMUX)	+= apple-gmux.o
> >  obj-$(CONFIG_CHROMEOS_LAPTOP)	+= chromeos_laptop.o
> > +
> > +obj-$(CONFIG_PVPANIC)           += pvpanic.o
> > diff --git a/drivers/platform/x86/pvpanic.c b/drivers/platform/x86/pvpanic.c
> > new file mode 100644
> > index 0000000..ddec5cb
> > --- /dev/null
> > +++ b/drivers/platform/x86/pvpanic.c
> > @@ -0,0 +1,122 @@
> > +/*
> > + *  pvpanic.c - pvpanic Device Support
> > + *
> > + *  Copyright (C) 2013 Fujitsu.
> > + *
> > + *  This program is free software; you can redistribute it and/or modify
> > + *  it under the terms of the GNU General Public License as published by
> > + *  the Free Software Foundation; either version 2 of the License, or
> > + *  (at your option) any later version.
> > + *
> > + *  This program is distributed in the hope that it will be useful,
> > + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > + *  GNU General Public License for more details.
> > + *
> > + *  You should have received a copy of the GNU General Public License
> > + *  along with this program; if not, write to the Free Software
> > + *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
> > + */
> > +
> > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> > +
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/init.h>
> > +#include <linux/types.h>
> > +#include <acpi/acpi_bus.h>
> > +#include <acpi/acpi_drivers.h>
> > +
> > +MODULE_AUTHOR("Hu Tao <hutao@cn.fujitsu.com>");
> > +MODULE_DESCRIPTION("pvpanic device driver");
> > +MODULE_LICENSE("GPL");
> > +
> > +static int pvpanic_add(struct acpi_device *device);
> > +static int pvpanic_remove(struct acpi_device *device);
> > +
> > +static const struct acpi_device_id pvpanic_device_ids[] = {
> > +	{ "QEMU0001", 0},
> > +	{ "", 0},
> > +};
> > +MODULE_DEVICE_TABLE(acpi, pvpanic_device_ids);
> > +
> > +#define PVPANIC_PANICKED	(1 << 0)
> > +
> > +static u16 port;
> > +
> > +static struct acpi_driver pvpanic_driver = {
> > +	.name =		"pvpanic",
> > +	.class =	"QEMU",
> > +	.ids =		pvpanic_device_ids,
> > +	.ops =		{
> > +				.add =		pvpanic_add,
> > +				.remove =	pvpanic_remove,
> > +			},
> > +	.owner =	THIS_MODULE,
> > +};
> > +
> > +static void
> > +pvpanic_send_event(unsigned int event)
> > +{
> > +	if (port)
> > +		outb(event, port);
> > +}
> > +
> > +static int
> > +pvpanic_panic_notify(struct notifier_block *nb, unsigned long code,
> > +		     void *unused)
> > +{
> > +	pvpanic_send_event(PVPANIC_PANICKED);
> > +	return NOTIFY_DONE;
> > +}
> > +
> > +static struct notifier_block pvpanic_panic_nb = {
> > +	.notifier_call = pvpanic_panic_notify,
> > +};
> > +
> > +
> > +static acpi_status
> > +pvpanic_walk_resources(struct acpi_resource *res, void *context)
> > +{
> > +	switch (res->type) {
> > +	case ACPI_RESOURCE_TYPE_END_TAG:
> > +		return AE_OK;
> > +
> > +	case ACPI_RESOURCE_TYPE_IO:
> > +		port = res->data.io.minimum;
> > +		return AE_OK;
> > +
> > +	default:
> > +		return AE_ERROR;
> > +	}
> > +}
> > +
> > +static int pvpanic_add(struct acpi_device *device)
> > +{
> > +	acpi_status status;
> > +	u64 ret;
> > +
> > +	status = acpi_evaluate_integer(device->handle, "_STA", NULL,
> > +				       &ret);
> > +
> > +	if (ACPI_FAILURE(status) || (ret & 0x0B) != 0x0B)
> > +		return -ENODEV;
> > +
> > +	acpi_walk_resources(device->handle, METHOD_NAME__CRS,
> > +			    pvpanic_walk_resources, NULL);
> > +
> 
> Perhaps ENODEV if port is zero, so you can remove the if from
> pvpanic_send_event?

Yes, this matches what we do in seabios.