[PATCH v17 RESEND] pvpanic: pvpanic device driver

[PATCH v17 RESEND] pvpanic: pvpanic device driver

[Hu Tao]

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>
---
 drivers/platform/x86/Kconfig   |   7 +++
 drivers/platform/x86/Makefile  |   2 +
 drivers/platform/x86/pvpanic.c | 115 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 124 insertions(+)
 create mode 100644 drivers/platform/x86/pvpanic.c

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 3338437..527ed04 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -781,4 +781,11 @@ 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 pvpanic device, which is a qemu
+	  simulated device through which guest panic event is sent to 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..81c95ec
--- /dev/null
+++ b/drivers/platform/x86/pvpanic.c
@@ -0,0 +1,115 @@
+/*
+ *  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 acpi_handle handle;
+
+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)
+{
+	union acpi_object arg;
+	struct acpi_object_list arg_list;
+
+	if (!handle)
+		return;
+
+	arg.type = ACPI_TYPE_INTEGER;
+	arg.integer.value = event;
+
+	arg_list.count = 1;
+	arg_list.pointer = &arg;
+
+	acpi_evaluate_object(handle, "WRPT", &arg_list, NULL);
+}
+
+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 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;
+
+	handle = device->handle;
+	atomic_notifier_chain_register(&panic_notifier_list,
+				       &pvpanic_panic_nb);
+
+	return 0;
+}
+
+static int pvpanic_remove(struct acpi_device *device)
+{
+
+	atomic_notifier_chain_unregister(&panic_notifier_list,
+					 &pvpanic_panic_nb);
+	handle = NULL;
+	return 0;
+}
+
+module_acpi_driver(pvpanic_driver);
-- 
1.8.1.4

Re: [PATCH v17 RESEND] pvpanic: pvpanic device driver

[Paolo Bonzini]

Il 03/05/2013 04:47, 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>

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

but you may reword the help message as hinted below.

Paolo

> ---
>  drivers/platform/x86/Kconfig   |   7 +++
>  drivers/platform/x86/Makefile  |   2 +
>  drivers/platform/x86/pvpanic.c | 115 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 124 insertions(+)
>  create mode 100644 drivers/platform/x86/pvpanic.c
> 
> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> index 3338437..527ed04 100644
> --- a/drivers/platform/x86/Kconfig
> +++ b/drivers/platform/x86/Kconfig
> @@ -781,4 +781,11 @@ 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 pvpanic device, which is a qemu
> +	  simulated device through which guest panic event is sent to host.

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..81c95ec
> --- /dev/null
> +++ b/drivers/platform/x86/pvpanic.c
> @@ -0,0 +1,115 @@
> +/*
> + *  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 acpi_handle handle;
> +
> +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)
> +{
> +	union acpi_object arg;
> +	struct acpi_object_list arg_list;
> +
> +	if (!handle)
> +		return;
> +
> +	arg.type = ACPI_TYPE_INTEGER;
> +	arg.integer.value = event;
> +
> +	arg_list.count = 1;
> +	arg_list.pointer = &arg;
> +
> +	acpi_evaluate_object(handle, "WRPT", &arg_list, NULL);
> +}
> +
> +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 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;
> +
> +	handle = device->handle;
> +	atomic_notifier_chain_register(&panic_notifier_list,
> +				       &pvpanic_panic_nb);
> +
> +	return 0;
> +}
> +
> +static int pvpanic_remove(struct acpi_device *device)
> +{
> +
> +	atomic_notifier_chain_unregister(&panic_notifier_list,
> +					 &pvpanic_panic_nb);
> +	handle = NULL;
> +	return 0;
> +}
> +
> +module_acpi_driver(pvpanic_driver);
> 

Re: [PATCH v17 RESEND] pvpanic: pvpanic device driver

[Marcelo Tosatti]

On Fri, May 03, 2013 at 10:47:10AM +0800, Hu Tao wrote:
> 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>
> ---
>  drivers/platform/x86/Kconfig   |   7 +++
>  drivers/platform/x86/Makefile  |   2 +
>  drivers/platform/x86/pvpanic.c | 115 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 124 insertions(+)
>  create mode 100644 drivers/platform/x86/pvpanic.c
> 
> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> index 3338437..527ed04 100644
> --- a/drivers/platform/x86/Kconfig
> +++ b/drivers/platform/x86/Kconfig
> @@ -781,4 +781,11 @@ 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 pvpanic device, which is a qemu
> +	  simulated device through which guest panic event is sent to 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..81c95ec
> --- /dev/null
> +++ b/drivers/platform/x86/pvpanic.c
> @@ -0,0 +1,115 @@
> +/*
> + *  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 acpi_handle handle;
> +
> +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)
> +{
> +	union acpi_object arg;
> +	struct acpi_object_list arg_list;
> +
> +	if (!handle)
> +		return;
> +
> +	arg.type = ACPI_TYPE_INTEGER;
> +	arg.integer.value = event;
> +
> +	arg_list.count = 1;
> +	arg_list.pointer = &arg;
> +
> +	acpi_evaluate_object(handle, "WRPT", &arg_list, NULL);
> +}

Is it safe to call acpi_evaluate_object from a panic notifier? For
example:

- Has it been confirmed that no code invoked via acpi_evaluate_object can panic() ?
- acpi_ex_enter_interpreter grabs a mutex. Is that path ever used?

Re: [PATCH v17 RESEND] pvpanic: pvpanic device driver

[Hu Tao]

On Fri, May 03, 2013 at 06:59:18PM -0300, Marcelo Tosatti wrote:
> On Fri, May 03, 2013 at 10:47:10AM +0800, Hu Tao wrote:
> > 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>
> > ---
> >  drivers/platform/x86/Kconfig   |   7 +++
> >  drivers/platform/x86/Makefile  |   2 +
> >  drivers/platform/x86/pvpanic.c | 115 +++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 124 insertions(+)
> >  create mode 100644 drivers/platform/x86/pvpanic.c
> > 
> > diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> > index 3338437..527ed04 100644
> > --- a/drivers/platform/x86/Kconfig
> > +++ b/drivers/platform/x86/Kconfig
> > @@ -781,4 +781,11 @@ 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 pvpanic device, which is a qemu
> > +	  simulated device through which guest panic event is sent to 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..81c95ec
> > --- /dev/null
> > +++ b/drivers/platform/x86/pvpanic.c
> > @@ -0,0 +1,115 @@
> > +/*
> > + *  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 acpi_handle handle;
> > +
> > +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)
> > +{
> > +	union acpi_object arg;
> > +	struct acpi_object_list arg_list;
> > +
> > +	if (!handle)
> > +		return;
> > +
> > +	arg.type = ACPI_TYPE_INTEGER;
> > +	arg.integer.value = event;
> > +
> > +	arg_list.count = 1;
> > +	arg_list.pointer = &arg;
> > +
> > +	acpi_evaluate_object(handle, "WRPT", &arg_list, NULL);
> > +}
> 
> Is it safe to call acpi_evaluate_object from a panic notifier? For
> example:
> 
> - Has it been confirmed that no code invoked via acpi_evaluate_object can panic() ?

Confirmed.

> - acpi_ex_enter_interpreter grabs a mutex. Is that path ever used?

Unfortunately yes. As I can tell, there are 2 places in the path to grab
a mutex: when searching the namespace for the method, and when executing
the method. I didn't find a non-blocking version of acpi_evaluate_object.

Re: [PATCH v17 RESEND] pvpanic: pvpanic device driver

[Marcelo Tosatti]

On Mon, May 06, 2013 at 11:39:35AM +0800, Hu Tao wrote:
> On Fri, May 03, 2013 at 06:59:18PM -0300, Marcelo Tosatti wrote:
> > On Fri, May 03, 2013 at 10:47:10AM +0800, Hu Tao wrote:
> > > 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>
> > > ---
> > >  drivers/platform/x86/Kconfig   |   7 +++
> > >  drivers/platform/x86/Makefile  |   2 +
> > >  drivers/platform/x86/pvpanic.c | 115 +++++++++++++++++++++++++++++++++++++++++
> > >  3 files changed, 124 insertions(+)
> > >  create mode 100644 drivers/platform/x86/pvpanic.c
> > > 
> > > diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> > > index 3338437..527ed04 100644
> > > --- a/drivers/platform/x86/Kconfig
> > > +++ b/drivers/platform/x86/Kconfig
> > > @@ -781,4 +781,11 @@ 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 pvpanic device, which is a qemu
> > > +	  simulated device through which guest panic event is sent to 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..81c95ec
> > > --- /dev/null
> > > +++ b/drivers/platform/x86/pvpanic.c
> > > @@ -0,0 +1,115 @@
> > > +/*
> > > + *  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 acpi_handle handle;
> > > +
> > > +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)
> > > +{
> > > +	union acpi_object arg;
> > > +	struct acpi_object_list arg_list;
> > > +
> > > +	if (!handle)
> > > +		return;
> > > +
> > > +	arg.type = ACPI_TYPE_INTEGER;
> > > +	arg.integer.value = event;
> > > +
> > > +	arg_list.count = 1;
> > > +	arg_list.pointer = &arg;
> > > +
> > > +	acpi_evaluate_object(handle, "WRPT", &arg_list, NULL);
> > > +}
> > 
> > Is it safe to call acpi_evaluate_object from a panic notifier? For
> > example:
> > 
> > - Has it been confirmed that no code invoked via acpi_evaluate_object can panic() ?
> 
> Confirmed.
> 
> > - acpi_ex_enter_interpreter grabs a mutex. Is that path ever used?
> 
> Unfortunately yes. As I can tell, there are 2 places in the path to grab
> a mutex: when searching the namespace for the method, and when executing
> the method. I didn't find a non-blocking version of acpi_evaluate_object.

Then thats a bug because the pvpanic notifier is called with interrupts
disabled.

Suppose its safer to use an OUT instruction?

Re: [PATCH v17 RESEND] pvpanic: pvpanic device driver

[Paolo Bonzini]

Il 06/05/2013 13:38, Marcelo Tosatti ha scritto:
> On Mon, May 06, 2013 at 11:39:35AM +0800, Hu Tao wrote:
>> On Fri, May 03, 2013 at 06:59:18PM -0300, Marcelo Tosatti wrote:
>>> On Fri, May 03, 2013 at 10:47:10AM +0800, Hu Tao wrote:
>>>> 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>
>>>> ---
>>>>  drivers/platform/x86/Kconfig   |   7 +++
>>>>  drivers/platform/x86/Makefile  |   2 +
>>>>  drivers/platform/x86/pvpanic.c | 115 +++++++++++++++++++++++++++++++++++++++++
>>>>  3 files changed, 124 insertions(+)
>>>>  create mode 100644 drivers/platform/x86/pvpanic.c
>>>>
>>>> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
>>>> index 3338437..527ed04 100644
>>>> --- a/drivers/platform/x86/Kconfig
>>>> +++ b/drivers/platform/x86/Kconfig
>>>> @@ -781,4 +781,11 @@ 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 pvpanic device, which is a qemu
>>>> +	  simulated device through which guest panic event is sent to 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..81c95ec
>>>> --- /dev/null
>>>> +++ b/drivers/platform/x86/pvpanic.c
>>>> @@ -0,0 +1,115 @@
>>>> +/*
>>>> + *  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 acpi_handle handle;
>>>> +
>>>> +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)
>>>> +{
>>>> +	union acpi_object arg;
>>>> +	struct acpi_object_list arg_list;
>>>> +
>>>> +	if (!handle)
>>>> +		return;
>>>> +
>>>> +	arg.type = ACPI_TYPE_INTEGER;
>>>> +	arg.integer.value = event;
>>>> +
>>>> +	arg_list.count = 1;
>>>> +	arg_list.pointer = &arg;
>>>> +
>>>> +	acpi_evaluate_object(handle, "WRPT", &arg_list, NULL);
>>>> +}
>>>
>>> Is it safe to call acpi_evaluate_object from a panic notifier? For
>>> example:
>>>
>>> - Has it been confirmed that no code invoked via acpi_evaluate_object can panic() ?
>>
>> Confirmed.
>>
>>> - acpi_ex_enter_interpreter grabs a mutex. Is that path ever used?
>>
>> Unfortunately yes. As I can tell, there are 2 places in the path to grab
>> a mutex: when searching the namespace for the method, and when executing
>> the method. I didn't find a non-blocking version of acpi_evaluate_object.
> 
> Then thats a bug because the pvpanic notifier is called with interrupts
> disabled.
> 
> Suppose its safer to use an OUT instruction?

Yeah, it probably is...  You can still use acpi_walk_resources to find
the port number instead of hard-coding 0x505...

Paolo

[PATCH v18] pvpanic: pvpanic device driver

[Hu Tao]

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);
+
+	atomic_notifier_chain_register(&panic_notifier_list,
+				       &pvpanic_panic_nb);
+
+	return 0;
+}
+
+static int pvpanic_remove(struct acpi_device *device)
+{
+
+	atomic_notifier_chain_unregister(&panic_notifier_list,
+					 &pvpanic_panic_nb);
+	return 0;
+}
+
+module_acpi_driver(pvpanic_driver);
-- 
1.8.1.4

Re: [PATCH v18] pvpanic: pvpanic device driver

[Paolo Bonzini]

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?

Paolo

> +	atomic_notifier_chain_register(&panic_notifier_list,
> +				       &pvpanic_panic_nb);
> +
> +	return 0;
> +}
> +
> +static int pvpanic_remove(struct acpi_device *device)
> +{
> +
> +	atomic_notifier_chain_unregister(&panic_notifier_list,
> +					 &pvpanic_panic_nb);
> +	return 0;
> +}
> +
> +module_acpi_driver(pvpanic_driver);
> 

Re: [PATCH v18] pvpanic: pvpanic device driver

[Hu Tao]

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.