[Qemu-devel] [PATCH v2 7/8] hw/arm/virt: Add QEMU powerdown notifier and hook it to GPIO Pin 3

[Shannon Zhao]

Currently mach-virt model doesn't support powerdown request. Guest VM
doesn't react to system_powerdown from monitor console (or QMP) because
there is no communication mechanism for such requests. This patch registers
GPIO Pin 3 with powerdown notification. So guest VM can receive notification
when such powerdown request is triggered.

Signed-off-by: Wei Huang 
Signed-off-by: Shannon Zhao 
Signed-off-by: Shannon Zhao 
---
 hw/arm/virt.c | 17 -
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 5c505a4..6f1b9d6 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -540,6 +540,18 @@ static void create_rtc(const VirtBoardInfo *vbi, qemu_irq 
*pic)
 g_free(nodename);
 }
 
+static DeviceState *pl061_dev;
+static void virt_powerdown_req(Notifier *n, void *opaque)
+{
+/* use gpio Pin 3 for power button event */
+qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0);
+qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1);
+}
+
+static Notifier virt_system_powerdown_notifier = {
+.notify = virt_powerdown_req
+};
+
 static void create_gpio(const VirtBoardInfo *vbi, qemu_irq *pic)
 {
 char *nodename;
@@ -548,7 +560,7 @@ static void create_gpio(const VirtBoardInfo *vbi, qemu_irq 
*pic)
 int irq = vbi->irqmap[VIRT_GPIO];
 const char compat[] = "arm,pl061\0arm,primecell";
 
-sysbus_create_simple("pl061", base, pic[irq]);
+pl061_dev = sysbus_create_simple("pl061", base, pic[irq]);
 
 nodename = g_strdup_printf("/pl061@%" PRIx64, base);
 qemu_fdt_add_subnode(vbi->fdt, nodename);
@@ -563,6 +575,9 @@ static void create_gpio(const VirtBoardInfo *vbi, qemu_irq 
*pic)
 qemu_fdt_setprop_cell(vbi->fdt, nodename, "clocks", vbi->clock_phandle);
 qemu_fdt_setprop_string(vbi->fdt, nodename, "clock-names", "apb_pclk");
 
+/* connect powerdown request */
+qemu_register_powerdown_notifier(&virt_system_powerdown_notifier);
+
 g_free(nodename);
 }
 
-- 
2.1.0

Re: [Qemu-devel] [PATCH v2 7/8] hw/arm/virt: Add QEMU powerdown notifier and hook it to GPIO Pin 3

[Wei Huang]

On 10/29/2015 09:27 AM, Shannon Zhao wrote:
> Currently mach-virt model doesn't support powerdown request. Guest VM
> doesn't react to system_powerdown from monitor console (or QMP) because
> there is no communication mechanism for such requests. This patch registers
> GPIO Pin 3 with powerdown notification. So guest VM can receive notification
> when such powerdown request is triggered.
> 
> Signed-off-by: Wei Huang 
> Signed-off-by: Shannon Zhao 
> Signed-off-by: Shannon Zhao 
> ---
>  hw/arm/virt.c | 17 -
>  1 file changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index 5c505a4..6f1b9d6 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -540,6 +540,18 @@ static void create_rtc(const VirtBoardInfo *vbi, 
> qemu_irq *pic)
>  g_free(nodename);
>  }
>  
> +static DeviceState *pl061_dev;
> +static void virt_powerdown_req(Notifier *n, void *opaque)
> +{
> +/* use gpio Pin 3 for power button event */
> +qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0);
> +qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1);

This pull-down and then pull-up is for extra safety, right? It actually
also works with only pull-up call. But I am OK with your design here;
please add additional comments to explain the design.

> +}
> +
> +static Notifier virt_system_powerdown_notifier = {
> +.notify = virt_powerdown_req
> +};
> +
>  static void create_gpio(const VirtBoardInfo *vbi, qemu_irq *pic)
>  {
>  char *nodename;
> @@ -548,7 +560,7 @@ static void create_gpio(const VirtBoardInfo *vbi, 
> qemu_irq *pic)
>  int irq = vbi->irqmap[VIRT_GPIO];
>  const char compat[] = "arm,pl061\0arm,primecell";
>  
> -sysbus_create_simple("pl061", base, pic[irq]);
> +pl061_dev = sysbus_create_simple("pl061", base, pic[irq]);
>  
>  nodename = g_strdup_printf("/pl061@%" PRIx64, base);
>  qemu_fdt_add_subnode(vbi->fdt, nodename);
> @@ -563,6 +575,9 @@ static void create_gpio(const VirtBoardInfo *vbi, 
> qemu_irq *pic)
>  qemu_fdt_setprop_cell(vbi->fdt, nodename, "clocks", vbi->clock_phandle);
>  qemu_fdt_setprop_string(vbi->fdt, nodename, "clock-names", "apb_pclk");
>  
> +/* connect powerdown request */
> +qemu_register_powerdown_notifier(&virt_system_powerdown_notifier);
> +
>  g_free(nodename);
>  }
>  
> 

Reviewed-by: Wei Huang 

Re: [Qemu-devel] [PATCH v2 7/8] hw/arm/virt: Add QEMU powerdown notifier and hook it to GPIO Pin 3

[Peter Maydell]

On 11 November 2015 at 06:57, Wei Huang  wrote:
>
>
> On 10/29/2015 09:27 AM, Shannon Zhao wrote:
>> Currently mach-virt model doesn't support powerdown request. Guest VM
>> doesn't react to system_powerdown from monitor console (or QMP) because
>> there is no communication mechanism for such requests. This patch registers
>> GPIO Pin 3 with powerdown notification. So guest VM can receive notification
>> when such powerdown request is triggered.
>>
>> Signed-off-by: Wei Huang 
>> Signed-off-by: Shannon Zhao 
>> Signed-off-by: Shannon Zhao 
>> ---
>>  hw/arm/virt.c | 17 -
>>  1 file changed, 16 insertions(+), 1 deletion(-)
>>
>> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
>> index 5c505a4..6f1b9d6 100644
>> --- a/hw/arm/virt.c
>> +++ b/hw/arm/virt.c
>> @@ -540,6 +540,18 @@ static void create_rtc(const VirtBoardInfo *vbi, 
>> qemu_irq *pic)
>>  g_free(nodename);
>>  }
>>
>> +static DeviceState *pl061_dev;
>> +static void virt_powerdown_req(Notifier *n, void *opaque)
>> +{
>> +/* use gpio Pin 3 for power button event */
>> +qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0);
>> +qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1);
>
> This pull-down and then pull-up is for extra safety, right? It actually
> also works with only pull-up call. But I am OK with your design here;
> please add additional comments to explain the design.

It's a bit weird though. Usually you use qemu_pulse_irq,
which does a 0->1 then 1->0 transition, if the thing you're
signalling needs an edge. If the thing you're signalling
only cares about level then you just need to set the
level to 1.

thanks
-- PMM