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

[Wei Huang <wei@redhat.com>]

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 <wei@redhat.com>
> Signed-off-by: Shannon Zhao <zhaoshenglong@huawei.com>
> Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
> ---
>  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 <wei@redhat.com>