[Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Wei Huang]

When QEMU is hook'ed up with libvirt/virsh, the first ACPI reboot
request will succeed; but the following shutdown/reboot requests
fail to trigger VMs to react. Notice that in mach-virt machine
model GPIO is defined as edge-triggered and active-high in ACPI.
This patch changes the behavior of powerdown notifier from PULLUP
to PULSE. It solves the problem described above (i.e. reboot
continues to work).

Signed-off-by: Wei Huang <wei@redhat.com>
---
 hw/arm/virt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 05f9087..b5468a9 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -546,7 +546,7 @@ 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), 1);
+    qemu_irq_pulse(qdev_get_gpio_in(pl061_dev, 3));
 }
 
 static Notifier virt_system_powerdown_notifier = {
-- 
1.8.3.1

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Shannon Zhao]

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Hi，

This makes ACPI work well but makes DT not work. The reason is systemd or
acpid open /dev/input/event0 failed. So the interrupt could be injected and
could see under /proc/interrupts but guest doesn't have any action. I'll
investigate why it opens failed later.

2016年1月29日星期五，Wei Huang <wei@redhat.com> 写道：

> When QEMU is hook'ed up with libvirt/virsh, the first ACPI reboot
> request will succeed; but the following shutdown/reboot requests
> fail to trigger VMs to react. Notice that in mach-virt machine
> model GPIO is defined as edge-triggered and active-high in ACPI.
> This patch changes the behavior of powerdown notifier from PULLUP
> to PULSE. It solves the problem described above (i.e. reboot
> continues to work).
>
> Signed-off-by: Wei Huang <wei@redhat.com <javascript:;>>
> ---
>  hw/arm/virt.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index 05f9087..b5468a9 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -546,7 +546,7 @@ 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), 1);
> +    qemu_irq_pulse(qdev_get_gpio_in(pl061_dev, 3));
>  }
>
>  static Notifier virt_system_powerdown_notifier = {
> --
> 1.8.3.1
>
>

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Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Wei Huang]

On 01/29/2016 04:10 AM, Shannon Zhao wrote:
> Hi，
> 
> This makes ACPI work well but makes DT not work. The reason is systemd or
> acpid open /dev/input/event0 failed. So the interrupt could be injected and
> could see under /proc/interrupts but guest doesn't have any action. I'll
> investigate why it opens failed later.

That is interesting. Could you try it with the following? This reverses
the order to down-up and worked on ACPI case.

qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0);
qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1);

Thanks,
-Wei

> 
> 2016年1月29日星期五，Wei Huang <wei@redhat.com> 写道：
> 
>> When QEMU is hook'ed up with libvirt/virsh, the first ACPI reboot
>> request will succeed; but the following shutdown/reboot requests
>> fail to trigger VMs to react. Notice that in mach-virt machine
>> model GPIO is defined as edge-triggered and active-high in ACPI.
>> This patch changes the behavior of powerdown notifier from PULLUP
>> to PULSE. It solves the problem described above (i.e. reboot
>> continues to work).
>>
>> Signed-off-by: Wei Huang <wei@redhat.com <javascript:;>>
>> ---
>>  hw/arm/virt.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
>> index 05f9087..b5468a9 100644
>> --- a/hw/arm/virt.c
>> +++ b/hw/arm/virt.c
>> @@ -546,7 +546,7 @@ 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), 1);
>> +    qemu_irq_pulse(qdev_get_gpio_in(pl061_dev, 3));
>>  }
>>
>>  static Notifier virt_system_powerdown_notifier = {
>> --
>> 1.8.3.1
>>
>>
> 

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Shannon Zhao]

On 2016/1/29 22:35, Wei Huang wrote:
>
>
> On 01/29/2016 04:10 AM, Shannon Zhao wrote:
>> Hi，
>>
>> This makes ACPI work well but makes DT not work. The reason is systemd or
>> acpid open /dev/input/event0 failed. So the interrupt could be injected and
>> could see under /proc/interrupts but guest doesn't have any action. I'll
>> investigate why it opens failed later.
>
> That is interesting. Could you try it with the following? This reverses
> the order to down-up and worked on ACPI case.
>
Yeah, that's very weird.

> qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0);
> qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1);
>
I'll try this tomorrow. But even if this works, it's still weird.

> Thanks,
> -Wei
>
>>
>> 2016年1月29日星期五，Wei Huang <wei@redhat.com> 写道：
>>
>>> When QEMU is hook'ed up with libvirt/virsh, the first ACPI reboot
>>> request will succeed; but the following shutdown/reboot requests
>>> fail to trigger VMs to react. Notice that in mach-virt machine
>>> model GPIO is defined as edge-triggered and active-high in ACPI.
>>> This patch changes the behavior of powerdown notifier from PULLUP
>>> to PULSE. It solves the problem described above (i.e. reboot
>>> continues to work).
>>>
>>> Signed-off-by: Wei Huang <wei@redhat.com <javascript:;>>
>>> ---
>>>   hw/arm/virt.c | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
>>> index 05f9087..b5468a9 100644
>>> --- a/hw/arm/virt.c
>>> +++ b/hw/arm/virt.c
>>> @@ -546,7 +546,7 @@ 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), 1);
>>> +    qemu_irq_pulse(qdev_get_gpio_in(pl061_dev, 3));
>>>   }
>>>
>>>   static Notifier virt_system_powerdown_notifier = {
>>> --
>>> 1.8.3.1
>>>
>>>
>>

-- 
Shannon

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Wei Huang]

On 01/29/2016 08:46 AM, Shannon Zhao wrote:
> 
> 
> On 2016/1/29 22:35, Wei Huang wrote:
>>
>>
>> On 01/29/2016 04:10 AM, Shannon Zhao wrote:
>>> Hi，
>>>
>>> This makes ACPI work well but makes DT not work. The reason is
>>> systemd or
>>> acpid open /dev/input/event0 failed. So the interrupt could be
>>> injected and
>>> could see under /proc/interrupts but guest doesn't have any action. I'll
>>> investigate why it opens failed later.
>>
>> That is interesting. Could you try it with the following? This reverses
>> the order to down-up and worked on ACPI case.
>>
> Yeah, that's very weird.
> 
>> qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0);
>> qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1);
>>
> I'll try this tomorrow. But even if this works, it's still weird.

To reproduce this case, do the following steps using current upstream
qemu: create vm => reboot vm (succeed) => reboot or shutdown vm (fail).
Apparently the last interrupt wasn't received correctly.

-Wei


> 
>> Thanks,
>> -Wei
>>
>>>
>>> 2016年1月29日星期五，Wei Huang <wei@redhat.com> 写道：
>>>
>>>> When QEMU is hook'ed up with libvirt/virsh, the first ACPI reboot
>>>> request will succeed; but the following shutdown/reboot requests
>>>> fail to trigger VMs to react. Notice that in mach-virt machine
>>>> model GPIO is defined as edge-triggered and active-high in ACPI.
>>>> This patch changes the behavior of powerdown notifier from PULLUP
>>>> to PULSE. It solves the problem described above (i.e. reboot
>>>> continues to work).
>>>>
>>>> Signed-off-by: Wei Huang <wei@redhat.com <javascript:;>>
>>>> ---
>>>>   hw/arm/virt.c | 2 +-
>>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
>>>> index 05f9087..b5468a9 100644
>>>> --- a/hw/arm/virt.c
>>>> +++ b/hw/arm/virt.c
>>>> @@ -546,7 +546,7 @@ 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), 1);
>>>> +    qemu_irq_pulse(qdev_get_gpio_in(pl061_dev, 3));
>>>>   }
>>>>
>>>>   static Notifier virt_system_powerdown_notifier = {
>>>> -- 
>>>> 1.8.3.1
>>>>
>>>>
>>>
> 

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Peter Maydell]

On 29 January 2016 at 14:46, Shannon Zhao <shannon.zhao@linaro.org> wrote:
> On 2016/1/29 22:35, Wei Huang wrote:
>> On 01/29/2016 04:10 AM, Shannon Zhao wrote:
>>> This makes ACPI work well but makes DT not work. The reason is systemd or
>>> acpid open /dev/input/event0 failed. So the interrupt could be injected
>>> and
>>> could see under /proc/interrupts but guest doesn't have any action. I'll
>>> investigate why it opens failed later.
>>
>>
>> That is interesting. Could you try it with the following? This reverses
>> the order to down-up and worked on ACPI case.
>>
> Yeah, that's very weird.
>
>> qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0);
>> qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1);
>>
> I'll try this tomorrow. But even if this works, it's still weird.

I wonder if we should be asserting the GPIO pin in the powerdown-request
hook and then deasserting it on system reset somewhere...

thanks
-- PMM

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Wei Huang]

On 01/29/2016 08:50 AM, Peter Maydell wrote:
> On 29 January 2016 at 14:46, Shannon Zhao <shannon.zhao@linaro.org> wrote:
>> On 2016/1/29 22:35, Wei Huang wrote:
>>> On 01/29/2016 04:10 AM, Shannon Zhao wrote:
>>>> This makes ACPI work well but makes DT not work. The reason is systemd or
>>>> acpid open /dev/input/event0 failed. So the interrupt could be injected
>>>> and
>>>> could see under /proc/interrupts but guest doesn't have any action. I'll
>>>> investigate why it opens failed later.
>>>
>>>
>>> That is interesting. Could you try it with the following? This reverses
>>> the order to down-up and worked on ACPI case.
>>>
>> Yeah, that's very weird.
>>
>>> qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0);
>>> qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1);
>>>
>> I'll try this tomorrow. But even if this works, it's still weird.
> 
> I wonder if we should be asserting the GPIO pin in the powerdown-request
> hook and then deasserting it on system reset somewhere...

This is another possibility. We can try to reset the pl061 state by
hooking up with dc->reset and see what happens.

> 
> thanks
> -- PMM
> 

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Shannon Zhao]

On 2016/1/29 22:50, Wei Huang wrote:
>
> On 01/29/2016 08:46 AM, Shannon Zhao wrote:
>> >
>> >
>> >On 2016/1/29 22:35, Wei Huang wrote:
>>> >>
>>> >>
>>> >>On 01/29/2016 04:10 AM, Shannon Zhao wrote:
>>>> >>>Hi，
>>>> >>>
>>>> >>>This makes ACPI work well but makes DT not work. The reason is
>>>> >>>systemd or
>>>> >>>acpid open /dev/input/event0 failed. So the interrupt could be
>>>> >>>injected and
>>>> >>>could see under /proc/interrupts but guest doesn't have any action. I'll
>>>> >>>investigate why it opens failed later.
>>> >>
>>> >>That is interesting. Could you try it with the following? This reverses
>>> >>the order to down-up and worked on ACPI case.
>>> >>
>> >Yeah, that's very weird.
>> >
>>> >>qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0);
>>> >>qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1);
>>> >>
>> >I'll try this tomorrow. But even if this works, it's still weird.
> To reproduce this case, do the following steps using current upstream
> qemu: create vm => reboot vm (succeed) => reboot or shutdown vm (fail).
> Apparently the last interrupt wasn't received correctly.

Yes, I reproduce this today. Let's clarify current state.
Firstly, for ACPI it should use qemu_irq_pulse since we make the GPIO 
pin edge-triggered. And for DT, it uses gpio-key which is also 
edge-triggered that we could get from output of guest /proc/interrupts.

Secondly, current upstream qemu with your patch makes second reboot 
works when using ACPI. But first shutdown/reboot doesn't works when 
using DT since the systemd or acpid open /dev/input/event0 failed. This 
is what I'm surprised.

Wei, what userspace program your guest uses? systemd or acpid? Could you 
please try to use DT to test your patch? And see if there is a same 
result with me.(I know Redhat kernel uses ACPI by default, so you could 
append acpi=off to switch to DT)

Thanks,
-- 
Shannon

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Peter Maydell]

On 29 January 2016 at 15:13, Wei Huang <wei@redhat.com> wrote:
>
>
> On 01/29/2016 08:50 AM, Peter Maydell wrote:
>> I wonder if we should be asserting the GPIO pin in the powerdown-request
>> hook and then deasserting it on system reset somewhere...
>
> This is another possibility. We can try to reset the pl061 state by
> hooking up with dc->reset and see what happens.

Ah, yes, PL061 hasn't been updated to implement reset. That is almost
certainly your problem.

thanks
-- PMM

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Shannon Zhao]

On 2016/1/29 22:35, Wei Huang wrote:
> 
> On 01/29/2016 04:10 AM, Shannon Zhao wrote:
>> > Hi，
>> > 
>> > This makes ACPI work well but makes DT not work. The reason is systemd or
>> > acpid open /dev/input/event0 failed.
To correct, systemd or acpid open /dev/input/event0 successfully but it
waits for events and when we input "system_powerdown", it doesn't get
the event.

> So the interrupt could be injected and
>> > could see under /proc/interrupts but guest doesn't have any action. I'll
>> > investigate why it opens failed later.
> That is interesting. Could you try it with the following? This reverses
> the order to down-up and worked on ACPI case.
> 
> qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0);
> qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1);
If we don't input "system_powerdown" during guest booting(before device
driver load), current QEMU with above codes could work for DT. But if we
input "system_powerdown" during guest booting, guest has no action when
we input "system_powerdown" again after guest booting completely.
I add dc->reset for pl061 but get the same result.

Below is the output of acpid:

./acpid -l -n -d
input layer /dev/input/event0 (gpio-keys) opened successfully, fd 4
inotify fd: 5
inotify wd: 1
RTNETLINK1 answers: No such file or directory
acpid: error talking to the kernel via netlink
netlink opened successfully
acpid: starting up with netlink and the input layer
parsing conf file /etc/acpi/events/powerbtn
acpid: 1 rule loaded
acpid: waiting for events: event logging is on

It will stuck here even if we input "system_powerdown".

Below is the right output when we input "system_powerdown".

./acpid -l -n -d
input layer /dev/input/event0 (gpio-keys) opened successfully, fd 4
inotify fd: 5
inotify wd: 1
RTNETLINK1 answers: No such file or directory
acpid: error talking to the kernel via netlink
netlink opened successfully
acpid: starting up with netlink and the input layer
parsing conf file /etc/acpi/events/powerbtn
acpid: 1 rule loaded
acpid: waiting for events: event logging is on
acpid: received input layer event "button/power PBTN 00000080 00000000"
acpid: rule from /etc/acpi/events/powerbtn matched
acpid: executing action "/etc/acpi/powerbtn.sh"

Thanks,
-- 
Shannon

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Igor Mammedov]

On Fri, 29 Jan 2016 09:13:15 -0600
Wei Huang <wei@redhat.com> wrote:

> On 01/29/2016 08:50 AM, Peter Maydell wrote:
> > On 29 January 2016 at 14:46, Shannon Zhao <shannon.zhao@linaro.org> wrote:  
> >> On 2016/1/29 22:35, Wei Huang wrote:  
> >>> On 01/29/2016 04:10 AM, Shannon Zhao wrote:  
> >>>> This makes ACPI work well but makes DT not work. The reason is systemd or
> >>>> acpid open /dev/input/event0 failed. So the interrupt could be injected
> >>>> and
> >>>> could see under /proc/interrupts but guest doesn't have any action. I'll
> >>>> investigate why it opens failed later.  
> >>>
> >>>
> >>> That is interesting. Could you try it with the following? This reverses
> >>> the order to down-up and worked on ACPI case.
> >>>  
> >> Yeah, that's very weird.
> >>  
> >>> qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0);
> >>> qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1);
> >>>  
> >> I'll try this tomorrow. But even if this works, it's still weird.  
> > 
> > I wonder if we should be asserting the GPIO pin in the powerdown-request
> > hook and then deasserting it on system reset somewhere...  
> 
> This is another possibility. We can try to reset the pl061 state by
> hooking up with dc->reset and see what happens.
I think that's what we do on x86.

> 
> > 
> > thanks
> > -- PMM
> >   
> 

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Wei Huang]

On 02/01/2016 04:17 AM, Igor Mammedov wrote:
> On Fri, 29 Jan 2016 09:13:15 -0600
> Wei Huang <wei@redhat.com> wrote:
> 
>> On 01/29/2016 08:50 AM, Peter Maydell wrote:
>>> On 29 January 2016 at 14:46, Shannon Zhao <shannon.zhao@linaro.org> wrote:  
>>>> On 2016/1/29 22:35, Wei Huang wrote:  
>>>>> On 01/29/2016 04:10 AM, Shannon Zhao wrote:  
>>>>>> This makes ACPI work well but makes DT not work. The reason is systemd or
>>>>>> acpid open /dev/input/event0 failed. So the interrupt could be injected
>>>>>> and
>>>>>> could see under /proc/interrupts but guest doesn't have any action. I'll
>>>>>> investigate why it opens failed later.  
>>>>>
>>>>>
>>>>> That is interesting. Could you try it with the following? This reverses
>>>>> the order to down-up and worked on ACPI case.
>>>>>  
>>>> Yeah, that's very weird.
>>>>  
>>>>> qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0);
>>>>> qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1);
>>>>>  
>>>> I'll try this tomorrow. But even if this works, it's still weird.  
>>>
>>> I wonder if we should be asserting the GPIO pin in the powerdown-request
>>> hook and then deasserting it on system reset somewhere...  
>>
>> This is another possibility. We can try to reset the pl061 state by
>> hooking up with dc->reset and see what happens.
> I think that's what we do on x86.

So the device state is wrong after reset. I just sent out a fix for it,
which was verified on ACPI code path. Basically the old_in_data is stale
after reboot, causing QEMU to believe that it isn't necessary to raise
up IRQ again for the second reboot/shutdown (see s->old_in_data ^
s->data in pl061.c file).

Shannon: could you double check from your side with my patch?

-Wei

> 
>>
>>>
>>> thanks
>>> -- PMM
>>>   
>>
> 

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Michael Tokarev]

28.01.2016 21:22, Wei Huang wrote:
> When QEMU is hook'ed up with libvirt/virsh, the first ACPI reboot
> request will succeed; but the following shutdown/reboot requests
> fail to trigger VMs to react. Notice that in mach-virt machine
> model GPIO is defined as edge-triggered and active-high in ACPI.
> This patch changes the behavior of powerdown notifier from PULLUP
> to PULSE. It solves the problem described above (i.e. reboot
> continues to work).

So, what's the outcome of this? :)

Thanks,

/mjt

> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index 05f9087..b5468a9 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -546,7 +546,7 @@ 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), 1);
> +    qemu_irq_pulse(qdev_get_gpio_in(pl061_dev, 3));
>  }
>  
>  static Notifier virt_system_powerdown_notifier = {
> 

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Peter Maydell]

On 3 February 2016 at 07:15, Michael Tokarev <mjt@tls.msk.ru> wrote:
> 28.01.2016 21:22, Wei Huang wrote:
>> When QEMU is hook'ed up with libvirt/virsh, the first ACPI reboot
>> request will succeed; but the following shutdown/reboot requests
>> fail to trigger VMs to react. Notice that in mach-virt machine
>> model GPIO is defined as edge-triggered and active-high in ACPI.
>> This patch changes the behavior of powerdown notifier from PULLUP
>> to PULSE. It solves the problem described above (i.e. reboot
>> continues to work).
>
> So, what's the outcome of this? :)

This patch is definitely wrong. The patch to fix up the
gpio reset stuff is definitely the right idea. Whether it
fixes the reported failure or some further change is also
needed is currently unclear.

thanks
-- PMM

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Wei Huang]

On 2/3/16 04:46, Peter Maydell wrote:
> On 3 February 2016 at 07:15, Michael Tokarev <mjt@tls.msk.ru> wrote:
>> 28.01.2016 21:22, Wei Huang wrote:
>>> When QEMU is hook'ed up with libvirt/virsh, the first ACPI reboot
>>> request will succeed; but the following shutdown/reboot requests
>>> fail to trigger VMs to react. Notice that in mach-virt machine
>>> model GPIO is defined as edge-triggered and active-high in ACPI.
>>> This patch changes the behavior of powerdown notifier from PULLUP
>>> to PULSE. It solves the problem described above (i.e. reboot
>>> continues to work).
>>
>> So, what's the outcome of this? :)
> 
> This patch is definitely wrong. The patch to fix up the
> gpio reset stuff is definitely the right idea. Whether it
> fixes the reported failure or some further change is also
> needed is currently unclear.

I will NAK this one for now. Please see V2 patch, which is necessary. In
the meanwhile, I think there is a problem with pulling-up only in
current implementation. Let me debug Shannon's DT problem first.

> 
> thanks
> -- PMM
> 

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Shannon Zhao]

On 2016/2/4 0:01, Wei Huang wrote:
> 
> On 2/3/16 04:46, Peter Maydell wrote:
>> > On 3 February 2016 at 07:15, Michael Tokarev <mjt@tls.msk.ru> wrote:
>>> >> 28.01.2016 21:22, Wei Huang wrote:
>>>> >>> When QEMU is hook'ed up with libvirt/virsh, the first ACPI reboot
>>>> >>> request will succeed; but the following shutdown/reboot requests
>>>> >>> fail to trigger VMs to react. Notice that in mach-virt machine
>>>> >>> model GPIO is defined as edge-triggered and active-high in ACPI.
>>>> >>> This patch changes the behavior of powerdown notifier from PULLUP
>>>> >>> to PULSE. It solves the problem described above (i.e. reboot
>>>> >>> continues to work).
>>> >>
>>> >> So, what's the outcome of this? :)
>> > 
>> > This patch is definitely wrong. The patch to fix up the
>> > gpio reset stuff is definitely the right idea. Whether it
>> > fixes the reported failure or some further change is also
>> > needed is currently unclear.
> I will NAK this one for now. Please see V2 patch, which is necessary. In
> the meanwhile, I think there is a problem with pulling-up only in
> current implementation. Let me debug Shannon's DT problem first.
> 
Hi Wei,

The reason of DT problem is that when we use qemu_irq_pulse(i.e
qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1);
qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0);), it will inject the
GPIO interrupt until it executes
qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0) because the qemu main
thread is serialized and then guest will get the button value as zero,
so it's failed to report the input event.

See gpio_keys_gpio_report_event
 in drivers/input/keyboard/gpio_keys.c
int state = gpio_get_value_cansleep(button->gpio);

The state is always zero.

The solution I think would be making the each
qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1 or 0) cloud inject an
interrupt to guest.

Thanks,
-- 
Shannon

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Wei Huang]

On 02/03/2016 07:44 PM, Shannon Zhao wrote:
> 
> 
> On 2016/2/4 0:01, Wei Huang wrote:
>>
>> On 2/3/16 04:46, Peter Maydell wrote:
>>>> On 3 February 2016 at 07:15, Michael Tokarev <mjt@tls.msk.ru> wrote:
>>>>>> 28.01.2016 21:22, Wei Huang wrote:
>>>>>>>> When QEMU is hook'ed up with libvirt/virsh, the first ACPI reboot
>>>>>>>> request will succeed; but the following shutdown/reboot requests
>>>>>>>> fail to trigger VMs to react. Notice that in mach-virt machine
>>>>>>>> model GPIO is defined as edge-triggered and active-high in ACPI.
>>>>>>>> This patch changes the behavior of powerdown notifier from PULLUP
>>>>>>>> to PULSE. It solves the problem described above (i.e. reboot
>>>>>>>> continues to work).
>>>>>>
>>>>>> So, what's the outcome of this? :)
>>>>
>>>> This patch is definitely wrong. The patch to fix up the
>>>> gpio reset stuff is definitely the right idea. Whether it
>>>> fixes the reported failure or some further change is also
>>>> needed is currently unclear.
>> I will NAK this one for now. Please see V2 patch, which is necessary. In
>> the meanwhile, I think there is a problem with pulling-up only in
>> current implementation. Let me debug Shannon's DT problem first.
>>
> Hi Wei,
> 
> The reason of DT problem is that when we use qemu_irq_pulse(i.e
> qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1);
> qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0);), it will inject the
> GPIO interrupt until it executes
> qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0) because the qemu main
> thread is serialized and then guest will get the button value as zero,
> so it's failed to report the input event.
> 
> See gpio_keys_gpio_report_event
>  in drivers/input/keyboard/gpio_keys.c
> int state = gpio_get_value_cansleep(button->gpio);
> 
> The state is always zero.

I reversed the order of edge pulling. The state is 1 according to printk
inside gpio_keys driver. However the reboot still failed with two
reboots (1 very early, 1 later).

> 
> The solution I think would be making the each
> qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1 or 0) cloud inject an
> interrupt to guest.
> 
> Thanks,
> 

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Shannon Zhao]

On 2016/2/4 14:10, Wei Huang wrote:
> 
> On 02/03/2016 07:44 PM, Shannon Zhao wrote:
>> > 
>> > 
>> > On 2016/2/4 0:01, Wei Huang wrote:
>>> >>
>>> >> On 2/3/16 04:46, Peter Maydell wrote:
>>>>> >>>> On 3 February 2016 at 07:15, Michael Tokarev <mjt@tls.msk.ru> wrote:
>>>>>>> >>>>>> 28.01.2016 21:22, Wei Huang wrote:
>>>>>>>>> >>>>>>>> When QEMU is hook'ed up with libvirt/virsh, the first ACPI reboot
>>>>>>>>> >>>>>>>> request will succeed; but the following shutdown/reboot requests
>>>>>>>>> >>>>>>>> fail to trigger VMs to react. Notice that in mach-virt machine
>>>>>>>>> >>>>>>>> model GPIO is defined as edge-triggered and active-high in ACPI.
>>>>>>>>> >>>>>>>> This patch changes the behavior of powerdown notifier from PULLUP
>>>>>>>>> >>>>>>>> to PULSE. It solves the problem described above (i.e. reboot
>>>>>>>>> >>>>>>>> continues to work).
>>>>>>> >>>>>>
>>>>>>> >>>>>> So, what's the outcome of this? :)
>>>>> >>>>
>>>>> >>>> This patch is definitely wrong. The patch to fix up the
>>>>> >>>> gpio reset stuff is definitely the right idea. Whether it
>>>>> >>>> fixes the reported failure or some further change is also
>>>>> >>>> needed is currently unclear.
>>> >> I will NAK this one for now. Please see V2 patch, which is necessary. In
>>> >> the meanwhile, I think there is a problem with pulling-up only in
>>> >> current implementation. Let me debug Shannon's DT problem first.
>>> >>
>> > Hi Wei,
>> > 
>> > The reason of DT problem is that when we use qemu_irq_pulse(i.e
>> > qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1);
>> > qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0);), it will inject the
>> > GPIO interrupt until it executes
>> > qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0) because the qemu main
>> > thread is serialized and then guest will get the button value as zero,
>> > so it's failed to report the input event.
>> > 
>> > See gpio_keys_gpio_report_event
>> >  in drivers/input/keyboard/gpio_keys.c
>> > int state = gpio_get_value_cansleep(button->gpio);
>> > 
>> > The state is always zero.
> I reversed the order of edge pulling. The state is 1 according to printk
> inside gpio_keys driver. However the reboot still failed with two
> reboots (1 very early, 1 later).
> 
Because to make the input work, it should call input_event twice I think.

input_event(input, type, button->code, 1) means the button pressed
input_event(input, type, button->code, 0) means the button released

But We only see guest entering gpio_keys_gpio_report_event once.

My original purpose is like below:

call qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1) to make guest
execute input_event(input, type, button->code, 1)
call qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0) to make guest
execute input_event(input, type, button->code, 0).

But even though it calls qemu_set_irq twice, it only calls pl061_update
once in qemu.

-- 
Shannon

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Wei Huang]

[-- Attachment #1: Type: text/plain, Size: 3720 bytes --]


On 02/04/2016 12:51 AM, Shannon Zhao wrote:
> 
> 
> On 2016/2/4 14:10, Wei Huang wrote:
>>
>> On 02/03/2016 07:44 PM, Shannon Zhao wrote:

<snip>

>> I reversed the order of edge pulling. The state is 1 according to printk
>> inside gpio_keys driver. However the reboot still failed with two
>> reboots (1 very early, 1 later).
>>
> Because to make the input work, it should call input_event twice I think.
> 
> input_event(input, type, button->code, 1) means the button pressed
> input_event(input, type, button->code, 0) means the button released
> 
> But We only see guest entering gpio_keys_gpio_report_event once.
> 
> My original purpose is like below:
> 
> call qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1) to make guest
> execute input_event(input, type, button->code, 1)
> call qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0) to make guest
> execute input_event(input, type, button->code, 0).
> 
> But even though it calls qemu_set_irq twice, it only calls pl061_update
> once in qemu.

Hi Shannon,

Assuming that we are talking about the special case you found (i.e. send
reboot very early and then send another one after guest VM fully
booted). Dug into the code further, here are my findings:

=== Why ACPI case failed? ===
QEMU pl061.c checks the current request against the new request (see
s->old_in_data ^ s->data in pl061.c file). If no change, nothing will
happen.

So two consecutive reboots will cause the following state change;
apparently the second request won't trigger VM reboot because
pl01_update() decides _not_ to inject IRQ into guest VM.

  (PL061State fields)           data   old_in_data   istate
VM boot                         0      0             0
1st ACPI reboot request         8      0             0
After VM PL061 driver ACK       8      8             0
2nd ACPI reboot request         8     no-change, no IRQ <==

To solve this problem, we have to invert PL061State->data at least once
to trigger IRQ inside VM. Two solutions:

S1: "Pulse"
static void virt_powerdown_req(Notifier *n, void *opaque)
{
    qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0);
    qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1);
}

S2: "Invert"
static int old_gpio_level = 0;
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), !old_gpio_level);
    old_gpio_level = !old_gpio_level;
}

Both S1 and S2 works for ACPI. But S1 has problem with DT, which is
explained below.

=== Why DT fails with S1 ===
DT approach requires both PL061 and gpio-keys to work together. Looking
into guest kernel gpio-keys/input code, you will find that it only
reacts to both LEVEL-HI and input changes. Here is the code snip from
drivers/input/input.c file:

    /* auto-repeat bypasses state updates */
    if (value == 2) {
            disposition = INPUT_PASS_TO_HANDLERS;
            break;
    }

    if (!!test_bit(code, dev->key) != !!value) {
            __change_bit(code, dev->key);
            disposition = INPUT_PASS_TO_HANDLERS;
    }

Unless we adds gpio-keys DT property to "autorepeat", the
"!!test_bit(code, dev->key) != !!value" is always FALSE with S1. Thus
systemd won't receive any input event; and no power-switch will be
triggered.

In comparison S2 will work because value is changed very time.

=== Summary ===
1. Cleaning PL061 state is required. That means "[PATCH V2 1/2] ARM:
PL061: Clear PL061 device state after reset" is necessary.
2. S2 is better. To support S2, we needs to change GPIO IRQ polarity to
AML_ACTIVE_BOTH in ACPI description.

I attach a small patch in this email. It should work for your DT case.
Please test it and let me know your comments.

Thanks,
-Wei


> 

[-- Attachment #2: gpio-fix.txt --]
[-- Type: text/plain, Size: 1280 bytes --]

diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
index 7b124f6..7b1dc5e 100644
--- a/hw/arm/virt-acpi-build.c
+++ b/hw/arm/virt-acpi-build.c
@@ -326,7 +326,7 @@ static void acpi_dsdt_add_gpio(Aml *scope, const MemMapEntry *gpio_memmap,
     Aml *aei = aml_resource_template();
     /* Pin 3 for power button */
     const uint32_t pin_list[1] = {3};
-    aml_append(aei, aml_gpio_int(AML_CONSUMER, AML_EDGE, AML_ACTIVE_HIGH,
+    aml_append(aei, aml_gpio_int(AML_CONSUMER, AML_EDGE, 3,
                                  AML_EXCLUSIVE, AML_PULL_UP, 0, pin_list, 1,
                                  "GPO0", NULL, 0));
     aml_append(dev, aml_name_decl("_AEI", aei));
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 5695e72..ed02a6c 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -547,10 +547,12 @@ static void create_rtc(const VirtBoardInfo *vbi, qemu_irq *pic)
 }
 
 static DeviceState *pl061_dev;
+static int old_gpio_level = 0;
 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), 1);
+    qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), !old_gpio_level);
+    old_gpio_level = !old_gpio_level;
 }
 
 static Notifier virt_system_powerdown_notifier = {

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Shannon Zhao]

Hi Wei,

On 2016/2/10 6:59, Wei Huang wrote:
> 
> On 02/04/2016 12:51 AM, Shannon Zhao wrote:
>>
>>
>> On 2016/2/4 14:10, Wei Huang wrote:
>>>
>>> On 02/03/2016 07:44 PM, Shannon Zhao wrote:
> 
> <snip>
> 
>>> I reversed the order of edge pulling. The state is 1 according to printk
>>> inside gpio_keys driver. However the reboot still failed with two
>>> reboots (1 very early, 1 later).
>>>
>> Because to make the input work, it should call input_event twice I think.
>>
>> input_event(input, type, button->code, 1) means the button pressed
>> input_event(input, type, button->code, 0) means the button released
>>
>> But We only see guest entering gpio_keys_gpio_report_event once.
>>
>> My original purpose is like below:
>>
>> call qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1) to make guest
>> execute input_event(input, type, button->code, 1)
>> call qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0) to make guest
>> execute input_event(input, type, button->code, 0).
>>
>> But even though it calls qemu_set_irq twice, it only calls pl061_update
>> once in qemu.
> 
> Hi Shannon,
> 
> Assuming that we are talking about the special case you found (i.e. send
> reboot very early and then send another one after guest VM fully
> booted). Dug into the code further, here are my findings:
> 
> === Why ACPI case failed? ===
> QEMU pl061.c checks the current request against the new request (see
> s->old_in_data ^ s->data in pl061.c file). If no change, nothing will
> happen.
> 
> So two consecutive reboots will cause the following state change;
> apparently the second request won't trigger VM reboot because
> pl01_update() decides _not_ to inject IRQ into guest VM.
> 
>   (PL061State fields)           data   old_in_data   istate
> VM boot                         0      0             0
> 1st ACPI reboot request         8      0             0
> After VM PL061 driver ACK       8      8             0
> 2nd ACPI reboot request         8     no-change, no IRQ <==
> 
> To solve this problem, we have to invert PL061State->data at least once
> to trigger IRQ inside VM. Two solutions:
> 
> S1: "Pulse"
> static void virt_powerdown_req(Notifier *n, void *opaque)
> {
>     qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0);
>     qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1);
> }
> 
> S2: "Invert"
> static int old_gpio_level = 0;
> 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), !old_gpio_level);
>     old_gpio_level = !old_gpio_level;
> }
> 
The S2 still doesn't work. After sending the early first reboot, whne
guest boots well, it doesn't react to the second reboot while it reacts
to the third one.

> Both S1 and S2 works for ACPI. But S1 has problem with DT, which is
> explained below.
> 
> === Why DT fails with S1 ===
> DT approach requires both PL061 and gpio-keys to work together. Looking
> into guest kernel gpio-keys/input code, you will find that it only
> reacts to both LEVEL-HI and input changes. Here is the code snip from
> drivers/input/input.c file:
> 
>     /* auto-repeat bypasses state updates */
>     if (value == 2) {
>             disposition = INPUT_PASS_TO_HANDLERS;
>             break;
>     }
> 
>     if (!!test_bit(code, dev->key) != !!value) {
>             __change_bit(code, dev->key);
>             disposition = INPUT_PASS_TO_HANDLERS;
>     }
> 
> Unless we adds gpio-keys DT property to "autorepeat", the
> "!!test_bit(code, dev->key) != !!value" is always FALSE with S1. Thus
> systemd won't receive any input event; and no power-switch will be
> triggered.
> 
> In comparison S2 will work because value is changed very time.
> 
> === Summary ===
> 1. Cleaning PL061 state is required. That means "[PATCH V2 1/2] ARM:
> PL061: Clear PL061 device state after reset" is necessary.
> 2. S2 is better. To support S2, we needs to change GPIO IRQ polarity to
> AML_ACTIVE_BOTH in ACPI description.
> 
Thanks. But we don't have the AML_ACTIVE_BOTH since there is only one
bit for "Interrupt Polarity" in ACPI table.
See ACPI SPEC 6.0 "Table 6-216 Extended Interrupt Descriptor Definition"
Bit [2] Interrupt Polarity, _LL
0 Active-High: This interrupt is sampled when the signal is high,
or true.
1 Active-Low: This interrupt is sampled when the signal is low, or
false.

> --- a/hw/arm/virt-acpi-build.c
> +++ b/hw/arm/virt-acpi-build.c
> @@ -326,7 +326,7 @@ static void acpi_dsdt_add_gpio(Aml *scope, const MemMapEntry *gpio_memmap,
>      Aml *aei = aml_resource_template();
>      /* Pin 3 for power button */
>      const uint32_t pin_list[1] = {3};
> -    aml_append(aei, aml_gpio_int(AML_CONSUMER, AML_EDGE, AML_ACTIVE_HIGH,
> +    aml_append(aei, aml_gpio_int(AML_CONSUMER, AML_EDGE, 3,
What's the meaning of 3 here?

>                                   AML_EXCLUSIVE, AML_PULL_UP, 0, pin_list, 1,
>                                   "GPO0", NULL, 0));
>      aml_append(dev, aml_name_decl("_AEI", aei));

Thanks,
-- 
Shannon

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Wei Huang]

On 02/20/2016 04:53 AM, Shannon Zhao wrote:
> Hi Wei,
> 
> On 2016/2/10 6:59, Wei Huang wrote:
>>
>> On 02/04/2016 12:51 AM, Shannon Zhao wrote:
>>>
>>>
>>> On 2016/2/4 14:10, Wei Huang wrote:
>>>>
>>>> On 02/03/2016 07:44 PM, Shannon Zhao wrote:
>>
>> <snip>
>>
>>>> I reversed the order of edge pulling. The state is 1 according to printk
>>>> inside gpio_keys driver. However the reboot still failed with two
>>>> reboots (1 very early, 1 later).
>>>>
>>> Because to make the input work, it should call input_event twice I think.
>>>
>>> input_event(input, type, button->code, 1) means the button pressed
>>> input_event(input, type, button->code, 0) means the button released
>>>
>>> But We only see guest entering gpio_keys_gpio_report_event once.
>>>
>>> My original purpose is like below:
>>>
>>> call qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1) to make guest
>>> execute input_event(input, type, button->code, 1)
>>> call qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0) to make guest
>>> execute input_event(input, type, button->code, 0).
>>>
>>> But even though it calls qemu_set_irq twice, it only calls pl061_update
>>> once in qemu.
>>
>> Hi Shannon,
>>
>> Assuming that we are talking about the special case you found (i.e. send
>> reboot very early and then send another one after guest VM fully
>> booted). Dug into the code further, here are my findings:
>>
>> === Why ACPI case failed? ===
>> QEMU pl061.c checks the current request against the new request (see
>> s->old_in_data ^ s->data in pl061.c file). If no change, nothing will
>> happen.
>>
>> So two consecutive reboots will cause the following state change;
>> apparently the second request won't trigger VM reboot because
>> pl01_update() decides _not_ to inject IRQ into guest VM.
>>
>>   (PL061State fields)           data   old_in_data   istate
>> VM boot                         0      0             0
>> 1st ACPI reboot request         8      0             0
>> After VM PL061 driver ACK       8      8             0
>> 2nd ACPI reboot request         8     no-change, no IRQ <==
>>
>> To solve this problem, we have to invert PL061State->data at least once
>> to trigger IRQ inside VM. Two solutions:
>>
>> S1: "Pulse"
>> static void virt_powerdown_req(Notifier *n, void *opaque)
>> {
>>     qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0);
>>     qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1);
>> }
>>
>> S2: "Invert"
>> static int old_gpio_level = 0;
>> 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), !old_gpio_level);
>>     old_gpio_level = !old_gpio_level;
>> }
>>
> The S2 still doesn't work. After sending the early first reboot, whne
> guest boots well, it doesn't react to the second reboot while it reacts
> to the third one.

I can reproduce it. The problem is that gpio-keys only handles
GPIO_ACTIVE_LOW or GPIO_ACTIVE_HIGH. It can't react to ACTIVE_BOTH. That
explains why it reacts to the 3rd request: HIGH (ingored, too early,
keyboard driver not loaded) ==> LOW (ignored, ACTIVE_HIGH only) ==> HIGH
(received).

This problem is full of dilemma, across different components in QEMU or
guest VM:

* For qemu/pl011.c to generate IRQ, we need to have level transition.
That means qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1) in
virt_powerdown_req() isn't enough.
* If we do "invert" (i.e. S2 above), gpio-keys inside VM isn't happy
with it.
* If we do pulse (i.e. S1 above), DT fails because of the reason
explained below. Plus the GPIO seems to receive the same state due to
non-preemptive (you mentioned it long time ago).

Not sure what to do next. Some wild ideas can be:
1) set up a worker thread to pull down GPIO after a fix time. This
emulates real world scenario.
2) enable PL061 to support auto-ACK after receiving ACK from guest VM.

Thanks,
-Wei

> 
>> Both S1 and S2 works for ACPI. But S1 has problem with DT, which is
>> explained below.
>>
>> === Why DT fails with S1 ===
>> DT approach requires both PL061 and gpio-keys to work together. Looking
>> into guest kernel gpio-keys/input code, you will find that it only
>> reacts to both LEVEL-HI and input changes. Here is the code snip from
>> drivers/input/input.c file:
>>
>>     /* auto-repeat bypasses state updates */
>>     if (value == 2) {
>>             disposition = INPUT_PASS_TO_HANDLERS;
>>             break;
>>     }
>>
>>     if (!!test_bit(code, dev->key) != !!value) {
>>             __change_bit(code, dev->key);
>>             disposition = INPUT_PASS_TO_HANDLERS;
>>     }
>>
>> Unless we adds gpio-keys DT property to "autorepeat", the
>> "!!test_bit(code, dev->key) != !!value" is always FALSE with S1. Thus
>> systemd won't receive any input event; and no power-switch will be
>> triggered.
>>
>> In comparison S2 will work because value is changed very time.
>>
>> === Summary ===
>> 1. Cleaning PL061 state is required. That means "[PATCH V2 1/2] ARM:
>> PL061: Clear PL061 device state after reset" is necessary.
>> 2. S2 is better. To support S2, we needs to change GPIO IRQ polarity to
>> AML_ACTIVE_BOTH in ACPI description.
>>
> Thanks. But we don't have the AML_ACTIVE_BOTH since there is only one
> bit for "Interrupt Polarity" in ACPI table.
> See ACPI SPEC 6.0 "Table 6-216 Extended Interrupt Descriptor Definition"
> Bit [2] Interrupt Polarity, _LL
> 0 Active-High: This interrupt is sampled when the signal is high,
> or true.
> 1 Active-Low: This interrupt is sampled when the signal is low, or
> false.



> 
>> --- a/hw/arm/virt-acpi-build.c
>> +++ b/hw/arm/virt-acpi-build.c
>> @@ -326,7 +326,7 @@ static void acpi_dsdt_add_gpio(Aml *scope, const MemMapEntry *gpio_memmap,
>>      Aml *aei = aml_resource_template();
>>      /* Pin 3 for power button */
>>      const uint32_t pin_list[1] = {3};
>> -    aml_append(aei, aml_gpio_int(AML_CONSUMER, AML_EDGE, AML_ACTIVE_HIGH,
>> +    aml_append(aei, aml_gpio_int(AML_CONSUMER, AML_EDGE, 3,
> What's the meaning of 3 here?
> 
>>                                   AML_EXCLUSIVE, AML_PULL_UP, 0, pin_list, 1,
>>                                   "GPO0", NULL, 0));
>>      aml_append(dev, aml_name_decl("_AEI", aei));
> 
> Thanks,
> 

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Shannon Zhao]

On 2016/2/25 6:22, Wei Huang wrote:
> 
> 
> On 02/20/2016 04:53 AM, Shannon Zhao wrote:
>> Hi Wei,
>>
>> On 2016/2/10 6:59, Wei Huang wrote:
>>>
>>> On 02/04/2016 12:51 AM, Shannon Zhao wrote:
>>>>
>>>>
>>>> On 2016/2/4 14:10, Wei Huang wrote:
>>>>>
>>>>> On 02/03/2016 07:44 PM, Shannon Zhao wrote:
>>>
>>> <snip>
>>>
>>>>> I reversed the order of edge pulling. The state is 1 according to printk
>>>>> inside gpio_keys driver. However the reboot still failed with two
>>>>> reboots (1 very early, 1 later).
>>>>>
>>>> Because to make the input work, it should call input_event twice I think.
>>>>
>>>> input_event(input, type, button->code, 1) means the button pressed
>>>> input_event(input, type, button->code, 0) means the button released
>>>>
>>>> But We only see guest entering gpio_keys_gpio_report_event once.
>>>>
>>>> My original purpose is like below:
>>>>
>>>> call qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1) to make guest
>>>> execute input_event(input, type, button->code, 1)
>>>> call qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0) to make guest
>>>> execute input_event(input, type, button->code, 0).
>>>>
>>>> But even though it calls qemu_set_irq twice, it only calls pl061_update
>>>> once in qemu.
>>>
>>> Hi Shannon,
>>>
>>> Assuming that we are talking about the special case you found (i.e. send
>>> reboot very early and then send another one after guest VM fully
>>> booted). Dug into the code further, here are my findings:
>>>
>>> === Why ACPI case failed? ===
>>> QEMU pl061.c checks the current request against the new request (see
>>> s->old_in_data ^ s->data in pl061.c file). If no change, nothing will
>>> happen.
>>>
>>> So two consecutive reboots will cause the following state change;
>>> apparently the second request won't trigger VM reboot because
>>> pl01_update() decides _not_ to inject IRQ into guest VM.
>>>
>>>   (PL061State fields)           data   old_in_data   istate
>>> VM boot                         0      0             0
>>> 1st ACPI reboot request         8      0             0
>>> After VM PL061 driver ACK       8      8             0
>>> 2nd ACPI reboot request         8     no-change, no IRQ <==
>>>
>>> To solve this problem, we have to invert PL061State->data at least once
>>> to trigger IRQ inside VM. Two solutions:
>>>
>>> S1: "Pulse"
>>> static void virt_powerdown_req(Notifier *n, void *opaque)
>>> {
>>>     qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0);
>>>     qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1);
>>> }
>>>
>>> S2: "Invert"
>>> static int old_gpio_level = 0;
>>> 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), !old_gpio_level);
>>>     old_gpio_level = !old_gpio_level;
>>> }
>>>
>> The S2 still doesn't work. After sending the early first reboot, whne
>> guest boots well, it doesn't react to the second reboot while it reacts
>> to the third one.
> 
> I can reproduce it. The problem is that gpio-keys only handles
> GPIO_ACTIVE_LOW or GPIO_ACTIVE_HIGH. It can't react to ACTIVE_BOTH. That
> explains why it reacts to the 3rd request: HIGH (ingored, too early,
> keyboard driver not loaded) ==> LOW (ignored, ACTIVE_HIGH only) ==> HIGH
> (received).
> 
> This problem is full of dilemma, across different components in QEMU or
> guest VM:
> 
> * For qemu/pl011.c to generate IRQ, we need to have level transition.
> That means qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 1) in
> virt_powerdown_req() isn't enough.
> * If we do "invert" (i.e. S2 above), gpio-keys inside VM isn't happy
> with it.
> * If we do pulse (i.e. S1 above), DT fails because of the reason
> explained below. Plus the GPIO seems to receive the same state due to
> non-preemptive (you mentioned it long time ago).
> 
> Not sure what to do next. Some wild ideas can be:
> 1) set up a worker thread to pull down GPIO after a fix time. This
> emulates real world scenario.
Yeah, right! But other than a worker thread, I'd like to use a timer.
Then set a latency between pull up and down like we press a button in
real world.

So how about below patch? I've tested it and it works both for ACPI and
DT. Could you help verify if it works for you? Thanks.

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 15658f4..4d45ea2 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -558,11 +558,20 @@ static void create_rtc(const VirtBoardInfo *vbi,
qemu_irq *pic)
     g_free(nodename);
 }

+#define GPIO_KEY_LATENCY 500 /* 500ms */
 static DeviceState *pl061_dev;
+static QEMUTimer *gpio_key_timer;
+static void gpio_key_timer_expired(void *vp)
+{
+    qemu_set_irq(qdev_get_gpio_in(pl061_dev, 3), 0);
+}
+
 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), 1);
+    timer_mod(gpio_key_timer,
+              qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + GPIO_KEY_LATENCY);
 }

 static Notifier virt_system_powerdown_notifier = {
@@ -609,6 +618,8 @@ static void create_gpio(const VirtBoardInfo *vbi,
qemu_irq *pic)

     /* connect powerdown request */
     qemu_register_powerdown_notifier(&virt_system_powerdown_notifier);
+    gpio_key_timer = timer_new_ms(QEMU_CLOCK_VIRTUAL,
gpio_key_timer_expired,
+                                  NULL);

     g_free(nodename);
 }

Thanks,
-- 
Shannon

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Peter Maydell]

On 26 February 2016 at 12:31, Shannon Zhao <zhaoshenglong@huawei.com> wrote:
> So how about below patch? I've tested it and it works both for ACPI and
> DT. Could you help verify if it works for you? Thanks.
>
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index 15658f4..4d45ea2 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -558,11 +558,20 @@ static void create_rtc(const VirtBoardInfo *vbi,
> qemu_irq *pic)
>      g_free(nodename);
>  }
>
> +#define GPIO_KEY_LATENCY 500 /* 500ms */

I don't understand why a 500ms pulse is better than a short one.

> +static QEMUTimer *gpio_key_timer;

This is state, and must be migrated somehow.

thanks
-- PMM

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Shannon Zhao]

On 2016/2/26 20:53, Peter Maydell wrote:
> On 26 February 2016 at 12:31, Shannon Zhao <zhaoshenglong@huawei.com> wrote:
>> So how about below patch? I've tested it and it works both for ACPI and
>> DT. Could you help verify if it works for you? Thanks.
>>
>> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
>> index 15658f4..4d45ea2 100644
>> --- a/hw/arm/virt.c
>> +++ b/hw/arm/virt.c
>> @@ -558,11 +558,20 @@ static void create_rtc(const VirtBoardInfo *vbi,
>> qemu_irq *pic)
>>       g_free(nodename);
>>   }
>>
>> +#define GPIO_KEY_LATENCY 500 /* 500ms */
>
> I don't understand why a 500ms pulse is better than a short one.
>
Oh, I just pick a value which seems like a real latency for pressing a 
button. What's your suggestion?

>> +static QEMUTimer *gpio_key_timer;
>
> This is state, and must be migrated somehow.
>
Ah, yes. So is it fine if we move this timer and the notifier 
virt_system_powerdown_notifier to VirtMachineState?

Thanks,
-- 
Shannon

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Peter Maydell]

On 26 February 2016 at 14:54, Shannon Zhao <shannon.zhao@linaro.org> wrote:
> On 2016/2/26 20:53, Peter Maydell wrote:
>> I don't understand why a 500ms pulse is better than a short one.
>>
> Oh, I just pick a value which seems like a real latency for pressing a
> button. What's your suggestion?

I would prefer to avoid the pain of having a timer whose state
needs to be migrated. It's unclear to me why a 500ms pulse
will solve anything that an instantaneous pulse does not,
so I'd like to better understand the problem first.

thanks
-- PMM

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Wei Huang]

On 02/26/2016 09:06 AM, Peter Maydell wrote:
> On 26 February 2016 at 14:54, Shannon Zhao <shannon.zhao@linaro.org> wrote:
>> On 2016/2/26 20:53, Peter Maydell wrote:
>>> I don't understand why a 500ms pulse is better than a short one.
>>>
>> Oh, I just pick a value which seems like a real latency for pressing a
>> button. What's your suggestion?
> 
> I would prefer to avoid the pain of having a timer whose state
> needs to be migrated. It's unclear to me why a 500ms pulse
> will solve anything that an instantaneous pulse does not,
> so I'd like to better understand the problem first.

The problem we found with pulse was: only the last state change in GPIO
is received by guest VM. In other words, with 0(L)->1(H)->0(L) or
1(H)->0(L)->1(0), PL061 only sees the last state (0 and 1). I guess this
is because QEMU is non-preemptive. The solution is to have the following
steps:
  * qemu_set_irq(gpio_in, 1)
  * yeild to guest VM
  * qemu_set_irq(gpio_in, 0)

Is there any way to do so in QEMU without using timer?

> 
> thanks
> -- PMM
> 

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Peter Maydell]

On 26 February 2016 at 15:28, Wei Huang <wei@redhat.com> wrote:
>
>
> On 02/26/2016 09:06 AM, Peter Maydell wrote:
>> On 26 February 2016 at 14:54, Shannon Zhao <shannon.zhao@linaro.org> wrote:
>>> On 2016/2/26 20:53, Peter Maydell wrote:
>>>> I don't understand why a 500ms pulse is better than a short one.
>>>>
>>> Oh, I just pick a value which seems like a real latency for pressing a
>>> button. What's your suggestion?
>>
>> I would prefer to avoid the pain of having a timer whose state
>> needs to be migrated. It's unclear to me why a 500ms pulse
>> will solve anything that an instantaneous pulse does not,
>> so I'd like to better understand the problem first.
>
> The problem we found with pulse was: only the last state change in GPIO
> is received by guest VM. In other words, with 0(L)->1(H)->0(L) or
> 1(H)->0(L)->1(0), PL061 only sees the last state (0 and 1). I guess this
> is because QEMU is non-preemptive. The solution is to have the following
> steps:
>   * qemu_set_irq(gpio_in, 1)
>   * yeild to guest VM
>   * qemu_set_irq(gpio_in, 0)
>
> Is there any way to do so in QEMU without using timer?

You have no guarantee that the guest VM will necessarily
make any progress even with a 500ms pulse length, so I don't
think increasing the length of the pulse is going to solidly
fix this.

As usual with any kind of interrupt you either need to
trigger on an edge (and latch the trigger in the interrupt
controller until the guest picks it up), or trigger on a
level, and keep the level high until the guest acknowledges
by writing back to the original device to tell it to drop
the level.

thanks
-- PMM

Re: [Qemu-devel] [PATCH 1/1] arm: virt: change GPIO trigger interrupt to pulse

[Shannon Zhao]

On 2016/2/26 23:42, Peter Maydell wrote:
> On 26 February 2016 at 15:28, Wei Huang <wei@redhat.com> wrote:
>>
>>
>> On 02/26/2016 09:06 AM, Peter Maydell wrote:
>>> On 26 February 2016 at 14:54, Shannon Zhao <shannon.zhao@linaro.org> wrote:
>>>> On 2016/2/26 20:53, Peter Maydell wrote:
>>>>> I don't understand why a 500ms pulse is better than a short one.
>>>>>
>>>> Oh, I just pick a value which seems like a real latency for pressing a
>>>> button. What's your suggestion?
>>>
>>> I would prefer to avoid the pain of having a timer whose state
>>> needs to be migrated. It's unclear to me why a 500ms pulse
>>> will solve anything that an instantaneous pulse does not,
>>> so I'd like to better understand the problem first.
>>
>> The problem we found with pulse was: only the last state change in GPIO
>> is received by guest VM. In other words, with 0(L)->1(H)->0(L) or
>> 1(H)->0(L)->1(0), PL061 only sees the last state (0 and 1). I guess this
>> is because QEMU is non-preemptive. The solution is to have the following
>> steps:
>>   * qemu_set_irq(gpio_in, 1)
>>   * yeild to guest VM
>>   * qemu_set_irq(gpio_in, 0)
>>
>> Is there any way to do so in QEMU without using timer?
> 
> You have no guarantee that the guest VM will necessarily
> make any progress even with a 500ms pulse length, 
Yeah, if the guest is very busy! But it's true in the real world like
that we press a GPIO_KEY button, but guest is too busy that it can't
react to this then the guest can't shutdown.

> so I don't
> think increasing the length of the pulse is going to solidly
> fix this.
> 
This is not simply increasing the length. It just makes the guest not
blocked after the first qemu_set_irq so that the guest can detect the
button is pressed(i.e. get the value 1). Then after any time, call the
second qemu_set_irq then guest can detect the button is released.

You must be aware that here the purpose of qemu_set_irq is only to set
the value of gpio pin not directly set the interrupt controller. As for
injecting the interrupt, it's what the PL061 device does which detects
the pin value changed.

And for GPIO_KEY, it must detect 1 and 0 then it realizes it as a valid
input.

Have a look at the below function in drivers/input/keyboard/gpio_keys.c.

static void gpio_keys_gpio_report_event(struct gpio_button_data *bdata)
{
	const struct gpio_keys_button *button = bdata->button;
	struct input_dev *input = bdata->input;
	unsigned int type = button->type ?: EV_KEY;
	int state = (gpio_get_value_cansleep(button->gpio) ? 1 : 0) ^
button->active_low;

	if (type == EV_ABS) {
		if (state)
			input_event(input, type, button->code, button->value);
	} else {
		input_event(input, type, button->code, !!state);
	}
	input_sync(input);
}


> As usual with any kind of interrupt you either need to
> trigger on an edge (and latch the trigger in the interrupt
> controller until the guest picks it up), or trigger on a
> level, and keep the level high until the guest acknowledges
> by writing back to the original device to tell it to drop
> the level.
> 
As said, here we only want change the some pin value and want guest to
get the value. The interrupt is triggered by PL061 device which just
notifies the guest that pin value is changed, please read.

Thanks,
-- 
Shannon