[Qemu-devel] [PATCH for-2.3] powerpc: fix -machine usb=no for newworld and pseries machines

[Qemu-devel] [PATCH for-2.3] powerpc: fix -machine usb=no for newworld and pseries machines

[Paolo Bonzini]

Capture the explicit setting of "usb=no" into a separate bool, and
use it to skip the update of machine->usb in the board init function.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/core/machine.c     | 1 +
 hw/ppc/mac_newworld.c | 2 +-
 hw/ppc/spapr.c        | 2 +-
 include/hw/boards.h   | 1 +
 4 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/hw/core/machine.c b/hw/core/machine.c
index cb1185a..25c45e6 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -223,6 +223,7 @@ static void machine_set_usb(Object *obj, bool value, Error **errp)
     MachineState *ms = MACHINE(obj);
 
     ms->usb = value;
+    ms->usb_disabled = !value;
 }
 
 static char *machine_get_firmware(Object *obj, Error **errp)
diff --git a/hw/ppc/mac_newworld.c b/hw/ppc/mac_newworld.c
index e0397bc..a365bf9 100644
--- a/hw/ppc/mac_newworld.c
+++ b/hw/ppc/mac_newworld.c
@@ -371,7 +371,7 @@ static void ppc_core99_init(MachineState *machine)
         /* 970 gets a U3 bus */
         pci_bus = pci_pmac_u3_init(pic, get_system_memory(), get_system_io());
         machine_arch = ARCH_MAC99_U3;
-        machine->usb |= defaults_enabled();
+        machine->usb |= defaults_enabled() && !machine->usb_disabled;
     } else {
         pci_bus = pci_pmac_init(pic, get_system_memory(), get_system_io());
         machine_arch = ARCH_MAC99;
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 0487f52..dd5e101 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1563,7 +1563,7 @@ static void ppc_spapr_init(MachineState *machine)
     /* Graphics */
     if (spapr_vga_init(phb->bus)) {
         spapr->has_graphics = true;
-        machine->usb |= defaults_enabled();
+        machine->usb |= defaults_enabled() && !machine->usb_disabled;
     }
 
     if (machine->usb) {
diff --git a/include/hw/boards.h b/include/hw/boards.h
index 1feea2b..be6a0ed 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -141,6 +141,7 @@ struct MachineState {
     bool dump_guest_core;
     bool mem_merge;
     bool usb;
+    bool usb_disabled;
     char *firmware;
     bool iommu;
     bool suppress_vmdesc;
-- 
2.3.3

Re: [Qemu-devel] [PATCH for-2.3] powerpc: fix -machine usb=no for newworld and pseries machines

[Alexander Graf]

On 03/23/2015 06:05 PM, Paolo Bonzini wrote:
> Capture the explicit setting of "usb=no" into a separate bool, and
> use it to skip the update of machine->usb in the board init function.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Thanks, applied to ppc-next (for 2.3).


Alex

Re: [Qemu-devel] [PATCH for-2.3] powerpc: fix -machine usb=no for newworld and pseries machines

[Marcel Apfelbaum]

On 03/23/2015 07:05 PM, Paolo Bonzini wrote:
> Capture the explicit setting of "usb=no" into a separate bool, and
> use it to skip the update of machine->usb in the board init function.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>   hw/core/machine.c     | 1 +
>   hw/ppc/mac_newworld.c | 2 +-
>   hw/ppc/spapr.c        | 2 +-
>   include/hw/boards.h   | 1 +
>   4 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/hw/core/machine.c b/hw/core/machine.c
> index cb1185a..25c45e6 100644
> --- a/hw/core/machine.c
> +++ b/hw/core/machine.c
> @@ -223,6 +223,7 @@ static void machine_set_usb(Object *obj, bool value, Error **errp)
>       MachineState *ms = MACHINE(obj);
>
>       ms->usb = value;
> +    ms->usb_disabled = !value;
Maybe is too late now, but I really not like this pollution of MachineState
with 'usb_disabled'. (Imagine we have this kind of fields for lots of objects and lots
of corner cases...)
I know it comes to solve a bug, but we talked about it in another mail thread and
this change in semantics was approved.

Let me explain *why* I don't like it.
1. We add an "usb_disabled" field to a base class (actually object)
    of all the machines and the only place it is interesting is
    for 2 machines on ppc.
2. Even for these 2 machines, the scenario of defaults=on and usb=off
    is not practical.

I hope I helped,
Thanks,
Marcel

P.S. If you still want it there, maybe move it to a ppc base class?

>   }
>
>   static char *machine_get_firmware(Object *obj, Error **errp)
> diff --git a/hw/ppc/mac_newworld.c b/hw/ppc/mac_newworld.c
> index e0397bc..a365bf9 100644
> --- a/hw/ppc/mac_newworld.c
> +++ b/hw/ppc/mac_newworld.c
> @@ -371,7 +371,7 @@ static void ppc_core99_init(MachineState *machine)
>           /* 970 gets a U3 bus */
>           pci_bus = pci_pmac_u3_init(pic, get_system_memory(), get_system_io());
>           machine_arch = ARCH_MAC99_U3;
> -        machine->usb |= defaults_enabled();
> +        machine->usb |= defaults_enabled() && !machine->usb_disabled;
>       } else {
>           pci_bus = pci_pmac_init(pic, get_system_memory(), get_system_io());
>           machine_arch = ARCH_MAC99;
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 0487f52..dd5e101 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -1563,7 +1563,7 @@ static void ppc_spapr_init(MachineState *machine)
>       /* Graphics */
>       if (spapr_vga_init(phb->bus)) {
>           spapr->has_graphics = true;
> -        machine->usb |= defaults_enabled();
> +        machine->usb |= defaults_enabled() && !machine->usb_disabled;
>       }
>
>       if (machine->usb) {
> diff --git a/include/hw/boards.h b/include/hw/boards.h
> index 1feea2b..be6a0ed 100644
> --- a/include/hw/boards.h
> +++ b/include/hw/boards.h
> @@ -141,6 +141,7 @@ struct MachineState {
>       bool dump_guest_core;
>       bool mem_merge;
>       bool usb;
> +    bool usb_disabled;
>       char *firmware;
>       bool iommu;
>       bool suppress_vmdesc;
>

Re: [Qemu-devel] [PATCH for-2.3] powerpc: fix -machine usb=no for newworld and pseries machines

[Alexander Graf]

On 03/23/2015 07:20 PM, Marcel Apfelbaum wrote:
> On 03/23/2015 07:05 PM, Paolo Bonzini wrote:
>> Capture the explicit setting of "usb=no" into a separate bool, and
>> use it to skip the update of machine->usb in the board init function.
>>
>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>> ---
>>   hw/core/machine.c     | 1 +
>>   hw/ppc/mac_newworld.c | 2 +-
>>   hw/ppc/spapr.c        | 2 +-
>>   include/hw/boards.h   | 1 +
>>   4 files changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/hw/core/machine.c b/hw/core/machine.c
>> index cb1185a..25c45e6 100644
>> --- a/hw/core/machine.c
>> +++ b/hw/core/machine.c
>> @@ -223,6 +223,7 @@ static void machine_set_usb(Object *obj, bool 
>> value, Error **errp)
>>       MachineState *ms = MACHINE(obj);
>>
>>       ms->usb = value;
>> +    ms->usb_disabled = !value;
> Maybe is too late now, but I really not like this pollution of 
> MachineState
> with 'usb_disabled'. (Imagine we have this kind of fields for lots of 
> objects and lots
> of corner cases...)
> I know it comes to solve a bug, but we talked about it in another mail 
> thread and
> this change in semantics was approved.
>
> Let me explain *why* I don't like it.
> 1. We add an "usb_disabled" field to a base class (actually object)
>    of all the machines and the only place it is interesting is
>    for 2 machines on ppc.
> 2. Even for these 2 machines, the scenario of defaults=on and usb=off
>    is not practical.

I'm personally fine either way, but I assumed that Paolo had a good 
reason for writing the patch?


Alex

Re: [Qemu-devel] [PATCH for-2.3] powerpc: fix -machine usb=no for newworld and pseries machines

[Paolo Bonzini]

On 23/03/2015 19:21, Alexander Graf wrote:
> On 03/23/2015 07:20 PM, Marcel Apfelbaum wrote:
>> On 03/23/2015 07:05 PM, Paolo Bonzini wrote:
>>> Capture the explicit setting of "usb=no" into a separate bool, and
>>> use it to skip the update of machine->usb in the board init function.
>>>
>>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>>> ---
>>>   hw/core/machine.c     | 1 +
>>>   hw/ppc/mac_newworld.c | 2 +-
>>>   hw/ppc/spapr.c        | 2 +-
>>>   include/hw/boards.h   | 1 +
>>>   4 files changed, 4 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/hw/core/machine.c b/hw/core/machine.c
>>> index cb1185a..25c45e6 100644
>>> --- a/hw/core/machine.c
>>> +++ b/hw/core/machine.c
>>> @@ -223,6 +223,7 @@ static void machine_set_usb(Object *obj, bool
>>> value, Error **errp)
>>>       MachineState *ms = MACHINE(obj);
>>>
>>>       ms->usb = value;
>>> +    ms->usb_disabled = !value;
>> Maybe is too late now, but I really not like this pollution of
>> MachineState
>> with 'usb_disabled'. (Imagine we have this kind of fields for lots of
>> objects and lots
>> of corner cases...)
>> I know it comes to solve a bug, but we talked about it in another mail
>> thread and
>> this change in semantics was approved.
>>
>> Let me explain *why* I don't like it.
>> 1. We add an "usb_disabled" field to a base class (actually object)
>>    of all the machines and the only place it is interesting is
>>    for 2 machines on ppc.

So we do for kernel_irqchip_requested/allowed.  Both approaches could be
replaced by a tri-state on/off/auto.

>> 2. Even for these 2 machines, the scenario of defaults=on and usb=off
>>    is not practical.

Why?  For example you could add a virtio-input device instead of a USB
keyboard and mouse.

> I'm personally fine either way, but I assumed that Paolo had a good
> reason for writing the patch?

Actually, two.

One good reason is that no matter how you look at it, it's at least
surprising and at worst a bug that "-machine usb=no" includes a default
USB controller.

The second good reason is that it's a guest ABI change for the versioned
pSeries machines, and as such it breaks migration.

Paolo

Re: [Qemu-devel] [PATCH for-2.3] powerpc: fix -machine usb=no for newworld and pseries machines

[Marcel Apfelbaum]

On 03/23/2015 10:11 PM, Paolo Bonzini wrote:
>
>
> On 23/03/2015 19:21, Alexander Graf wrote:
>> On 03/23/2015 07:20 PM, Marcel Apfelbaum wrote:
>>> On 03/23/2015 07:05 PM, Paolo Bonzini wrote:
>>>> Capture the explicit setting of "usb=no" into a separate bool, and
>>>> use it to skip the update of machine->usb in the board init function.
>>>>
>>>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>>>> ---
>>>>    hw/core/machine.c     | 1 +
>>>>    hw/ppc/mac_newworld.c | 2 +-
>>>>    hw/ppc/spapr.c        | 2 +-
>>>>    include/hw/boards.h   | 1 +
>>>>    4 files changed, 4 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/hw/core/machine.c b/hw/core/machine.c
>>>> index cb1185a..25c45e6 100644
>>>> --- a/hw/core/machine.c
>>>> +++ b/hw/core/machine.c
>>>> @@ -223,6 +223,7 @@ static void machine_set_usb(Object *obj, bool
>>>> value, Error **errp)
>>>>        MachineState *ms = MACHINE(obj);
>>>>
>>>>        ms->usb = value;
>>>> +    ms->usb_disabled = !value;
>>> Maybe is too late now, but I really not like this pollution of
>>> MachineState
>>> with 'usb_disabled'. (Imagine we have this kind of fields for lots of
>>> objects and lots
>>> of corner cases...)
>>> I know it comes to solve a bug, but we talked about it in another mail
>>> thread and
>>> this change in semantics was approved.
>>>
>>> Let me explain *why* I don't like it.
>>> 1. We add an "usb_disabled" field to a base class (actually object)
>>>     of all the machines and the only place it is interesting is
>>>     for 2 machines on ppc.
>
> So we do for kernel_irqchip_requested/allowed.  Both approaches could be
> replaced by a tri-state on/off/auto.
Personally I prefer this one, but out of the scope of this patch.

>
>>> 2. Even for these 2 machines, the scenario of defaults=on and usb=off
>>>     is not practical.
>
> Why?  For example you could add a virtio-input device instead of a USB
> keyboard and mouse.
You got me there :)
 From what I understood for those boards there is no need for this
combination but I don't know them enough (OK.. at all).

>
>> I'm personally fine either way, but I assumed that Paolo had a good
>> reason for writing the patch?
>
> Actually, two.
>
> One good reason is that no matter how you look at it, it's at least
> surprising and at worst a bug that "-machine usb=no" includes a default
> USB controller.
>
> The second good reason is that it's a guest ABI change for the versioned
> pSeries machines, and as such it breaks migration.
Always migration wins.

Bottom line, of course I don't have anything against fixing this bug,
my problem was only with the way we add those fields (usb_disabled), maybe a three state
QOM property (and variable behind it) is a solution, but not for now of course.

I also didn't like the required/allowed fields and I added them anyway...

Thanks,
Marcel


>
> Paolo
>

Re: [Qemu-devel] [PATCH for-2.3] powerpc: fix -machine usb=no for newworld and pseries machines

[Paolo Bonzini]

On 23/03/2015 23:00, Marcel Apfelbaum wrote:
>>>> I know it comes to solve a bug, but we talked about it in another mail
>>>> thread and this change in semantics was approved.

I forgot to reply to this---my understanding is that it was okay for the
sake of your patch series, but it would be fixed before 2.3.

>>>> Let me explain *why* I don't like it.
>>>> 1. We add an "usb_disabled" field to a base class (actually object)
>>>>     of all the machines and the only place it is interesting is
>>>>     for 2 machines on ppc.
>>
>> So we do for kernel_irqchip_requested/allowed.  Both approaches could be
>> replaced by a tri-state on/off/auto.
> Personally I prefer this one, but out of the scope of this patch.

Yes, that was my rationale as well.

>>>> 2. Even for these 2 machines, the scenario of defaults=on and usb=off
>>>>     is not practical.
>>
>> Why?  For example you could add a virtio-input device instead of a USB
>> keyboard and mouse.
> You got me there :)
> From what I understood for those boards there is no need for this
> combination but I don't know them enough (OK.. at all).

Well, you can always find a reason.  USB is a good default, but it
doesn't have to be the only one.  You might even be okay with USB, but
prefer a different host controller.

> Bottom line, of course I don't have anything against fixing this bug,
> my problem was only with the way we add those fields (usb_disabled),
> maybe a three state QOM property (and variable behind it) is a
> solution, but not for now of course.

I think the QOM property should not be tristate, only the variable.
Another possibility is backing "xyz" with a bool xyz, but adding a
bool xyz_set.

Then irqchip_required = irqchip_set && irqchip, and irqchip_allowed =
!irqchip_set || irqchip.

Paolo

> I also didn't like the required/allowed fields and I added them anyway...
> 
> Thanks,
> Marcel
> 
> 
>>
>> Paolo
>>
> 
> 
>