Re: [PATCH kvmtool 01/21] ioport: Remove ioport__setup_arch()

[Alexandru Elisei <alexandru.elisei@arm.com>]

Hi Andre,

On 2/11/21 5:16 PM, Andre Przywara wrote:
> On Wed, 10 Feb 2021 17:44:59 +0000
> Alexandru Elisei <alexandru.elisei@arm.com> wrote:
>
> Hi Alex,
>
>> On 12/10/20 2:28 PM, Andre Przywara wrote:
>>> Since x86 had a special need for registering tons of special I/O ports,
>>> we had an ioport__setup_arch() callback, to allow each architecture
>>> to do the same. As it turns out no one uses it beside x86, so we remove
>>> that unnecessary abstraction.
>>>
>>> The generic function was registered via a device_base_init() call, so
>>> we just do the same for the x86 specific function only, and can remove
>>> the unneeded ioport__setup_arch().
>>>
>>> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
>>> ---
>>>  arm/ioport.c         |  5 -----
>>>  include/kvm/ioport.h |  1 -
>>>  ioport.c             | 28 ----------------------------
>>>  mips/kvm.c           |  5 -----
>>>  powerpc/ioport.c     |  6 ------
>>>  x86/ioport.c         | 25 ++++++++++++++++++++++++-
>>>  6 files changed, 24 insertions(+), 46 deletions(-)
>>>
>>> diff --git a/arm/ioport.c b/arm/ioport.c
>>> index 2f0feb9a..24092c9d 100644
>>> --- a/arm/ioport.c
>>> +++ b/arm/ioport.c
>>> @@ -1,11 +1,6 @@
>>>  #include "kvm/ioport.h"
>>>  #include "kvm/irq.h"
>>>  
>>> -int ioport__setup_arch(struct kvm *kvm)
>>> -{
>>> -	return 0;
>>> -}
>>> -
>>>  void ioport__map_irq(u8 *irq)
>>>  {
>>>  	*irq = irq__alloc_line();
>>> diff --git a/include/kvm/ioport.h b/include/kvm/ioport.h
>>> index 039633f7..d0213541 100644
>>> --- a/include/kvm/ioport.h
>>> +++ b/include/kvm/ioport.h
>>> @@ -35,7 +35,6 @@ struct ioport_operations {
>>>  							    enum irq_type));
>>>  };
>>>  
>>> -int ioport__setup_arch(struct kvm *kvm);
>>>  void ioport__map_irq(u8 *irq);
>>>  
>>>  int __must_check ioport__register(struct kvm *kvm, u16 port, struct ioport_operations *ops,
>>> diff --git a/ioport.c b/ioport.c
>>> index 844a832d..667e8386 100644
>>> --- a/ioport.c
>>> +++ b/ioport.c
>>> @@ -158,21 +158,6 @@ int ioport__unregister(struct kvm *kvm, u16 port)
>>>  	return 0;
>>>  }
>>>  
>>> -static void ioport__unregister_all(void)
>>> -{
>>> -	struct ioport *entry;
>>> -	struct rb_node *rb;
>>> -	struct rb_int_node *rb_node;
>>> -
>>> -	rb = rb_first(&ioport_tree);
>>> -	while (rb) {
>>> -		rb_node = rb_int(rb);
>>> -		entry = ioport_node(rb_node);
>>> -		ioport_unregister(&ioport_tree, entry);
>>> -		rb = rb_first(&ioport_tree);
>>> -	}
>>> -}  
>> I get the impression this is a rebasing artifact. The commit message doesn't
>> mention anything about removing ioport__exit() -> ioport__unregister_all(), and as
>> far as I can tell it's still needed because there are places other than
>> ioport__setup_arch() from where ioport__register() is called.
> I agree that the commit message is a bit thin on this fact, but the
> functionality of ioport__unregister_all() is now in
> x86/ioport.c:ioport__remove_arch(). I think removing ioport__init()
> without removing ioport__exit() as well would look very weird, if not
> hackish.

Not necessarily. ioport__unregister_all() removes the ioports added by
x86/ioport.c::ioport__setup_arch(), *plus* ioports added by different devices,
like serial, rtc, virtio-pci and vfio-pci (which are used by arm/arm64).

Thanks,

Alex

>
> I can amend the commit message to mention this, or is there anything
> else I missed?
>
> Cheers,
> Andre
>
>>> -
>>>  static const char *to_direction(int direction)
>>>  {
>>>  	if (direction == KVM_EXIT_IO_IN)
>>> @@ -220,16 +205,3 @@ out:
>>>  
>>>  	return !kvm->cfg.ioport_debug;
>>>  }
>>> -
>>> -int ioport__init(struct kvm *kvm)
>>> -{
>>> -	return ioport__setup_arch(kvm);
>>> -}
>>> -dev_base_init(ioport__init);
>>> -
>>> -int ioport__exit(struct kvm *kvm)
>>> -{
>>> -	ioport__unregister_all();
>>> -	return 0;
>>> -}
>>> -dev_base_exit(ioport__exit);
>>> diff --git a/mips/kvm.c b/mips/kvm.c
>>> index 26355930..e110e5d5 100644
>>> --- a/mips/kvm.c
>>> +++ b/mips/kvm.c
>>> @@ -100,11 +100,6 @@ void kvm__irq_trigger(struct kvm *kvm, int irq)
>>>  		die_perror("KVM_IRQ_LINE ioctl");
>>>  }
>>>  
>>> -int ioport__setup_arch(struct kvm *kvm)
>>> -{
>>> -	return 0;
>>> -}
>>> -
>>>  bool kvm__arch_cpu_supports_vm(void)
>>>  {
>>>  	return true;
>>> diff --git a/powerpc/ioport.c b/powerpc/ioport.c
>>> index 0c188b61..a5cff4ee 100644
>>> --- a/powerpc/ioport.c
>>> +++ b/powerpc/ioport.c
>>> @@ -12,12 +12,6 @@
>>>  
>>>  #include <stdlib.h>
>>>  
>>> -int ioport__setup_arch(struct kvm *kvm)
>>> -{
>>> -	/* PPC has no legacy ioports to set up */
>>> -	return 0;
>>> -}
>>> -
>>>  void ioport__map_irq(u8 *irq)
>>>  {
>>>  }
>>> diff --git a/x86/ioport.c b/x86/ioport.c
>>> index 7ad7b8f3..8c5c7699 100644
>>> --- a/x86/ioport.c
>>> +++ b/x86/ioport.c
>>> @@ -69,7 +69,7 @@ void ioport__map_irq(u8 *irq)
>>>  {
>>>  }
>>>  
>>> -int ioport__setup_arch(struct kvm *kvm)
>>> +static int ioport__setup_arch(struct kvm *kvm)
>>>  {
>>>  	int r;
>>>  
>>> @@ -150,3 +150,26 @@ int ioport__setup_arch(struct kvm *kvm)
>>>  
>>>  	return 0;
>>>  }
>>> +dev_base_init(ioport__setup_arch);
>>> +
>>> +static int ioport__remove_arch(struct kvm *kvm)
>>> +{
>>> +	ioport__unregister(kvm, 0x510);
>>> +	ioport__unregister(kvm, 0x402);
>>> +	ioport__unregister(kvm, 0x03D5);
>>> +	ioport__unregister(kvm, 0x03D4);
>>> +	ioport__unregister(kvm, 0x0378);
>>> +	ioport__unregister(kvm, 0x0278);
>>> +	ioport__unregister(kvm, 0x00F0);
>>> +	ioport__unregister(kvm, 0x00ED);
>>> +	ioport__unregister(kvm, IOPORT_DBG);
>>> +	ioport__unregister(kvm, 0x00C0);
>>> +	ioport__unregister(kvm, 0x00A0);
>>> +	ioport__unregister(kvm, 0x0092);
>>> +	ioport__unregister(kvm, 0x0040);
>>> +	ioport__unregister(kvm, 0x0020);
>>> +	ioport__unregister(kvm, 0x0000);
>>> +
>>> +	return 0;
>>> +}
>>> +dev_base_exit(ioport__remove_arch);