From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jan Kiszka <jan.kiszka@siemens.com>
Subject: Re: [PATCH v3 1/8] ARM: KVM: Initial skeleton to compile KVM support
Date: Fri, 03 Jun 2011 17:53:59 +0200
Message-ID: <4DE90397.5080801@siemens.com>
References: <20110603150318.17011.82777.stgit@ubuntu> <4DE8FE38.6030405@siemens.com>
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Cc: catalin.marinas@arm.com, android-virt@lists.cs.columbia.edu,
	s.raho@virtualopensystems.com, a.motakis@virtualopensystems.com,
	c.dall@virtualopensystems.com, kvm@vger.kernel.org,
	a.costa@virtualopensystems.com
To: Christoffer Dall <cdall@cs.columbia.edu>
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On 2011-06-03 17:31, Jan Kiszka wrote:
> On 2011-06-03 17:03, Christoffer Dall wrote:
>> Targets KVM support for Cortex A-15 processors.
>>
>> Contains no real functionality but all the framework components,
>> make files, header files and some tracing functionality.
>> ---
> 
> ...
> 
>> diff --git a/include/linux/kvm.h b/include/linux/kvm.h
>> index ea2dc1a..d2ab07e 100644
>> --- a/include/linux/kvm.h
>> +++ b/include/linux/kvm.h
>> @@ -310,6 +310,7 @@ struct kvm_translation {
>>  struct kvm_interrupt {
>>  	/* in */
>>  	__u32 irq;
>> +	__u8  raise;
>>  };
> 
> This touches an existing ABI and corrupts the definition of
> KVM_INTERRUPT IOCTL. The might exist jurisdictions considering this a
> capital crime. :)
> 
> You rather have to define a new CPU IRQ injection interface that
> supports both raising and lowering and declare its availability via a
> KVM_CAP. Don't forget to make it extensible (flags field) so that future
> requirements can be added without breaking existing users.

Or much easier (this is what PowerPC is doing): Define irq values in a
way that they include a raise/lower flag.

Jan

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