Re: [PATCH 10/18] KVM/MIPS32-VZ: Add API for VZ-ASE Capability

[David Daney <ddaney.cavm@gmail.com>]

On 05/28/2013 09:34 AM, Paolo Bonzini wrote:
> Il 19/05/2013 07:47, Sanjay Lal ha scritto:
>> - Add API to allow clients (QEMU etc.) to check whether the H/W
>>    supports the MIPS VZ-ASE.
>
> Why does this matter to userspace?  Do the userspace have some way to
> detect if the kernel is unmodified or minimally-modified?
>

There are (will be) two types of VM presented by MIPS KVM:

1) That provided by the initial patch where a faux-MIPS is emulated and 
all kernel code must be in the USEG address space.

2) Real MIPS, addressing works as per the architecture specification.

Presumably the user-space client would like to know which of these are 
supported, as well as be able to select the desired model.

I don't know the best way to do this, but I agree that 
KVM_CAP_MIPS_VZ_ASE is probably not the best name for it.

My idea was to have the arg of the KVM_CREATE_VM ioctl specify the 
desired style

David Daney



> Paolo
>
>> Signed-off-by: Sanjay Lal <sanjayl@kymasys.com>
>> ---
>>   include/uapi/linux/kvm.h | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
>> index a5c86fc..5889e976 100644
>> --- a/include/uapi/linux/kvm.h
>> +++ b/include/uapi/linux/kvm.h
>> @@ -666,6 +666,7 @@ struct kvm_ppc_smmu_info {
>>   #define KVM_CAP_IRQ_MPIC 90
>>   #define KVM_CAP_PPC_RTAS 91
>>   #define KVM_CAP_IRQ_XICS 92
>> +#define KVM_CAP_MIPS_VZ_ASE 93
>>
>>   #ifdef KVM_CAP_IRQ_ROUTING
>>
>>
>
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