Re: [PATCH] powerpc/kvm: Handle the boundary condition correctly

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

Alexander Graf <agraf@suse.de> writes:

> On 26.08.2013, at 05:28, Aneesh Kumar K.V wrote:
>
>> Alexander Graf <agraf@suse.de> writes:
>> 
>>> On 23.08.2013, at 04:31, Aneesh Kumar K.V wrote:
>>> 
>>>> Alexander Graf <agraf@suse.de> writes:
>>>> 
>>>>> On 22.08.2013, at 12:37, Aneesh Kumar K.V wrote:
>>>>> 
>>>>>> From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
>>>>> 
>>>>> Isn't this you?
>>>> 
>>>> Yes. The patches are generated using git format-patch and sent by
>>>> git send-email. That's how it always created patches for me. I am not sure if
>>>> there is a config I can change to avoid having From:
>>>> 
>>>>> 
>>>>>> 
>>>>>> We should be able to copy upto count bytes
>>>>> 
>>>>> Why?
>>>>> 
>>>> 
>>>> Without this we end up doing
>>>> 
>>>> +    struct kvm_get_htab_buf {
>>>> +        struct kvm_get_htab_header header;
>>>> +        /*
>>>> +         * Older kernel required one extra byte.
>>>> +         */
>>>> +        unsigned long hpte[3];
>>>> +    } hpte_buf;
>>>> 
>>>> 
>>>> even though we are only looking for one hpte entry.
>>> 
>>> Ok, please give me an example with real numbers and why it breaks.
>>> 
>>>> 
>>>> http://mid.gmane.org/1376995766-16526-4-git-send-email-aneesh.kumar@linux.vnet.ibm.com
>>>> 
>> 
>> Didn't quiet get what you are looking for. As explained before, we now
>> need to pass an array with array size 3 even though we know we need to
>> read only 2 entries because kernel doesn't loop correctly.
>
> But we need to do that regardless, because newer QEMU needs to be able to run on older kernels, no?
>

yes. So use space will have to pass an array of size 3. But that should
not prevent us from fixing this right ?

-aneesh