Re: [Xen-devel] [PATCH v3 23/38] arm/p2m: Cosmetic fixes -- __p2m_get_mem_access

[Sergej Proskurin <proskurin@xxxxxxxxxxxxx>]

Hi Julien,


On 09/13/2016 03:30 PM, Julien Grall wrote:
>
>
> On 13/09/16 14:27, Sergej Proskurin wrote:
>> Hi Julien,
>
> Hello Sergej,
>
>>
>> On 09/12/2016 10:53 AM, Julien Grall wrote:
>>> Hello Sergej,
>>>
>>> On 16/08/2016 23:16, Sergej Proskurin wrote:
>>>> This commit extends the function prototypes of the functions:
>>>> * __p2m_get_mem_access
>>>> * p2m_mem_access_check_and_get_page
>>>>
>>>> We extend the function prototype of "__p2m_get_mem_access" to hold an
>>>> argument of type "struct p2m_domain*", as we need to distinguish
>>>> between
>>>> the host's p2m and different altp2m views. While doing so, we
>>>> needed to
>>>> extend the function's prototype of "p2m_mem_access_check_and_get_page"
>>>> to hold an argument of type "struct vcpu*".
>>>
>>> Please details in the commit message why it is necessary to pass a
>>> "struct vcpu *" to p2m_mem_access_check_and_get_page.
>>>
>>
>> Actually, it is already sufficient to provide a "struct domain *".
>> Thanks for the hint. I will extend the commit message in the next patch
>> accordingly.
>
> No it is not, the stage-1 page table (VTTBR0, VTTBR1...) are per-vCPU
> and if the current vCPU is not the correct one, you will have to
> context switch few registers before.
>
> It is not handled today, but we should avoid to have a broken interface.

I see. Ok, since it is not really used today, I will state that we will
need the "struct vcpu*" to access vcpu-related registers in the future.
Would that be ok?

Cheers,
~Sergej

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