Re: [PATCH v2 02/15] xen/arm: vpsci: Add support for PSCI 1.1

[Volodymyr Babchuk <volodymyr_babchuk@epam.com>]

On 09.02.18 18:13, Julien Grall wrote:
> 
> 
> On 02/09/2018 04:07 PM, Volodymyr Babchuk wrote:
>> Hi Julien,
> 
> Hi Volodymyr,
> 
>> On 08.02.18 21:21, Julien Grall wrote:
>>> At the moment, Xen provides virtual PSCI interface compliant with 0.1
>>> and 0.2. Since them, the specification has been updated and the latest
>>> version is 1.1 (see ARM DEN 0022D).
>>>
>>>  From an implementation point of view, only PSCI_FEATURES is mandatory.
>>> The rest is optional and can be left unimplemented for now.
>>>
>>> At the same time, the compatible for PSCI node have been updated to
>>> expose "arm,psci-1.0".
>>>
>>> Signed-off-by: Julien Grall <julien.grall@arm.com>
>>> Cc: Wei Liu <wei.liu2@citrix.com>
>>> Cc: Ian Jackson <ian.jackson@eu.citrix.com>
>>> Cc: mirela.simonovic@aggios.com
Reviewed-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com>

>>> ---
>>>      We may want to provide a way for the toolstack to specify a PSCI
>>>      version. This could be useful if a guest is expecting a given
>>>      version.
>>>
>>>      Changes in v2:
>>>          - Return v1.1 on GET_VERSION call as claimed by this patch
>>>          - Order by function ID the calls in FEATURES call
>>> ---
>>>   tools/libxl/libxl_arm.c          |  3 ++-
>>>   xen/arch/arm/domain_build.c      |  1 +
>>>   xen/arch/arm/vpsci.c             | 39 
>>> ++++++++++++++++++++++++++++++++++++++-
>>>   xen/include/asm-arm/perfc_defn.h |  1 +
>>>   xen/include/asm-arm/psci.h       |  1 +
>>>   xen/include/asm-arm/vpsci.h      |  2 +-
>>>   6 files changed, 44 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/tools/libxl/libxl_arm.c b/tools/libxl/libxl_arm.c
>>> index 3e46554301..86f59c0d80 100644
>>> --- a/tools/libxl/libxl_arm.c
>>> +++ b/tools/libxl/libxl_arm.c
>>> @@ -410,7 +410,8 @@ static int make_psci_node(libxl__gc *gc, void *fdt)
>>>       res = fdt_begin_node(fdt, "psci");
>>>       if (res) return res;
>>> -    res = fdt_property_compat(gc, fdt, 2, "arm,psci-0.2","arm,psci");
>>> +    res = fdt_property_compat(gc, fdt, 3, "arm,psci-1.0",
>>> +                              "arm,psci-0.2", "arm,psci");
>> What about this place? Should it be "arm,psci-1.1"?
> 
> arm,psci-1.1 compatible string does not exist. Technically after 0.2 you 
> should discover the PSCI version through GET_VERSION. So I am not 
> entirely sure why arm,psci-1.0 compatible was added.
> 
>  From the documentation 
> (Documentation/devicetree/bindings/arm/psci.txt), the compatibles means 
> the PSCI implementation comply to a given version. Our implementation 
> complies to 0.1, 0.2 and 1.0. So I have added 1.0 just in case a guest 
> decides to check the compatible.

Okay, makes sense

-- 
Volodymyr Babchuk

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