Re: [PATCH v7 05/12] arm/sve: save/restore SVE context switch

[Luca Fancellu <Luca.Fancellu@xxxxxxx>]

> On 24 May 2023, at 10:47, Bertrand Marquis <Bertrand.Marquis@xxxxxxx> wrote:
> 
> Hi Luca,
> 
>> On 23 May 2023, at 09:43, Luca Fancellu <Luca.Fancellu@xxxxxxx> wrote:
>> 
>> Save/restore context switch for SVE, allocate memory to contain
>> the Z0-31 registers whose length is maximum 2048 bits each and
>> FFR who can be maximum 256 bits, the allocated memory depends on
>> how many bits is the vector length for the domain and how many bits
>> are supported by the platform.
>> 
>> Save P0-15 whose length is maximum 256 bits each, in this case the
>> memory used is from the fpregs field in struct vfp_state,
>> because V0-31 are part of Z0-31 and this space would have been
>> unused for SVE domain otherwise.
>> 
>> Create zcr_el{1,2} fields in arch_vcpu, initialise zcr_el2 on vcpu
>> creation given the requested vector length and restore it on
>> context switch, save/restore ZCR_EL1 value as well.
>> 
>> List import macros from Linux in README.LinuxPrimitives.
>> 
>> Signed-off-by: Luca Fancellu <luca.fancellu@xxxxxxx>
> Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>
> 
> Just ...
> 
>> ---
>> Changes from v6:
>> - Add comment for explain why sve_save/sve_load are different from
>>  Linux, add macros in xen/arch/arm/README.LinuxPrimitives (Julien)
>> - Add comments in sve_context_init and sve_context_free, handle the
>>  case where sve_zreg_ctx_end is NULL, move setting of v->arch.zcr_el2
>>  in sve_context_init (Julien)
>> - remove stubs for sve_context_* and sve_save_* and rely on compiler
>>  DCE (Jan)
>> - Add comments for sve_save_ctx/sve_load_ctx (Julien)
>> Changes from v5:
>> - use XFREE instead of xfree, keep the headers (Julien)
>> - Avoid math computation for every save/restore, store the computation
>>  in struct vfp_state once (Bertrand)
>> - protect access to v->domain->arch.sve_vl inside arch_vcpu_create now
>>  that sve_vl is available only on arm64
>> Changes from v4:
>> - No changes
>> Changes from v3:
>> - don't use fixed len types when not needed (Jan)
>> - now VL is an encoded value, decode it before using.
>> Changes from v2:
>> - No changes
>> Changes from v1:
>> - No changes
>> Changes from RFC:
>> - Moved zcr_el2 field introduction in this patch, restore its
>>  content inside sve_restore_state function. (Julien)
>> 
>> fix patch 5
>> 
>> Signed-off-by: Luca Fancellu <luca.fancellu@xxxxxxx>
>> Change-Id: Ief65b2ff14fd579afa4fd110ce08a19980e64fa9
> 
> You have a signed off and a change-id that should not be here.
> They are in the comment section so should be removed during push so might be 
> ok :-)

Ohh yeah I missed that, probably it’s from a squash! 

> 
> Cheers
> Bertrand