Re: [Xen-devel] [PATCH v2 4/7] xen/arm: page: Clarify the Xen TLBs helpers name

[Julien Grall <Julien.Grall@xxxxxxx>]

Hi,

On 09/05/2019 21:13, Stefano Stabellini wrote:
> On Wed, 8 May 2019, Julien Grall wrote:
>>   /* Release all __init and __initdata ranges to be reused */
>> diff --git a/xen/include/asm-arm/arm32/page.h 
>> b/xen/include/asm-arm/arm32/page.h
>> index 40a77daa9d..0b41b9214b 100644
>> --- a/xen/include/asm-arm/arm32/page.h
>> +++ b/xen/include/asm-arm/arm32/page.h
>> @@ -61,12 +61,8 @@ static inline void invalidate_icache_local(void)
>>       isb();                      /* Synchronize fetched instruction stream. 
>> */
>>   }
>>   
>> -/*
>> - * Flush all hypervisor mappings from the data TLB of the local
>> - * processor. This is not sufficient when changing code mappings or
>> - * for self modifying code.
>> - */
>> -static inline void flush_xen_data_tlb_local(void)
>> +/* Flush all hypervisor mappings from the TLB of the local processor. */
> 
> I realize that the statement "This is not sufficient when changing code
> mappings or for self modifying code" is not quite accurate, but I would
> prefer not to remove it completely. It would be good to retain a warning
> somewhere about IC been needed when changing Xen's own mappings. Maybe
> on top of invalidate_icache_local?

Can you please expand in which circumstance you need to invalid the 
instruction cache when changing Xen's own mappings?

Cheers,

-- 
Julien Grall
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