Re: [Xen-devel] [For Xen-4.10 RFC PATCH 2/3] arm: p2m: Prevent redundant icache flushes

[Punit Agrawal <punit.agrawal@xxxxxxx>]

Hi Stefano,

Stefano Stabellini <sstabellini@xxxxxxxxxx> writes:

> On Fri, 31 Mar 2017, Punit Agrawal wrote:
>> When toolstack requests flushing the caches, flush_page_to_ram() is
>> called for each page of the requested domain. This needs to unnecessary
>> icache invalidation operations.
>> 
>> Let's take the responsibility of performing icache operations and use
>> the recently introduced flag to prevent redundant icache operations by
>> flush_page_to_ram().
>> 
>> Signed-off-by: Punit Agrawal <punit.agrawal@xxxxxxx>
>
> Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>

Thanks for the review and comments on the other patches. I've now
addressed them locally.

I'll wait to see if there are anymore comments before posting an update.

Regards,
Punit

>
>
>> ---
>>  xen/arch/arm/p2m.c | 4 +++-
>>  1 file changed, 3 insertions(+), 1 deletion(-)
>> 
>> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
>> index 76cd1c34f3..8136522ed8 100644
>> --- a/xen/arch/arm/p2m.c
>> +++ b/xen/arch/arm/p2m.c
>> @@ -1400,13 +1400,15 @@ int p2m_cache_flush(struct domain *d, gfn_t start, 
>> unsigned long nr)
>>          /* XXX: Implement preemption */
>>          while ( gfn_x(start) < gfn_x(next_gfn) )
>>          {
>> -            flush_page_to_ram(mfn_x(mfn), true);
>> +            flush_page_to_ram(mfn_x(mfn), false);
>>  
>>              start = gfn_add(start, 1);
>>              mfn = mfn_add(mfn, 1);
>>          }
>>      }
>>  
>> +    invalidate_icache();
>> +
>>      p2m_read_unlock(p2m);
>>  
>>      return 0;
>> -- 
>> 2.11.0
>> 

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