Re: [Qemu-devel] [PATCH 1/3] tcg: add TCG_TARGET_TLB_DISPLACEMENT_BITS

[Alexander Graf <agraf@suse.de>]

On 20.02.15 20:36, Richard Henderson wrote:
> On 02/20/2015 09:57 AM, Paolo Bonzini wrote:
>> diff --git a/tcg/i386/tcg-target.h b/tcg/i386/tcg-target.h
>> index 7a9980e..8ba977a 100644
>> --- a/tcg/i386/tcg-target.h
>> +++ b/tcg/i386/tcg-target.h
>> @@ -25,6 +25,7 @@
>>  #define TCG_TARGET_I386 1
>>  
>>  #define TCG_TARGET_INSN_UNIT_SIZE  1
>> +#define TCG_TARGET_TLB_DISPLACEMENT_BITS 32
> 
> 31.
> 
> Positive displacements only in 64-bit mode.  I don't think it's worth
> conditionalizing this for 32-bit, since we can't actually allocate 2G of TLBs
> and then actually accomplish anything.  ;-)

I suppose Paolo is already off to the hospital ;). Richard, if I just
s/32/31/ in the hunk above, does that mean you ack the patch?


Alex

> 
>> diff --git a/tcg/mips/tcg-target.h b/tcg/mips/tcg-target.h
>> index c88a1c9..f5ba52c 100644
>> --- a/tcg/mips/tcg-target.h
>> +++ b/tcg/mips/tcg-target.h
>> @@ -27,6 +27,7 @@
>>  #define TCG_TARGET_MIPS 1
>>  
>>  #define TCG_TARGET_INSN_UNIT_SIZE 4
>> +#define TCG_TARGET_TLB_DISPLACEMENT_BITS 16
>>  #define TCG_TARGET_NB_REGS 32
>>  
>>  typedef enum {
>> diff --git a/tcg/ppc/tcg-target.h b/tcg/ppc/tcg-target.h
>> index 32ac442..7ce7048 100644
>> --- a/tcg/ppc/tcg-target.h
>> +++ b/tcg/ppc/tcg-target.h
>> @@ -32,6 +32,7 @@
>>  
>>  #define TCG_TARGET_NB_REGS 32
>>  #define TCG_TARGET_INSN_UNIT_SIZE 4
>> +#define TCG_TARGET_TLB_DISPLACEMENT_BITS 16
> 
> Close enough, since the BUILD_BUG_ON should still catch this out if somehow the
> size is within that last 16 bytes of 64k.
> 
> 
> r~
>