Re: [PATCH 2/6] Use correct types to enable > 2G support (v2)

[Avi Kivity <avi@qumranet.com>]

Izik Eidus wrote:
>>
>>> Index: qemu/cpu-all.h
>>> ===================================================================
>>> --- qemu.orig/cpu-all.h	2008-02-01 15:24:45.000000000 -0600
>>> +++ qemu/cpu-all.h	2008-02-01 15:28:48.000000000 -0600
>>> @@ -695,7 +695,7 @@
>>>  
>>>  /* page related stuff */
>>>  
>>> -#define TARGET_PAGE_SIZE (1 << TARGET_PAGE_BITS)
>>> +#define TARGET_PAGE_SIZE (1ul << TARGET_PAGE_BITS)
>>>  #define TARGET_PAGE_MASK ~(TARGET_PAGE_SIZE - 1)
>>>  #define TARGET_PAGE_ALIGN(addr) (((addr) + TARGET_PAGE_SIZE - 1) & TARGET_PAGE_MASK
>>>       
>> Do you recall what this change fixed?  As Paul pointed out in IRC, using 
>> the host type here doesn't really fix the problem (target_ulong would be 
>> more appropriate).  However, we're both curious what problem it's 
>> actually fixing since sign extending the int should just work.
>>     
>
> ok the commit say:
>
>    kvm: qemu: change the type of the various page masks to unsigned long
>     
>    prevents truncation with >=4GB of guest physical memory
>
>
> as far as i remember it was used to address something with
> cpu_physical_memory_rw() probably related to &TARGET_PAGE_SIZE
> or ~TARGET_PAGE_SIZE,
>
> the fact is that i dont know if it ever fixed anything
>   

It fixes TARGET_PAGE_MASK, defined one line downscreen.  I agree it 
should be changed to ((target_ulong)1 << TARGET_PAGE_BITS).

-- 
error compiling committee.c: too many arguments to function


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