Re: [Qemu-devel] [RFC PATCH] cputlb: use uint64_t for interim values for unaligned load

[Alex Bennée]

Andrew Randrianasulu <address@hidden> writes:

> В сообщении от Monday 03 June 2019 18:01:20 Alex Bennée написал(а):
>> When running on 32 bit TCG backends a wide unaligned load ends up
>> truncating data before returning to the guest. We specifically have
>> the return type as uint64_t to avoid any premature truncation so we
>> should use the same for the interim types.
>>
>> Hopefully fixes #1830872
>>
>> Signed-off-by: Alex Bennée <address@hidden>
>> ---
>>  accel/tcg/cputlb.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
>> index cdcc3771020..b796ab1cbea 100644
>> --- a/accel/tcg/cputlb.c
>> +++ b/accel/tcg/cputlb.c
>> @@ -1303,7 +1303,7 @@ load_helper(CPUArchState *env, target_ulong addr, 
>> TCGMemOpIdx oi,
>>          && unlikely((addr & ~TARGET_PAGE_MASK) + size - 1
>>                      >= TARGET_PAGE_SIZE)) {
>>          target_ulong addr1, addr2;
>> -        tcg_target_ulong r1, r2;
>> +        uint64_t r1, r2;
>>          unsigned shift;
>>      do_unaligned_access:
>>          addr1 = addr & ~(size - 1);
>
> Unfortunatly, this doesn't fix 32-bit qemu-system-x86_64 .... so, my
> bug is separate from #1830872 ?

I think you've hit two - one of which we have just fixed. With my
expanded memory test on i386 I'm seeing a hang but it's ok @
pull-demacro-softmmu-100519-1. Unfortunately bisecting through the slirp
move and other i386 Werror stuff is proving painful.

>
> I also was unable to convince qemu to use my kernel-only x86_64 gcc 6.5.0 
> cross-compiler ..
> probably x86-64 testing on i686 requires either docker (I don't have this
> ) or 'real' cross-compiler (build with glibc support).


--
Alex Bennée