Re: [Qemu-devel] [PATCH v1 1/3] cputlb: ensure tbl_set_dirty1 updates addr_write atomically

["Alex Bennée" <alex.bennee@linaro.org>]

Paolo Bonzini <pbonzini@redhat.com> writes:

> On 20/03/2017 16:34, Alex Bennée wrote:
>>  static inline void tlb_set_dirty1(CPUTLBEntry *tlb_entry, target_ulong vaddr)
>>  {
>> +#if TCG_OVERSIZED_GUEST
>>      if (tlb_entry->addr_write == (vaddr | TLB_NOTDIRTY)) {
>>          tlb_entry->addr_write = vaddr;
>>      }
>> +#else
>> +    uintptr_t orig_addr = atomic_mb_read(&tlb_entry->addr_write);
>
> atomic_read is enough, since we don't care at all about cases where the
> address doesn't match.  Otherwise

Good catch. Will fix for my pullreq

>
> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
>
> Paolo
>
>> +    if (orig_addr == (vaddr | TLB_NOTDIRTY)) {
>> +        atomic_cmpxchg(&tlb_entry->addr_write, orig_addr, vaddr);
>> +    }
>> +#endif
>>  }


--
Alex Bennée