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

[Paolo Bonzini]

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

Reviewed-by: Paolo Bonzini <pbonz...@redhat.com>

Paolo

> +    if (orig_addr == (vaddr | TLB_NOTDIRTY)) {
> +        atomic_cmpxchg(&tlb_entry->addr_write, orig_addr, vaddr);
> +    }
> +#endif
>  }