On 08/23/2016 02:32 PM, Yuanhan Liu wrote: >>> + >>> > >+ /* FIXME */ >>> > >+ RTE_LOG(INFO, VHOST_CONFIG, ":: %u ::\n", pre_read); >> > For my information, what is the purpose of pre_read? > Again, I put a FIXME here, but I forgot to add some explanation. > > Here is the thing: the read will make sure the kernel populate the > corresponding PTE entry, so that rte_mem_virt2phy() will return proper > physical address, otherwise, invalid value is returned. > > I can't simply do the read but do not actually reference/consume it. > Otherwise, the compiler will treat it as some noops and remove it. > > An ugly RTE_LOG will make sure the read operation is not eliminated. > I'm seeking a more proper way to achieve that. Maybe I can add a new > field in virtio_net structure and store it there. > > Or, do you have better ideas?
This behavior is pretty twisted, no? Shouldn't be rte_mem_virt2phy() role to ensure returning a valid value? I have no better idea for now, but I will think about it. Regards, Maxime
