On 2014/9/17 17:56, Michael S. Tsirkin wrote: > On Wed, Sep 17, 2014 at 05:39:04PM +0800, Linhaifeng wrote: >> I think maybe is not need for the backend to wait for response. >> >> There is another way.vhost-user send "VHOST_GET_MEM_TABLE" to qemu then qemu >> send VHOST_SET_MEM_TABLE to update the regions of vhost-user.same as other >> command. >> If qemu could response the request of the vhost-user.the vhost-user could >> update date at anytime. > > The updates are initiated by QEMU, as a result of IOMMU, > memory hotplug or some other configuration change.
How to deal with the vhost-user restart? when vhost-user restart it will lost the infomation which QEMU send. In the kernel mode vhost will restart with QEMU but in the user mode vhost will not. > >> I think it's very useful for Commercialization. >> >> On 2014/9/17 16:38, Michael S. Tsirkin wrote: >>> Reply-To: >>> >>> Thinking about the vhost-user protocol, VHOST_SET_MEM_TABLE >>> is used to update the memory mappings. >>> >>> So shouldn't we want for response? >>> Otherwise e.g. guest can start using the memory >>> that vhost-user can't access. >>> >>> Similarly, with an IOMMU vhost-user might access memory it shouldn't. >>> >>> VHOST_SET_VRING_CALL is used for MSI-X masking. >>> Again, after vector is masted by switching the call fd, >>> backend shouldn't assert the old one. >>> >>> Thoughts? >>> >>> > > . >