On 2019/9/10 0:14, Stefan Hajnoczi wrote: > On Sun, Sep 08, 2019 at 07:53:55PM +0800, piaojun wrote: >> >> >> On 2019/9/6 19:52, Miklos Szeredi wrote: >>> On Fri, Sep 6, 2019 at 12:36 PM Stefan Hajnoczi <stefanha@xxxxxxxxxx> wrote: >>>> >>>> On Fri, Sep 06, 2019 at 10:15:14AM +0200, Miklos Szeredi wrote: >>>>> On Thu, Sep 5, 2019 at 9:49 PM Vivek Goyal <vgoyal@xxxxxxxxxx> wrote: >>>>>> >>>>>> Hi, >>>>>> >>>>>> Michael Tsirkin pointed out issues w.r.t various locking related TODO >>>>>> items and races w.r.t device removal. >>>>>> >>>>>> In this first round of cleanups, I have taken care of most pressing >>>>>> issues. >>>>>> >>>>>> These patches apply on top of following. >>>>>> >>>>>> git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse.git#virtiofs-v4 >>>>>> >>>>>> I have tested these patches with mount/umount and device removal using >>>>>> qemu monitor. For example. >>>>> >>>>> Is device removal mandatory? Can't this be made a non-removable >>>>> device? Is there a good reason why removing the virtio-fs device >>>>> makes sense? >>>> >>>> Hot plugging and unplugging virtio PCI adapters is common. I'd very >>>> much like removal to work from the beginning. >>> >>> Can you give an example use case? >> >> I think VirtFS migration need hot plugging, or it may cause QEMU crash >> or some problems. > > Live migration is currently unsupported. Hot unplugging the virtio-fs > device would allow the guest to live migrate successfully, so it's a > useful feature to work around the missing live migration support. > > Is this what you mean? Agreed, migration support is necessary for user, and hot plugging/unplugging is also common for virtio device. Jun
