On Tue, Jul 11, 2023 at 05:52:22PM +0200, Hanna Czenczek wrote: > Hi, > > As discussed on the previous version of the virtio-fs migration series > (https://lists.nongnu.org/archive/html/qemu-devel/2023-04/msg01575.html), > we currently don’t have a good way to have a vhost-user back-end fully > cease all operations, including background operations. To work around > this, we reset it, which is not an option for stateful devices like > virtio-fs. > > Instead, we want the same SUSPEND/RESUME model that vhost-vdpa already > has, so that we can suspend back-ends when we want them to stop doing > anything (i.e. on VM stop), and resume them later (i.e. on VM resume). > This series adds these vhost-user operations to the protocol and > implements them in qemu. Furthermore, it has vhost-user and vhost-vdpa > do roughly the same thing in their reset paths, as far as possible. > That path will still remain as a fall-back if SUSPEND/RESUME is not > implemented, and, given that qemu’s vhost-vdpa code currently does not > make use of RESUME, it is actually always used for vhost-vdpa (to take > the device out of a suspended state). > > > Hanna Czenczek (6): > vhost-user.rst: Add suspend/resume > vhost-vdpa: Move vhost_vdpa_reset_status() up > vhost: Do not reset suspended devices on stop > vhost-user: Implement suspend/resume > vhost-vdpa: Match vhost-user's status reset > vhost-user: Have reset_status fall back to reset > > docs/interop/vhost-user.rst | 35 +++++++++++- > include/hw/virtio/vhost-vdpa.h | 2 - > include/hw/virtio/vhost.h | 8 +++ > hw/virtio/vhost-user.c | 101 ++++++++++++++++++++++++++++++++- > hw/virtio/vhost-vdpa.c | 41 ++++++------- > hw/virtio/vhost.c | 8 ++- > 6 files changed, 169 insertions(+), 26 deletions(-)
Hi Hanna, I posted comments but wanted to say great job! There was a long and somewhat messy email discussion to figure out how to proceed and you came up with a clean patch series that solves the issues. Stefan
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