Re: [PATCH 9.0 00/13] Consolidate common vdpa members in VhostVDPAShared

[Eugenio Perez Martin]

On Thu, Nov 30, 2023 at 4:22 AM Lei Yang <leiyang@redhat.com> wrote:
>
> Hi Eugenio
>
> QE performed regression testing after applying this patch. This series
> patch introduced a qemu core dump bug, for the core dump information
> please review the attached file.
>

Hi Lei, thank you very much for the testing!

Can you describe the test steps that lead to the crash? I think you
removed the vdpa device via QMP, but I'd like to be sure.

Thanks!

> Tested-by: Lei Yang <leiyang@redhat.com>
>
>
>
>
> On Sat, Nov 25, 2023 at 1:14 AM Eugenio Pérez <eperezma@redhat.com> wrote:
> >
> > Current memory operations like pinning may take a lot of time at the
> > destination.  Currently they are done after the source of the migration is
> > stopped, and before the workload is resumed at the destination.  This is a
> > period where neigher traffic can flow, nor the VM workload can continue
> > (downtime).
> >
> > We can do better as we know the memory layout of the guest RAM at the
> > destination from the moment the migration starts.  Moving that operation 
> > allows
> > QEMU to communicate the kernel the maps while the workload is still running 
> > in
> > the source, so Linux can start mapping them.  Ideally, all IOMMU is 
> > configured,
> > but if the vDPA parent driver uses on-chip IOMMU and .set_map we're still
> > saving all the pinning time.
> >
> > This is a first required step to consolidate all the members in a common
> > struct.  This is needed because the destination does not know what 
> > vhost_vdpa
> > struct will have the registered listener member, so it is easier to place 
> > them
> > in a shared struct rather to keep them in vhost_vdpa struct.
> >
> > v1 from RFC:
> > * Fix vhost_vdpa_net_cvq_start checking for always_svq instead of
> >   shadow_data.  This could cause CVQ not being shadowed if
> >   vhost_vdpa_net_cvq_start was called in the middle of a migration.
> >
> > Eugenio Pérez (13):
> >   vdpa: add VhostVDPAShared
> >   vdpa: move iova tree to the shared struct
> >   vdpa: move iova_range to vhost_vdpa_shared
> >   vdpa: move shadow_data to vhost_vdpa_shared
> >   vdpa: use vdpa shared for tracing
> >   vdpa: move file descriptor to vhost_vdpa_shared
> >   vdpa: move iotlb_batch_begin_sent to vhost_vdpa_shared
> >   vdpa: move backend_cap to vhost_vdpa_shared
> >   vdpa: remove msg type of vhost_vdpa
> >   vdpa: move iommu_list to vhost_vdpa_shared
> >   vdpa: use VhostVDPAShared in vdpa_dma_map and unmap
> >   vdpa: use dev_shared in vdpa_iommu
> >   vdpa: move memory listener to vhost_vdpa_shared
> >
> >  include/hw/virtio/vhost-vdpa.h |  36 +++++---
> >  hw/virtio/vdpa-dev.c           |   7 +-
> >  hw/virtio/vhost-vdpa.c         | 160 +++++++++++++++++----------------
> >  net/vhost-vdpa.c               | 117 ++++++++++++------------
> >  hw/virtio/trace-events         |  14 +--
> >  5 files changed, 174 insertions(+), 160 deletions(-)
> >
> > --
> > 2.39.3
> >
> >