Re: [Qemu-devel] [PATCH] hw/net: fix vmxnet3 live migration

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Marcel Apfelbaum (marcel.apfelbaum@gmail.com) wrote:
> 
> 
> On 7/5/19 2:14 PM, Sukrit Bhatnagar wrote:
> > On Fri, 5 Jul 2019 at 16:29, Dmitry Fleytman <dmitry.fleytman@gmail.com> wrote:
> > > 
> > > > On 5 Jul 2019, at 4:07, Marcel Apfelbaum <marcel.apfelbaum@gmail.com> wrote:
> > > > 
> > > > At some point vmxnet3 live migration stopped working and git-bisect
> > > > didn't help finding a working version.
> > > > The issue is the PCI configuration space is not being migrated
> > > > successfully and MSIX remains masked at destination.
> > > > 
> > > > Remove the migration differentiation between PCI and PCIe since
> > > > the logic resides now inside VMSTATE_PCI_DEVICE.
> > > > Remove also the VMXNET3_COMPAT_FLAG_DISABLE_PCIE based differentiation
> > > > since at 'realize' time is decided if the device is PCI or PCIe,
> > > > then the above macro is enough.
> > > > 
> > > > Use the opportunity to move to the standard VMSTATE_MSIX
> > > > instead of the deprecated SaveVMHandlers.
> > > > 
> > > > Signed-off-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
> > > 
> > > Reviewed-by: Dmitry Fleytman <dmitry.fleytman@gmail.com>
> > > 
> > Tested-by: Sukrit Bhatnagar <skrtbhtngr@gmail.com>
> 
> Thanks for the fast testing and review!
> 
> David, since the live migration was broken long before this patch,
> I don't need  to add any compatibility code, right?

Right, although we should probably bump the version_id field, that way
you'll get a nice clean error if you try and migrate from the old<->new.

(It's nice to get rid of the old msix oddity).

> If so, can you merge it using your migration tree?

I could do; or since it's entirely in vmxnet3 Dmitry can take it.

Dave

> Thanks,
> Marcel
> 
> 
> > > > ---
> > > > hw/net/vmxnet3.c | 52 ++----------------------------------------------
> > > > 1 file changed, 2 insertions(+), 50 deletions(-)
> > > > 
> > > > diff --git a/hw/net/vmxnet3.c b/hw/net/vmxnet3.c
> > > > index 10d01d0058..8b17548b02 100644
> > > > --- a/hw/net/vmxnet3.c
> > > > +++ b/hw/net/vmxnet3.c
> > > > @@ -2141,21 +2141,6 @@ vmxnet3_cleanup_msi(VMXNET3State *s)
> > > >      msi_uninit(d);
> > > > }
> > > > 
> > > > -static void
> > > > -vmxnet3_msix_save(QEMUFile *f, void *opaque)
> > > > -{
> > > > -    PCIDevice *d = PCI_DEVICE(opaque);
> > > > -    msix_save(d, f);
> > > > -}
> > > > -
> > > > -static int
> > > > -vmxnet3_msix_load(QEMUFile *f, void *opaque, int version_id)
> > > > -{
> > > > -    PCIDevice *d = PCI_DEVICE(opaque);
> > > > -    msix_load(d, f);
> > > > -    return 0;
> > > > -}
> > > > -
> > > > static const MemoryRegionOps b0_ops = {
> > > >      .read = vmxnet3_io_bar0_read,
> > > >      .write = vmxnet3_io_bar0_write,
> > > > @@ -2176,11 +2161,6 @@ static const MemoryRegionOps b1_ops = {
> > > >      },
> > > > };
> > > > 
> > > > -static SaveVMHandlers savevm_vmxnet3_msix = {
> > > > -    .save_state = vmxnet3_msix_save,
> > > > -    .load_state = vmxnet3_msix_load,
> > > > -};
> > > > -
> > > > static uint64_t vmxnet3_device_serial_num(VMXNET3State *s)
> > > > {
> > > >      uint64_t dsn_payload;
> > > > @@ -2203,7 +2183,6 @@ static uint64_t vmxnet3_device_serial_num(VMXNET3State *s)
> > > > 
> > > > static void vmxnet3_pci_realize(PCIDevice *pci_dev, Error **errp)
> > > > {
> > > > -    DeviceState *dev = DEVICE(pci_dev);
> > > >      VMXNET3State *s = VMXNET3(pci_dev);
> > > >      int ret;
> > > > 
> > > > @@ -2249,8 +2228,6 @@ static void vmxnet3_pci_realize(PCIDevice *pci_dev, Error **errp)
> > > >          pcie_dev_ser_num_init(pci_dev, VMXNET3_DSN_OFFSET,
> > > >                                vmxnet3_device_serial_num(s));
> > > >      }
> > > > -
> > > > -    register_savevm_live(dev, "vmxnet3-msix", -1, 1, &savevm_vmxnet3_msix, s);
> > > > }
> > > > 
> > > > static void vmxnet3_instance_init(Object *obj)
> > > > @@ -2440,29 +2417,6 @@ static const VMStateDescription vmstate_vmxnet3_int_state = {
> > > >      }
> > > > };
> > > > 
> > > > -static bool vmxnet3_vmstate_need_pcie_device(void *opaque)
> > > > -{
> > > > -    VMXNET3State *s = VMXNET3(opaque);
> > > > -
> > > > -    return !(s->compat_flags & VMXNET3_COMPAT_FLAG_DISABLE_PCIE);
> > > > -}
> > > > -
> > > > -static bool vmxnet3_vmstate_test_pci_device(void *opaque, int version_id)
> > > > -{
> > > > -    return !vmxnet3_vmstate_need_pcie_device(opaque);
> > > > -}
> > > > -
> > > > -static const VMStateDescription vmstate_vmxnet3_pcie_device = {
> > > > -    .name = "vmxnet3/pcie",
> > > > -    .version_id = 1,
> > > > -    .minimum_version_id = 1,
> > > > -    .needed = vmxnet3_vmstate_need_pcie_device,
> > > > -    .fields = (VMStateField[]) {
> > > > -        VMSTATE_PCI_DEVICE(parent_obj, VMXNET3State),
> > > > -        VMSTATE_END_OF_LIST()
> > > > -    }
> > > > -};
> > > > -
> > > > static const VMStateDescription vmstate_vmxnet3 = {
> > > >      .name = "vmxnet3",
> > > >      .version_id = 1,
> > > > @@ -2470,9 +2424,8 @@ static const VMStateDescription vmstate_vmxnet3 = {
> > > >      .pre_save = vmxnet3_pre_save,
> > > >      .post_load = vmxnet3_post_load,
> > > >      .fields = (VMStateField[]) {
> > > > -            VMSTATE_STRUCT_TEST(parent_obj, VMXNET3State,
> > > > -                                vmxnet3_vmstate_test_pci_device, 0,
> > > > -                                vmstate_pci_device, PCIDevice),
> > > > +            VMSTATE_PCI_DEVICE(parent_obj, VMXNET3State),
> > > > +            VMSTATE_MSIX(parent_obj, VMXNET3State),
> > > >              VMSTATE_BOOL(rx_packets_compound, VMXNET3State),
> > > >              VMSTATE_BOOL(rx_vlan_stripping, VMXNET3State),
> > > >              VMSTATE_BOOL(lro_supported, VMXNET3State),
> > > > @@ -2508,7 +2461,6 @@ static const VMStateDescription vmstate_vmxnet3 = {
> > > >      },
> > > >      .subsections = (const VMStateDescription*[]) {
> > > >          &vmxstate_vmxnet3_mcast_list,
> > > > -        &vmstate_vmxnet3_pcie_device,
> > > >          NULL
> > > >      }
> > > > };
> > > > --
> > > > 2.17.1
> > > > 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK