On Wed, Jul 21, 2021 at 06:09:05PM +0200, Laurent Vivier wrote:
> The intend of failover is to allow to migrate a VM with a VFIO
> networking card without disrupting the network operation by switching
> to a virtio-net device during the migration.
>
> This simple change allows to test failover with a simulated device
> like e1000e rather than a vfio device, even if it's useless in real
> life it can help to debug failover.
>
> This is interesting to developers that want to test failover on
> a system with no vfio device. Moreover it simplifies host networking
> configuration as we can use the same bridge for virtio-net and
> the other failover networking device.
>
> Without this change the migration of a system configured with failover
> fails with:
>
> ...
> -device virtio-net-pci,id=virtionet0,failover=on,... \
> -device e1000,failover_pair_id=virtionet0,... \
> ...
>
> (qemu) migrate ...
>
> Unknown ramblock "0000:00:01.1:00.0/e1000e.rom", cannot accept migration
> error while loading state for instance 0x0 of device 'ram'
> load of migration failed: Invalid argument
>
> This happens because QEMU correctly unregisters the interface vmstate but
> not the ROM one. This patch fixes that.
>
> Signed-off-by: Laurent Vivier <lviv...@redhat.com>
Build fails on qemu-system-m68k:
/usr/bin/ld: libqemu-m68k-softmmu.fa.p/hw_net_virtio-net.c.o: in function
`virtio_net_handle_migration_primary':
/scm/qemu/build/../hw/net/virtio-net.c:3259: undefined reference to
`pci_del_option_rom'
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.
make[1]: *** [Makefile:154: run-ninja] Error 1
It's not pretty to poke at pci from generic virtio.
Should we maybe wrap vmstate_unregister and pci_del_option_rom
to allow removing all migrateable things related to the device
in one go somehow?
> ---
>
> Notes:
> v4:
> export and use pci_del_option_rom()
>
> v3:
> remove useless space before comma
>
> v2:
> reset has_rom to false
> update commit log message
>
> include/hw/pci/pci.h | 2 ++
> hw/net/virtio-net.c | 1 +
> hw/pci/pci.c | 3 +--
> 3 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
> index d0f4266e3725..84707034cbf8 100644
> --- a/include/hw/pci/pci.h
> +++ b/include/hw/pci/pci.h
> @@ -369,6 +369,8 @@ void pci_register_vga(PCIDevice *pci_dev, MemoryRegion
> *mem,
> void pci_unregister_vga(PCIDevice *pci_dev);
> pcibus_t pci_get_bar_addr(PCIDevice *pci_dev, int region_num);
>
> +void pci_del_option_rom(PCIDevice *pdev);
> +
> int pci_add_capability(PCIDevice *pdev, uint8_t cap_id,
> uint8_t offset, uint8_t size,
> Error **errp);
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 16d20cdee52a..d6f03633f1b3 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -3256,6 +3256,7 @@ static void
> virtio_net_handle_migration_primary(VirtIONet *n, MigrationState *s)
> if (migration_in_setup(s) && !should_be_hidden) {
> if (failover_unplug_primary(n, dev)) {
> vmstate_unregister(VMSTATE_IF(dev), qdev_get_vmsd(dev), dev);
> + pci_del_option_rom(PCI_DEVICE(dev));
> qapi_event_send_unplug_primary(dev->id);
> qatomic_set(&n->failover_primary_hidden, true);
> } else {
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index 23d2ae2ab232..c210d92b5ba7 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -228,7 +228,6 @@ static PCIBus *pci_find_bus_nr(PCIBus *bus, int bus_num);
> static void pci_update_mappings(PCIDevice *d);
> static void pci_irq_handler(void *opaque, int irq_num, int level);
> static void pci_add_option_rom(PCIDevice *pdev, bool is_default_rom, Error
> **);
> -static void pci_del_option_rom(PCIDevice *pdev);
>
> static uint16_t pci_default_sub_vendor_id = PCI_SUBVENDOR_ID_REDHAT_QUMRANET;
> static uint16_t pci_default_sub_device_id = PCI_SUBDEVICE_ID_QEMU;
> @@ -2429,7 +2428,7 @@ static void pci_add_option_rom(PCIDevice *pdev, bool
> is_default_rom,
> pci_register_bar(pdev, PCI_ROM_SLOT, 0, &pdev->rom);
> }
>
> -static void pci_del_option_rom(PCIDevice *pdev)
> +void pci_del_option_rom(PCIDevice *pdev)
> {
> if (!pdev->has_rom)
> return;
> --
> 2.31.1
