[PATCH] qemu_migration: check for interface type 'hostdev'

[Michal Prívozník]

On 7/28/21 6:17 PM, Kristina Hanicova wrote:
> When we try to migrate vm, we check if it contains only devices
> that are able to migrate. If a hostdev device is not able to
> migrate we raise an error with <hostdev/>, but it can actually be
> <interface/>, so we need to check if hostdev device was created
> by us from interface and show the right error message.
> 
> Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1942315
> 
> Signed-off-by: Kristina Hanicova <khanicov at redhat.com>
> ---
>  src/qemu/qemu_migration.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
> index 4d651aeb1a..34eee9c8b6 100644
> --- a/src/qemu/qemu_migration.c
> +++ b/src/qemu/qemu_migration.c
> @@ -1272,9 +1272,15 @@ qemuMigrationSrcIsAllowedHostdev(const virDomainDef *def)
>                  }
>  
>                  /* all other PCI hostdevs can't be migrated */
> -                virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
> -                               _("cannot migrate a domain with <hostdev mode='subsystem' type='%s'>"),
> -                               virDomainHostdevSubsysTypeToString(hostdev->source.subsys.type));
> +                if (hostdev->parentnet) {
> +                    virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
> +                                   _("cannot migrate a domain with <interface type='%s'>"),
> +                                   virDomainNetTypeToString(hostdev->parentnet->type));

Small nit, I wonder whether we should report actual type here. Looking
into virDomainNetDefFormat() it looks like for a running VM we do report
actual type (unless inactive or migratable XML was requested). Thus I
think the error message should follow that logic. Otherwise we might
report "cannot migrate a domain with interface type=network" while in
fact in 'virsh dumpxml' there is just interface type='hostdev' (the
type='network' is in inactive XML).

Laine, what's your opinion?

Michal