From de8607d77d92b6bca0075265502286cc3b3915d8 Mon Sep 17 00:00:00 2001 From: Joao Martins Date: Wed, 14 Dec 2016 10:53:32 +0000 Subject: [PATCH] libxl: reverse defaults on HVM net device attach libvirt libxl picks its own default with respect to the default NIC to use. libxlMakeNic is the one responsible for this and on boot it picks LIBXL_NIC_TYPE_VIF_IOEMU for HVM domains such that it accomodates both PV and emulated one. The good behaving guest at boot will then select the pv and unplug the emulated device. Now, on HVM when attaching an interface it will pick the same default that is LIBXL_NIC_TYPE_VIF_IOEMU which as a result will fail the attach (see xen commit 32e9d0f ("libxl: nic type defaults to vif in hotplug for hvm guest"). Xen doesn't yet support the hotplug of emulated devices, but we don't want to rule out that case either, which might get support in the future. Hence we simply reverse the defaults when we are attaching the interface which allows libvirt to prefer the PV nic first without adding "model='netfront'" following the same pattern as above commit. Also to avoid ruling out the emulated one we set to LIBXL_NIC_TYPE_IOEMU when setting a model type that is not 'netfront'. Signed-off-by: Joao Martins Signed-off-by: Jim Fehlig --- src/libxl/libxl_conf.c | 39 +++++++++++++++++++++++++++++++-------- src/libxl/libxl_conf.h | 3 ++- src/libxl/libxl_driver.c | 2 +- 3 files changed, 34 insertions(+), 10 deletions(-) diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c index 237dc67ee8..b569ddad82 100644 --- a/src/libxl/libxl_conf.c +++ b/src/libxl/libxl_conf.c @@ -892,9 +892,9 @@ libxlMakeDiskList(virDomainDefPtr def, libxl_domain_config *d_config) int libxlMakeNic(virDomainDefPtr def, virDomainNetDefPtr l_nic, - libxl_device_nic *x_nic) + libxl_device_nic *x_nic, + bool attach) { - bool ioemu_nic = def->os.type == VIR_DOMAIN_OSTYPE_HVM; virDomainNetType actual_type = virDomainNetGetActualType(l_nic); virNetworkPtr network = NULL; virConnectPtr conn = NULL; @@ -918,16 +918,39 @@ libxlMakeNic(virDomainDefPtr def, virMacAddrGetRaw(&l_nic->mac, x_nic->mac); - if (ioemu_nic) - x_nic->nictype = LIBXL_NIC_TYPE_VIF_IOEMU; - else - x_nic->nictype = LIBXL_NIC_TYPE_VIF; - + /* + * The nictype field of libxl_device_nic structure tells Xen which type of + * NIC device to create for the domain. LIBXL_NIC_TYPE_VIF specifies a + * PV NIC. LIBXL_NIC_TYPE_VIF_IOEMU specifies a PV and emulated NIC, + * allowing the domain to choose which NIC to use and unplug the unused + * one. LIBXL_NIC_TYPE_VIF_IOEMU is only valid for HVM domains. Further, + * if hotplugging the NIC, emulated NICs are currently not supported. + * Alternatively one could set LIBXL_NIC_TYPE_UNKNOWN and let libxl decide, + * but its behaviour might not be consistent across all libvirt supported + * versions. The other nictype values are well established already, hence + * we manually select our own default and mimic xl/libxl behaviour starting + * xen commit 32e9d0f ("libxl: nic type defaults to vif in hotplug for + * hvm guest"). + */ if (l_nic->model) { + if (def->os.type == VIR_DOMAIN_OSTYPE_XEN && + STRNEQ(l_nic->model, "netfront")) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", + _("only model 'netfront' is supported for " + "Xen PV domains")); + return -1; + } if (VIR_STRDUP(x_nic->model, l_nic->model) < 0) goto cleanup; if (STREQ(l_nic->model, "netfront")) x_nic->nictype = LIBXL_NIC_TYPE_VIF; + else + x_nic->nictype = LIBXL_NIC_TYPE_VIF_IOEMU; + } else { + if (def->os.type == VIR_DOMAIN_OSTYPE_HVM && !attach) + x_nic->nictype = LIBXL_NIC_TYPE_VIF_IOEMU; + else + x_nic->nictype = LIBXL_NIC_TYPE_VIF; } if (VIR_STRDUP(x_nic->ifname, l_nic->ifname) < 0) @@ -1058,7 +1081,7 @@ libxlMakeNicList(virDomainDefPtr def, libxl_domain_config *d_config) if (virDomainNetGetActualType(l_nics[i]) == VIR_DOMAIN_NET_TYPE_HOSTDEV) continue; - if (libxlMakeNic(def, l_nics[i], &x_nics[nvnics])) + if (libxlMakeNic(def, l_nics[i], &x_nics[nvnics], false)) goto error; /* * The devid (at least right now) will not get initialized by diff --git a/src/libxl/libxl_conf.h b/src/libxl/libxl_conf.h index 0ea76b4df5..851f3afb41 100644 --- a/src/libxl/libxl_conf.h +++ b/src/libxl/libxl_conf.h @@ -178,7 +178,8 @@ libxlMakeDisk(virDomainDiskDefPtr l_dev, libxl_device_disk *x_dev); int libxlMakeNic(virDomainDefPtr def, virDomainNetDefPtr l_nic, - libxl_device_nic *x_nic); + libxl_device_nic *x_nic, + bool attach); int libxlMakeVfb(virPortAllocatorPtr graphicsports, virDomainGraphicsDefPtr l_vfb, libxl_device_vfb *x_vfb); diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c index b19b17e2c4..7e5d9b69e5 100644 --- a/src/libxl/libxl_driver.c +++ b/src/libxl/libxl_driver.c @@ -3379,7 +3379,7 @@ libxlDomainAttachNetDevice(libxlDriverPrivatePtr driver, goto cleanup; } - if (libxlMakeNic(vm->def, net, &nic) < 0) + if (libxlMakeNic(vm->def, net, &nic, true) < 0) goto cleanup; if (libxl_device_nic_add(cfg->ctx, vm->def->id, &nic, 0)) {