Re: [libvirt] [PATCH 1/2] xenFormatNet: correct `type=netfront' to 'type=vif' to match libxl

>> On 5/14/2016 at 12:54 AM, in message <573606AB.4080200(a)suse.com&gt;, Jim Fehlig

On 05/13/2016 06:59 AM, Joao Martins wrote: > > On 05/12/2016 09:55 PM, Jim Fehlig wrote: >> Joao Martins wrote: >>> On 05/12/2016 12:54 AM, Jim Fehlig wrote: >>>> On 04/21/2016 05:10 AM, Chunyan Liu wrote: >>>>> According to current xl.cfg docs and xl codes, it uses type=vif >>>>> instead of type=netfront. >>>>> >>>>> Currently after domxml-to-native, libvirt xml model=netfront will be >>>>> converted to xl type=netfront. This has no problem before, xen codes >>>>> for a long time just check type=ioemu, if not, set type to _VIF. >>>>> >>>>> Since libxl uses parse_nic_config to avoid duplicate codes, it >>>>> compares 'type=vif' and 'type=ioemu' for valid parameters, others >>>>> are considered as invalid, thus we have problem with type=netfront >>>>> in xl config file. >>>>> #xl create sles12gm-hvm.orig >>>>> Parsing config from sles12gm-hvm.orig >>>>> Invalid parameter `type'. >>>>> >>>>> Correct the convertion in libvirt, so that it matchs libxl codes >>>>> and also xl.cfg. >>>>> >>>>> Signed-off-by: Chunyan Liu <cyliu(a)suse.com&gt; >>>>> --- >>>>> src/xenconfig/xen_common.c | 38 ++++++++++++++++++++++++-------------- >>>>> src/xenconfig/xen_common.h | 7 ++++--- >>>>> src/xenconfig/xen_xl.c | 4 ++-- >>>>> src/xenconfig/xen_xm.c | 8 ++++---- >>>>> 4 files changed, 34 insertions(+), 23 deletions(-) >>>>> >>>>> diff --git a/src/xenconfig/xen_common.c b/src/xenconfig/xen_common.c >>>>> index e1d9cf6..f54d6b6 100644 >>>>> --- a/src/xenconfig/xen_common.c >>>>> +++ b/src/xenconfig/xen_common.c >>>>> @@ -801,9 +801,8 @@ xenParseCharDev(virConfPtr conf, virDomainDefPtr def) >>>>> return -1; >>>>> } >>>>> >>>>> - >>>>> static int >>>>> -xenParseVif(virConfPtr conf, virDomainDefPtr def) >>>>> +xenParseVif(virConfPtr conf, virDomainDefPtr def, const char *vif_typename) >>>>> { >>>>> char *script = NULL; >>>>> virDomainNetDefPtr net = NULL; >>>>> @@ -942,7 +941,7 @@ xenParseVif(virConfPtr conf, virDomainDefPtr def) >>>>> VIR_STRDUP(net->model, model) < 0) >>>>> goto cleanup; >>>>> >>>>> - if (!model[0] && type[0] && STREQ(type, "netfront") && >>>>> + if (!model[0] && type[0] && STREQ(type, vif_typename) && >>>>> VIR_STRDUP(net->model, "netfront") < 0) >>>>> goto cleanup; >>>>> >>>>> @@ -1042,11 +1041,17 @@ xenParseGeneralMeta(virConfPtr conf, virDomainDefPtr def, virCapsPtr caps) >>>>> >>>>> /* >>>>> * A convenience function for parsing all config common to both XM and XL >>>>> + * >>>>> + * vif_typename: type name for a paravirtualized network could >>>>> + * be different for xm and xl. For xm, it uses type=netfront; >>>>> + * for xl, it uses type=vif. So, for xm, should pass "netfront"; >>>>> + * for xl, should pass "vif". >>>>> */ >>>>> int >>>>> xenParseConfigCommon(virConfPtr conf, >>>>> virDomainDefPtr def, >>>>> - virCapsPtr caps) >>>>> + virCapsPtr caps, >>>>> + const char *vif_typename) >>>> One thing I didn't recall when suggesting this approach is that xenParseVif() is >>>> called in xenParseConfigCommon(). I was thinking it was called from >>>> xen_{xl,xm}.c and the extra parameter would only be added to the >>>> xen{Format,Parse}Vif functions. I don't particularly like seeing the device >>>> specific parameter added to the common functions, but wont object if others are >>>> fine with it. Any other opinions on that? Joao? >>> That's a good point - probably we can avoid it by using >>> xen{Format,Parse}Vif (with the signature change Chunyan proposes) individually >>> on xenParseXM and xenParseXL. >> Nod. >> >>> And there wouldn't be any xenParseConfigCommon >>> with device-specific parameters (as vif being one of the many devices that the >>> routine is handling). The vif config is the same between xm and xl, with the >>> small difference wrt to the validation on xen libxl side - so having in >>> xen_common.c makes sense. >> Nod again :-). >> >>>> And one reason I wont object is that the alternative (calling >>>> xen{Format,Parse}Vif from xen_{xl,xm}.c) is a rather large change since all the >>>> tests/{xl,xm}configdata/ files would need to be adjusted. >>> Hm, perhaps I fail to see what the large change would be. We would keep the same >>> interface (i.e. model=netfront as valid on libvirt-side and converting to >>> type="vif" where applicable (libxl)) then the xml and .cfg won't change. >>> Furthermore, we only use e1000 which is valid for both cases and Chunyan adds >>> one test case to cover this series. So may be the adjustment you suggest above >>> wouldn't be as cumbersome as to change all the tests/{xl,xm}configdata files? >> On the Parse side we would be fine, but on the Format side 'vif =' would now be >> emitted after xenFormatConfigCommon executed. So the xl.cfg output would change >> from e.g. >> > Ah, totally missed that out: it looks a large change. I think XL vif won't > diverge from XM anytime soon unless we start adding support for more qemu-ish > features on xen libxl (e.g. vhostuser, or even block "target" field equivalent). That's a good point. Instead of creating a bunch of turmoil now over 'netfront' vs 'vif', we should wait until something more substantial drives the change. > I am fine with the approach on the patch, but the way you suggested is indeed > more correct. Perhaps as a compromise, the new xen{Format,Parse}ConfigCommon parameter could be of type 'enum xenConfigFlavor' or similar, with flavors XEN_CONFIG_FLAVOR_XL and XEN_CONFIG_FLAVOR_XM.

That would accommodate other trivial differences we might find in the future. Regards, Jim