[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [RFC 21/22] arm: Allow the user to specify the GIC version
On 05/06/15 13:42, Ian Campbell wrote: > On Fri, 2015-05-08 at 14:29 +0100, Julien Grall wrote: >> A platform may have a GIC compatible with previous version of the >> device. >> >> This is allow to virtualize an unmodified OS on new hardware if the GIC >> is compatible with older version. >> >> When a guest is created, the vGIC will emulate same version as the >> hardware. Although, the user can specify in the configuration file the >> preferred version (currently on GICv2 and GICv3 are supported). >> >> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx> >> Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx> >> Cc: Wei Liu <wei.liu2@xxxxxxxxxx> >> >> --- >> >> The hypervisor will check if the GIC is able to virtualize the >> version specified by the user (via the DOMCTL createdomain). >> If it's not compatible an error will be send on the Xen console >> which will make the error not obvious for user. >> >> I'm wondering if we should expose to the toolstack the vGIC versions >> supported via a mecanism similar to xen_get_caps? > > There may even be room in xencaps, although it isn't very scalable. > > Another option might be to overwrite bad fields in the config struct > with some sentinel to indicate they weren't usable. Not sure I like that > though. What about extending XENVER_get_features? >> I didn't add the documention because I wasn't sure in which section >> I should put it in the xl man. > > Probably needs a new ARCHITECTURE: ARM section, and I bet a lot of stuff > could move to ARCH: X86 (you don't have to do all that though). > >> @@ -387,7 +393,9 @@ libxl_domain_build_info = Struct("domain_build_info",[ >> ("blkdev_start", string), >> >> ("vnuma_nodes", Array(libxl_vnode_info, "num_vnuma_nodes")), >> - >> + >> + ("gic_version", libxl_gic_version), > > For historical reasons the domain config is rather x86 centric. Fixing > that is hard without breaking the API, but I think we should at least > think about putting new arch specific stuff in a per-arch location. Good idea. > Just wrapping this in a struct named arm would be an ok start, we can > add x86 when the next thing which should live there comes along. > > I think having the fields always present, even for builds on arches > where they don't make sense is ok, the alternative is to extend the IDL > language to allow things to be made arch specific and generate suitable > ifdefs... I can give a look to see how hard it is to do it. Parameter such device tree could go there too. > > >> + >> ("device_model_version", libxl_device_model_version), >> ("device_model_stubdomain", libxl_defbool), >> # if you set device_model you must set device_model_version too >> diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c >> index 648ca08..b033c0b 100644 >> --- a/tools/libxl/xl_cmdimpl.c >> +++ b/tools/libxl/xl_cmdimpl.c >> @@ -1298,6 +1298,18 @@ static void parse_config_data(const char >> *config_source, >> !xlu_cfg_get_string (config, "cpus_soft", &buf, 0)) >> parse_vcpu_affinity(b_info, cpus, buf, num_cpus, false); >> >> + if (!xlu_cfg_get_string (config, "gic_version", &buf, 1)) { > > Could we just make this an integer? I choose the string solution over integer to not rule out the possibility to expose to the user a specific extension of the GICvn (such as V2M or ITS). Regards, -- Julien Grall _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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