>>> On 06.03.17 at 12:38, <julien.gr...@arm.com> wrote: > > On 06/03/17 11:32, Jan Beulich wrote: >>>>> On 06.03.17 at 12:15, <julien.gr...@arm.com> wrote: >>> On 06/03/17 11:01, Zhongze Liu wrote: >>>> Added 3 new config entries in common/Kconfig: >>>> CMDLINE_BOOL, CMDLINE and CMDLINE_OVERRIDE >>>> >>>> These 3 entries enable an embedded command line >>>> to be compiled in the hypervisor. >>>> >>>> If CMDLINE_BOOL is set to y, both arm and x86 startup routines >>>> will combine the compiled-in command line and the boot loader command line >>>> together to form a complete command line before calling cmdline_parse(). >>>> And if CMDLINE_OVERRIDE is set to y, boot loader command line >>>> will be ignored. >>> >>> This behavior seems a little odd to me. Why would you want to append the >>> two command line? And more importantly if the same option is passed >>> twice, how will this behave? >>> >>> For example the compile command line could contain iommu=off, but the >>> bootloader is passing iommu=on. What would be the final state of the IOMMU? >>> >>> This one is quite simple, but you could have options which set flags. So >>> if you want to override it, the new option would have to unset it. >> >> I don't understand this concern - overriding an earlier option by a >> later one is (supposed to be) well defined, and we even suggest this >> to people when wanting to try out options without having to edit >> bootloader (or whatever) config files. > > My concern is not about the override itself but about appending two > commandlines option without any explanation whether the built-in > commandline will be parsed first.
Oh, agreed - as Andrew has also pointed out, the ordering (and hence override behavior) needs to be clearly spelled out here. Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel
