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Date: Thu, 21 May 2015 20:47:05 +0200 From: "Luis R. Rodriguez" <mcgrof@...e.com> To: Masahiro Yamada <yamada.masahiro@...ionext.com> Cc: "Luis R. Rodriguez" <mcgrof@...not-panic.com>, Michal Marek <mmarek@...e.cz>, david.vrabel@...rix.com, konrad.wilk@...cle.com, Ian.Campbell@...rix.com, xen-devel@...ts.xenproject.org, josh@...htriplett.org, Borislav Petkov <bp@...e.de>, penberg@...nel.org, rientjes@...gle.com, rdunlap@...radead.org, levinsasha928@...il.com, mtosatti@...hat.com, fengguang.wu@...el.com, Linux Kernel Mailing List <linux-kernel@...r.kernel.org> Subject: Re: [PATCH v6 2/2] kconfig: add xenconfig defconfig helper On Thu, May 21, 2015 at 11:49:17PM +0900, Masahiro Yamada wrote: > Hi, > > I am not familiar with xen at all, just some comments > from the build system side. > > > > 2015-05-21 3:53 GMT+09:00 Luis R. Rodriguez <mcgrof@...not-panic.com>: > > From: "Luis R. Rodriguez" <mcgrof@...e.com> > > > > This lets you build a kernel which can support xen dom0 > > or xen guests on i386, x86-64 and arm64 by just using: > > > > make xenconfig > > > > You can start from an allnoconfig and then switch to xenconfig. > > This also splits out the options which are available currently > > to be built with x86 and 'make ARCH=arm64' under a shared config. > > > > Technically xen supports a dom0 kernel and also a guest > > kernel configuration but upon review with the xen team > > since we don't have many dom0 options its best to just > > combine these two into one. > > > > A few generic notes: we enable both of these: > > > > CONFIG_INET=y > > CONFIG_BINFMT_ELF=y > > > > although technically not required given you likely will > > end up with a pretty useless system otherwise. > > > > A few architectural differences worth noting: > > > > $ make allnoconfig; make xenconfig > /dev/null ; \ > > grep XEN .config > 64-bit-config > > $ make ARCH=i386 allnoconfig; make ARCH=i386 xenconfig > /dev/null; \ > > grep XEN .config > 32-bit-config > > $ make ARCH=arm64 allnoconfig; make ARCH=arm64 xenconfig > /dev/null; \ > > grep XEN .config > arm64-config > > > > Since the options are already split up with a generic config and > > architecture specific configs you anything on the x86 configs > > are known to only work right now on x86. For instance arm64 doesn't > > support MEMORY_HOTPLUG yet as such although we try to enabe it > > generically arm64 doesn't have it yet, so we leave the xen > > specific kconfig option XEN_BALLOON_MEMORY_HOTPLUG on x86's config > > file to set expecations correctly. > > > > Then on x86 we have differences between i386 and x86-64. The difference > > between 64-bit-config and 32-bit-config is you don't get XEN_MCE_LOG as > > this is only supported on 64-bit. You also do not get on i386 > > XEN_BALLOON_MEMORY_HOTPLUG, there does not seem to be any technical > > reasons to not allow this but I gave up after a few attempts. > > > > Cc: Josh Triplett <josh@...htriplett.org> > > Cc: Borislav Petkov <bp@...e.de> > > Cc: Pekka Enberg <penberg@...nel.org> > > Cc: David Rientjes <rientjes@...gle.com> > > Cc: Michal Marek <mmarek@...e.cz> > > Cc: Randy Dunlap <rdunlap@...radead.org> > > Cc: penberg@...nel.org > > Cc: levinsasha928@...il.com > > Cc: mtosatti@...hat.com > > Cc: fengguang.wu@...el.com > > Cc: David Vrabel <david.vrabel@...rix.com> > > Cc: Ian Campbell <Ian.Campbell@...rix.com> > > Cc: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com> > > Cc: xen-devel@...ts.xenproject.org > > Acked-by: Stefano Stabellini <stefano.stabellini@...citrix.com> > > Acked-by: Julien Grall <julien.grall@...aro.org> > > Acked-by: Michal Marek <mmarek@...e.cz> > > Acked-by: David Rientjes <rientjes@...gle.com> > > Reviewed-by: Josh Triplett <josh@...htriplett.org> > > Signed-off-by: Luis R. Rodriguez <mcgrof@...e.com> > > --- > > > diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile > > index 6950032..f52abae 100644 > > --- a/scripts/kconfig/Makefile > > +++ b/scripts/kconfig/Makefile > > @@ -115,6 +115,10 @@ PHONY += kvmconfig > > kvmconfig: kvm_guest.config > > @: > > > > +PHONY += xenconfig > > +xenconfig: xen.config > > + @: > > + > > PHONY += tinyconfig > > tinyconfig: > > $(Q)$(MAKE) -f $(srctree)/Makefile allnoconfig tiny.config > > > "make xenconfig" is equivalent to "make xen.config" > and only saves one character. > > Now we have only three targets for mergeconfig (tiny, kvm, xen), > so it is OK to add this as an alias. > But if we have more such targets, we might have > to consider to use generic targets (*.config) at some point. I'm frankly terrified of all these config target options growing more and the possible large collateral of patches to Kconfig files in the future. Since this is a small specialized group now, I think we should treat it as such but I think what you say has good merit long run. For now I'm more of a fan we limit what we stuff in here and if this explodes then only have new options use the subject.config target. Thoughts? > I do not intend to block this. > Just take my comment with a grain of salt.. > > > > @@ -140,6 +144,7 @@ help: > > @echo ' listnewconfig - List new options' > > @echo ' olddefconfig - Same as silentoldconfig but sets new symbols to their default value' > > @echo ' kvmconfig - Enable additional options for kvm guest kernel support' > > + @echo ' xenconfig - Enable additional options for xen dom0 and guest kernel support' > > @echo ' tinyconfig - Configure the tiniest possible kernel' > > > > # lxdialog stuff > > > If kvmconfig and xenconfig are only available for x86, > is it better to enclose those helps with > ifeq ($(ARCH),x86) > ... > endif That's true if kvm was only for x86 but it is not, and likewise for xen. mcgrof@...on ~/linux-next (git::sumadre)$ git grep "config KVM$" arch/arm/kvm/Kconfig:config KVM arch/arm64/kvm/Kconfig:config KVM arch/mips/kvm/Kconfig:config KVM arch/powerpc/kvm/Kconfig:config KVM arch/s390/kvm/Kconfig:config KVM arch/tile/kvm/Kconfig:config KVM arch/x86/kvm/Kconfig:config KVM mcgrof@...on ~/linux-next (git::supadre)$ git grep "config XEN$" arch/arm/Kconfig:config XEN arch/arm64/Kconfig:config XEN arch/x86/xen/Kconfig:config XEN Luis -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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