On Thu, 2014-01-30 at 17:13 +0000, Marc Zyngier wrote: > Hi Ian, > > On 30/01/14 16:11, Ian Campbell wrote: > > mach-virt has existed for a while but it is not written down what it actually > > consists of. Although it seems a bit unusual to document a binding for an > > entire platform since mach-virt is entirely virtual it is helpful to have > > something to refer to in the absence of a single concrete implementation. > > > > I've done my best to capture the requirements based on the git log and my > > memory/understanding. > > > > While here remove the xenvm dts example, the Xen tools will now build a > > suitable mach-virt compatible dts when launching the guest. > > > > Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx> > > Cc: Rob Herring <robh+dt@xxxxxxxxxx> > > Cc: Pawel Moll <pawel.moll@xxxxxxx> > > Cc: Mark Rutland <mark.rutland@xxxxxxx> > > Cc: Kumar Gala <galak@xxxxxxxxxxxxxx> > > Cc: Olof Johansson <olof@xxxxxxxxx> > > Cc: Arnd Bergmann <arnd@xxxxxxxx> > > Cc: Marc Zyngier <marc.zyngier@xxxxxxx> > > Cc: Will Deacon <will.deacon@xxxxxxx> > > Cc: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx> > > Cc: devicetree@xxxxxxxxxxxxxxx > > Cc: linux-kernel@xxxxxxxxxxxxxxx > > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > > --- > > I'm not sure which tree this sort of thing should go though, sorry for the > > huge Cc. > > --- > > .../devicetree/bindings/arm/mach-virt.txt | 32 ++++++++ > > arch/arm/boot/dts/xenvm-4.2.dts | 81 -------------------- > > 2 files changed, 32 insertions(+), 81 deletions(-) > > create mode 100644 Documentation/devicetree/bindings/arm/mach-virt.txt > > delete mode 100644 arch/arm/boot/dts/xenvm-4.2.dts > > > > diff --git a/Documentation/devicetree/bindings/arm/mach-virt.txt b/Documentation/devicetree/bindings/arm/mach-virt.txt > > new file mode 100644 > > index 0000000..562bcda > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/arm/mach-virt.txt > > @@ -0,0 +1,32 @@ > > +* Mach-virt "Dummy Virtual Machine" platform > > + > > +"mach-virt" is the smallest, dumbest platform possible, to be used as > > +a guest for Xen, KVM and other hypervisors. It has no > > +properties/functionality of its own and is driven entirely by device > > +tree. > > + > > +This document defines the requirements for such a platform. > > + > > +* Required properties: > > + > > +- compatible: should be one of: > > + "linux,dummy-virt" > > + "xen,xenvm" > > + > > +In addition to the standard nodes (chosen, cpus, memory etc) the > > +platform is required to provide certain other basic functionality > > +which must be described in the device tree: > > + > > + The platform must provide an ARM Generic Interrupt Controller > > + (GIC), defined in Documentation/devicetree/bindings/arm/gic.txt. > > + > > + The platform must provide ARM architected timer, defined in > > + Documentation/devicetree/bindings/arm/arch_timer.txt. > > + > > + If the platform is SMP then it must provide the Power State > > + Coordination Interface (PSCI) described in > > + Documentation/devicetree/bindings/arm/psci.txt. > > I'm afraid I disagree with most of the above. The whole point of > mach-virt is to provide a shell for DT platforms. None of this hardware > is mandated. Instead, all the necessary information should be described > in DT. "Add support for the smallest, dumbest possible platform, to be used as a guest for KVM or other hypervisors. It only mandates a GIC and architected timers" (your original commit message :-P) > Actually, mach-virt doesn't really stand for Virtual Machine. It stands > for virtual mach-* directory! Eventually, mach-virt should become the > default platform, the one we use when we don't match anything else in > the kernel I can word it more like that for sure, along with the alternative wording suggested by Christopher/Stefano to clarify the intent that everything comes from DTB and removal of the specific requirements for GIC/timer/PSCI I think that suit the (new) intention better? > What you've described here are requirements for a hypervisor like Xen or > KVM. mach-virt itself shouldn't have any of that. > > Cheers, > > M. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
