On Thu, 30 Jan 2014, Christopher Covington wrote: > Hi Ian, > > On 01/30/2014 11:11 AM, 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. > > [...] > > > +++ 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. > > The platform is also useful to, and used by, simulators like QEMU in TCG mode. > > > It has no > > +properties/functionality of its own and is driven entirely by device > > +tree. > > I find this wording confusing. I read it as saying the platform has no > properties or functionality. Perhaps you could phrase it slightly differently, > such as having no properties or functionality beyond what's described in the > device tree. Right, something like making no assumptions on the presence of devices or hardware interfaces beyond what is described on 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. > > + > > +The platform may also provide hypervisor specific functionality > > +(e.g. PV I/O), if it does so then this functionality must be > > +discoverable (directly or indirectly) via device tree. > > I think it would be informative to provide pointers here to commonly used > paravirtualized devices, especially VirtIO PCI/MMIO. In that case I would appreciate a link to the Xen hypervisor node: Documentation/devicetree/bindings/arm/xen.txt -- 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
