Re: [Xen-devel] [RFC] Add support for Xen ARM guest on FreeBSD

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hello Nathan,

On 01/17/2014 03:04 AM, Nathan Whitehorn wrote:
> On 01/16/14 18:36, Julien Grall wrote:
> > On 01/16/2014 01:56 AM, Nathan Whitehorn wrote:
> > As I understand, only the simple bus code (see simplebus_attach) is
> > translating the interrupts in the device on a resource.
> > So if you have a node directly attached to the root node with
> > interrupts and MMIO, the driver won't be able to retrieve and
> > translate the interrupts via bus_alloc_resources.
> Why not? nexus on ARM, MIPS, PowerPC, and sparc64 can do this.
I have digged into the code to find the reason of my issue. FreeBSD is 
receiving a VM fault when the driver (xen-dt) is trying to setup the IRQ.
This is because the GIC is not yet initialized but FreeBSD asks to 
unmask the IRQ (sys/arm/arm/gic.c:306).
With this problem, all device nodes that are before the GIC in the 
device tree can't have interrupts. For instance this simple device will 
segfault on FreeBSD:
/ {

  mybus {
     compatible = "simple-bus";

     mynode {
        interrupt-parent = &gic;
        interrupts = <...>;
     };

     gic: gic@xxxx {
        interrupt-controller;
     }
  };
};

The node "mynode" will have to move after the GIC to be able to work 
correctly.
--
Julien Grall

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