Re: [PATCH 4/4] xen: arm: create dom0 DTB /hypervisor/ node dynamically.

[Anthony PERARD <anthony.perard@citrix.com>]

On 30/01/13 14:26, Ian Campbell wrote:
> I initially added hypervisor-new and confirmed via /proc/device-model
> that the content is the same before changing it to drop and replace
> an existing node.
> 
> NB: There is an ambiguity in the compatibility property.
> linux/arch/arm/boot/dts/xenvm-4.2.dts says "xen,xen-4.2" while
> Documentation/devicetree/bindings/arm/xen.txt says "xen,xen-4.3". I
> don't know which is correct but I've erred on the side of the DTS.
> 
> Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
> ---
>  xen/arch/arm/domain_build.c |   53 +++++++++++++++++++++++++++++++++++++++++-
>  1 files changed, 51 insertions(+), 2 deletions(-)
> 
> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
> index bb10096..d3ef180 100644
> --- a/xen/arch/arm/domain_build.c
> +++ b/xen/arch/arm/domain_build.c
> @@ -34,7 +34,7 @@ custom_param("dom0_mem", parse_dom0_mem);
>   * are added (yet) but one terminating reserve map entry (16 bytes) is
>   * added.
>   */
> -#define DOM0_FDT_EXTRA_SIZE (sizeof(struct fdt_reserve_entry))
> +#define DOM0_FDT_EXTRA_SIZE (128 + sizeof(struct fdt_reserve_entry))
>  
>  struct vcpu *__init alloc_dom0_vcpu0(void)
>  {
> @@ -186,6 +186,13 @@ static int fdt_next_dom0_node(const void *fdt, int node,
>          if ( depth >= DEVICE_TREE_MAX_DEPTH )
>              break;
>  
> +        /* Skip /hypervisor/ node. We will inject our own. */
> +        if ( fdt_node_check_compatible(fdt, node, "xen,xen" ) == 0 )
> +        {
> +            printk("Device-tree contains \"xen,xen\" node. Ignoring.\n");
> +            continue;
> +        }
> +
>          /* Skip multiboot subnodes */
>          if ( fdt_node_check_compatible(fdt, node,
>                                         "xen,multiboot-module" ) == 0 )
> @@ -199,6 +206,45 @@ static int fdt_next_dom0_node(const void *fdt, int node,
>      return node;
>  }
>  
> +static void make_hypervisor_node(void *fdt, int addrcells, int sizecells)
> +{
> +    const char compat[] = "xen,xen-4.2\0xen,xen";
> +    u32 reg[4];
> +    u32 intr[3];
> +    u32 *cell;
> +
> +    /*
> +     * Sanity-check address sizes, since addresses and sizes which do not take
> +     * up exactly 4 or 8 bytes are not supported.
> +     */
> +    if ((addrcells != 1 && addrcells != 2) ||
> +        (sizecells != 1 && sizecells != 2))
> +        panic("Cannot cope with this size");

You could add those two properties in the hypervisor node if they don't
match what we expect them to be. This would avoid panicking with a
device tree that have different default values.

-- 
Anthony PERARD