Re: [Xen-devel] [PATCH v2 08/10] xen/arm: keep track of reserved-memory regions

[Julien Grall <julien.grall@xxxxxxx>]

Hi,

Some more review on this patch.

On 4/30/19 10:02 PM, Stefano Stabellini wrote:
> As we parse the device tree in Xen, keep track of the reserved-memory
> regions as they need special treatment (follow-up patches will make use
> of the stored information.)
>
> Reuse process_memory_node to add reserved-memory regions to the
> bootinfo.reserved_mem array. Remove the warning if there is no reg in
> process_memory_node because it is a normal condition for
> reserved-memory.
>
> Signed-off-by: Stefano Stabellini <stefanos@xxxxxxxxxx>
>
> ---
>
> Not done: create an e820-like structure on ARM.
>
> Changes in v2:
> - call process_memory_node from process_reserved_memory_node to avoid
>    duplication
> ---
>   xen/arch/arm/bootfdt.c      | 30 ++++++++++++++++++++++--------
>   xen/include/asm-arm/setup.h |  1 +
>   2 files changed, 23 insertions(+), 8 deletions(-)
>
> diff --git a/xen/arch/arm/bootfdt.c b/xen/arch/arm/bootfdt.c
> index b6600ab..9355a6e 100644
> --- a/xen/arch/arm/bootfdt.c
> +++ b/xen/arch/arm/bootfdt.c
> @@ -135,6 +135,8 @@ static int __init process_memory_node(const void *fdt, int 
> node,
>       const __be32 *cell;
>       paddr_t start, size;
>       u32 reg_cells = address_cells + size_cells;
> +    struct meminfo *mem;
> +    bool reserved = (bool)data;
>   
>       if ( address_cells < 1 || size_cells < 1 )
>       {
> @@ -143,29 +145,39 @@ static int __init process_memory_node(const void *fdt, 
> int node,
>           return 0;
>       }
>   
> +    if ( reserved )
> +        mem = &bootinfo.reserved_mem;
> +    else
> +        mem = &bootinfo.mem;
> +
>       prop = fdt_get_property(fdt, node, "reg", NULL);
>       if ( !prop )
> -    {
> -        printk("fdt: node `%s': missing `reg' property\n", name);
>           return 0;
> -    }
>   
>       cell = (const __be32 *)prop->data;
>       banks = fdt32_to_cpu(prop->len) / (reg_cells * sizeof (u32));
>   
> -    for ( i = 0; i < banks && bootinfo.mem.nr_banks < NR_MEM_BANKS; i++ )
> +    for ( i = 0; i < banks && mem->nr_banks < NR_MEM_BANKS; i++ )
>       {
>           device_tree_get_reg(&cell, address_cells, size_cells, &start, &size);
>           if ( !size )
>               continue;
> -        bootinfo.mem.bank[bootinfo.mem.nr_banks].start = start;
> -        bootinfo.mem.bank[bootinfo.mem.nr_banks].size = size;
> -        bootinfo.mem.nr_banks++;
> +        mem->bank[mem->nr_banks].start = start;
> +        mem->bank[mem->nr_banks].size = size;
> +        mem->nr_banks++;
>       }
>   
>       return 0;
>   }
>   
> +static int __init process_reserved_memory_node(const void *fdt, int node,
> +                                               const char *name, int depth,
> +                                               u32 address_cells, u32 
> size_cells)
> +{
> +    device_tree_for_each_node(fdt, node, depth, process_memory_node, 
> (void*)true);
> +    return 0;
> +}
> +
>   static void __init process_multiboot_node(const void *fdt, int node,
>                                             const char *name,
>                                             u32 address_cells, u32 size_cells)
> @@ -297,7 +309,9 @@ static int __init early_scan_node(const void *fdt,
>   {
>       if ( device_tree_node_matches(fdt, node, "memory") )
>           process_memory_node(fdt, node, name, depth, address_cells, size_cells,
> -                            NULL);
> +                            (void*)false);
> +    else if ( device_tree_node_matches(fdt, node, "reserved-memory") )
> +        process_reserved_memory_node(fdt, node, name, depth, address_cells, 
> size_cells);
This will match reserved-memory@... or even /foo/reserved-memory. Here, 
we only want to match /reserved-memory.
>       else if ( depth <= 3 && (device_tree_node_compatible(fdt, node, 
> "xen,multiboot-module" ) ||
>                 device_tree_node_compatible(fdt, node, "multiboot,module" )))
>           process_multiboot_node(fdt, node, name, address_cells, size_cells);
> diff --git a/xen/include/asm-arm/setup.h b/xen/include/asm-arm/setup.h
> index 48187e1..5c3fc2d 100644
> --- a/xen/include/asm-arm/setup.h
> +++ b/xen/include/asm-arm/setup.h
> @@ -66,6 +66,7 @@ struct bootcmdlines {
>   
>   struct bootinfo {
>       struct meminfo mem;
> +    struct meminfo reserved_mem;
>       struct bootmodules modules;
>       struct bootcmdlines cmdlines;
>   #ifdef CONFIG_ACPI
Cheers,

--
Julien Grall

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