Re: [XEN RFC PATCH 28/40] xen/x86: decouple nodes_cover_memory with E820 map

[Stefano Stabellini <sstabellini@kernel.org>]

On Wed, 11 Aug 2021, Wei Chen wrote:
> We will reuse nodes_cover_memory for Arm to check its bootmem
> info. So we introduce two arch helpers to get memory map's
> entry number and specified entry's range:
>     arch_get_memory_bank_number
>     arch_get_memory_bank_range
> 
> Depends above two helpers, we make nodes_cover_memory become
> architecture independent.

You might want to note that the only change from an x86 perspective is
the additional checks:

  !start || !end


> Signed-off-by: Wei Chen <wei.chen@arm.com>
> ---
>  xen/arch/x86/numa.c    | 18 ++++++++++++++++++
>  xen/arch/x86/srat.c    |  8 +++-----
>  xen/include/xen/numa.h |  4 ++++
>  3 files changed, 25 insertions(+), 5 deletions(-)
> 
> diff --git a/xen/arch/x86/numa.c b/xen/arch/x86/numa.c
> index 6908738305..8b43be4aa7 100644
> --- a/xen/arch/x86/numa.c
> +++ b/xen/arch/x86/numa.c
> @@ -128,6 +128,24 @@ unsigned int __init arch_get_dma_bitsize(void)
>                   + PAGE_SHIFT, 32);
>  }
>  
> +uint32_t __init arch_meminfo_get_nr_bank(void)
> +{
> +	return e820.nr_map;
> +}
> +
> +int __init arch_meminfo_get_ram_bank_range(int bank,
> +	unsigned long long *start, unsigned long long *end)
> +{
> +	if (e820.map[bank].type != E820_RAM || !start || !end) {
> +		return -1;
> +	}
> +
> +	*start = e820.map[bank].addr;
> +	*end = e820.map[bank].addr + e820.map[bank].size;
> +
> +	return 0;
> +}
> +
>  static void dump_numa(unsigned char key)
>  {
>      s_time_t now = NOW();
> diff --git a/xen/arch/x86/srat.c b/xen/arch/x86/srat.c
> index 6d68b8a614..2298353846 100644
> --- a/xen/arch/x86/srat.c
> +++ b/xen/arch/x86/srat.c
> @@ -316,18 +316,16 @@ acpi_numa_memory_affinity_init(const struct acpi_srat_mem_affinity *ma)
>  static int __init nodes_cover_memory(void)
>  {
>  	int i;
> +	uint32_t nr_banks = arch_meminfo_get_nr_bank();
>  
> -	for (i = 0; i < e820.nr_map; i++) {
> +	for (i = 0; i < nr_banks; i++) {
>  		int j, found;
>  		unsigned long long start, end;
>  
> -		if (e820.map[i].type != E820_RAM) {
> +		if (arch_meminfo_get_ram_bank_range(i, &start, &end)) {
>  			continue;
>  		}
>  
> -		start = e820.map[i].addr;
> -		end = e820.map[i].addr + e820.map[i].size;
> -
>  		do {
>  			found = 0;
>  			for_each_node_mask(j, memory_nodes_parsed)
> diff --git a/xen/include/xen/numa.h b/xen/include/xen/numa.h
> index 0475823b13..6d18059bcd 100644
> --- a/xen/include/xen/numa.h
> +++ b/xen/include/xen/numa.h
> @@ -89,6 +89,10 @@ static inline void clear_node_cpumask(int cpu)
>  	cpumask_clear_cpu(cpu, &node_to_cpumask[cpu_to_node(cpu)]);
>  }
>  
> +extern uint32_t arch_meminfo_get_nr_bank(void);
> +extern int arch_meminfo_get_ram_bank_range(int bank,
> +    unsigned long long *start, unsigned long long *end);
> +
>  #endif /* CONFIG_NUMA */
>  
>  #endif /* _XEN_NUMA_H */
> -- 
> 2.25.1
>