Re: [PATCH v2 06/10] mini-os: add memory map service functions

[Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>]

Juergen Gross, le lun. 20 déc. 2021 17:07:12 +0100, a ecrit:
> Add two functions for adding reserved areas to the memory map and
> for removing them again.
> 
> Those will be needed for proper grant table/mapping support in PVH
> mode.
> 
> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>

Reviewed-by: Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>

> ---
> V2:
> - fix e820_put_reserved_pfns() (Samuel Thibault)
> ---
>  e820.c         | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  include/e820.h |  4 ++++
>  2 files changed, 54 insertions(+)
> 
> diff --git a/e820.c b/e820.c
> index 659f71c..25e2f9d 100644
> --- a/e820.c
> +++ b/e820.c
> @@ -283,6 +283,56 @@ void arch_print_memmap(void)
>          printk("%012lx-%012lx: %s\n", from, to, type);
>      }
>  }
> +
> +unsigned long e820_get_reserved_pfns(int pages)
> +{
> +    int i;
> +    unsigned long last = 0, needed = (long)pages << PAGE_SHIFT;
> +
> +    for ( i = 0; i < e820_entries && e820_map[i].addr < last + needed; i++ )
> +        last = e820_map[i].addr + e820_map[i].size;
> +
> +    if ( i == 0 || e820_map[i - 1].type != E820_RESERVED )
> +        e820_insert_entry_at(i, last, needed, E820_RESERVED);
> +    else
> +        e820_map[i - 1].size += needed;
> +
> +    return last >> PAGE_SHIFT;
> +}
> +
> +void e820_put_reserved_pfns(unsigned long start_pfn, int pages)
> +{
> +    int i;
> +    unsigned long addr = start_pfn << PAGE_SHIFT;
> +    unsigned long size = (long)pages << PAGE_SHIFT;
> +
> +    for ( i = 0;
> +          i < e820_entries && addr >= e820_map[i].addr + e820_map[i].size;
> +          i++ );
> +
> +    BUG_ON(i == e820_entries || e820_map[i].type != E820_RESERVED ||
> +           addr + size > e820_map[i].addr + e820_map[i].size);
> +
> +    if ( addr == e820_map[i].addr )
> +    {
> +        e820_map[i].addr += size;
> +        e820_map[i].size -= size;
> +        if ( e820_map[i].size == 0 )
> +            e820_remove_entry(i);
> +        return;
> +    }
> +
> +    if ( addr + size == e820_map[i].addr + e820_map[i].size )
> +    {
> +        e820_map[i].size -= size;
> +        return;
> +    }
> +
> +    e820_insert_entry_at(i + 1, addr + size,
> +                         e820_map[i].addr + e820_map[i].size - addr - size,
> +                         E820_RESERVED);
> +    e820_map[i].size = addr - e820_map[i].addr;
> +}
>  #endif
>  
>  unsigned long e820_get_maxpfn(unsigned long pages)
> diff --git a/include/e820.h b/include/e820.h
> index 8d4d371..aaf2f2c 100644
> --- a/include/e820.h
> +++ b/include/e820.h
> @@ -51,5 +51,9 @@ extern unsigned e820_entries;
>  
>  unsigned long e820_get_maxpfn(unsigned long pages);
>  unsigned long e820_get_max_contig_pages(unsigned long pfn, unsigned long 
> pages);
> +#ifndef CONFIG_E820_TRIVIAL
> +unsigned long e820_get_reserved_pfns(int pages);
> +void e820_put_reserved_pfns(unsigned long start_pfn, int pages);
> +#endif
>  
>  #endif /*__E820_HEADER*/
> -- 
> 2.26.2
> 

-- 
Samuel
<A> sauf que le firewall bloque tout sauf internet
 -+- ben ouais, il bloque ipx/spx ! -+-