Re: [PATCH] x86/setup: call early_reserve_memory() earlier

[Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>]

On Tue, Sep 14, 2021 at 11:41:08AM +0200, Juergen Gross wrote:
> Commit a799c2bd29d19c565 ("x86/setup: Consolidate early memory
> reservations") introduced early_reserve_memory() to do all needed
> initial memblock_reserve() calls in one function. Unfortunately the
> call of early_reserve_memory() is done too late for Xen dom0, as in
> some cases a Xen hook called by e820__memory_setup() will need those
> memory reservations to have happened already.
> 
> Move the call of early_reserve_memory() to the beginning of
> setup_arch() in order to avoid such problems.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: a799c2bd29d19c565 ("x86/setup: Consolidate early memory reservations")
> Reported-by: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>

Thanks, it works!

Tested-by: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>

> ---
>  arch/x86/kernel/setup.c | 24 ++++++++++++------------
>  1 file changed, 12 insertions(+), 12 deletions(-)
> 
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index 79f164141116..f369c51ec580 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -757,6 +757,18 @@ dump_kernel_offset(struct notifier_block *self, unsigned 
> long v, void *p)
>  
>  void __init setup_arch(char **cmdline_p)
>  {
> +     /*
> +      * Do some memory reservations *before* memory is added to
> +      * memblock, so memblock allocations won't overwrite it.
> +      * Do it after early param, so we could get (unlikely) panic from
> +      * serial.
> +      *
> +      * After this point everything still needed from the boot loader or
> +      * firmware or kernel text should be early reserved or marked not
> +      * RAM in e820. All other memory is free game.
> +      */
> +     early_reserve_memory();
> +
>  #ifdef CONFIG_X86_32
>       memcpy(&boot_cpu_data, &new_cpu_data, sizeof(new_cpu_data));
>  
> @@ -876,18 +888,6 @@ void __init setup_arch(char **cmdline_p)
>  
>       parse_early_param();
>  
> -     /*
> -      * Do some memory reservations *before* memory is added to
> -      * memblock, so memblock allocations won't overwrite it.
> -      * Do it after early param, so we could get (unlikely) panic from
> -      * serial.
> -      *
> -      * After this point everything still needed from the boot loader or
> -      * firmware or kernel text should be early reserved or marked not
> -      * RAM in e820. All other memory is free game.
> -      */
> -     early_reserve_memory();
> -
>  #ifdef CONFIG_MEMORY_HOTPLUG
>       /*
>        * Memory used by the kernel cannot be hot-removed because Linux
> -- 
> 2.26.2
> 

-- 
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab

Attachment: signature.asc
Description: PGP signature