Re: [Xen-devel] [PATCH 2/4] EFI/early: add /mapbs to map EfiBootServices{Code, Data}

[Roy Franz <roy.franz@xxxxxxxxxx>]

On Wed, Jun 10, 2015 at 11:34 PM, Jan Beulich <JBeulich@xxxxxxxx> wrote:
>>>> On 10.06.15 at 19:22, <roy.franz@xxxxxxxxxx> wrote:
>> On Wed, Jun 10, 2015 at 2:37 AM, Jan Beulich <JBeulich@xxxxxxxx> wrote:
>>>>>> On 10.06.15 at 11:26, <ian.campbell@xxxxxxxxxx> wrote:
>>>> On Wed, 2015-06-10 at 10:15 +0100, Jan Beulich wrote:
>>>>> >>> On 10.06.15 at 10:56, <ian.campbell@xxxxxxxxxx> wrote:
>>>>> > On Tue, 2015-06-09 at 14:53 +0100, Jan Beulich wrote:
>>>>> >> From: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
>>>>> >>
>>>>> >> To help on certain platforms to run.
>>>>> >>
>>>>> >> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
>>>>> >> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>>>>> >
>>>>> > To be effective (or at least consistent) on ARM, would we also want to
>>>>> > change its efi_process_memory_map_bootinfo:
>>>>> >         if ( desc_ptr->Type == EfiConventionalMemory
>>>>> >              || desc_ptr->Type == EfiBootServicesCode
>>>>> >              || desc_ptr->Type == EfiBootServicesData )
>>>>> > to include a check on map_bs?
>>>>>
>>>>> I'm not convinced, but I also don't know the history of why boot
>>>>> services areas are being included here in the first place - Roy?
>>>>> I.e. if the checks weren't there already, I'd agree that an addition
>>>>> similar to the other ones would be needed here, but with the x86
>>>>> side getting relaxed I don't see why you would want to tighten the
>>>>> ARM side at the same time.
>>
>> The boot services code/data is "memory available for general use", just
>> like EfiConventionalMemory after ExitBootServices() is called.  Since the
>> memory
>> map being created here is going to be used after ExitBootServices() is
>> called,
>> I think this matches the UEFI specification. This matches x86 behavior
>> before
>> the patch (modulo some address range checks used to set cfg.addr.)
>
> Ouch - looks like I read this the wrong way round, and Ian was right
> in wanting a map_bs check added here:
>
> EFI/ARM: don't treat EfiBootServices{Code,Data} as normal RAM under /mapbs
>
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>
> --- a/xen/arch/arm/efi/efi-boot.h
> +++ b/xen/arch/arm/efi/efi-boot.h
> @@ -131,9 +131,10 @@ static EFI_STATUS __init efi_process_mem
>
>      for ( Index = 0; Index < (mmap_size / desc_size); Index++ )
>      {
> -        if ( desc_ptr->Type == EfiConventionalMemory
> -             || desc_ptr->Type == EfiBootServicesCode
> -             || desc_ptr->Type == EfiBootServicesData )
> +        if ( desc_ptr->Type == EfiConventionalMemory ||
> +             (!map_bs &&
> +              (desc_ptr->Type == EfiBootServicesCode ||
> +               desc_ptr->Type == EfiBootServicesData)) )
>          {
>              if ( i >= NR_MEM_BANKS )
>              {
>
> Jan
>

Reviewed-by: Roy Franz <roy.franz@xxxxxxxxxx>

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