Re: [RFC v2 0/2] Early use of boot service memory

From: H. Peter Anvin
Date: Thu Nov 21 2013 - 18:19:43 EST


On 11/21/2013 03:07 PM, Matthew Garrett wrote:
> On Thu, Nov 21, 2013 at 02:01:24PM -0700, Jerry Hoemann wrote:
>>
>> Some platform have firmware that violates the UEFI spec and access boot
>> service code or data segments after the system has called ExitBootServices().
>> The call to efi_reserve_boot_services in setup_arch is a workaround to
>> avoid using boot service memory until after the kernel has done
>> SetVirtualAddressMap. However, this reservation fragments memory
>> which can cause large allocations early in boot (e.g. crash kernel)
>> to fail.
>
> This is a problem we have to solve, but I don't think this is the right
> way to solve it. Why do we not just reattempt to perform the allocation
> immediately after we've freed the boot services regions?
>

Wouldn't the memory map already have gotten scrambled all to hell by then?

-hpa

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