Re: Query on Variable Services

[Andrew Fish <afish@apple.com>]

Galla,

The PCD value usually get set as the result of the build. 

EFI_MEMORY_RUNTIME attribute is used to request a virtual mapping from the OS. When the variable services are called from the OS the run in a virtual address space provided by the OS. Thus trying to access 0xFFE00000 would page fault. 

You can run the memmap command from the EFI Shell and see if bit 63 is set. If your SPI controller is a memory mapped hardware device you may also need to map the SPI register via EFI_MEMORY_RUNTIME. The SPI driver also needs to deal with the SetVirtualAddress map event to convert its pointers over to the new OS provided virtual memory space.

Thanks,

Andrew Fish


> On Jan 17, 2019, at 9:23 AM, galla rao <galla.rao80@gmail.com> wrote:
> 
> Hi All,
> 
> Have a question for Variable services
> 
> Given PCD's are initialized
> 
> gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableBase   | 0xFFE00000
> 
>  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwWorkingBase |
> 0xFFE3E000
> 
>  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageFtwSpareBase   |
> 0xFFE40000
> 
> Do i need to make these regions as *EFI_MEMORY_RUNTIME *through
> *gDS->SetMemorySpaceAttributes*
> 
> SPI Flash writes within BIOS works good!
> 
> *when trying to change BootOrder from efibootmgr, the failure is seen*
> 
> It would be useful if someone has faced this issue earlier and can respond
> kindly.
> 
> Best Regards
> Galla
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