access efi variables

I need to obtain a uefi variable so I went looking at the API in include/linux/efi.h. I found the following definition:

/*
* The maximum size of VariableName + Data = 1024
* Therefore, it's reasonable to save that much
* space in each part of the structure,
* and we use a page for reading/writing. */

struct efi_variable {
     efi_char16_t  VariableName[1024/sizeof(efi_char16_t)];
     efi_guid_t    VendorGuid;
     unsigned long DataSize;
     __u8          Data[1024];
     efi_status_t  Status;
     __u32         Attributes;
} __attribute__((packed));

But according to the specs the variable I need to obtain is 2k bytes.

Should I expect trouble :-p

Regards,
Arend

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I need to obtain a uefi variable so I went looking at the API in include/linux/efi.h. I found the following definition:

But according to the specs the variable I need to obtain is 2k bytes. Should I expect trouble :-p

Quoted 6 lines · Arend van Spriel

I need to obtain a uefi variable so I went looking at the API in include/linux/efi.h. I found the following definition:

But according to the specs the variable I need to obtain is 2k bytes. Should I expect trouble :-p

efivarfs doesn't have those limitations.

Quoted 9 lines · H. Peter Anvin

Quoted 6 lines · Arend van Spriel

I need to obtain a uefi variable so I went looking at the API in include/linux/efi.h. I found the following definition:

But according to the specs the variable I need to obtain is 2k bytes. Should I expect trouble :-p

efivarfs doesn't have those limitations.

Thanks, Peter

Looking into efivarfs it seems to use the functions that I looked at in efi.h so I guess I am misinterpreting the 1024 bytes limitation in the comment (either that or you are mistaken ;-) ). I need to access the variable from within a device driver so using efivarfs does not feel like the way to go here.