Re: how do I use RamDiskDxe?

[Andrew Fish <afish@apple.com>]

> On Feb 12, 2018, at 1:07 PM, Rick Warner <rick@microway.com> wrote:
> 
> Hi All,
> 
> I'm trying to develop a tool for automated BIOS flashing from the EFI shell using IPMI serial over lan to drive it.  To accomplish this, my plan is to use a network booted EFI shell with a tftp client and a ramdisk to download the flash tools and ROM into as a workspace and then run the flash commands from that ram disk.
> 
> I've been able to successfully build and boot an efi shell from the edk 2 sources including the tftp client.  I've also been able to separately build the RamDiskDxe driver from the MdeModulePkg. Loading the RamDiskDxe.efi driver file results in a successful message, but I do not get any usable ram disk made available to me?
> 
> How do I get a usable drive letter/name (ie blk0: or any other name) from the RamDiskDxe driver?
> 

Looks like when you load the RamDiskDxe it registers gEfiRamDiskProtocolGuid https://github.com/tianocore/edk2/blob/master/MdePkg/Include/Protocol/RamDisk.h <https://github.com/tianocore/edk2/blob/master/MdePkg/Include/Protocol/RamDisk.h> which notes this API was added in UEFI 2.6 so you can read up on it in that version of the EFI Spec. 

>From a quick site read of the code it looks like the driver just produces a Protocol that lets you create a RAM disk and VRF (Setup Pages) that let you configure one. Seems like you still need to call it and give the raw disk image. 

> Once I've done that, will it be possible to include the RamDiskDxe driver as part of the network bootable efi shell image?  I assume I'll need to modify the .dsc file for the ShellPkg to include the MdeModulePkg pieces.
> 
> If anyone has any other suggestions for this, I'm open to ideas. The only way I've been successful in network booting EFI shell is using just that file directly.  I tried creating a dos filesystem image with the efi shell file in it just like would work with a USB key, but that would not boot over the network stack. If there is some way of creating a network bootable EFI shell filesystem image (similar to how Linux can network boot a separate vmlinuz kernel and initrd image)?
> 
> Are there any docs that I've missed (I've tried looking in the user docs and on the wiki) regarding setting up RamDiskDxe?
> 

Traditionally network booting has involved loading a single file over the network (like an OS Loader) and that file uses the UEFI networking stack to download (TFTP read) more images (like the Kernel) from a location implied by the location used to download the single file (OS Loader).

Thanks,

Andrew Fish  

> Thanks!
> Rick Warner
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