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From: "Matthew Lazarowitz (mlazarow)" <mlazarow@cisco.com>
To: "edk2-devel@lists.01.org" <edk2-devel@lists.01.org>
Subject: Handling multiple paths to the same EFI system partition?
Date: Fri, 2 Dec 2016 21:26:16 +0000	[thread overview]
Message-ID: <D46726C1.1B022%mlazarow@cisco.com> (raw)

I am trying to deal with a requirement that our firmware show 2 boot options when there are multiple paths to a GPT disk with an EFI system partition. The specific ask is for both paths to be shown in the boot order. However, the short form device path means these would be duplicate entries which would cause more issues.
Fibre Channel and iSCSI connected drives are the two cases I need to cope with.
The UEFI specification seems to sound as if I could violate the spec if I do something like this.
In section 5.3.3 of the 2.6 spec, there is a statement "If GPT-cognizant software encounters two disks or partitions with identical GUIDs, results will be indeterminate." Other than section 10.12.2 specifying a iScsiMpioCapability field for network boots, I do not see guidance on how to handle a multi path scenario to a single disk.

The best I can think of right now is to modify the OS created option with the full path of of each path if 2 or more paths to a specific disk are detected. However, this would seem to be a potential source of conflict between the OS and the firmware since firmware would be modifying data the OS may require in a specific format.

Is there anything out there to provide some guidance on either rejecting this request and blatantly violating the spec, or being able to successfully fulfill it?

Thanks
Mathew



                 reply	other threads:[~2016-12-02 21:26 UTC|newest]

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