kernel: add support for MegaRAID SAS

[etungsten]

Issue number:
N/A

Description of changes:

    kernel-5.10: add kernel config to enable support for RAID
    
    This adds kernel configs to enable support for MegaRAID SAS RAID
    controllers.

Testing done:
I was able to boot Bottlerocket from RAID0 on a baremetal server.

Terms of contribution:

By submitting this pull request, I agree that this contribution is dual-licensed under the terms of both the Apache License, version 2.0, and the MIT license.

[bcressey]

I'd tend to also want to change 5.4 as well, even though 5.4 is on its way out, just to minimize the delta.

Can you add a diff of the final config for x86_64 and aarch64? Just to give a complete picture of what's changed.

[etungsten]

Can you add a diff of the final config for x86_64 and aarch64? Just to give a complete picture of what's changed.

$ git diff --no-index aarch64_without aarch64_with_new_conf
diff --git a/aarch64_without b/aarch64_with_new_conf
index fa8ddb4a..49173034 100644
--- a/aarch64_without
+++ b/aarch64_with_new_conf
@@ -2251,7 +2251,7 @@ CONFIG_SCSI_MVUMI=m
 # CONFIG_SCSI_ESAS2R is not set
 # CONFIG_MEGARAID_NEWGEN is not set
 # CONFIG_MEGARAID_LEGACY is not set
-CONFIG_MEGARAID_SAS=m
+CONFIG_MEGARAID_SAS=y
 CONFIG_SCSI_MPT3SAS=m
 CONFIG_SCSI_MPT2SAS_MAX_SGE=128
 CONFIG_SCSI_MPT3SAS_MAX_SGE=128


$ git diff --no-index x86_without x86_with_new_conf
diff --git a/x86_without b/x86_with_new_conf
index fa7b6b1b..b39e1785 100644
--- a/x86_without
+++ b/x86_with_new_conf
@@ -2081,7 +2081,7 @@ CONFIG_ISCSI_BOOT_SYSFS=m
 # CONFIG_SCSI_ESAS2R is not set
 # CONFIG_MEGARAID_NEWGEN is not set
 # CONFIG_MEGARAID_LEGACY is not set
-# CONFIG_MEGARAID_SAS is not set
+CONFIG_MEGARAID_SAS=y
 CONFIG_SCSI_MPT3SAS=m
 CONFIG_SCSI_MPT2SAS_MAX_SGE=128
 CONFIG_SCSI_MPT3SAS_MAX_SGE=128

Interesting how CONFIG_SCSI=y isn't part of the diff. I guess it's =y by default?

[etungsten]

Push above removes CONFIG_SCSI=y since it's already =y by default in the kernel config.

[zmrow]

nit: Could we change the commit message to say something like Add Megaraid SAS modules? There are other RAID controllers and modules so saying we added support for RAID isn't pedantically accurate. :)

[foersleo]

With enabling more hardware through including drivers like this one we might want to put all of these into a separate file like config-bottlerocket-hardware that lives co-located to the current config and then have that additional config added to the merge-config step in the spec file.

That would enable us in the future to easily make this configurable for potential separate variants with and without that hardware support (similar to the conditional addition of config-microcode on x86).

But we can also move these things around at a later point in a separate PR to not keep this one open for too long. If that makes sense to folks I can take care of that separate PR. Let me know what you think.

[zmrow]

But we can also move these things around at a later point in a separate PR to not keep this one open for too long. If that makes sense to folks I can take care of that separate PR. Let me know what you think.

Sounds like a perfect idea!