Re: [PATCH v3 4/4] KVM: selftests: aarch64: Test VGIC ITS tables save/restore

[Marc Zyngier <maz@kernel.org>]

[Adding Eric to the list, since he worked a lot on the save/restore code]

On Wed, 06 Nov 2024 08:30:35 +0000,
Jing Zhang <jingzhangos@google.com> wrote:
> 
> Add a selftest to verify the correctness of the VGIC ITS mappings after
> the save/restore operations (KVM_DEV_ARM_ITS_SAVE_TABLES /
> KVM_DEV_ARM_ITS_RESTORE_TABLES).

What are you checking? The saved data? The restored data?

> Also calculate the time spending on save/restore operations.

Is that really relevant? I don't think performance matters at this
stage, if we can't even have reliable data.

> This test uses some corner cases to capture the save/restore bugs. It

Which corner cases?

> will be used to verify the future incoming changes for the VGIC ITS
> tables save/restore.
> 
> To capture the "Invalid argument (-22)" error, run the test without any
> option. To capture the wrong/lost mappings, run the test with '-s'
> option.
> Since the VGIC ITS save/restore bug is caused by orphaned DTE/ITE
> entries, if we run the test with '-c' option whih clears the tables
> before the save operation, the test will complete successfully.

I'm sorry, but this description is meaningless, as you need to know
what is the bug that has been fixed.

Also, how is someone supposed to run this thing? Without options? With
options? With any combination of options?

From what I understand, the various options are designed to help
debugging a broken vgic implementation. So please document what the
options do rather than an bug that is supposed to be already fixed.

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.