linux-kernel - Re: [PATCH 0/2 v3] kdump,vmcoreinfo: Export the value of sme mask to vmcoreinfo

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Message-ID: <20181217115438.GB12165@zn.tnic>
Date:   Mon, 17 Dec 2018 12:54:38 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Lianbo Jiang <lijiang@...hat.com>
Cc:     linux-kernel@...r.kernel.org, kexec@...ts.infradead.org,
        tglx@...utronix.de, mingo@...hat.com, x86@...nel.org,
        akpm@...ux-foundation.org, bhe@...hat.com, dyoung@...hat.com,
        linux-doc@...r.kernel.org
Subject: Re: [PATCH 0/2 v3] kdump,vmcoreinfo: Export the value of sme mask to
 vmcoreinfo

On Sun, Dec 16, 2018 at 09:16:15PM +0800, Lianbo Jiang wrote:
> This patchset did two things:
> a. add a new document for vmcoreinfo
> 
> This document lists some variables that export to vmcoreinfo, and briefly
> describles what these variables indicate. It should be instructive for
> many people who do not know the vmcoreinfo, and it would normalize the
> exported variable as a standard ABI between kernel and use-space.
> 
> b. export the value of sme mask to vmcoreinfo
> 
> For AMD machine with SME feature, makedumpfile tools need to know whether
> the crash kernel was encrypted or not. If SME is enabled in the first
> kernel, the crash kernel's page table(pgd/pud/pmd/pte) contains the
> memory encryption mask, so need to remove the sme mask to obtain the true
> physical address.
> 
> Changes since v1:
> 1. No need to export a kernel-internal mask to userspace, so copy the
> value of sme_me_mask to a local variable 'sme_mask' and write the value
> of sme_mask to vmcoreinfo.
> 2. Add comment for the code.
> 3. Improve the patch log.
> 4. Add the vmcoreinfo documentation.
> 
> Changes since v2:
> 1. Improve the vmcoreinfo document, add more descripts for these
> variables exported.
> 2. Fix spelling errors in the document.

Yes, it is starting to look better.

The last thing that's missing is a checkpatch.pl check which verifies
whether a new VMCOREINFO export is not being documented and warn if so.
But you can do that later.

Thx.

-- 
Regards/Gruss,
    Boris.

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