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References: <20201223062412.343-1-zhenzhong.duan@gmail.com> <20201230070244.GA22022@zn.tnic>
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From:   Zhenzhong Duan <zhenzhong.duan@gmail.com>
Date:   Mon, 4 Jan 2021 13:43:53 +0800
Message-ID: <CAFH1YnMDqmOayVU8gahmndCgZtVic2JBqfoH5VQCcyya0UfCLQ@mail.gmail.com>
Subject: Re: [PATCH] x86/iommu: Fix two minimal issues in check_iommu_entries()
To:     Borislav Petkov <bp@alien8.de>
Cc:     linux-kernel <linux-kernel@vger.kernel.org>, zhongjiang@huawei.com,
        joe@perches.com, konrad.wilk@oracle.com,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        iommu@lists.linux-foundation.org,
        David Woodhouse <dwmw2@infradead.org>,
        Lu Baolu <baolu.lu@linux.intel.com>,
        Joerg Roedel <joro@8bytes.org>, will@kernel.org
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On Wed, Dec 30, 2020 at 3:02 PM Borislav Petkov <bp@alien8.de> wrote:
>
> On Wed, Dec 23, 2020 at 02:24:12PM +0800, Zhenzhong Duan wrote:
> > check_iommu_entries() checks for cyclic dependency in iommu entries
> > and fixes the cyclic dependency by setting x->depend to NULL. But
> > this repairing isn't correct if q is in front of p, there will be
> > "EXECUTION ORDER INVALID!" report following. Fix it by NULLing
> > whichever in the front.
>
> When does "q is in front of p" happen? How does it happen?

Sorry, just realized it never happen.
>
> > The second issue is about the report of exectuion order reverse,
> > the order is reversed incorrectly in the report, fix it.
>
> I have no clue what that means.

I mean if p depends on q, then q->detect should be called before p->detect.
The message generated by printk() is wrong.

Regards
Zhenzhong