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From:   Dan Williams <dan.j.williams@intel.com>
Date:   Tue, 12 Oct 2021 15:00:01 -0700
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Subject: Re: [PATCH v5 12/16] PCI: Add pci_iomap_host_shared(), pci_iomap_host_shared_range()
To:     Andi Kleen <ak@linux.intel.com>
Cc:     "Michael S. Tsirkin" <mst@redhat.com>,
        Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@linux.intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
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        Andy Lutomirski <luto@kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Richard Henderson <rth@twiddle.net>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        James E J Bottomley <James.Bottomley@hansenpartnership.com>,
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        Tony Luck <tony.luck@intel.com>,
        Kirill Shutemov <kirill.shutemov@linux.intel.com>,
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On Tue, Oct 12, 2021 at 2:28 PM Andi Kleen <ak@linux.intel.com> wrote:
[..]
> >> But how do you debug the kernel then? Making early undebuggable seems
> >> just bad policy to me.
> > I am not proposing making the early undebuggable.
>
>
> That's the implication of moving the policy into initrd.
>
>
> If only initrd can authorize then it won't be possible to authorize
> before initrd, thus the early console won't work.

Again, the proposal is that the allow-list is limited to just enough
devices to startup and debug the initramfs and no more. Everything
else can be dynamic, and this allows for a powerful custom override
interface without needing to debate additional ABI like command line
overrides, and minimizes future changes to this kernel-internal
allow-list.