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From:   Dan Williams <dan.j.williams@intel.com>
Date:   Thu, 8 Jul 2021 19:04:40 -0700
Message-ID: <CAPcyv4jPqv43Hh836bpDUwMYAsPHDrjUhXoJ0Ufgjbqc3h2eyQ@mail.gmail.com>
Subject: Re: [PATCH v2 5/6] platform/x86: intel_tdx_attest: Add TDX Guest
 attestation interface driver
To:     Andi Kleen <ak@linux.intel.com>
Cc:     "Kuppuswamy, Sathyanarayanan" 
        <sathyanarayanan.kuppuswamy@linux.intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Andy Lutomirski <luto@kernel.org>,
        Hans de Goede <hdegoede@redhat.com>,
        Mark Gross <mgross@linux.intel.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Peter H Anvin <hpa@zytor.com>,
        Dave Hansen <dave.hansen@intel.com>,
        Tony Luck <tony.luck@intel.com>,
        Kirill Shutemov <kirill.shutemov@linux.intel.com>,
        Sean Christopherson <seanjc@google.com>,
        Kuppuswamy Sathyanarayanan <knsathya@kernel.org>,
        X86 ML <x86@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        platform-driver-x86@vger.kernel.org, bpf@vger.kernel.org,
        Netdev <netdev@vger.kernel.org>
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On Thu, Jul 8, 2021 at 6:44 PM Andi Kleen <ak@linux.intel.com> wrote:
>
>
> > One allocation for the life of the driver that can have its direct map
> > permissions changed rather than an allocation per-file descriptor and
> > fragmenting the direct map.
>
> The vmap() approach discussed in another mail will solve that.

Ok, not my first choice for how to handle the allocation side of that,
but not broken.

I'd still feel better if there was an actual data structure assigned
to file->private_data rather than using that 'void *' pointer directly
and casting throughout the driver.