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From:   Thomas Gleixner <tglx@linutronix.de>
To:     Hou Wenlong <houwenlong.hwl@antgroup.com>,
        Dave Hansen <dave.hansen@intel.com>
Cc:     linux-kernel@vger.kernel.org,
        Lai Jiangshan <jiangshan.ljs@antgroup.com>,
        Alexey Makhalov <amakhalov@vmware.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andy Lutomirski <luto@kernel.org>,
        Anshuman Khandual <anshuman.khandual@arm.com>,
        Borislav Petkov <bp@alien8.de>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Brian Gerst <brgerst@gmail.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        David Woodhouse <dwmw@amazon.co.uk>,
        "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
        Josh Poimboeuf <jpoimboe@kernel.org>,
        Juergen Gross <jgross@suse.com>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        "Mike Rapoport (IBM)" <rppt@kernel.org>,
        Pasha Tatashin <pasha.tatashin@soleen.com>,
        Peter Zijlstra <peterz@infradead.org>,
        "Srivatsa S. Bhat (VMware)" <srivatsa@csail.mit.edu>,
        Suren Baghdasaryan <surenb@google.com>,
        Usama Arif <usama.arif@bytedance.com>,
        virtualization@lists.linux-foundation.org,
        VMware PV-Drivers Reviewers <pv-drivers@vmware.com>,
        x86@kernel.org, xen-devel@lists.xenproject.org
Subject: Re: [PATCH RFC 0/4] x86/fixmap: Unify FIXADDR_TOP
In-Reply-To: <20230608093303.GA16983@k08j02272.eu95sqa>
References: <cover.1684137557.git.houwenlong.hwl@antgroup.com>
 <1f633e99-d294-6932-31e9-0eb158d030ea@intel.com>
 <20230608093303.GA16983@k08j02272.eu95sqa>
Date:   Sat, 10 Jun 2023 20:37:18 +0200
Message-ID: <87y1kr88pt.ffs@tglx>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

On Thu, Jun 08 2023 at 17:33, Hou Wenlong wrote:
> On Wed, Jun 07, 2023 at 08:49:15PM +0800, Dave Hansen wrote:
>> What problems does this patch set solve?  How might that solution be
>> visible to end users?  Why is this problem important to you?
>
> We want to build the kernel as PIE and allow the kernel image area,
> including the fixmap area, to be placed at any virtual address.

You are still failing to tell us why you want that and which problem
this solves. Just that fact that you want to something is not an
argument.

> We have also implemented a PV Linux guest based on PIE, which can be
> used in software virtualization similar to Lguest. PIE makes the guest
> kernel share the host kernel space similar to a normal userspace
> process.  Additionally, we are considering whether it is possible to
> use PIE and PVOPS to implement a user-mode kernel.

That solves what?

Thanks,

        tglx