From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id CE771C77B7A for ; Sat, 10 Jun 2023 18:37:51 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.546583.853555 (Exim 4.92) (envelope-from ) id 1q83Sn-00023e-D6; Sat, 10 Jun 2023 18:37:25 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 546583.853555; Sat, 10 Jun 2023 18:37:25 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1q83Sn-00023X-9y; Sat, 10 Jun 2023 18:37:25 +0000 Received: by outflank-mailman (input) for mailman id 546583; Sat, 10 Jun 2023 18:37:24 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1q83Sm-00023O-0e for xen-devel@lists.xenproject.org; Sat, 10 Jun 2023 18:37:24 +0000 Received: from galois.linutronix.de (galois.linutronix.de [193.142.43.55]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id d509df91-07bd-11ee-8611-37d641c3527e; Sat, 10 Jun 2023 20:37:20 +0200 (CEST) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: d509df91-07bd-11ee-8611-37d641c3527e From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1686422239; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=N7WjIOv23GkoARnLqItYOF1clW2sOuIKmsM3GXO5Xpg=; b=YCL2WcdNIO0s3K7UdC06CzI1RNfJDkJe7HEF4v5qdxN8RrO3sAaq8xX62f444BjcyFpI8P dvsdlA/V4XzVxCD0n8uz5bQYGAgwsvDqWJ8rNLJDHj8k8iQwRRGGrRVWI0YDNiCXV818Ht GruRrk0/QYF97Rhj5uVOQfTLlEitAY6Rs+rjvdpG7tob605G0Kvr/fVugOur6hufdowyf4 Ax62Ig7bPHia5hggr2KaWqBtF0qOBpkmhrvFk02kMofvAv6EhF1xBRXZSKW4DrYvu52o5K D3W+c9UFX4owv7UrRYBLocORMja3sAJWQxRmRkowpokWoNy9GULDK6NIlr681w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1686422239; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=N7WjIOv23GkoARnLqItYOF1clW2sOuIKmsM3GXO5Xpg=; b=S7g5PoBvQUVBSn498XvK9vJHSGy+5G3W0vpFYxeTng6YEJJyB4cAG/EGEkYC18Ui7RMwlG 7oqYWL4zDKXltfCg== To: Hou Wenlong , Dave Hansen Cc: linux-kernel@vger.kernel.org, Lai Jiangshan , Alexey Makhalov , Andrew Morton , Andy Lutomirski , Anshuman Khandual , Borislav Petkov , Boris Ostrovsky , Brian Gerst , Dave Hansen , David Woodhouse , "H. Peter Anvin" , Ingo Molnar , Josh Poimboeuf , Juergen Gross , "Kirill A. Shutemov" , "Mike Rapoport (IBM)" , Pasha Tatashin , Peter Zijlstra , "Srivatsa S. Bhat (VMware)" , Suren Baghdasaryan , Usama Arif , virtualization@lists.linux-foundation.org, VMware PV-Drivers Reviewers , 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: <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 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