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 X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 50F48C433F4 for ; Sat, 25 Aug 2018 04:47:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0026B208E8 for ; Sat, 25 Aug 2018 04:47:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0026B208E8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727077AbeHYIZR (ORCPT ); Sat, 25 Aug 2018 04:25:17 -0400 Received: from mx2.suse.de ([195.135.220.15]:45414 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726159AbeHYIZQ (ORCPT ); Sat, 25 Aug 2018 04:25:16 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 1DEC9AEA7; Sat, 25 Aug 2018 04:47:38 +0000 (UTC) Date: Sat, 25 Aug 2018 06:47:49 +0200 From: Borislav Petkov To: Brijesh Singh Cc: Paolo Bonzini , Sean Christopherson , "x86@kernel.org" , "linux-kernel@vger.kernel.org" , "kvm@vger.kernel.org" , "Lendacky, Thomas" , Thomas Gleixner Subject: Re: SEV guest regression in 4.18 Message-ID: <20180825044749.GA19545@nazgul.tnic> References: <92e2b80c-0dcc-94be-8d3a-5e11e5cf2370@amd.com> <20180822081417.GB4069@nazgul.tnic> <20180822150033.GA14200@linux.intel.com> <4d6ee892-a34f-28b3-18b7-1c663eb281c6@amd.com> <9635ebf0-7c99-6edf-1240-8dec28036a70@redhat.com> <20180823152907.GA1488@linux.intel.com> <60acb594-abe3-912f-9702-2f34961e575d@redhat.com> <25d2cf1f-11ee-ecba-73a9-15a9553a3d96@redhat.com> <47b8f9dc-fb55-f14d-cb88-343810ad5763@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <47b8f9dc-fb55-f14d-cb88-343810ad5763@amd.com> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 24, 2018 at 01:47:10PM -0500, Brijesh Singh wrote: > I am more inclined towards creating a new section with PMD aligned and > sized. This section will contains the decrypted data. In early > boot code we will update the mapping with C=0. If caller wants to create > a shared variable then it can do so with: > > static int foo __decrypted; Right, and keeping the SEV-ES's GHCB in mind, you could make that section extensible so that the GHCB's 4K page can land there too. Maybe something like a PMD-aligned range of 4K pages which are fully defined and which hypervisor and guest can share and can be used for all kinds of communication in the future... -- Regards/Gruss, Boris. SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) --