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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 D2125C433B4 for ; Tue, 20 Apr 2021 09:47:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 96E0D613AE for ; Tue, 20 Apr 2021 09:47:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231382AbhDTJru (ORCPT ); Tue, 20 Apr 2021 05:47:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45330 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229937AbhDTJrt (ORCPT ); Tue, 20 Apr 2021 05:47:49 -0400 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2FC23C06174A; Tue, 20 Apr 2021 02:47:17 -0700 (PDT) Received: from zn.tnic (p200300ec2f0e52003145dfcc247b909a.dip0.t-ipconnect.de [IPv6:2003:ec:2f0e:5200:3145:dfcc:247b:909a]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 211971EC0103; Tue, 20 Apr 2021 11:47:16 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1618912036; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=RA9OKky7ZNF04E7Df2ew/ZUVIaSCqLlCAKVZUi2ytbI=; b=Z5IPqA3Dj6rCvU1FW2fGNMookHdlY3WCXL8wnlBGmBbAxD8xvtvmKnj12I48HYvUriAZsC G89fIO73z1hh67u8EpWSsatS5UBQw5Jtz0yO0eAqVnk16vi6/F5PanO7+uMQtQZFkfrWjH Xl7nUdtgHXMWRtFUk6la5ReMnUTPZJY= Date: Tue, 20 Apr 2021 11:47:13 +0200 From: Borislav Petkov To: Brijesh Singh Cc: linux-kernel@vger.kernel.org, x86@kernel.org, kvm@vger.kernel.org, linux-crypto@vger.kernel.org, ak@linux.intel.com, herbert@gondor.apana.org.au, Thomas Gleixner , Ingo Molnar , Joerg Roedel , "H. Peter Anvin" , Tony Luck , Dave Hansen , "Peter Zijlstra (Intel)" , Paolo Bonzini , Tom Lendacky , David Rientjes , Sean Christopherson , Vlastimil Babka Subject: Re: [RFC Part2 PATCH 04/30] x86/mm: split the physmap when adding the page in RMP table Message-ID: <20210420094713.GD5029@zn.tnic> References: <20210324170436.31843-1-brijesh.singh@amd.com> <20210324170436.31843-5-brijesh.singh@amd.com> <20210419123226.GC9093@zn.tnic> <20210419165214.GF9093@zn.tnic> <30bff969-e8cf-a991-7660-054ea136855a@amd.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <30bff969-e8cf-a991-7660-054ea136855a@amd.com> Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org On Mon, Apr 19, 2021 at 12:46:53PM -0500, Brijesh Singh wrote: > - KVM calls  alloc_page() to allocate a VMSA page. The allocator returns > 0xffffc80000200000 (PFN 0x200, page-level=2M). The VMSA page is private > page so KVM will call RMPUPDATE to add the page as a private page in the > RMP table. While adding the RMP entry the KVM will use the page level=4K. Right, and *here* we split the 2M page on the *host* so that there's no discrepancy between the host pagetable and the RMP. I guess your patch does exactly that. :) And AFAIR, set_memory.c doesn't have the functionality to coalesce 4K pages back into the corresponding 2M page. Which means, the RMP table is in sync, more or less. Thx and thanks for elaborating. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette