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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 931F7C04AB4 for ; Tue, 14 May 2019 17:05:31 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 48CEE2084A for ; Tue, 14 May 2019 17:05:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="jmPpBeXU" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 48CEE2084A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id D8EA46B0005; Tue, 14 May 2019 13:05:30 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D3FC96B0006; Tue, 14 May 2019 13:05:30 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C2E6D6B0007; Tue, 14 May 2019 13:05:30 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-pf1-f197.google.com (mail-pf1-f197.google.com [209.85.210.197]) by kanga.kvack.org (Postfix) with ESMTP id 8A0256B0005 for ; Tue, 14 May 2019 13:05:30 -0400 (EDT) Received: by mail-pf1-f197.google.com with SMTP id c7so12320176pfp.14 for ; Tue, 14 May 2019 10:05:30 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:date:from:to:cc:subject :message-id:references:mime-version:content-disposition:in-reply-to :user-agent; bh=KlbgFAVXgBXigN146B3nlFdjOxF2TXPML68s5DT9K4M=; b=cBmqAnBWmhj/jDHui5iMVxxkAlwqh0vvMtQgirHbVG3GGZoqlv4BT+pr42GsmVhURU nAZAdPTYRyG9yCj7pZo7E+zizzUdpJMp/QjFqUs1d+/QUfsQWSIVSWS5YhYq/oc6TZik kBeitfAEYBGM3Ot2O455Dg9nGKggzWFrtvRetdZgp9/9/gY3P4sPJ8+HpdoJQ1W+cchx F7rXv86yeH3ZZmPqjf7zW/2iLqIXZWIvKXjRzo67B7dmsmP8TFmKQIqn8U1DOCwZu+ma i2zSjnItgP5GPLPriyLO64CgSxtJL90woRfJXEiCxUSjLklduV+3cPwyuaj3++7Sgw77 GJwQ== X-Gm-Message-State: APjAAAUiUhp9cfGaHgttzcHRSH3+FwMkbQ2ZRKJeDp2uzkOBUxhQCKwY ltQUOruk83jXE8HMhP4IyzSzwWOLIwj34g7OVMEECfGtgpaZcp4G8PIGuHWDYaPFE8FYaj5me97 hLP4P2lpcCKrjdeeIaiStg92bDMWX5CmDJoUXvC2Ox6LKWH7FH1MNtAkM59lTmE4dTA== X-Received: by 2002:a63:2b96:: with SMTP id r144mr24341838pgr.314.1557853530096; Tue, 14 May 2019 10:05:30 -0700 (PDT) X-Google-Smtp-Source: APXvYqy5XFTBjU2XQO3UH+MPgTVFlHXYK3EwvAzRWW8EOPpfgZ3IxycrNCpuGaDYPsDQJo5Z83sQ X-Received: by 2002:a63:2b96:: with SMTP id r144mr24341693pgr.314.1557853528649; Tue, 14 May 2019 10:05:28 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1557853528; cv=none; d=google.com; s=arc-20160816; b=z372bxLqt4klF8+6EI9N3vig+WQtPB/SBnm1x12Not4gPoMVA/ukSZeLFcdWPYEXQ/ 35rWdgh5KAr5zLEarXLencyr3LD08w1rl9fRABug3H9XHSvKILUMAU4RvEbbANbe/bcu 9+CG3xQM5SRaLCqC+mDVtWupDzdL0lZLu16e+6aUNPumaxXsBRNdcM3tH6YUycQ053cv XCbs6Y6YV/MpKdPbJ4aFqFodr+dkdEoaUzv6QuxXaV6Y553y7pwOy5+t0XWd/wLL8gbN fVWhJ7L9bUfc81VmQUuF6nMmTrOTwFyni+KChw+cxJypBf13to4oL3YpVdRPk7ePPImm hjRA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:dkim-signature; bh=KlbgFAVXgBXigN146B3nlFdjOxF2TXPML68s5DT9K4M=; b=ipzh+LJskFTrWufZB+bzg8gzw/1SKA3ZE1ItyzYSvgILS/0mgcS8HDYV8nOsoYTI37 RS9rtRtrOeCu7UtKEFQrqfbBrB3SSYvd6LwIf5rziHJis55oWbDvHQ8BNdYgQhR1c/dy EZjj2Hs9Ho2IwMbSUJTR2DajekPPJKYzWGJ0TNGuz9eDlMNnB1k9qcr2iq4s9DjpzVok kzgA5g3z72jlqzkyx9WiS0p4LwM32eELM8cYWwee2wnDT6q+EibXYxJdWQGEnbBaL4Kn W2BCMbE++ZYsNZt8mjYGQsVA6tIIMl//SVPfrvGHqfi0GlogwoHPGKV0Pc9wIl8dAhne RjJw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20170209 header.b=jmPpBeXU; spf=pass (google.com: best guess record for domain of peterz@infradead.org designates 2607:7c80:54:e::133 as permitted sender) smtp.mailfrom=peterz@infradead.org Received: from bombadil.infradead.org (bombadil.infradead.org. [2607:7c80:54:e::133]) by mx.google.com with ESMTPS id d21si20184320pgv.353.2019.05.14.10.05.28 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 14 May 2019 10:05:28 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of peterz@infradead.org designates 2607:7c80:54:e::133 as permitted sender) client-ip=2607:7c80:54:e::133; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20170209 header.b=jmPpBeXU; spf=pass (google.com: best guess record for domain of peterz@infradead.org designates 2607:7c80:54:e::133 as permitted sender) smtp.mailfrom=peterz@infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=KlbgFAVXgBXigN146B3nlFdjOxF2TXPML68s5DT9K4M=; b=jmPpBeXUM05r6s4bzTOSf6IqR +gcxkAlmEIZHWVOGUSv2eKJST1OuQS90zya54qlP9PNVULIwibJlblBwZsXAe2Tw9v0vEg7MjiaM/ boWCqM4HmbVadcMDA2prEGa3avhoxYuF2vh3xSdRIHCKv6faoneacq3v8ilnKkxoDdFTuTgPbsDuT uLEdi9/F+FBWIQlm1a1dv6w5TIgPFvJ8BPFmU5wT6QPVgtTBJ1vdYZpeSo4AAqT0EWeUhZDUEIjFO FrcTQwOxOHFzl5NUcBxEpfOaWiTDtXCsTRjQU4nGpWW7HpkKES1Iudvt4IdtGHjcxL1Q9sWZFMh2Z b4JKSdzYg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1hQark-0000lD-Qy; Tue, 14 May 2019 17:05:25 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id D00982029F888; Tue, 14 May 2019 19:05:22 +0200 (CEST) Date: Tue, 14 May 2019 19:05:22 +0200 From: Peter Zijlstra To: Alexandre Chartre Cc: Andy Lutomirski , Paolo Bonzini , Radim Krcmar , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Dave Hansen , kvm list , X86 ML , Linux-MM , LKML , Konrad Rzeszutek Wilk , jan.setjeeilers@oracle.com, Liran Alon , Jonathan Adams Subject: Re: [RFC KVM 18/27] kvm/isolation: function to copy page table entries for percpu buffer Message-ID: <20190514170522.GW2623@hirez.programming.kicks-ass.net> References: <1557758315-12667-1-git-send-email-alexandre.chartre@oracle.com> <1557758315-12667-19-git-send-email-alexandre.chartre@oracle.com> <20190514070941.GE2589@hirez.programming.kicks-ass.net> <4e7d52d7-d4d2-3008-b967-c40676ed15d2@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, May 14, 2019 at 06:24:48PM +0200, Alexandre Chartre wrote: > On 5/14/19 5:23 PM, Andy Lutomirski wrote: > > How important is the ability to enable IRQs while running with the KVM > > page tables? > > > > I can't say, I would need to check but we probably need IRQs at least for > some timers. Sounds like you would really prefer IRQs to be disabled. > I think what amluto is getting at, is: again: local_irq_disable(); switch_to_kvm_mm(); /* do very little -- (A) */ VMEnter() /* runs as guest */ /* IRQ happens */ WMExit() /* inspect exit raisin */ if (/* IRQ pending */) { switch_from_kvm_mm(); local_irq_restore(); goto again; } but I don't know anything about VMX/SVM at all, so the above might not be feasible, specifically I read something about how VMX allows NMIs where SVM did not somewhere around (A) -- or something like that, earlier in this thread.