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[209.132.180.67]) by mx.google.com with ESMTP id z3si2525663oth.163.2020.04.08.05.20.48; Wed, 08 Apr 2020 05:21:03 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@alien8.de header.s=dkim header.b="l0/4LVJW"; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=alien8.de Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727837AbgDHKB4 (ORCPT + 99 others); Wed, 8 Apr 2020 06:01:56 -0400 Received: from mail.skyhub.de ([5.9.137.197]:40042 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725932AbgDHKB4 (ORCPT ); Wed, 8 Apr 2020 06:01:56 -0400 Received: from zn.tnic (p200300EC2F0A9300FDE94558DB0629D0.dip0.t-ipconnect.de [IPv6:2003:ec:2f0a:9300:fde9:4558:db06:29d0]) (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 F1EBC1EC0A02; Wed, 8 Apr 2020 12:01:54 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1586340115; 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=vNYTeV2b64ZBxmOavtdQ8bkFeF6KZzWWTytnRjR7vL8=; b=l0/4LVJWPuFrF7GMaqLg9UPQuF3QuNtio4dgEZosgiwzYEeOHCmk8sIaC3BBFrmBns2qac VH1oyLhjdpkJVZbcd49C5lhyP673vvZjLT/JBLfQCejHbh8S095gXtx9k516KWG++Kk7kI Lo79YX7Rnim0kCCtTbyzXiFaEX4cEYw= Date: Wed, 8 Apr 2020 12:01:51 +0200 From: Borislav Petkov To: Vivek Goyal Cc: Andy Lutomirski , Thomas Gleixner , Peter Zijlstra , Andy Lutomirski , Paolo Bonzini , LKML , X86 ML , kvm list , stable Subject: Re: [PATCH v2] x86/kvm: Disable KVM_ASYNC_PF_SEND_ALWAYS Message-ID: <20200408100151.GD24663@zn.tnic> References: <87eeszjbe6.fsf@nanos.tec.linutronix.de> <20200407224903.GC64635@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20200407224903.GC64635@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 07, 2020 at 06:49:03PM -0400, Vivek Goyal wrote: > > 2. Access to bad memory results in #MC. Sure, #MC is a turd, but it’s an *architectural* turd. By all means, have a nice simple PV mechanism to tell the #MC code exactly what went wrong, but keep the overall flow the same as in the native case. > > > > Should we differentiate between two error cases. In this case memory is > not bad. Just that page being asked for can't be faulted in anymore. And > another error case is real memory failure. So for the first case it > could be injected into guest using #PF or #VE or something paravirt > specific and real hardware failures take #MC path (if they are not > already doing so). For handling memory failures with guests there's this whole thing described Documentation/vm/hwpoison.rst and KVM has support for that. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette