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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8EC2CC433FE for ; Tue, 2 Nov 2021 17:17:54 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 30AD061050 for ; Tue, 2 Nov 2021 17:17:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 30AD061050 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=alien8.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id E92BC607A7; Tue, 2 Nov 2021 17:17:53 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id cToEKQX5n1JF; Tue, 2 Nov 2021 17:17:53 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [IPv6:2605:bc80:3010:104::8cd3:938]) by smtp3.osuosl.org (Postfix) with ESMTPS id 84763607D1; Tue, 2 Nov 2021 17:17:52 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 51753C0019; Tue, 2 Nov 2021 17:17:52 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id C4BD1C000E for ; Tue, 2 Nov 2021 17:17:50 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id BE24E607D1 for ; Tue, 2 Nov 2021 17:17:50 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id GLlSWdu7OCd5 for ; Tue, 2 Nov 2021 17:17:48 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.8.0 Received: from mail.skyhub.de (mail.skyhub.de [5.9.137.197]) by smtp3.osuosl.org (Postfix) with ESMTPS id D695C607A7 for ; Tue, 2 Nov 2021 17:17:47 +0000 (UTC) Received: from zn.tnic (p200300ec2f0f6200599060f0a067c463.dip0.t-ipconnect.de [IPv6:2003:ec:2f0f:6200:5990:60f0:a067:c463]) (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 0B5881EC011B; Tue, 2 Nov 2021 18:17:44 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1635873464; 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:in-reply-to:in-reply-to: references:references; bh=3k4UAR3waP1O7QGWGVCIvAvoqbPAyUfbTyj8oUzmI68=; b=SeyOgVQjj3BQhQf5sHXtuXpKsQ++nRNdi9c43JfJi45//PBZmGZ8tAHWFoXXTFS75b2FpU nifTwIFZsxidse9XB6WTzJ0MaQjjwyO8b0Nw3BSrGpJb9FoM8urYmB4pdNQ7nUzDej/dYg k/eADB0zWg+TZRUOYZNnV0PKhD0DvbM= Date: Tue, 2 Nov 2021 18:17:39 +0100 From: Borislav Petkov To: "Eric W. Biederman" Subject: Re: [PATCH v2 01/12] kexec: Allow architecture code to opt-out at runtime Message-ID: References: <20210913155603.28383-1-joro@8bytes.org> <20210913155603.28383-2-joro@8bytes.org> <87pmrjbmy9.fsf@disp2133> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <87pmrjbmy9.fsf@disp2133> Cc: kvm@vger.kernel.org, Peter Zijlstra , Dave Hansen , virtualization@lists.linux-foundation.org, Arvind Sankar , hpa@zytor.com, Jiri Slaby , Joerg Roedel , x86@kernel.org, David Rientjes , Martin Radev , Tom Lendacky , Joerg Roedel , Kees Cook , Cfir Cohen , linux-coco@lists.linux.dev, Andy Lutomirski , Dan Williams , Juergen Gross , Mike Stunes , Sean Christopherson , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Masami Hiramatsu , Erdem Aktas X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" On Mon, Nov 01, 2021 at 04:11:42PM -0500, Eric W. Biederman wrote: > I seem to remember the consensus when this was reviewed that it was > unnecessary and there is already support for doing something like > this at a more fine grained level so we don't need a new kexec hook. Well, the executive summary is that you have a guest whose memory *and* registers are encrypted so the hypervisor cannot have a poke inside and reset the vCPU like it would normally do. So you need to do that dance differently, i.e, the patchset. If you try to kexec such a guest now, it'll init only the BSP, as Joerg said. So I guess a single-threaded kdump. And yes, one of the prominent use cases is kdumping from such a guest, as distros love doing kdump for debugging. I hope that explains it better. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization