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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AD25FC433FE for ; Fri, 11 Nov 2022 12:19:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233037AbiKKMTu (ORCPT ); Fri, 11 Nov 2022 07:19:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45026 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231564AbiKKMTr (ORCPT ); Fri, 11 Nov 2022 07:19:47 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3C436627F8; Fri, 11 Nov 2022 04:19:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.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; bh=TrDl26UsM79jWFLz4hQEcMFLuhNP+LrmD1HvrzIRqQ4=; b=WUiY5ty1bQBGkV9KPNLMZzL8H7 XqcORPxICEQQf07CBPhAaeW/D0mx+3X20oul9/09wz8IwTaOYtV6d1YLRMwPRpBOujHeFL8gTqGS3 dkbXK5ShksixPARtpRr6ocYYGyLPGGuwCAYUznuVVoT04tFAFicH1mX3Va4IsMb6xcjAWhkFJfoBr 8gtBiTZSZO/k2JcQtyE6a00g/sfSH7zSQAKBzM7Bz15UpqkT88Q0HrZXvWlixaV2rJgkXR6Mm83MU kWUvOEunBQDp4phng54TlZuxHIFE3MDOghnqxJOdwahUmjX6VbpWMpqqMYXMNK5Aw+Z2TiDEAoXpj HicRFA2A==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1otT0T-00D2IT-Mu; Fri, 11 Nov 2022 12:19:37 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id E046C30013F; Fri, 11 Nov 2022 13:19:31 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id CF06820831B7F; Fri, 11 Nov 2022 13:19:31 +0100 (CET) Date: Fri, 11 Nov 2022 13:19:31 +0100 From: Peter Zijlstra To: Paolo Bonzini Cc: "Li, Xin3" , "linux-kernel@vger.kernel.org" , "x86@kernel.org" , "kvm@vger.kernel.org" , "tglx@linutronix.de" , "mingo@redhat.com" , "bp@alien8.de" , "dave.hansen@linux.intel.com" , "hpa@zytor.com" , "Christopherson,, Sean" , "Tian, Kevin" Subject: Re: [RESEND PATCH 5/6] KVM: x86/VMX: add kvm_vmx_reinject_nmi_irq() for NMI/IRQ reinjection Message-ID: References: <20221110061545.1531-1-xin3.li@intel.com> <20221110061545.1531-6-xin3.li@intel.com> <6097036e-063f-5175-72b2-8935b12af853@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6097036e-063f-5175-72b2-8935b12af853@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 11, 2022 at 01:04:27PM +0100, Paolo Bonzini wrote: > On 11/11/22 10:15, Peter Zijlstra wrote: > > I don't speak virt (but this all sounds disguisting) > > Yes, it is. AMD does not need this, they just hold onto the interrupt > until the host has issued both STGI (for NMIs) and STI (for IRQs). Right -- Cooper just explained that to me. > On Intel you can optionally make it hold onto IRQs, but NMIs are always > eaten by the VMEXIT and have to be reinjected manually. That 'optionally' thing worries me -- as in, KVM is currently opting-out? Since much of this is about preparing for FRED, can we pretty *PLEASE* fix this VMX NMI hole instead so that all this nonsense isn't needed anymore, please, really please? Have FRED imply a GI flag for VMX or something and then we can all forget about these reinjection horrors.