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 C4956C4332F for ; Fri, 11 Nov 2022 14:24:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233754AbiKKOYk (ORCPT ); Fri, 11 Nov 2022 09:24:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37104 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233172AbiKKOYK (ORCPT ); Fri, 11 Nov 2022 09:24:10 -0500 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 07EC043863; Fri, 11 Nov 2022 06:23:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=Sb7rhzFRTTVumBbHTQESASP2OPrWEPxQZs1Su9jVIS0=; b=k7bnVmG5wpWVyC1+0eVzQvuOPX MQhjYm/BIy+ccLdUF+xyA/giCUzSMkBXuC59bUHm2ZcizyQSJtaOKDVV6kRk8+sWsPOXy6marMMgP 0PDuJ/m1cJK5WwGYpZM7u3jjdVBR10VtQ5FmcaihgGNHYKQLtxqDVh689CbJpdjZIPOq/Rz4qeBJh gT4jzJparsbJHfYofxho2RCagrUoEPpFBULfHBKoTeJCN/Q53TOvfyL74CUkWAJWddiAazhYilwbP 14gHE55QmeZbHUZlxGxGT278Zqcjw0PC7WNHby0gwvf5KBH11F292rNAepWnRw2KDzBImyPdp9VLj jWSk7/Og==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1otUw6-0003qY-NW; Fri, 11 Nov 2022 14:23:15 +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 7DBFA30036B; Fri, 11 Nov 2022 15:23:13 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 6593D2016A1E7; Fri, 11 Nov 2022 15:23:13 +0100 (CET) Date: Fri, 11 Nov 2022 15:23:13 +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> <6fd26a70-3774-6ae7-73ea-4653aee106f0@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <6fd26a70-3774-6ae7-73ea-4653aee106f0@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 11, 2022 at 01:48:26PM +0100, Paolo Bonzini wrote: > On 11/11/22 13:19, Peter Zijlstra wrote: > > On Fri, Nov 11, 2022 at 01:04:27PM +0100, Paolo Bonzini wrote: > > > 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? > > Yes, because "If the “process posted interrupts” VM-execution control is 1, > the “acknowledge interrupt on exit” VM-exit control is 1" (SDM 26.2.1.1, > checks on VM-Execution Control Fields). Ipse dixit. Posted interrupts are > available and used on all processors since I think Ivy Bridge. (imagine the non-coc compliant reaction here) So instead of fixing it, they made it worse :-( And now FRED is arguably making it worse again, and people wonder why I hate virt...