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 8C818C83F12 for ; Mon, 28 Aug 2023 14:05:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231476AbjH1OEv (ORCPT ); Mon, 28 Aug 2023 10:04:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55610 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231573AbjH1OEj (ORCPT ); Mon, 28 Aug 2023 10:04:39 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5258A120 for ; Mon, 28 Aug 2023 07:04:36 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id 3f1490d57ef6-d77fa2e7771so3939479276.1 for ; Mon, 28 Aug 2023 07:04:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1693231475; x=1693836275; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=AeZG/LqUiqF0MY2HczEpiH5CLGzioag7c/FugDpORz8=; b=VDcqxgpas3p1DadFWmbrWR5W8zqdrer9COaNEUBB1oI49CRtv7rUwXZcz2B1roOES4 t91WwsHdDptsL2uFPeGzNcTUQzA0J9dHVWDSoyKP9JvvDkzch/vRG2AeCoJHA9P33xKK FxHWYdo61qlISm/tXRqNfKrnouiujqpE08oXautkXjpqrNPD1MovrLYO5Ut0LVX8sfnN VpqnwISUMAkC5NSHhoQQoZPAwobzneKYYVe8hrJMOBpSdN7EuTsQWItkRL5aywz5VKZ3 WQUElBwjYV9P785Ipgx1X3/7TH+AqgYDxmOB9qQvTr9CP0GHJ8sgiBnpdjhPK1/UExN6 wWlw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1693231475; x=1693836275; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=AeZG/LqUiqF0MY2HczEpiH5CLGzioag7c/FugDpORz8=; b=NLhTUtgB8KADJajVZM/UN5eanHWl8SEl3xxVCVZI3zKTJao85a2Z20FPZyeFPbwvou JMqjIXormVf6MsjOclivBBLfhgLjBE2hj/u32O/LeC56dDyTcrstA8wVL1BLSvfdDQcU fBQkq9C1M8f91PfLaJ//VBS9MduSpvauLzAomiYcXmrPeQQGiJ6MsXwDbYZg8j0/wJR9 SAM6ZpAo+zTF36E17QsDV9uSHP7g0C2Xk4zgKBj1xfqYMIByDrvotdjGoLO2qwMPGK1q yvsDIv//+5hhSPbzvZ2hA45gpZCgVbKsJAVm0hfqP4H1/nDQSIkBlQ1QwNyhD7MFt8V4 qkYg== X-Gm-Message-State: AOJu0YxHKpfydpO3nbFJr38jwHYm4jRe7wsLTIjNNPRPXBBVw6suo0SK sS3i/5fHt8o7Z0DKAeMFe9wUyPKZn/k= X-Google-Smtp-Source: AGHT+IHKKQw6ctp5TNMc7wshvgitTEG6NUyakQ1wy/mJelNNbJkdGOiLVuLUBvj6d5ocDvVJfaBiaJTiyLM= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a25:d890:0:b0:d10:5b67:843c with SMTP id p138-20020a25d890000000b00d105b67843cmr832409ybg.4.1693231475583; Mon, 28 Aug 2023 07:04:35 -0700 (PDT) Date: Mon, 28 Aug 2023 07:04:35 -0700 In-Reply-To: Mime-Version: 1.0 References: Message-ID: Subject: Re: [PATCH] KVM: VMX: Fix NMI event loss From: Sean Christopherson To: Tianyi Liu Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, peterz@infradead.org Content-Type: text/plain; charset="us-ascii" Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Mon, Aug 28, 2023, Tianyi Liu wrote: > Hi, Sean: > > I have found that in the latest version of the kernel, some PMU events are > being lost. I used bisect and found out the breaking commit [1], which > moved the handling of NMI events from `handle_exception_irqoff` to > `vmx_vcpu_enter_exit`. > > If I revert this part as done in this patch, it works correctly. However, > I'm not really familiar with KVM, and I'm not sure about the intent behind > the original patch [1]. FWIW, the goal was to invoke vmx_do_nmi_irqoff() before leaving the "noinstr" region. I messed up and forgot that vmx_get_intr_info() relied on metadata being reset after VM-Exit :-/ > Could you please take a look on this? Thanks a lot. Please try this patch, it should fix the problem but I haven't fully tested it against an affected workload yet. I'll do that later today. https://lore.kernel.org/all/20230825014532.2846714-1-seanjc@google.com