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 EAB7EC433F5 for ; Tue, 16 Nov 2021 18:03:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C9F6461545 for ; Tue, 16 Nov 2021 18:03:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239295AbhKPSGJ (ORCPT ); Tue, 16 Nov 2021 13:06:09 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:54925 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239262AbhKPSGI (ORCPT ); Tue, 16 Nov 2021 13:06:08 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1637085791; 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=RyiwGFV9nDr9Oh5QgswyHQLt8G1b9iomHWUtbCQgEdg=; b=iQetPDSmTobYRT83hkTqDR7ELB9qsDCvoj6FMh0Cr0N6cL4GQhWjHYaPEJPDirKaj6mjwN Lg1gsL8AB0Q1/4YKADHLDECgo01rsMKsKqJcWtl+b8vOivlHul3w8lSlXDYZkSX7IAYEwp qq5KbfKKDYieVMrLVRJdwRKCv/vTjDw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-269-aInQcEeRP_ytE2YvZtSAkQ-1; Tue, 16 Nov 2021 13:03:09 -0500 X-MC-Unique: aInQcEeRP_ytE2YvZtSAkQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 46767875047; Tue, 16 Nov 2021 18:03:08 +0000 (UTC) Received: from [10.39.192.245] (unknown [10.39.192.245]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7F0A65D9DE; Tue, 16 Nov 2021 18:03:07 +0000 (UTC) Message-ID: Date: Tue, 16 Nov 2021 19:03:06 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 Subject: Re: [PATCH kvm-unit-tests] pmu: fix conditions for emulation test Content-Language: en-US To: Jim Mattson Cc: kvm@vger.kernel.org, Like Xu References: <20211116105038.683627-1-pbonzini@redhat.com> From: Paolo Bonzini In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 11/16/21 18:49, Jim Mattson wrote: > Thanks for fixing this. By the way, one of the reasons that we don't > expose a virtual PMU to more customers is the conflict with the NMI > watchdog. We aren't willing to give up the NMI watchdog on the host, > and we don't really want to report a reduced number of general purpose > counters to the guest. (On AMD, we *can't* report a reduced number of > counters to the guest; the architectural specification doesn't allow > it.) FWIW we also generally use the PMU emulation only for debugging of guest performance issues. > We can't be the only ones running with the NMI watchdog enabled. How > do others deal with this? Is there any hope of suspending the NMI > watchdog while in VMX non-root mode (or guest mode on AMD)? Like, what do you think? Paolo >> This also hid a typo for the force_emulation_prefix module parameter, >> which is part of the kvm module rather than the kvm_intel module, >> so fix that. >> >> Reported-by: Like Xu >> Signed-off-by: Paolo Bonzini > Reviewed-by: Jim Mattson >