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 C84CCC433F5 for ; Sat, 11 Dec 2021 02:15:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232586AbhLKCTG (ORCPT ); Fri, 10 Dec 2021 21:19:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51434 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229596AbhLKCTG (ORCPT ); Fri, 10 Dec 2021 21:19:06 -0500 Received: from mail-ed1-x536.google.com (mail-ed1-x536.google.com [IPv6:2a00:1450:4864:20::536]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0D035C061714; Fri, 10 Dec 2021 18:15:29 -0800 (PST) Received: by mail-ed1-x536.google.com with SMTP id l25so35671471eda.11; Fri, 10 Dec 2021 18:15:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=8aqRn2SUIOh4potQe4XVSMC19lM8tBZYzY1tBnkVsCs=; b=b3WUs5YMwutlir2ynpVadeN3Rx7ynFx+5P8/+qM4qX40IE/A5GZLHA7Lxg4L4QB3qF rOgi6/u0w+9P8j2V1ciMI2nAlDyij0OzKwW8gVr1sjBNgl2GNEw3jMake/ZxAxqXZoto k4+qdcSFA52I8KqnKUbf0A6dClrw27bOSvgh/tKvlNsekPecU38MXJFxPnjnvt5xzJLd SOCpD7vYHTHLVicMZxBx8Cfh35muNmiTKSthupU4s1K83EbUP3ZZ3s3NissJ7AbyfDSM HN958pWmKwI44Ex+WmiHuIJbtxa/JpLTDTzI43YskyX5UAcpOINo2oOzA2qK2PUxTQnS EJ3A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:message-id:date:mime-version:user-agent :subject:content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=8aqRn2SUIOh4potQe4XVSMC19lM8tBZYzY1tBnkVsCs=; b=kG5TrN8ejrGV1OlXGu8yILN0E3NvckusRx8LrqLXZf0rxRGQmOFm0z10fORPiCPkgB 7VzVNYGlxDNEknkhwLF5zJz2++7vgQcZ8H93umJtEAg9S22KMg/P+8eyF9/Wtl8l+NSz o0SLR/C3wytOEqdjIo+sKH2jz/P8Kpdv9E5F1HAP/Rujv/SIbNUuVBxSzjwatq5JHYGB qI1CGtL7/Yhg7WAfUToYdZ2R5n8TcM+uxj5KVLz3StEbSFanQrsf90d4V/dKwaYbLRVT 2zC+lv2hJsftxeGii/dNgzjv9dUcCcsN7EU8eVfLXket+pmrxgrtBRlnNgLGyesXvtmP mGCA== X-Gm-Message-State: AOAM533Md/GCpLz2mO/W4gC0biibynBsDwmrbvP+sodCK2cyzGQNk+/g cjZj0B3j4GidOT0YFtBkd+E= X-Google-Smtp-Source: ABdhPJw1wozLjtvPMMXA+6i0oAY/knATkITAGW+2ToQT/g0ZRbo6rI9Rh7szN3mXoDqa3eFN7q3rvQ== X-Received: by 2002:a05:6402:5cc:: with SMTP id n12mr44176038edx.246.1639188928473; Fri, 10 Dec 2021 18:15:28 -0800 (PST) Received: from ?IPV6:2001:b07:6468:f312:48f9:bea:a04c:3dfe? ([2001:b07:6468:f312:48f9:bea:a04c:3dfe]) by smtp.googlemail.com with ESMTPSA id y15sm2611084eda.13.2021.12.10.18.15.26 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 10 Dec 2021 18:15:28 -0800 (PST) Sender: Paolo Bonzini Message-ID: <438d42de-78e1-0ce9-6a06-38194de4abd4@redhat.com> Date: Sat, 11 Dec 2021 03:15:25 +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: x86/svm: Add module param to control PMU virtualization Content-Language: en-US To: Jim Mattson Cc: Like Xu , Maxim Levitsky , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org References: <20211117080304.38989-1-likexu@tencent.com> From: Paolo Bonzini In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/10/21 20:25, Jim Mattson wrote: > In the long run, I'd like to be able to override this system-wide > setting on a per-VM basis, for VMs that I trust. (Of course, this > implies that I trust the userspace process as well.) > > How would you feel if we were to add a kvm ioctl to override this > setting, for a particular VM, guarded by an appropriate permissions > check, like capable(CAP_SYS_ADMIN) or capable(CAP_SYS_MODULE)? What's the rationale for guarding this with a capability check? IIRC you don't have such checks for perf_event_open (apart for getting kernel addresses, which is not a problem for virtualization). Paolo