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 X-Spam-Level: X-Spam-Status: No, score=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B8214C433E3 for ; Fri, 29 May 2020 12:08:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9665B20814 for ; Fri, 29 May 2020 12:08:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="al4aZyJY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726579AbgE2MIl (ORCPT ); Fri, 29 May 2020 08:08:41 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:36950 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726476AbgE2MIh (ORCPT ); Fri, 29 May 2020 08:08:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1590754116; 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: in-reply-to:in-reply-to:references:references; bh=gkkeI9/4O+LTTEQ+7u8ZuAx4cOWBRh3lwyxYXdlPlcc=; b=al4aZyJYU94MDwvF+FvnyFyrlIsw9/0MyGb+byotId1bUnf6erOdk0nmbAJexbB19dXT8s j2UVZRGR6oCvk2GM/FnforXL0H8lZ/9MZ//yv3YUrS8fwN7+VS7zTtPEyfBAMMIg3IIeOQ JEws5N7NZiEeY+TTMnSi+/YXCHT6KNg= Received: from mail-wr1-f70.google.com (mail-wr1-f70.google.com [209.85.221.70]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-28--E7yCknbPimPclxT8EEokA-1; Fri, 29 May 2020 08:08:35 -0400 X-MC-Unique: -E7yCknbPimPclxT8EEokA-1 Received: by mail-wr1-f70.google.com with SMTP id s17so964887wrt.7 for ; Fri, 29 May 2020 05:08:34 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:in-reply-to:references:date :message-id:mime-version; bh=gkkeI9/4O+LTTEQ+7u8ZuAx4cOWBRh3lwyxYXdlPlcc=; b=KeMAn9UzPG9InHz/U5gMZiX1PTN2zsVUnxPQehM1gbQD1o4J08B39xoxXML9zET2Ve o/PD/t4G5f9IrGQsGtqPWkbuwC+LgNzl4MTbmRaRSaPDQ5UPS6Qrk8DMp1ce5fal+KJe YKasbdDBJvt0O3GkXKTiEKngGmXepKaEgIA9IRO+AL79+bisKPCIwv6N8lfAkoosynFm lMYHXAJN7eQuKBiHLuA5DzYQYGNnylF0QBPB/1YXG1mfUg/oxOadD35jPf3wHNagHE3r kUFV3tIfkoNlCUGtMOZFomzsh4eShmMCCQ96uUbg37+uYx9qrEmra9IhJq12Sn+8RBnT yAGA== X-Gm-Message-State: AOAM532DutKtwJEmjjuiViBgRzPYc8BsHJJM1a230Npyb2P5CwV2/3PG LtadfZ2T/XzcwvwJgny6NdqK9CgtFstQzLSKfTaQb2fszpcYbm/0+HVZVR3DFw8lN7jAyhPV82I SHoMLW3iaeYZXk0qOS4DAr8BC X-Received: by 2002:a7b:cb0a:: with SMTP id u10mr7719803wmj.146.1590754113432; Fri, 29 May 2020 05:08:33 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyIUKYN6RpJQ13GHibiYf05FEqiCpNM7pxTEl/HoRQDNE4g/S/lPW2gzkydzA3AWHeqXJVAog== X-Received: by 2002:a7b:cb0a:: with SMTP id u10mr7719792wmj.146.1590754113190; Fri, 29 May 2020 05:08:33 -0700 (PDT) Received: from vitty.brq.redhat.com (g-server-2.ign.cz. [91.219.240.2]) by smtp.gmail.com with ESMTPSA id p65sm9911728wmp.36.2020.05.29.05.08.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 29 May 2020 05:08:32 -0700 (PDT) From: Vitaly Kuznetsov To: Paolo Bonzini Cc: Jon Doron , kvm@vger.kernel.org, linux-hyperv@vger.kernel.org Subject: Re: [PATCH v11 4/7] x86/kvm/hyper-v: Add support for synthetic debugger capability In-Reply-To: <12df4348-3dc1-a4cc-aa41-4492cd42dcc8@redhat.com> References: <20200424113746.3473563-1-arilou@gmail.com> <20200424113746.3473563-5-arilou@gmail.com> <12df4348-3dc1-a4cc-aa41-4492cd42dcc8@redhat.com> Date: Fri, 29 May 2020 14:08:31 +0200 Message-ID: <87ftbjhrk0.fsf@vitty.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-hyperv-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org Paolo Bonzini writes: > On 24/04/20 13:37, Jon Doron wrote: >> +static int syndbg_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, bool host) >> +{ >> + struct kvm_hv_syndbg *syndbg = vcpu_to_hv_syndbg(vcpu); >> + >> + if (!syndbg->active && !host) >> + return 1; >> + > > One small thing: is the ENABLE_CAP and active field needed? Can you > just check if the guest has the syndbg CPUID bits set? > Yes, we can probably get away with a static capability (so userspace knows that the interface is supported and CPUID bit can be set) and check guest_cpuid_has() here but we don't have Hyper-V feature leaves exposed as X86_FEATURE_* (yet). It is probably possible to implement an interim solution by open coding the check with kvm_find_cpuid_entry() or something like that. -- Vitaly