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=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 8A885C4361B for ; Mon, 14 Dec 2020 21:46:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4DDD220798 for ; Mon, 14 Dec 2020 21:46:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2503583AbgLNVq1 (ORCPT ); Mon, 14 Dec 2020 16:46:27 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:33808 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2503565AbgLNVqS (ORCPT ); Mon, 14 Dec 2020 16:46:18 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1607982292; 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=Y5+S7Ad2XyX9pkxnkrXX2LGZ2aRhSIyfHipDehm+l+E=; b=L1H+m8+YRl71EexhEwq9at0A6xffBmkgYf8LnfWfW9bgw4bRv+IsVItvyCBkJYEm2oinU1 dwEijEDQgJ7kOrxrBiWRX70DzxwRp8nOzbpPgmnYSknlEd3aaZtwBYmdRApp8GZkgGuFxJ qYI9pXWDWdD/x6wq9S3Ih9TPes08vz8= Received: from mail-ed1-f72.google.com (mail-ed1-f72.google.com [209.85.208.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-484-bgBY6BcYPlmx4X6yEMLN_A-1; Mon, 14 Dec 2020 16:44:50 -0500 X-MC-Unique: bgBY6BcYPlmx4X6yEMLN_A-1 Received: by mail-ed1-f72.google.com with SMTP id d12so8980606edx.23 for ; Mon, 14 Dec 2020 13:44:50 -0800 (PST) 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=Y5+S7Ad2XyX9pkxnkrXX2LGZ2aRhSIyfHipDehm+l+E=; b=OTHAMH7SRiYSH3hCBSEfVpgMkSB7WHe3mWMC3RisKnCwRalKSPAPYpHZiomg1lRorc 2nTKGcqmKt2FyllbaI5MX2s/Ob47YGLqmAEF7Q88Tg0/4+AMbg/fgbV2CiSGL2Amzmbh 1BQKL6Ai3UnIfHQTpCib+jLlVIkcJuBHLQ+D7OUPSdFAvwmrTmAYIB5LlP9rzaz7KjTg nC5zEYAaYHRwCvel2vXbZfCAFVKCEXwEv1p981Oy0cvAdrmTWcrCgUvxefrDgHvKZalL 2xZ/eO9D14UEQSsfzVS43XlnhZpEiXMR2sCB7W8l98IkQQKpcZCBwJgEk/Xuow85ttBr cubQ== X-Gm-Message-State: AOAM5307lIdU9slG/WXu3tWZO4qS9G2GqW4u9eZhLGyM1ypM/YD3OXZn jpeayFt53IA5iYkXVIjP9L5V0wXoLGYkvGpkEre+mXGPbWJk2FNEHwekSJBjdsUuOxNYuAKFpLK RFBv2EXd6bnxK X-Received: by 2002:a17:906:7146:: with SMTP id z6mr24248208ejj.379.1607982289242; Mon, 14 Dec 2020 13:44:49 -0800 (PST) X-Google-Smtp-Source: ABdhPJzpP/qHyvqyAW3R6HFy98z0QrKXZtowZdOYvRvJsjvgoFnL/28dB06toMKKxPeFTfy30xKWZA== X-Received: by 2002:a17:906:7146:: with SMTP id z6mr24248186ejj.379.1607982289063; Mon, 14 Dec 2020 13:44:49 -0800 (PST) Received: from vitty.brq.redhat.com (g-server-2.ign.cz. [91.219.240.2]) by smtp.gmail.com with ESMTPSA id i4sm165405eje.90.2020.12.14.13.44.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Dec 2020 13:44:48 -0800 (PST) From: Vitaly Kuznetsov To: David Woodhouse , kvm@vger.kernel.org Cc: Paolo Bonzini , Ankur Arora , Joao Martins , Boris Ostrovsky , Sean Christopherson , graf@amazon.com, iaslan@amazon.de, pdurrant@amazon.com, aagch@amazon.com, fandree@amazon.com Subject: Re: [PATCH v3 02/17] KVM: x86/xen: fix Xen hypercall page msr handling In-Reply-To: <58AC82A4-ADE4-4A8F-9522-16B8A4B9CBDD@infradead.org> References: <20201214083905.2017260-1-dwmw2@infradead.org> <20201214083905.2017260-3-dwmw2@infradead.org> <87czzcw020.fsf@vitty.brq.redhat.com> <58AC82A4-ADE4-4A8F-9522-16B8A4B9CBDD@infradead.org> Date: Mon, 14 Dec 2020 22:44:47 +0100 Message-ID: <877dpkvz8w.fsf@vitty.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org David Woodhouse writes: >>> @@ -3001,6 +3001,9 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, >>struct msr_data *msr_info) >>> u32 msr = msr_info->index; >>> u64 data = msr_info->data; >>> >>> + if (msr && (msr == vcpu->kvm->arch.xen_hvm_config.msr)) >>> + return xen_hvm_config(vcpu, data); >>> + >> >>Can we generalize this maybe? E.g. before handling KVM and >>architectural >>MSRs we check that the particular MSR is not overriden by an emulated >>hypervisor, >> >>e.g. >> if (kvm_emulating_hyperv(kvm) && kvm_hyperv_msr_overriden(kvm,msr) >> return kvm_hyperv_handle_msr(kvm, msr); >> if (kvm_emulating_xen(kvm) && kvm_xen_msr_overriden(kvm,msr) >> return kvm_xen_handle_msr(kvm, msr); > > That smells a bit like overengineering. As I said, I did have a play > with "improving" Joao's original patch but nothing I tried actually > made more sense to me than this once the details were ironed out. This actually looks more or less like hypercall distinction from after PATCH3: if (kvm_xen_hypercall_enabled(vcpu->kvm)) return kvm_xen_hypercall(vcpu); if (kvm_hv_hypercall_enabled(vcpu->kvm)) return kvm_hv_hypercall(vcpu); .... so my idea was why not do the same for MSRs? -- Vitaly