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 1CEDBCD8CA6 for ; Tue, 10 Oct 2023 16:03:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233699AbjJJQD4 (ORCPT ); Tue, 10 Oct 2023 12:03:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44038 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233674AbjJJQDy (ORCPT ); Tue, 10 Oct 2023 12:03:54 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CE1D2B8 for ; Tue, 10 Oct 2023 09:03:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1696953784; 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; bh=5AesHVAQUxcR1GAtYtYzOkU6c6/CTxsVJcL3ikJVYAI=; b=hamdaLKWZhqk+cdKK9MXjaSFZJSMqIqi5eGwxEiOl3xxtCPdkmCqKbDWji0Gvf9GukkEOJ Cb7StLOcXQZrszbZdxIx3vOnRENCbIN1UCn1WnTeU3/2uZAtcXO+r/pB8WFjUcxkKiqUiq cL3TEq+O7jS2auHmPAGrwToZzl5gKIU= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-487-x0HiwtMcPpWoaVmCvGtVbA-1; Tue, 10 Oct 2023 12:03:03 -0400 X-MC-Unique: x0HiwtMcPpWoaVmCvGtVbA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 512A41C11712; Tue, 10 Oct 2023 16:03:02 +0000 (UTC) Received: from fedora.redhat.com (unknown [10.45.226.166]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7F386158; Tue, 10 Oct 2023 16:03:01 +0000 (UTC) From: Vitaly Kuznetsov To: kvm@vger.kernel.org, Paolo Bonzini , Sean Christopherson Cc: linux-kernel@vger.kernel.org Subject: [PATCH RFC 00/11] KVM: x86: Make Hyper-V emulation optional (AKA introduce CONFIG_KVM_HYPERV) Date: Tue, 10 Oct 2023 18:02:49 +0200 Message-ID: <20231010160300.1136799-1-vkuznets@redhat.com> MIME-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ideas to make Hyper-V emulation by KVM optional were expressed in the past so I've decided to take a look at what would it take us to implement it. Turns out it's quite a lot of code churn but the gain is also significant. Just comparing the resulting module sizes, I can see: # CONFIG_KVM_HYPERV is not set # CONFIG_HYPERV is not set -rw-r--r--. 1 user user 3612632 Oct 10 16:53 arch/x86/kvm/kvm-amd.ko -rw-r--r--. 1 user user 5343968 Oct 10 16:53 arch/x86/kvm/kvm-intel.ko CONFIG_KVM_HYPERV=y # CONFIG_HYPERV is not set -rw-r--r--. 1 user user 3925704 Oct 10 16:51 arch/x86/kvm/kvm-amd.ko -rw-r--r--. 1 user user 5819192 Oct 10 16:51 arch/x86/kvm/kvm-intel.ko # CONFIG_KVM_HYPERV is not set CONFIG_HYPERV=m -rw-r--r--. 1 user user 3928440 Oct 10 16:40 arch/x86/kvm/kvm-amd.ko -rw-r--r--. 1 user user 8156464 Oct 10 16:40 arch/x86/kvm/kvm-intel.ko CONFIG_KVM_HYPERV=y CONFIG_HYPERV=m -rw-r--r--. 1 user user 4245440 Oct 10 16:37 arch/x86/kvm/kvm-amd.ko -rw-r--r--. 1 user user 8583872 Oct 10 16:37 arch/x86/kvm/kvm-intel.ko While code churn is certainly something we can survive, adding more CONFIG options always comes with a risk of a broken build somewhere in the future. Early RFC. I have only compile tested these patches in these four configurations and I'd like to get your opinion on whether it's worth it or not. The first patch of the series is not Hyper-V related but as I hide Hyper-V emulation context under CONFIG_KVM_HYPERV I think it would make sense to do the same for Xen. Vitaly Kuznetsov (11): KVM: x86: xen: Remove unneeded xen context from struct kvm_arch when !CONFIG_KVM_XEN KVM: x86: hyper-v: Move Hyper-V partition assist page out of Hyper-V emulation context KVM: VMX: Split off vmx_onhyperv.{ch} from hyperv.{ch} KVM: x86: hyper-v: Introduce kvm_hv_synic_auto_eoi_set() KVM: x86: hyper-v: Introduce kvm_hv_synic_has_vector() KVM: VMX: Split off hyperv_evmcs.{ch} KVM: x86: Make Hyper-V emulation optional KVM: nVMX: hyper-v: Introduce nested_vmx_evmptr() accessor KVM: nVMX: hyper-v: Introduce nested_vmx_evmcs() accessor KVM: nVMX: hyper-v: Hide more stuff under CONFIG_KVM_HYPERV KVM: nSVM: hyper-v: Hide more stuff under CONFIG_KVM_HYPERV/CONFIG_HYPERV arch/x86/include/asm/kvm_host.h | 11 +- arch/x86/kvm/Kconfig | 9 + arch/x86/kvm/Makefile | 19 +- arch/x86/kvm/cpuid.c | 6 + arch/x86/kvm/hyperv.h | 39 ++- arch/x86/kvm/irq.c | 2 + arch/x86/kvm/irq_comm.c | 9 +- arch/x86/kvm/lapic.c | 5 +- arch/x86/kvm/svm/hyperv.h | 7 + arch/x86/kvm/svm/nested.c | 22 +- arch/x86/kvm/svm/svm.h | 2 + arch/x86/kvm/svm/svm_onhyperv.c | 2 +- arch/x86/kvm/svm/svm_onhyperv.h | 2 + arch/x86/kvm/vmx/hyperv.c | 447 -------------------------------- arch/x86/kvm/vmx/hyperv.h | 191 ++------------ arch/x86/kvm/vmx/hyperv_evmcs.c | 311 ++++++++++++++++++++++ arch/x86/kvm/vmx/hyperv_evmcs.h | 162 ++++++++++++ arch/x86/kvm/vmx/nested.c | 94 ++++--- arch/x86/kvm/vmx/nested.h | 3 +- arch/x86/kvm/vmx/vmx.c | 6 +- arch/x86/kvm/vmx/vmx.h | 2 + arch/x86/kvm/vmx/vmx_onhyperv.c | 36 +++ arch/x86/kvm/vmx/vmx_onhyperv.h | 125 +++++++++ arch/x86/kvm/vmx/vmx_ops.h | 2 +- arch/x86/kvm/x86.c | 60 +++-- 25 files changed, 885 insertions(+), 689 deletions(-) create mode 100644 arch/x86/kvm/vmx/hyperv_evmcs.c create mode 100644 arch/x86/kvm/vmx/hyperv_evmcs.h create mode 100644 arch/x86/kvm/vmx/vmx_onhyperv.c create mode 100644 arch/x86/kvm/vmx/vmx_onhyperv.h -- 2.41.0