From patchwork Wed Aug 10 14:00:07 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vitaly Kuznetsov X-Patchwork-Id: 12940612 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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9E631C00140 for ; Wed, 10 Aug 2022 14:13:02 +0000 (UTC) Received: from localhost ([::1]:39746 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oLmSD-0005dw-1r for qemu-devel@archiver.kernel.org; Wed, 10 Aug 2022 10:13:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:35356) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oLmGw-0003zG-Nz for qemu-devel@nongnu.org; Wed, 10 Aug 2022 10:01:23 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:39235) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oLmGt-0003kz-8k for qemu-devel@nongnu.org; Wed, 10 Aug 2022 10:01:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1660140078; 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=0tdCM5vKV1BcfXVNshc9f+y0jmZSwpZA+iGbwzlc/zQ=; b=UvY10FI3Xow8KxEequfKkdcdszLTxyIdemChuOKCsJQsAY51kR7er7aTWglWuejg/IY/jI sjXhZqvBw5WmLde/FJCXgfc53ua4+lwmC9/OuPrsqar5zxhl0VCm/Eiz2Edhe5Wniw8KcN nw5nHBb3IZXgyjKWdf6P3eTylfIiEbk= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-75-sck4XjFrN8CREdUrT3bN9w-1; Wed, 10 Aug 2022 10:00:13 -0400 X-MC-Unique: sck4XjFrN8CREdUrT3bN9w-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 1410F8037A9; Wed, 10 Aug 2022 14:00:12 +0000 (UTC) Received: from fedora.redhat.com (unknown [10.40.194.21]) by smtp.corp.redhat.com (Postfix) with ESMTP id 326D5492C3B; Wed, 10 Aug 2022 14:00:11 +0000 (UTC) From: Vitaly Kuznetsov To: qemu-devel@nongnu.org, Paolo Bonzini Cc: Sean Christopherson Subject: [PATCH RFC v1 2/2] i386: reorder kvm_put_sregs2() and kvm_put_nested_state() when vCPU is reset Date: Wed, 10 Aug 2022 16:00:07 +0200 Message-Id: <20220810140007.1036293-3-vkuznets@redhat.com> In-Reply-To: <20220810140007.1036293-1-vkuznets@redhat.com> References: <20220810140007.1036293-1-vkuznets@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.85 on 10.11.54.9 Received-SPF: pass client-ip=170.10.129.124; envelope-from=vkuznets@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Setting nested state upon migration needs to happen after kvm_put_sregs2() to e.g. have EFER.SVME set. This, however, doesn't work for vCPU reset: when vCPU is in VMX root operation, certain CR bits are locked and kvm_put_sregs2() may fail. As nested state is fully cleaned up upon vCPU reset (kvm_arch_reset_vcpu() -> kvm_init_nested_state()), calling kvm_put_nested_state() before kvm_put_sregs2() is OK, this will ensure that vCPU is *not* in VMX root opertaion. Signed-off-by: Vitaly Kuznetsov Reviewed-by: Maxim Levitsky --- target/i386/kvm/kvm.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c index 4f8dacc1d4b5..73e3880fa57b 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -4529,18 +4529,34 @@ int kvm_arch_put_registers(CPUState *cpu, int level) assert(cpu_is_stopped(cpu) || qemu_cpu_is_self(cpu)); - /* must be before kvm_put_nested_state so that EFER.SVME is set */ + /* + * When resetting a vCPU, make sure to reset nested state first to + * e.g clear VMXON state and unlock certain CR4 bits. + */ + if (level == KVM_PUT_RESET_STATE) { + ret = kvm_put_nested_state(x86_cpu); + if (ret < 0) { + return ret; + } + } + ret = has_sregs2 ? kvm_put_sregs2(x86_cpu) : kvm_put_sregs(x86_cpu); if (ret < 0) { return ret; } - if (level >= KVM_PUT_RESET_STATE) { + /* + * When putting full CPU state, kvm_put_nested_state() must happen after + * kvm_put_sregs{,2} so that e.g. EFER.SVME is already set. + */ + if (level == KVM_PUT_FULL_STATE) { ret = kvm_put_nested_state(x86_cpu); if (ret < 0) { return ret; } + } + if (level >= KVM_PUT_RESET_STATE) { ret = kvm_put_msr_feature_control(x86_cpu); if (ret < 0) { return ret;