From patchwork Mon Apr 26 11:13:28 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxim Levitsky X-Patchwork-Id: 12224171 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=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 C0702C43462 for ; Mon, 26 Apr 2021 11:14:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8B3B5613BF for ; Mon, 26 Apr 2021 11:14:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233348AbhDZLPQ (ORCPT ); Mon, 26 Apr 2021 07:15:16 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:40415 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233205AbhDZLPE (ORCPT ); Mon, 26 Apr 2021 07:15:04 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1619435663; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6XVGhAXBfo9MgQy1ty+oqe6SntrES8m23Sof78r/E/E=; b=IZXpeb5TvGbeASyH4WcqkzNxmY0dHKVSgTvd1sp9nX6qBLJER3Z41Hqn8YKJKQL6oNAasD /fvupI8n3pTbjMe9yJM3K5hYyrZrwArPdplJyH060xXPmEyoCgCO20dVimK75mM2Bvy5Si sK+lgPGrUMT0+vahbxAoItuFQB9BkK4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-141-T7jfQD7PPQiPaeAlmnN-3A-1; Mon, 26 Apr 2021 07:14:21 -0400 X-MC-Unique: T7jfQD7PPQiPaeAlmnN-3A-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D124F108BC2F; Mon, 26 Apr 2021 11:13:45 +0000 (UTC) Received: from localhost.localdomain (unknown [10.40.192.73]) by smtp.corp.redhat.com (Postfix) with ESMTP id 316595D9D0; Mon, 26 Apr 2021 11:13:40 +0000 (UTC) From: Maxim Levitsky To: kvm@vger.kernel.org Cc: linux-doc@vger.kernel.org (open list:DOCUMENTATION), Thomas Gleixner , Jonathan Corbet , Paolo Bonzini , x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)), linux-kernel@vger.kernel.org (open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)), "H. Peter Anvin" , Ingo Molnar , Borislav Petkov , Wanpeng Li , Vitaly Kuznetsov , Jim Mattson , Sean Christopherson , Joerg Roedel , Maxim Levitsky Subject: [PATCH v2 1/6] KVM: nSVM: refactor the CR3 reload on migration Date: Mon, 26 Apr 2021 14:13:28 +0300 Message-Id: <20210426111333.967729-2-mlevitsk@redhat.com> In-Reply-To: <20210426111333.967729-1-mlevitsk@redhat.com> References: <20210426111333.967729-1-mlevitsk@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Document the actual reason why we need to do it on migration and move the call to svm_set_nested_state to be closer to VMX code. To avoid loading the PDPTRs from possibly not up to date memory map, in nested_svm_load_cr3 after the move, move this code to .get_nested_state_pages. Signed-off-by: Maxim Levitsky --- arch/x86/kvm/svm/nested.c | 32 +++++++++++++++++++++++++------- 1 file changed, 25 insertions(+), 7 deletions(-) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 540d43ba2cf4..ceb37ed1dc98 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -385,12 +385,12 @@ static inline bool nested_npt_enabled(struct vcpu_svm *svm) * if we are emulating VM-Entry into a guest with NPT enabled. */ static int nested_svm_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3, - bool nested_npt) + bool nested_npt, bool reload_pdptrs) { if (CC(kvm_vcpu_is_illegal_gpa(vcpu, cr3))) return -EINVAL; - if (!nested_npt && is_pae_paging(vcpu) && + if (reload_pdptrs && !nested_npt && is_pae_paging(vcpu) && (cr3 != kvm_read_cr3(vcpu) || pdptrs_changed(vcpu))) { if (CC(!load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3))) return -EINVAL; @@ -576,7 +576,7 @@ int enter_svm_guest_mode(struct kvm_vcpu *vcpu, u64 vmcb12_gpa, nested_vmcb02_prepare_save(svm, vmcb12); ret = nested_svm_load_cr3(&svm->vcpu, vmcb12->save.cr3, - nested_npt_enabled(svm)); + nested_npt_enabled(svm), true); if (ret) return ret; @@ -806,7 +806,7 @@ int nested_svm_vmexit(struct vcpu_svm *svm) nested_svm_uninit_mmu_context(vcpu); - rc = nested_svm_load_cr3(vcpu, svm->vmcb->save.cr3, false); + rc = nested_svm_load_cr3(vcpu, svm->vmcb->save.cr3, false, true); if (rc) return 1; @@ -1291,6 +1291,19 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu, !nested_vmcb_valid_sregs(vcpu, save)) goto out_free; + /* + * While the nested guest CR3 is already checked and set by + * KVM_SET_SREGS, it was set when nested state was yet loaded, + * thus MMU might not be initialized correctly. + * Set it again to fix this. + */ + + ret = nested_svm_load_cr3(&svm->vcpu, vcpu->arch.cr3, + nested_npt_enabled(svm), false); + if (WARN_ON_ONCE(ret)) + goto out_free; + + /* * All checks done, we can enter guest mode. Userspace provides * vmcb12.control, which will be combined with L1 and stored into @@ -1343,9 +1356,14 @@ static bool svm_get_nested_state_pages(struct kvm_vcpu *vcpu) if (WARN_ON(!is_guest_mode(vcpu))) return true; - if (nested_svm_load_cr3(&svm->vcpu, vcpu->arch.cr3, - nested_npt_enabled(svm))) - return false; + if (!nested_npt_enabled(svm) && is_pae_paging(vcpu)) + /* + * Reload the guest's PDPTRs since after a migration + * the guest CR3 might be restored prior to setting the nested + * state which can lead to a load of wrong PDPTRs. + */ + if (CC(!load_pdptrs(vcpu, vcpu->arch.walk_mmu, vcpu->arch.cr3))) + return false; if (!nested_svm_vmrun_msrpm(svm)) { vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;