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 2D921C433F5 for ; Mon, 4 Apr 2022 09:54:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355242AbiDDJ4c (ORCPT ); Mon, 4 Apr 2022 05:56:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51762 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243336AbiDDJ41 (ORCPT ); Mon, 4 Apr 2022 05:56:27 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id E072EE020 for ; Mon, 4 Apr 2022 02:54:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1649066071; 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=KMb1GD24tmBMQaTuA4xnLnYoCbKxRRTT3IiDRoq85ns=; b=YFDqXlwJzUNAw+xW9dmJI7Fb3sUCtIq8RYAK9JpZds/rwozq5i2hZiMbjvo6N1CTzYarOW GgufskK4t6xTQOwqWFOeSj/twlVgSnl7oha0EvdxiVFZmdH2LMCJjWl3xgNRkfb7Z5lO1W uOPImlob4eJoT+/WoPmO360YT8QW3+w= Received: from mimecast-mx02.redhat.com (mx3-rdu2.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-404-BEBSKqy4Pa-CIeNKhoZhBg-1; Mon, 04 Apr 2022 05:54:27 -0400 X-MC-Unique: BEBSKqy4Pa-CIeNKhoZhBg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id BD0011C05EA6; Mon, 4 Apr 2022 09:54:26 +0000 (UTC) Received: from starship (unknown [10.40.194.231]) by smtp.corp.redhat.com (Postfix) with ESMTP id B12051111C72; Mon, 4 Apr 2022 09:54:24 +0000 (UTC) Message-ID: <2369d933f61073ca6788545f40b16b9c86d6d368.camel@redhat.com> Subject: Re: [PATCH 1/8] KVM: nSVM: Sync next_rip field from vmcb12 to vmcb02 From: Maxim Levitsky To: Sean Christopherson , Paolo Bonzini Cc: Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, "Maciej S . Szmigiero" Date: Mon, 04 Apr 2022 12:54:23 +0300 In-Reply-To: <20220402010903.727604-2-seanjc@google.com> References: <20220402010903.727604-1-seanjc@google.com> <20220402010903.727604-2-seanjc@google.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.36.5 (3.36.5-2.fc32) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2022-04-02 at 01:08 +0000, Sean Christopherson wrote: > From: Maciej S. Szmigiero > > The next_rip field of a VMCB is *not* an output-only field for a VMRUN. > This field value (instead of the saved guest RIP) in used by the CPU for > the return address pushed on stack when injecting a software interrupt or > INT3 or INTO exception. > > Make sure this field gets synced from vmcb12 to vmcb02 when entering L2 or > loading a nested state and NRIPS is exposed to L1. If NRIPS is supported > in hardware but not exposed to L1 (nrips=0 or hidden by userspace), stuff > vmcb02's next_rip from the new L2 RIP to emulate a !NRIPS CPU (which > saves RIP on the stack as-is). > > Signed-off-by: Maciej S. Szmigiero > Co-developed-by: Sean Christopherson > Signed-off-by: Sean Christopherson > --- > arch/x86/kvm/svm/nested.c | 22 +++++++++++++++++++--- > arch/x86/kvm/svm/svm.h | 1 + > 2 files changed, 20 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c > index 73b545278f5f..9a6dc2b38fcf 100644 > --- a/arch/x86/kvm/svm/nested.c > +++ b/arch/x86/kvm/svm/nested.c > @@ -369,6 +369,7 @@ void __nested_copy_vmcb_control_to_cache(struct kvm_vcpu *vcpu, > to->nested_ctl = from->nested_ctl; > to->event_inj = from->event_inj; > to->event_inj_err = from->event_inj_err; > + to->next_rip = from->next_rip; > to->nested_cr3 = from->nested_cr3; > to->virt_ext = from->virt_ext; > to->pause_filter_count = from->pause_filter_count; > @@ -606,7 +607,8 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12 > } > } > > -static void nested_vmcb02_prepare_control(struct vcpu_svm *svm) > +static void nested_vmcb02_prepare_control(struct vcpu_svm *svm, > + unsigned long vmcb12_rip) > { > u32 int_ctl_vmcb01_bits = V_INTR_MASKING_MASK; > u32 int_ctl_vmcb12_bits = V_TPR_MASK | V_IRQ_INJECTION_BITS_MASK; > @@ -660,6 +662,19 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm) > vmcb02->control.event_inj = svm->nested.ctl.event_inj; > vmcb02->control.event_inj_err = svm->nested.ctl.event_inj_err; > > + /* > + * next_rip is consumed on VMRUN as the return address pushed on the > + * stack for injected soft exceptions/interrupts. If nrips is exposed > + * to L1, take it verbatim from vmcb12. If nrips is supported in > + * hardware but not exposed to L1, stuff the actual L2 RIP to emulate > + * what a nrips=0 CPU would do (L1 is responsible for advancing RIP > + * prior to injecting the event). > + */ > + if (svm->nrips_enabled) > + vmcb02->control.next_rip = svm->nested.ctl.next_rip; > + else if (boot_cpu_has(X86_FEATURE_NRIPS)) > + vmcb02->control.next_rip = vmcb12_rip; > + > vmcb02->control.virt_ext = vmcb01->control.virt_ext & > LBR_CTL_ENABLE_MASK; > if (svm->lbrv_enabled) > @@ -743,7 +758,7 @@ int enter_svm_guest_mode(struct kvm_vcpu *vcpu, u64 vmcb12_gpa, > nested_svm_copy_common_state(svm->vmcb01.ptr, svm->nested.vmcb02.ptr); > > svm_switch_vmcb(svm, &svm->nested.vmcb02); > - nested_vmcb02_prepare_control(svm); > + nested_vmcb02_prepare_control(svm, vmcb12->save.rip); > nested_vmcb02_prepare_save(svm, vmcb12); > > ret = nested_svm_load_cr3(&svm->vcpu, svm->nested.save.cr3, > @@ -1422,6 +1437,7 @@ static void nested_copy_vmcb_cache_to_control(struct vmcb_control_area *dst, > dst->nested_ctl = from->nested_ctl; > dst->event_inj = from->event_inj; > dst->event_inj_err = from->event_inj_err; > + dst->next_rip = from->next_rip; > dst->nested_cr3 = from->nested_cr3; > dst->virt_ext = from->virt_ext; > dst->pause_filter_count = from->pause_filter_count; > @@ -1606,7 +1622,7 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu, > nested_copy_vmcb_control_to_cache(svm, ctl); > > svm_switch_vmcb(svm, &svm->nested.vmcb02); > - nested_vmcb02_prepare_control(svm); > + nested_vmcb02_prepare_control(svm, save->rip); > > /* > * While the nested guest CR3 is already checked and set by > diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h > index e246793cbeae..47e7427d0395 100644 > --- a/arch/x86/kvm/svm/svm.h > +++ b/arch/x86/kvm/svm/svm.h > @@ -139,6 +139,7 @@ struct vmcb_ctrl_area_cached { > u64 nested_ctl; > u32 event_inj; > u32 event_inj_err; > + u64 next_rip; > u64 nested_cr3; > u64 virt_ext; > u32 clean; Reviewed-by: Maxim Levitsky Best regards, Maxim Levitsky