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 7072EC433EF for ; Wed, 11 May 2022 11:34:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239732AbiEKLeE (ORCPT ); Wed, 11 May 2022 07:34:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35376 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235485AbiEKLeB (ORCPT ); Wed, 11 May 2022 07:34:01 -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 14DFF5EBF2 for ; Wed, 11 May 2022 04:34:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1652268840; 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=ZAMoYFHBoif19/LCt+zZ4I/wxVwYh0umbjCqfUO0Uys=; b=CAZHvJi4dwCkq29Etf/tzeCn32PrvQhlqENqaw86DHq+m/vDZmKrrjL811wIExDukHpvJq aPL0TXFfsTY31fJkoiz64mn2F0prw9rDAXaUpAH4ePXqiqs/9zCFG6OCsHieMcrKj+mO7R BKsoaS6EMkgh3ycYDygYXLOQDC56aeE= 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-672-c06PDqn9MVKVrE0-IjmS-g-1; Wed, 11 May 2022 07:33:57 -0400 X-MC-Unique: c06PDqn9MVKVrE0-IjmS-g-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 736531C01B27; Wed, 11 May 2022 11:33:56 +0000 (UTC) Received: from starship (unknown [10.40.192.26]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2F55240CF8E4; Wed, 11 May 2022 11:33:54 +0000 (UTC) Message-ID: <0cbef2ca32145857b209a81ad82a99479ade5f6c.camel@redhat.com> Subject: Re: [PATCH v3 21/34] KVM: nSVM: hyper-v: Enable L2 TLB flush From: Maxim Levitsky To: Vitaly Kuznetsov , kvm@vger.kernel.org, Paolo Bonzini Cc: Sean Christopherson , Wanpeng Li , Jim Mattson , Michael Kelley , Siddharth Chandrasekaran , linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 11 May 2022 14:33:53 +0300 In-Reply-To: <20220414132013.1588929-22-vkuznets@redhat.com> References: <20220414132013.1588929-1-vkuznets@redhat.com> <20220414132013.1588929-22-vkuznets@redhat.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 2.84 on 10.11.54.1 Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org On Thu, 2022-04-14 at 15:20 +0200, Vitaly Kuznetsov wrote: > Implement Hyper-V L2 TLB flush for nSVM. The feature needs to be enabled > both in extended 'nested controls' in VMCB and partition assist page. > According to Hyper-V TLFS, synthetic vmexit to L1 is performed with > - HV_SVM_EXITCODE_ENL exit_code. > - HV_SVM_ENL_EXITCODE_TRAP_AFTER_FLUSH exit_info_1. > > Signed-off-by: Vitaly Kuznetsov > --- > arch/x86/kvm/svm/hyperv.c | 7 +++++++ > arch/x86/kvm/svm/hyperv.h | 19 +++++++++++++++++++ > arch/x86/kvm/svm/nested.c | 22 +++++++++++++++++++++- > 3 files changed, 47 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/svm/hyperv.c b/arch/x86/kvm/svm/hyperv.c > index c0749fc282fe..3842548bb88c 100644 > --- a/arch/x86/kvm/svm/hyperv.c > +++ b/arch/x86/kvm/svm/hyperv.c > @@ -8,4 +8,11 @@ > > void svm_post_hv_l2_tlb_flush(struct kvm_vcpu *vcpu) > { > + struct vcpu_svm *svm = to_svm(vcpu); > + > + svm->vmcb->control.exit_code = HV_SVM_EXITCODE_ENL; > + svm->vmcb->control.exit_code_hi = 0; > + svm->vmcb->control.exit_info_1 = HV_SVM_ENL_EXITCODE_TRAP_AFTER_FLUSH; > + svm->vmcb->control.exit_info_2 = 0; > + nested_svm_vmexit(svm); > } > diff --git a/arch/x86/kvm/svm/hyperv.h b/arch/x86/kvm/svm/hyperv.h > index a2b0d7580b0d..cd33e89f9f61 100644 > --- a/arch/x86/kvm/svm/hyperv.h > +++ b/arch/x86/kvm/svm/hyperv.h > @@ -33,6 +33,9 @@ struct hv_enlightenments { > */ > #define VMCB_HV_NESTED_ENLIGHTENMENTS VMCB_SW > > +#define HV_SVM_EXITCODE_ENL 0xF0000000 > +#define HV_SVM_ENL_EXITCODE_TRAP_AFTER_FLUSH (1) > + > static inline void nested_svm_hv_update_vm_vp_ids(struct kvm_vcpu *vcpu) > { > struct vcpu_svm *svm = to_svm(vcpu); > @@ -48,6 +51,22 @@ static inline void nested_svm_hv_update_vm_vp_ids(struct kvm_vcpu *vcpu) > hv_vcpu->nested.vp_id = hve->hv_vp_id; > } > > +static inline bool nested_svm_l2_tlb_flush_enabled(struct kvm_vcpu *vcpu) > +{ > + struct vcpu_svm *svm = to_svm(vcpu); > + struct hv_enlightenments *hve = > + (struct hv_enlightenments *)svm->nested.ctl.reserved_sw; > + struct hv_vp_assist_page assist_page; > + > + if (unlikely(!kvm_hv_get_assist_page(vcpu, &assist_page))) > + return false; > + > + if (!hve->hv_enlightenments_control.nested_flush_hypercall) > + return false; > + > + return assist_page.nested_control.features.directhypercall; > +} > + > void svm_post_hv_l2_tlb_flush(struct kvm_vcpu *vcpu); > > #endif /* __ARCH_X86_KVM_SVM_HYPERV_H__ */ > diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c > index de3f27301b5c..a6d9807c09b1 100644 > --- a/arch/x86/kvm/svm/nested.c > +++ b/arch/x86/kvm/svm/nested.c > @@ -172,7 +172,8 @@ void recalc_intercepts(struct vcpu_svm *svm) > } > > /* We don't want to see VMMCALLs from a nested guest */ Minor nitpick: Maybe update the comment? > - vmcb_clr_intercept(c, INTERCEPT_VMMCALL); > + if (!nested_svm_l2_tlb_flush_enabled(&svm->vcpu)) > + vmcb_clr_intercept(c, INTERCEPT_VMMCALL); > > for (i = 0; i < MAX_INTERCEPT; i++) > c->intercepts[i] |= g->intercepts[i]; > @@ -488,6 +489,17 @@ static void nested_save_pending_event_to_vmcb12(struct vcpu_svm *svm, > > static void nested_svm_transition_tlb_flush(struct kvm_vcpu *vcpu) > { > + /* > + * KVM_REQ_HV_TLB_FLUSH flushes entries from either L1's VP_ID or > + * L2's VP_ID upon request from the guest. Make sure we check for > + * pending entries for the case when the request got misplaced (e.g. > + * a transition from L2->L1 happened while processing L2 TLB flush > + * request or vice versa). kvm_hv_vcpu_flush_tlb() will not flush > + * anything if there are no requests in the corresponding buffer. > + */ > + if (to_hv_vcpu(vcpu)) > + kvm_make_request(KVM_REQ_HV_TLB_FLUSH, vcpu); > + > /* > * TODO: optimize unconditional TLB flush/MMU sync. A partial list of > * things to fix before this can be conditional: > @@ -1357,6 +1369,7 @@ static int svm_check_nested_events(struct kvm_vcpu *vcpu) > int nested_svm_exit_special(struct vcpu_svm *svm) > { > u32 exit_code = svm->vmcb->control.exit_code; > + struct kvm_vcpu *vcpu = &svm->vcpu; > > switch (exit_code) { > case SVM_EXIT_INTR: > @@ -1375,6 +1388,13 @@ int nested_svm_exit_special(struct vcpu_svm *svm) > return NESTED_EXIT_HOST; > break; > } > + case SVM_EXIT_VMMCALL: > + /* Hyper-V L2 TLB flush hypercall is handled by L0 */ > + if (kvm_hv_l2_tlb_flush_exposed(vcpu) && > + nested_svm_l2_tlb_flush_enabled(vcpu) && > + kvm_hv_is_tlb_flush_hcall(vcpu)) > + return NESTED_EXIT_HOST; > + break; > default: > break; > } Reviewed-by: Maxim Levitsky Best regards, Maxim Levitsky