From patchwork Wed Apr 27 20:03:12 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxim Levitsky X-Patchwork-Id: 12829504 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 CA27EC433F5 for ; Wed, 27 Apr 2022 20:05:44 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 08E6910E58A; Wed, 27 Apr 2022 20:05:44 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by gabe.freedesktop.org (Postfix) with ESMTPS id B464110E5BB for ; Wed, 27 Apr 2022 20:05:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1651089941; 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=yA9Ogh+XZjCqc2vT+o0W3Eipd0C5KqefizxAchXjEVE=; b=Tne9iSDPebKu/feFFETnJrg5Y9qhaq4BU+iZXxi1q0bAQHObhPiNTvcvnLbnJBtzCcswdc SXDpZgYxWgYVFsILtaDn4QYNeWEtD5WBajukqIu5fBX5ExG7i6xOegCrXnGIR8rcbgXWqA VQ1EV6epGbeiF0kg6vqc/OJusfQ56go= 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-263-qLc1Y9eCOsGgT0TQKKNudg-1; Wed, 27 Apr 2022 16:05:36 -0400 X-MC-Unique: qLc1Y9eCOsGgT0TQKKNudg-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D94E980418D; Wed, 27 Apr 2022 20:05:34 +0000 (UTC) Received: from localhost.localdomain (unknown [10.40.192.41]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1676E9E74; Wed, 27 Apr 2022 20:05:08 +0000 (UTC) From: Maxim Levitsky To: kvm@vger.kernel.org Date: Wed, 27 Apr 2022 23:03:12 +0300 Message-Id: <20220427200314.276673-18-mlevitsk@redhat.com> In-Reply-To: <20220427200314.276673-1-mlevitsk@redhat.com> References: <20220427200314.276673-1-mlevitsk@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 Subject: [Intel-gfx] [RFC PATCH v3 17/19] KVM: x86: nSVM: implement nested AVIC doorbell emulation X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Wanpeng Li , David Airlie , Dave Hansen , dri-devel@lists.freedesktop.org, "H. Peter Anvin" , Brijesh Singh , Joerg Roedel , x86@kernel.org, Maxim Levitsky , Ingo Molnar , Tom Lendacky , intel-gfx@lists.freedesktop.org, Borislav Petkov , Rodrigo Vivi , Thomas Gleixner , intel-gvt-dev@lists.freedesktop.org, Jim Mattson , Sean Christopherson , linux-kernel@vger.kernel.org, Paolo Bonzini , Vitaly Kuznetsov Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" This patch implements the doorbell msr emulation for nested AVIC. Signed-off-by: Maxim Levitsky --- arch/x86/kvm/svm/avic.c | 49 +++++++++++++++++++++++++++++++++++++++++ arch/x86/kvm/svm/svm.c | 2 ++ arch/x86/kvm/svm/svm.h | 1 + 3 files changed, 52 insertions(+) diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c index e8c53fd77f0b1..149df26e17462 100644 --- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c @@ -1165,6 +1165,55 @@ unsigned long avic_vcpu_get_apicv_inhibit_reasons(struct kvm_vcpu *vcpu) return 0; } +int avic_emulate_doorbell_write(struct kvm_vcpu *vcpu, u64 data) +{ + int source_l1_apicid = vcpu->vcpu_id; + int target_l1_apicid = data & AVIC_DOORBELL_PHYSICAL_ID_MASK; + bool target_running, target_nested; + struct kvm_vcpu *target; + struct vcpu_svm *svm = to_svm(vcpu); + + if (!svm->avic_enabled || (data & ~AVIC_DOORBELL_PHYSICAL_ID_MASK)) + return 1; + + target = avic_vcpu_by_l1_apicid(vcpu->kvm, target_l1_apicid); + if (!target) + /* Guest bug: targeting invalid APIC ID. */ + return 0; + + target_running = READ_ONCE(target->mode) == IN_GUEST_MODE; + target_nested = is_guest_mode(target); + + trace_kvm_avic_nested_doorbell(source_l1_apicid, target_l1_apicid, + target_nested, target_running); + + /* + * Target is not in the nested mode, thus the doorbell doesn't affect it. + * If it just became nested after is_guest_mode was checked, + * it means that it just processed AVIC state and KVM doesn't need + * to send it another doorbell. + */ + if (!target_nested) + return 0; + + /* + * If the target vCPU is in guest mode, kick the real doorbell. + * Otherwise KVM needs to try to wake it up if it was sleeping. + * + * If the target is not longer in guest mode (just exited it), + * it will either halt and before that it will notice pending IRR + * bits, and cancel halting, or it will enter the guest mode again, + * and notice the IRR bits as well. + */ + if (target_running) + wrmsr(MSR_AMD64_SVM_AVIC_DOORBELL, + kvm_cpu_get_apicid(READ_ONCE(target->cpu)), 0); + else + kvm_vcpu_wake_up(target); + + return 0; +} + static u32 *avic_get_logical_id_entry(struct kvm_vcpu *vcpu, u32 ldr, bool flat) { struct kvm_svm *kvm_svm = to_kvm_svm(vcpu->kvm); diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index d96a73931d1e5..b31bab832360e 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -2772,6 +2772,8 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr) u32 ecx = msr->index; u64 data = msr->data; switch (ecx) { + case MSR_AMD64_SVM_AVIC_DOORBELL: + return avic_emulate_doorbell_write(vcpu, data); case MSR_AMD64_TSC_RATIO: if (!svm->tsc_scaling_enabled) { diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 93fd9d6f5fd85..14e2c5c451cad 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -714,6 +714,7 @@ unsigned long avic_vcpu_get_apicv_inhibit_reasons(struct kvm_vcpu *vcpu); void avic_reload_apic_pages(struct kvm_vcpu *vcpu); void avic_free_nested(struct kvm_vcpu *vcpu); bool avic_nested_has_interrupt(struct kvm_vcpu *vcpu); +int avic_emulate_doorbell_write(struct kvm_vcpu *vcpu, u64 data); struct avic_physid_table * avic_physid_shadow_table_get(struct kvm_vcpu *vcpu, gfn_t gfn);