From nobody Wed Sep 17 08:11:15 2025 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 A0CA4C10F1D for ; Fri, 23 Dec 2022 01:01:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235936AbiLWBBJ (ORCPT ); Thu, 22 Dec 2022 20:01:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58188 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235927AbiLWA7t (ORCPT ); Thu, 22 Dec 2022 19:59:49 -0500 Received: from mail-pl1-x64a.google.com (mail-pl1-x64a.google.com [IPv6:2607:f8b0:4864:20::64a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A818231DD3 for ; Thu, 22 Dec 2022 16:58:30 -0800 (PST) Received: by mail-pl1-x64a.google.com with SMTP id z10-20020a170902ccca00b001898329db72so2399233ple.21 for ; Thu, 22 Dec 2022 16:58:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:from:to:cc:subject:date:message-id:reply-to; bh=F68NRl2pI2gfNuGgfMnIAWelg21w3HsZ2MQHgdeJqA4=; b=msOJNFnhoMnqI73ZE5Z/qzHzk1j1M17RXCGluQf+a1yGw+P+1l2k09p3c4nsLWzmnN pGJWlqgSqAKnQE3mahhPADrmGu8jPVkEdf0n9y9CcUlINRrJ+5so3C4FqghwM1Rjeeyr dO8UGzGKn9lb1P79acr83Jg8pns4LgY5d0brjPfAzfMfNjGLfV912nDbKkrVinnQzvaP jDbT/T79j+5jmmgUG3JcATGeYhCiOKtdGiG9lC69hUz4SGXmq4dZN5jaYHcfXLF5ZhVn NQs6RGxqIHtcjcBmeXaX4Av/w15ydZTZs/qHPs1i3mEu6rnjqULNOFXAC2qPXEVe/gdv PlxQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:reply-to:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=F68NRl2pI2gfNuGgfMnIAWelg21w3HsZ2MQHgdeJqA4=; b=GOIfYFfAbm1zZtXGS2n0TXAQZMxtIRQLcAN6S4gHwbevsxajUtxdktBX57vp8sKSkf copF/DWhzlMgGfWgWy4UvlC3FhDQhLPoAzXYhKhAQTIt9QneO+tGmiSaQp+PD8g644ue UKsrljeDkGBY/DGj61K7fW5/B7RyJaglwgkNtHXUbgmYzdDnastakujJNFooYK4G5Qkd dEyzU/CPg2t05BimErIDfphU4SGoNx/2wJOvgM+G8474tiLEONq31RNQsVm3hkrNUi5a 6Z7bUJeFUvlrirpWz6k6yjcYU0UktNbaM1eU4xeXNNsOmowAlBofL+ty0k/4olez3HSQ sAJQ== X-Gm-Message-State: AFqh2kpBAWwnzsdvBi5zJzGaUOBSUQd4mP93bCbuD551K1UFRK1Fmp3O rWcwokT25k+/T2+ktYh29LRIqV2GRIc= X-Google-Smtp-Source: AMrXdXvbfGwlJd/u1wxfpzDD8Ky+xg1iXAqvTzrQ7pRY9+ichgHs9jry+/iz2oMhuB/PfPD8/qh+1mi/xP4= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:902:7d93:b0:189:680e:c2e5 with SMTP id a19-20020a1709027d9300b00189680ec2e5mr362426plm.51.1671757108048; Thu, 22 Dec 2022 16:58:28 -0800 (PST) Reply-To: Sean Christopherson Date: Fri, 23 Dec 2022 00:57:37 +0000 In-Reply-To: <20221223005739.1295925-1-seanjc@google.com> Mime-Version: 1.0 References: <20221223005739.1295925-1-seanjc@google.com> X-Mailer: git-send-email 2.39.0.314.g84b9a713c41-goog Message-ID: <20221223005739.1295925-26-seanjc@google.com> Subject: [PATCH 25/27] KVM: x86/mmu: Handle KVM bookkeeping in page-track APIs, not callers From: Sean Christopherson To: Sean Christopherson , Paolo Bonzini , Zhenyu Wang , Zhi Wang Cc: kvm@vger.kernel.org, intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, Yan Zhao , Ben Gardon Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Get/put references to KVM when a page-track notifier is (un)registered instead of relying on the caller to do so. Forcing the caller to do the bookkeeping is unnecessary and adds one more thing for users to get wrong, e.g. see commit 9ed1fdee9ee3 ("drm/i915/gvt: Get reference to KVM iff attachment to VM is successful"). Signed-off-by: Sean Christopherson --- arch/x86/include/asm/kvm_page_track.h | 10 ++++------ arch/x86/kvm/mmu/page_track.c | 18 ++++++++++++------ drivers/gpu/drm/i915/gvt/kvmgt.c | 23 ++++++++++------------- 3 files changed, 26 insertions(+), 25 deletions(-) diff --git a/arch/x86/include/asm/kvm_page_track.h b/arch/x86/include/asm/k= vm_page_track.h index 415537ce45b4..66a0d7c34311 100644 --- a/arch/x86/include/asm/kvm_page_track.h +++ b/arch/x86/include/asm/kvm_page_track.h @@ -47,12 +47,10 @@ struct kvm_page_track_notifier_node { enum pg_level kvm_page_track_max_mapping_level(struct kvm *kvm, gfn_t gfn, enum pg_level max_level); =20 -void -kvm_page_track_register_notifier(struct kvm *kvm, - struct kvm_page_track_notifier_node *n); -void -kvm_page_track_unregister_notifier(struct kvm *kvm, - struct kvm_page_track_notifier_node *n); +int kvm_page_track_register_notifier(struct kvm *kvm, + struct kvm_page_track_notifier_node *n); +void kvm_page_track_unregister_notifier(struct kvm *kvm, + struct kvm_page_track_notifier_node *n); =20 int kvm_write_track_add_gfn(struct kvm *kvm, gfn_t gfn); int kvm_write_track_remove_gfn(struct kvm *kvm, gfn_t gfn); diff --git a/arch/x86/kvm/mmu/page_track.c b/arch/x86/kvm/mmu/page_track.c index bc54afc1919c..1af431a41f71 100644 --- a/arch/x86/kvm/mmu/page_track.c +++ b/arch/x86/kvm/mmu/page_track.c @@ -157,17 +157,22 @@ int kvm_page_track_init(struct kvm *kvm) * register the notifier so that event interception for the tracked guest * pages can be received. */ -void -kvm_page_track_register_notifier(struct kvm *kvm, - struct kvm_page_track_notifier_node *n) +int kvm_page_track_register_notifier(struct kvm *kvm, + struct kvm_page_track_notifier_node *n) { struct kvm_page_track_notifier_head *head; =20 + if (!kvm || kvm->mm !=3D current->mm) + return -ESRCH; + + kvm_get_kvm(kvm); + head =3D &kvm->arch.track_notifier_head; =20 write_lock(&kvm->mmu_lock); hlist_add_head_rcu(&n->node, &head->track_notifier_list); write_unlock(&kvm->mmu_lock); + return 0; } EXPORT_SYMBOL_GPL(kvm_page_track_register_notifier); =20 @@ -175,9 +180,8 @@ EXPORT_SYMBOL_GPL(kvm_page_track_register_notifier); * stop receiving the event interception. It is the opposed operation of * kvm_page_track_register_notifier(). */ -void -kvm_page_track_unregister_notifier(struct kvm *kvm, - struct kvm_page_track_notifier_node *n) +void kvm_page_track_unregister_notifier(struct kvm *kvm, + struct kvm_page_track_notifier_node *n) { struct kvm_page_track_notifier_head *head; =20 @@ -187,6 +191,8 @@ kvm_page_track_unregister_notifier(struct kvm *kvm, hlist_del_rcu(&n->node); write_unlock(&kvm->mmu_lock); synchronize_srcu(&head->track_srcu); + + kvm_put_kvm(kvm); } EXPORT_SYMBOL_GPL(kvm_page_track_unregister_notifier); =20 diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kv= mgt.c index f9d21d29f533..e4227ac6ab58 100644 --- a/drivers/gpu/drm/i915/gvt/kvmgt.c +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c @@ -670,30 +670,28 @@ static bool __kvmgt_vgpu_exist(struct intel_vgpu *vgp= u) static int intel_vgpu_open_device(struct vfio_device *vfio_dev) { struct intel_vgpu *vgpu =3D vfio_dev_to_vgpu(vfio_dev); + int ret; =20 if (vgpu->attached) return -EEXIST; =20 - if (!vgpu->vfio_device.kvm || - vgpu->vfio_device.kvm->mm !=3D current->mm) { - gvt_vgpu_err("KVM is required to use Intel vGPU\n"); - return -ESRCH; - } - if (__kvmgt_vgpu_exist(vgpu)) return -EEXIST; =20 + vgpu->track_node.track_write =3D kvmgt_page_track_write; + vgpu->track_node.track_remove_region =3D kvmgt_page_track_remove_region; + ret =3D kvm_page_track_register_notifier(vgpu->vfio_device.kvm, + &vgpu->track_node); + if (ret) { + gvt_vgpu_err("KVM is required to use Intel vGPU\n"); + return ret; + } + vgpu->attached =3D true; =20 kvmgt_protect_table_init(vgpu); gvt_cache_init(vgpu); =20 - vgpu->track_node.track_write =3D kvmgt_page_track_write; - vgpu->track_node.track_remove_region =3D kvmgt_page_track_remove_region; - kvm_get_kvm(vgpu->vfio_device.kvm); - kvm_page_track_register_notifier(vgpu->vfio_device.kvm, - &vgpu->track_node); - debugfs_create_ulong(KVMGT_DEBUGFS_FILENAME, 0444, vgpu->debugfs, &vgpu->nr_cache_entries); =20 @@ -730,7 +728,6 @@ static void intel_vgpu_close_device(struct vfio_device = *vfio_dev) =20 kvm_page_track_unregister_notifier(vgpu->vfio_device.kvm, &vgpu->track_node); - kvm_put_kvm(vgpu->vfio_device.kvm); =20 kvmgt_protect_table_destroy(vgpu); gvt_cache_destroy(vgpu); --=20 2.39.0.314.g84b9a713c41-goog