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[2620:137:e000::1:20]) by mx.google.com with ESMTP id w1-20020a631601000000b00502d6998a4asi944560pgl.458.2023.03.10.16.41.14; Fri, 10 Mar 2023 16:41:29 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20210112 header.b="HO/j4jZx"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231332AbjCKAYY (ORCPT + 99 others); Fri, 10 Mar 2023 19:24:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44976 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230456AbjCKAXo (ORCPT ); Fri, 10 Mar 2023 19:23:44 -0500 Received: from mail-pj1-x104a.google.com (mail-pj1-x104a.google.com [IPv6:2607:f8b0:4864:20::104a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 862716B955 for ; Fri, 10 Mar 2023 16:23:28 -0800 (PST) Received: by mail-pj1-x104a.google.com with SMTP id q9-20020a17090a9f4900b00237d026fc55so5053360pjv.3 for ; Fri, 10 Mar 2023 16:23:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; t=1678494205; 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=C7JjSI0pT7joQ/rLMM2i7GRIoYFbucT/e+mgN6frquk=; b=HO/j4jZxJTPnNlCvqNIr5Y5KBfdMA+RArZQ6E8B+5VeFfzVshQ9PBvi1r5s9Vp2/Sj Pt7JTJKOBCqoqv8n4jxdK+8vBvs0GXZc7nW8k5IsbdneX9q7CcOtXcr5R6UJ39ls0eYZ 6Y7j9wTPtbZQ7b17m/bJYsT/8NjZnITyKuhsNfYb/UMAULXoEo4a2UglV221BRnLFrcy aZ8NirUFSobSolD6VpCWTPhefI1g6HcHwKuU3rrdgwuk0hOYJvzaVFIs94wOvTXe0KLT 3uHSd1BR6WrVPUWLMgcw8g7jirMBfMd7+Gjd/TGzPOcG5bhLVf8y0szkKmKHbV/rX64c Tdyg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678494205; 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=C7JjSI0pT7joQ/rLMM2i7GRIoYFbucT/e+mgN6frquk=; b=0PEzyqr15Wd6yNG98Zmu6+SmtSI5Hr49BgGI0liNzQowzfAE59qt0MghRCzbjBRyBS ktgXUk850Hut1JBI3wzuBw+c980jZyYdtKqTiGLylDUuPwVT9p4Cauf3Eqo6xaZesN9c jOzoaLrvCsolC3JG5OwDqr6hFzEAG/vT5eHXoQO3empyYuK8SVrNqZK8mBVWTreaQ2t+ QqDpKx0CSctZoone6ExORMBZ4js3sQHZ8BT9JxhPrbkj5HAHnphn/vtk1CVLrnESi+Pw 0kMVJqEbHtmiUKhiAtLbtjXtRpLy0XC1U2IPUNWkK01eBfXK0swWVk6XRZCm6yOgNWEz AG6A== X-Gm-Message-State: AO0yUKUCcOzHxTW8/cekgW+tWdVf4p5kkMYjALxi4q+pMckg89ZNqsUQ Hyt4t1uVA9ABzEFRbbmHZp+oePp7xBc= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a17:90a:420b:b0:237:29b1:188f with SMTP id o11-20020a17090a420b00b0023729b1188fmr10180694pjg.8.1678494205065; Fri, 10 Mar 2023 16:23:25 -0800 (PST) Reply-To: Sean Christopherson Date: Fri, 10 Mar 2023 16:22:41 -0800 In-Reply-To: <20230311002258.852397-1-seanjc@google.com> Mime-Version: 1.0 References: <20230311002258.852397-1-seanjc@google.com> X-Mailer: git-send-email 2.40.0.rc1.284.g88254d51c5-goog Message-ID: <20230311002258.852397-11-seanjc@google.com> Subject: [PATCH v2 10/27] drm/i915/gvt: Protect gfn hash table with vgpu_lock 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 X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1760029876225147885?= X-GMAIL-MSGID: =?utf-8?q?1760029876225147885?= Use vgpu_lock instead of KVM's mmu_lock to protect accesses to the hash table used to track which gfns are write-protected when shadowing the guest's GTT, and hoist the acquisition of vgpu_lock from intel_vgpu_page_track_handler() out to its sole caller, kvmgt_page_track_write(). This fixes a bug where kvmgt_page_track_write(), which doesn't hold kvm->mmu_lock, could race with intel_gvt_page_track_remove() and trigger a use-after-free. Fixing kvmgt_page_track_write() by taking kvm->mmu_lock is not an option as mmu_lock is a r/w spinlock, and intel_vgpu_page_track_handler() might sleep when acquiring vgpu->cache_lock deep down the callstack: intel_vgpu_page_track_handler() | |-> page_track->handler / ppgtt_write_protection_handler() | |-> ppgtt_handle_guest_write_page_table_bytes() | |-> ppgtt_handle_guest_write_page_table() | |-> ppgtt_handle_guest_entry_removal() | |-> ppgtt_invalidate_pte() | |-> intel_gvt_dma_unmap_guest_page() | |-> mutex_lock(&vgpu->cache_lock); Signed-off-by: Sean Christopherson Reviewed-by: Yan Zhao --- drivers/gpu/drm/i915/gvt/kvmgt.c | 55 +++++++++++++++------------ drivers/gpu/drm/i915/gvt/page_track.c | 10 +---- 2 files changed, 33 insertions(+), 32 deletions(-) diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c index 68be66395598..9824d075562e 100644 --- a/drivers/gpu/drm/i915/gvt/kvmgt.c +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c @@ -366,6 +366,8 @@ __kvmgt_protect_table_find(struct intel_vgpu *info, gfn_t gfn) { struct kvmgt_pgfn *p, *res = NULL; + lockdep_assert_held(&info->vgpu_lock); + hash_for_each_possible(info->ptable, p, hnode, gfn) { if (gfn == p->gfn) { res = p; @@ -1567,6 +1569,9 @@ int intel_gvt_page_track_add(struct intel_vgpu *info, u64 gfn) if (!test_bit(INTEL_VGPU_STATUS_ATTACHED, info->status)) return -ESRCH; + if (kvmgt_gfn_is_write_protected(info, gfn)) + return 0; + idx = srcu_read_lock(&kvm->srcu); slot = gfn_to_memslot(kvm, gfn); if (!slot) { @@ -1575,16 +1580,12 @@ int intel_gvt_page_track_add(struct intel_vgpu *info, u64 gfn) } write_lock(&kvm->mmu_lock); - - if (kvmgt_gfn_is_write_protected(info, gfn)) - goto out; - kvm_slot_page_track_add_page(kvm, slot, gfn, KVM_PAGE_TRACK_WRITE); + write_unlock(&kvm->mmu_lock); + + srcu_read_unlock(&kvm->srcu, idx); + kvmgt_protect_table_add(info, gfn); - -out: - write_unlock(&kvm->mmu_lock); - srcu_read_unlock(&kvm->srcu, idx); return 0; } @@ -1597,24 +1598,22 @@ int intel_gvt_page_track_remove(struct intel_vgpu *info, u64 gfn) if (!test_bit(INTEL_VGPU_STATUS_ATTACHED, info->status)) return -ESRCH; - idx = srcu_read_lock(&kvm->srcu); - slot = gfn_to_memslot(kvm, gfn); - if (!slot) { - srcu_read_unlock(&kvm->srcu, idx); - return -EINVAL; - } - - write_lock(&kvm->mmu_lock); - if (!kvmgt_gfn_is_write_protected(info, gfn)) - goto out; + return 0; + idx = srcu_read_lock(&kvm->srcu); + slot = gfn_to_memslot(kvm, gfn); + if (!slot) { + srcu_read_unlock(&kvm->srcu, idx); + return -EINVAL; + } + + write_lock(&kvm->mmu_lock); kvm_slot_page_track_remove_page(kvm, slot, gfn, KVM_PAGE_TRACK_WRITE); + write_unlock(&kvm->mmu_lock); + srcu_read_unlock(&kvm->srcu, idx); + kvmgt_protect_table_del(info, gfn); - -out: - write_unlock(&kvm->mmu_lock); - srcu_read_unlock(&kvm->srcu, idx); return 0; } @@ -1625,9 +1624,13 @@ static void kvmgt_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, struct intel_vgpu *info = container_of(node, struct intel_vgpu, track_node); + mutex_lock(&info->vgpu_lock); + if (kvmgt_gfn_is_write_protected(info, gpa_to_gfn(gpa))) intel_vgpu_page_track_handler(info, gpa, (void *)val, len); + + mutex_unlock(&info->vgpu_lock); } static void kvmgt_page_track_flush_slot(struct kvm *kvm, @@ -1639,16 +1642,20 @@ static void kvmgt_page_track_flush_slot(struct kvm *kvm, struct intel_vgpu *info = container_of(node, struct intel_vgpu, track_node); - write_lock(&kvm->mmu_lock); + mutex_lock(&info->vgpu_lock); + for (i = 0; i < slot->npages; i++) { gfn = slot->base_gfn + i; if (kvmgt_gfn_is_write_protected(info, gfn)) { + write_lock(&kvm->mmu_lock); kvm_slot_page_track_remove_page(kvm, slot, gfn, KVM_PAGE_TRACK_WRITE); + write_unlock(&kvm->mmu_lock); + kvmgt_protect_table_del(info, gfn); } } - write_unlock(&kvm->mmu_lock); + mutex_unlock(&info->vgpu_lock); } void intel_vgpu_detach_regions(struct intel_vgpu *vgpu) diff --git a/drivers/gpu/drm/i915/gvt/page_track.c b/drivers/gpu/drm/i915/gvt/page_track.c index df34e73cba41..60a65435556d 100644 --- a/drivers/gpu/drm/i915/gvt/page_track.c +++ b/drivers/gpu/drm/i915/gvt/page_track.c @@ -162,13 +162,9 @@ int intel_vgpu_page_track_handler(struct intel_vgpu *vgpu, u64 gpa, struct intel_vgpu_page_track *page_track; int ret = 0; - mutex_lock(&vgpu->vgpu_lock); - page_track = intel_vgpu_find_page_track(vgpu, gpa >> PAGE_SHIFT); - if (!page_track) { - ret = -ENXIO; - goto out; - } + if (!page_track) + return -ENXIO; if (unlikely(vgpu->failsafe)) { /* Remove write protection to prevent furture traps. */ @@ -179,7 +175,5 @@ int intel_vgpu_page_track_handler(struct intel_vgpu *vgpu, u64 gpa, gvt_err("guest page write error, gpa %llx\n", gpa); } -out: - mutex_unlock(&vgpu->vgpu_lock); return ret; }