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 A4427C433F5 for ; Fri, 29 Apr 2022 00:28:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352575AbiD2Abu (ORCPT ); Thu, 28 Apr 2022 20:31:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56936 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237176AbiD2Abs (ORCPT ); Thu, 28 Apr 2022 20:31:48 -0400 Received: from mail-yb1-xb30.google.com (mail-yb1-xb30.google.com [IPv6:2607:f8b0:4864:20::b30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BEE67B89A6 for ; Thu, 28 Apr 2022 17:28:30 -0700 (PDT) Received: by mail-yb1-xb30.google.com with SMTP id v59so11858853ybi.12 for ; Thu, 28 Apr 2022 17:28:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=9ICHE4YVmMxDEwnIKZ75c63DFS1ERzMwYHqAgAYiSNI=; b=FDVhw8pM/z0rNbidBdUuVJwYUELyOORKaWH0gCKjGVq5qqbJZDXCjqa/jtUDZfNYmd ZY7rhgyF3fhHOa3cgw2CZsgoSZUNDySKKIN1VfTHSPhg8LyuydL2PgbpAyMwbW5m8WGt NSGIb7vVXfvk/wbOWesDG4az2vkmmN/4f2hzP5j45waTjgDNdob4FYCAsIJl9fRW+uWk DpIXQrFnMwm/ih4uFZ7d4b6/+cZ16KAu6GZOxX0DhxFFqxHP8N8R9VwnCO8aY6eONh78 9hrwqTHcaA7co9KT7DgW5hHd6+7thDxTL+CTZpLW1fpNWVeAlWIWcm/g3YbeODGoeSbi 9DCQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=9ICHE4YVmMxDEwnIKZ75c63DFS1ERzMwYHqAgAYiSNI=; b=pXSTyrCrX02XrQ+VUtn1mikxWKxDlz4e3o+dqRKKAffN+AUAhiC/EMonLVCAjKcP8B tWKOpJw3xF4lByxWebbp5zGpmAaiRjdDP/5PqOlJV0WQY0RheFk4sQbWEh8J5tSZeJmK nPlD1UuaBjIq+ygCx6853Xf9vgSi77zaFoHWmURKCLuJvpGP8WHZGKBgmSypM4f0gBzs zpIaja2rmmQig1ZIYNr+W/kQG1R5n0LrYVzZKZQhv3VxVzp2woruVE7pTT7pPR8ZXuow 0y8OVmpbbSzpUVjR1dSWJAZVVlIrY9j4IExAb1geuYgWX5zXk3rIKE6t+XU/dKvMIdpQ bJzw== X-Gm-Message-State: AOAM530lwLeYb6NRA18xGPqKMpHM7in8GRz5Rx0gmcFK98eviEJ/vCso Tr3uS2/o5J+Ncr21TUBUIMamgGMgFjGQzPNaTU0ufA== X-Google-Smtp-Source: ABdhPJzf03nX+DBnOc3dqokWOxgwwgyaL2QvT4JiNAKyXAJhHAC0MKwvi1wLp2rAEC0/Tu7HIK1kH7ROmYmuS6Ku4rk= X-Received: by 2002:a25:3b8f:0:b0:644:afb4:57a6 with SMTP id i137-20020a253b8f000000b00644afb457a6mr33255886yba.40.1651192109561; Thu, 28 Apr 2022 17:28:29 -0700 (PDT) MIME-Version: 1.0 References: <7a5246c54427952728bd702bd7f2c6963eefa712.1646422845.git.isaku.yamahata@intel.com> In-Reply-To: <7a5246c54427952728bd702bd7f2c6963eefa712.1646422845.git.isaku.yamahata@intel.com> From: Sagi Shahar Date: Thu, 28 Apr 2022 17:28:18 -0700 Message-ID: Subject: Re: [RFC PATCH v5 048/104] KVM: x86/tdp_mmu: Support TDX private mapping for TDP MMU To: "Yamahata, Isaku" Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, isaku.yamahata@gmail.com, Paolo Bonzini , Jim Mattson , Erdem Aktas , Connor Kuehl , Sean Christopherson Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org is not . On Fri, Mar 4, 2022 at 12:14 PM wrote: > > From: Isaku Yamahata > > Use private EPT to mirror Secure EPT, and On the change of the private EPT > entry, invoke kvm_x86_ops hook in __handle_changed_spte() to propagate the > change to Secure EPT. > > On EPT violation, determine which EPT to use, private or shared, based on > faulted GPA. When allocating an EPT page, record it (private or shared) in > the page role. The private is passed down to the function as an argument > as necessary. When the private EPT entry is changed, call the hook. > > When zapping EPT, the EPT entry is frozen with the special EPT value that > clears the present bit. After the TLB shootdown, the entry is set to the > eventual value. On populating the EPT entry, atomically set the entry. > > For TDX, TDX SEAMCALL to update Secure EPT in addition to direct access to > the private EPT entry. For the zapping case, freeing the EPT entry > works. It can call TDX SEAMCALL in addition to TLB shootdown. For > populating the private EPT entry, there can be a race condition without > further protection > > vcpu 1: populating 2M private EPT entry > vcpu 2: populating 4K private EPT entry > vcpu 2: TDX SEAMCALL to update 4K secure EPT => error > vcpu 1: TDX SEAMCALL to update 4M secure EPT > > To avoid the race, the frozen EPT entry is utilized. Instead of atomic > update of the private EPT entry, freeze the entry, call the hook that > invokes TDX SEAMCALL, set the entry to the final value (unfreeze). > > Support 4K page only at this stage. 2M page support can be done in future > patches. > > Co-developed-by: Kai Huang > Signed-off-by: Kai Huang > Signed-off-by: Isaku Yamahata > --- > arch/x86/include/asm/kvm-x86-ops.h | 2 + > arch/x86/include/asm/kvm_host.h | 8 + > arch/x86/kvm/mmu/mmu.c | 31 +++- > arch/x86/kvm/mmu/tdp_iter.h | 2 +- > arch/x86/kvm/mmu/tdp_mmu.c | 226 +++++++++++++++++++++++------ > arch/x86/kvm/mmu/tdp_mmu.h | 13 +- > virt/kvm/kvm_main.c | 1 + > 7 files changed, 232 insertions(+), 51 deletions(-) > > diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h > index ef48dcc98cfc..7e27b73d839f 100644 > --- a/arch/x86/include/asm/kvm-x86-ops.h > +++ b/arch/x86/include/asm/kvm-x86-ops.h > @@ -91,6 +91,8 @@ KVM_X86_OP(set_tss_addr) > KVM_X86_OP(set_identity_map_addr) > KVM_X86_OP(get_mt_mask) > KVM_X86_OP(load_mmu_pgd) > +KVM_X86_OP(free_private_sp) > +KVM_X86_OP(handle_changed_private_spte) > KVM_X86_OP_NULL(has_wbinvd_exit) > KVM_X86_OP(get_l2_tsc_offset) > KVM_X86_OP(get_l2_tsc_multiplier) > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index 0c8cc7d73371..8406f8b5ab74 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -433,6 +433,7 @@ struct kvm_mmu { > struct kvm_mmu_page *sp); > void (*invlpg)(struct kvm_vcpu *vcpu, gva_t gva, hpa_t root_hpa); > hpa_t root_hpa; > + hpa_t private_root_hpa; > gpa_t root_pgd; > union kvm_mmu_role mmu_role; > u8 root_level; > @@ -1433,6 +1434,13 @@ struct kvm_x86_ops { > void (*load_mmu_pgd)(struct kvm_vcpu *vcpu, hpa_t root_hpa, > int root_level); > > + int (*free_private_sp)(struct kvm *kvm, gfn_t gfn, enum pg_level level, > + void *private_sp); > + void (*handle_changed_private_spte)( > + struct kvm *kvm, gfn_t gfn, enum pg_level level, > + kvm_pfn_t old_pfn, bool was_present, bool was_leaf, > + kvm_pfn_t new_pfn, bool is_present, bool is_leaf, void *sept_page); > + > bool (*has_wbinvd_exit)(void); > > u64 (*get_l2_tsc_offset)(struct kvm_vcpu *vcpu); > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index 8def8b97978f..0ec9548ff4dd 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -3422,6 +3422,7 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu) > { > struct kvm_mmu *mmu = vcpu->arch.mmu; > u8 shadow_root_level = mmu->shadow_root_level; > + gfn_t gfn_stolen = kvm_gfn_stolen_mask(vcpu->kvm); > hpa_t root; > unsigned i; > int r; > @@ -3432,7 +3433,11 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu) > goto out_unlock; > > if (is_tdp_mmu_enabled(vcpu->kvm)) { > - root = kvm_tdp_mmu_get_vcpu_root_hpa(vcpu); > + if (gfn_stolen && !VALID_PAGE(mmu->private_root_hpa)) { > + root = kvm_tdp_mmu_get_vcpu_root_hpa(vcpu, true); > + mmu->private_root_hpa = root; > + } > + root = kvm_tdp_mmu_get_vcpu_root_hpa(vcpu, false); > mmu->root_hpa = root; > } else if (shadow_root_level >= PT64_ROOT_4LEVEL) { > root = mmu_alloc_root(vcpu, 0, 0, shadow_root_level, true); > @@ -5596,6 +5601,7 @@ static int __kvm_mmu_create(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu) > int i; > > mmu->root_hpa = INVALID_PAGE; > + mmu->private_root_hpa = INVALID_PAGE; > mmu->root_pgd = 0; > for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++) > mmu->prev_roots[i] = KVM_MMU_ROOT_INFO_INVALID; > @@ -5772,6 +5778,10 @@ static void kvm_mmu_zap_all_fast(struct kvm *kvm) > > write_unlock(&kvm->mmu_lock); > > + /* > + * For now private root is never invalidate during VM is running, > + * so this can only happen for shared roots. > + */ > if (is_tdp_mmu_enabled(kvm)) { > read_lock(&kvm->mmu_lock); > kvm_tdp_mmu_zap_invalidated_roots(kvm); > @@ -5871,7 +5881,8 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end) > if (is_tdp_mmu_enabled(kvm)) { > for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) > flush = kvm_tdp_mmu_zap_gfn_range(kvm, i, gfn_start, > - gfn_end, flush); > + gfn_end, flush, > + false); > } > > if (flush) > @@ -5904,6 +5915,11 @@ void kvm_mmu_slot_remove_write_access(struct kvm *kvm, > write_unlock(&kvm->mmu_lock); > } > > + /* > + * For now this can only happen for non-TD VM, because TD private > + * mapping doesn't support write protection. kvm_tdp_mmu_wrprot_slot() > + * will give a WARN() if it hits for TD. > + */ > if (is_tdp_mmu_enabled(kvm)) { > read_lock(&kvm->mmu_lock); > flush |= kvm_tdp_mmu_wrprot_slot(kvm, memslot, start_level); > @@ -5952,6 +5968,9 @@ static bool kvm_mmu_zap_collapsible_spte(struct kvm *kvm, > sp = sptep_to_sp(sptep); > pfn = spte_to_pfn(*sptep); > > + /* Private page dirty logging is not supported. */ > + KVM_BUG_ON(is_private_spte(sptep), kvm); > + > /* > * We cannot do huge page mapping for indirect shadow pages, > * which are found on the last rmap (level = 1) when not using > @@ -5992,6 +6011,11 @@ void kvm_mmu_zap_collapsible_sptes(struct kvm *kvm, > write_unlock(&kvm->mmu_lock); > } > > + /* > + * This should only be reachable in case of log-dirty, wihch TD private > + * mapping doesn't support so far. kvm_tdp_mmu_zap_collapsible_sptes() > + * internally gives a WARN() when it hits. > + */ > if (is_tdp_mmu_enabled(kvm)) { > read_lock(&kvm->mmu_lock); > kvm_tdp_mmu_zap_collapsible_sptes(kvm, slot); > @@ -6266,6 +6290,9 @@ int kvm_mmu_module_init(void) > void kvm_mmu_destroy(struct kvm_vcpu *vcpu) > { > kvm_mmu_unload(vcpu); > + if (is_tdp_mmu_enabled(vcpu->kvm)) > + mmu_free_root_page(vcpu->kvm, &vcpu->arch.mmu->private_root_hpa, > + NULL); > free_mmu_pages(&vcpu->arch.root_mmu); > free_mmu_pages(&vcpu->arch.guest_mmu); > mmu_free_memory_caches(vcpu); > diff --git a/arch/x86/kvm/mmu/tdp_iter.h b/arch/x86/kvm/mmu/tdp_iter.h > index e19cabbcb65c..ad22d5b691c5 100644 > --- a/arch/x86/kvm/mmu/tdp_iter.h > +++ b/arch/x86/kvm/mmu/tdp_iter.h > @@ -28,7 +28,7 @@ struct tdp_iter { > tdp_ptep_t pt_path[PT64_ROOT_MAX_LEVEL]; > /* A pointer to the current SPTE */ > tdp_ptep_t sptep; > - /* The lowest GFN mapped by the current SPTE */ > + /* The lowest GFN (stolen bits included) mapped by the current SPTE */ > gfn_t gfn; > /* The level of the root page given to the iterator */ > int root_level; > diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c > index a68f3a22836b..acba2590b51e 100644 > --- a/arch/x86/kvm/mmu/tdp_mmu.c > +++ b/arch/x86/kvm/mmu/tdp_mmu.c > @@ -53,6 +53,11 @@ void kvm_mmu_uninit_tdp_mmu(struct kvm *kvm) > rcu_barrier(); > } > > +static gfn_t tdp_iter_gfn_unalias(struct kvm *kvm, struct tdp_iter *iter) > +{ > + return kvm_gfn_unalias(kvm, iter->gfn); > +} > + > static bool zap_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, > gfn_t start, gfn_t end, bool can_yield, bool flush, > bool shared); > @@ -175,10 +180,13 @@ static union kvm_mmu_page_role page_role_for_level(struct kvm_vcpu *vcpu, > } > > static struct kvm_mmu_page *alloc_tdp_mmu_page(struct kvm_vcpu *vcpu, gfn_t gfn, > - int level) > + int level, bool private) > { > struct kvm_mmu_page *sp; > > + WARN_ON(level != vcpu->arch.mmu->shadow_root_level && > + kvm_is_private_gfn(vcpu->kvm, gfn) != private); > + WARN_ON(level == vcpu->arch.mmu->shadow_root_level && gfn != 0); > sp = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache); > sp->spt = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_shadow_page_cache); > set_page_private(virt_to_page(sp->spt), (unsigned long)sp); > @@ -186,14 +194,19 @@ static struct kvm_mmu_page *alloc_tdp_mmu_page(struct kvm_vcpu *vcpu, gfn_t gfn, > sp->role.word = page_role_for_level(vcpu, level).word; > sp->gfn = gfn; > sp->tdp_mmu_page = true; > - kvm_mmu_init_private_sp(sp); > + > + if (private) > + kvm_mmu_alloc_private_sp(vcpu, sp); > + else > + kvm_mmu_init_private_sp(sp); > > trace_kvm_mmu_get_page(sp, true); > > return sp; > } > > -hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu) > +static struct kvm_mmu_page *kvm_tdp_mmu_get_vcpu_root(struct kvm_vcpu *vcpu, > + bool private) > { > union kvm_mmu_page_role role; > struct kvm *kvm = vcpu->kvm; > @@ -206,11 +219,13 @@ hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu) > /* Check for an existing root before allocating a new one. */ > for_each_tdp_mmu_root(kvm, root, kvm_mmu_role_as_id(role)) { > if (root->role.word == role.word && > + is_private_sp(root) == private && > kvm_tdp_mmu_get_root(kvm, root)) > goto out; > } > > - root = alloc_tdp_mmu_page(vcpu, 0, vcpu->arch.mmu->shadow_root_level); > + root = alloc_tdp_mmu_page(vcpu, 0, vcpu->arch.mmu->shadow_root_level, > + private); > refcount_set(&root->tdp_mmu_root_count, 1); > > spin_lock(&kvm->arch.tdp_mmu_pages_lock); > @@ -218,12 +233,17 @@ hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu) > spin_unlock(&kvm->arch.tdp_mmu_pages_lock); > > out: > - return __pa(root->spt); > + return root; > +} > + > +hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu, bool private) > +{ > + return __pa(kvm_tdp_mmu_get_vcpu_root(vcpu, private)->spt); > } > > static void handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn, > - u64 old_spte, u64 new_spte, int level, > - bool shared); > + bool private_spte, u64 old_spte, > + u64 new_spte, int level, bool shared); > > static void handle_changed_spte_acc_track(u64 old_spte, u64 new_spte, int level) > { > @@ -321,6 +341,7 @@ static void handle_removed_tdp_mmu_page(struct kvm *kvm, tdp_ptep_t pt, > int level = sp->role.level; > gfn_t base_gfn = sp->gfn; > int i; > + bool private_sp = is_private_sp(sp); > > trace_kvm_mmu_prepare_zap_page(sp); > > @@ -370,7 +391,7 @@ static void handle_removed_tdp_mmu_page(struct kvm *kvm, tdp_ptep_t pt, > */ > WRITE_ONCE(*sptep, SHADOW_REMOVED_SPTE); > } > - handle_changed_spte(kvm, kvm_mmu_page_as_id(sp), gfn, > + handle_changed_spte(kvm, kvm_mmu_page_as_id(sp), gfn, private_sp, > old_child_spte, SHADOW_REMOVED_SPTE, level, > shared); > } > @@ -378,6 +399,17 @@ static void handle_removed_tdp_mmu_page(struct kvm *kvm, tdp_ptep_t pt, > kvm_flush_remote_tlbs_with_address(kvm, base_gfn, > KVM_PAGES_PER_HPAGE(level + 1)); > > + if (private_sp && > + WARN_ON(static_call(kvm_x86_free_private_sp)( > + kvm, sp->gfn, sp->role.level, > + kvm_mmu_private_sp(sp)))) { > + /* > + * Failed to unlink Secure EPT page and there is nothing to do > + * further. Intentionally leak the page to prevent the kernel > + * from accessing the encrypted page. > + */ > + kvm_mmu_init_private_sp(sp); > + } > call_rcu(&sp->rcu_head, tdp_mmu_free_sp_rcu_callback); > } > > @@ -386,6 +418,7 @@ static void handle_removed_tdp_mmu_page(struct kvm *kvm, tdp_ptep_t pt, > * @kvm: kvm instance > * @as_id: the address space of the paging structure the SPTE was a part of > * @gfn: the base GFN that was mapped by the SPTE > + * @private_spte: the SPTE is private or not > * @old_spte: The value of the SPTE before the change > * @new_spte: The value of the SPTE after the change > * @level: the level of the PT the SPTE is part of in the paging structure > @@ -397,14 +430,16 @@ static void handle_removed_tdp_mmu_page(struct kvm *kvm, tdp_ptep_t pt, > * This function must be called for all TDP SPTE modifications. > */ > static void __handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn, > - u64 old_spte, u64 new_spte, int level, > - bool shared) > + bool private_spte, u64 old_spte, > + u64 new_spte, int level, bool shared) > { > bool was_present = is_shadow_present_pte(old_spte); > bool is_present = is_shadow_present_pte(new_spte); > bool was_leaf = was_present && is_last_spte(old_spte, level); > bool is_leaf = is_present && is_last_spte(new_spte, level); > - bool pfn_changed = spte_to_pfn(old_spte) != spte_to_pfn(new_spte); > + kvm_pfn_t old_pfn = spte_to_pfn(old_spte); > + kvm_pfn_t new_pfn = spte_to_pfn(new_spte); > + bool pfn_changed = old_pfn != new_pfn; > > WARN_ON(level > PT64_ROOT_MAX_LEVEL); > WARN_ON(level < PG_LEVEL_4K); > @@ -468,23 +503,49 @@ static void __handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn, > > if (was_leaf && is_dirty_spte(old_spte) && > (!is_present || !is_dirty_spte(new_spte) || pfn_changed)) > - kvm_set_pfn_dirty(spte_to_pfn(old_spte)); > + kvm_set_pfn_dirty(old_pfn); > + > + /* > + * Special handling for the private mapping. We are either > + * setting up new mapping at middle level page table, or leaf, > + * or tearing down existing mapping. > + */ > + if (private_spte) { > + void *sept_page = NULL; > + > + if (is_present && !is_leaf) { > + struct kvm_mmu_page *sp = to_shadow_page(pfn_to_hpa(new_pfn)); > + > + sept_page = kvm_mmu_private_sp(sp); > + WARN_ON(!sept_page); > + WARN_ON(sp->role.level + 1 != level); > + WARN_ON(sp->gfn != gfn); > + } > + > + static_call(kvm_x86_handle_changed_private_spte)( > + kvm, gfn, level, > + old_pfn, was_present, was_leaf, > + new_pfn, is_present, is_leaf, sept_page); > + } > > /* > * Recursively handle child PTs if the change removed a subtree from > * the paging structure. > */ > - if (was_present && !was_leaf && (pfn_changed || !is_present)) > + if (was_present && !was_leaf && (pfn_changed || !is_present)) { > + WARN_ON(private_spte != > + is_private_spte(spte_to_child_pt(old_spte, level))); > handle_removed_tdp_mmu_page(kvm, > spte_to_child_pt(old_spte, level), shared); > + } > } > > static void handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn, > - u64 old_spte, u64 new_spte, int level, > - bool shared) > + bool private_spte, u64 old_spte, u64 new_spte, > + int level, bool shared) > { > - __handle_changed_spte(kvm, as_id, gfn, old_spte, new_spte, level, > - shared); > + __handle_changed_spte(kvm, as_id, gfn, private_spte, > + old_spte, new_spte, level, shared); > handle_changed_spte_acc_track(old_spte, new_spte, level); > handle_changed_spte_dirty_log(kvm, as_id, gfn, old_spte, > new_spte, level); > @@ -505,6 +566,10 @@ static inline bool tdp_mmu_set_spte_atomic(struct kvm *kvm, > struct tdp_iter *iter, > u64 new_spte) > { > + bool freeze_spte = is_private_spte(iter->sptep) && > + !is_removed_spte(new_spte); > + u64 tmp_spte = freeze_spte ? SHADOW_REMOVED_SPTE : new_spte; > + > WARN_ON_ONCE(iter->yielded); > > lockdep_assert_held_read(&kvm->mmu_lock); > @@ -521,13 +586,16 @@ static inline bool tdp_mmu_set_spte_atomic(struct kvm *kvm, > * does not hold the mmu_lock. > */ > if (cmpxchg64(rcu_dereference(iter->sptep), iter->old_spte, > - new_spte) != iter->old_spte) > + tmp_spte) != iter->old_spte) > return false; > > - __handle_changed_spte(kvm, iter->as_id, iter->gfn, iter->old_spte, > - new_spte, iter->level, true); > + __handle_changed_spte(kvm, iter->as_id, iter->gfn, is_private_spte(iter->sptep), > + iter->old_spte, new_spte, iter->level, true); > handle_changed_spte_acc_track(iter->old_spte, new_spte, iter->level); > > + if (freeze_spte) > + WRITE_ONCE(*rcu_dereference(iter->sptep), new_spte); > + > return true; > } > > @@ -603,8 +671,8 @@ static inline void __tdp_mmu_set_spte(struct kvm *kvm, struct tdp_iter *iter, > > WRITE_ONCE(*rcu_dereference(iter->sptep), new_spte); > > - __handle_changed_spte(kvm, iter->as_id, iter->gfn, iter->old_spte, > - new_spte, iter->level, false); > + __handle_changed_spte(kvm, iter->as_id, iter->gfn, is_private_spte(iter->sptep), > + iter->old_spte, new_spte, iter->level, false); > if (record_acc_track) > handle_changed_spte_acc_track(iter->old_spte, new_spte, > iter->level); > @@ -644,9 +712,10 @@ static inline void tdp_mmu_set_spte_no_dirty_log(struct kvm *kvm, > continue; \ > else > > -#define tdp_mmu_for_each_pte(_iter, _mmu, _start, _end) \ > - for_each_tdp_pte(_iter, __va(_mmu->root_hpa), \ > - _mmu->shadow_root_level, _start, _end) > +#define tdp_mmu_for_each_pte(_iter, _mmu, _private, _start, _end) \ > + for_each_tdp_pte(_iter, \ > + __va((_private) ? _mmu->private_root_hpa : _mmu->root_hpa), \ > + _mmu->shadow_root_level, _start, _end) > > /* > * Yield if the MMU lock is contended or this thread needs to return control > @@ -731,6 +800,18 @@ static bool zap_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, > */ > end = min(end, max_gfn_host); > > + /* > + * Extend [start, end) to include GFN shared bit when TDX is enabled, > + * and for shared mapping range. > + */ > + if (is_private_sp(root)) { > + start = kvm_gfn_private(kvm, start); > + end = kvm_gfn_private(kvm, end); > + } else { > + start = kvm_gfn_shared(kvm, start); > + end = kvm_gfn_shared(kvm, end); > + } > + > kvm_lockdep_assert_mmu_lock_held(kvm, shared); > > rcu_read_lock(); > @@ -783,13 +864,18 @@ static bool zap_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root, > * MMU lock. > */ > bool __kvm_tdp_mmu_zap_gfn_range(struct kvm *kvm, int as_id, gfn_t start, > - gfn_t end, bool can_yield, bool flush) > + gfn_t end, bool can_yield, bool flush, > + bool zap_private) > { > struct kvm_mmu_page *root; > > - for_each_tdp_mmu_root_yield_safe(kvm, root, as_id, false) > + for_each_tdp_mmu_root_yield_safe(kvm, root, as_id, false) { > + /* Skip private page table if not requested */ > + if (!zap_private && is_private_sp(root)) > + continue; > flush = zap_gfn_range(kvm, root, start, end, can_yield, flush, > false); > + } > > return flush; > } > @@ -800,7 +886,7 @@ void kvm_tdp_mmu_zap_all(struct kvm *kvm) > int i; > > for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) > - flush = kvm_tdp_mmu_zap_gfn_range(kvm, i, 0, -1ull, flush); > + flush = kvm_tdp_mmu_zap_gfn_range(kvm, i, 0, -1ull, flush, true); > > if (flush) > kvm_flush_remote_tlbs(kvm); > @@ -851,6 +937,13 @@ void kvm_tdp_mmu_zap_invalidated_roots(struct kvm *kvm) > while (root) { > next_root = next_invalidated_root(kvm, root); > > + /* > + * Private table is only torn down when VM is destroyed. > + * It is a bug to zap private table here. > + */ > + if (WARN_ON(is_private_sp(root))) > + goto out; > + > rcu_read_unlock(); > > flush = zap_gfn_range(kvm, root, 0, -1ull, true, flush, true); > @@ -865,7 +958,7 @@ void kvm_tdp_mmu_zap_invalidated_roots(struct kvm *kvm) > > rcu_read_lock(); > } > - > +out: > rcu_read_unlock(); > > if (flush) > @@ -897,9 +990,16 @@ void kvm_tdp_mmu_invalidate_all_roots(struct kvm *kvm) > struct kvm_mmu_page *root; > > lockdep_assert_held_write(&kvm->mmu_lock); > - list_for_each_entry(root, &kvm->arch.tdp_mmu_roots, link) > + list_for_each_entry(root, &kvm->arch.tdp_mmu_roots, link) { > + /* > + * Skip private root since private page table > + * is only torn down when VM is destroyed. > + */ > + if (is_private_sp(root)) > + continue; > if (refcount_inc_not_zero(&root->tdp_mmu_root_count)) > root->role.invalid = true; > + } > } > > /* > @@ -914,14 +1014,23 @@ static int tdp_mmu_map_handle_target_level(struct kvm_vcpu *vcpu, > u64 new_spte; > int ret = RET_PF_FIXED; > bool wrprot = false; > + unsigned long pte_access = ACC_ALL; > > WARN_ON(sp->role.level != fault->goal_level); > + > + /* TDX shared GPAs are no executable, enforce this for the SDV. */ > + if (!kvm_is_private_gfn(vcpu->kvm, iter->gfn)) > + pte_access &= ~ACC_EXEC_MASK; > + > if (unlikely(!fault->slot)) > - new_spte = make_mmio_spte(vcpu, iter->gfn, ACC_ALL); > + new_spte = make_mmio_spte(vcpu, > + tdp_iter_gfn_unalias(vcpu->kvm, iter), > + pte_access); > else > - wrprot = make_spte(vcpu, sp, fault->slot, ACC_ALL, iter->gfn, > - fault->pfn, iter->old_spte, fault->prefetch, true, > - fault->map_writable, &new_spte); > + wrprot = make_spte(vcpu, sp, fault->slot, pte_access, > + tdp_iter_gfn_unalias(vcpu->kvm, iter), > + fault->pfn, iter->old_spte, fault->prefetch, > + true, fault->map_writable, &new_spte); > > if (new_spte == iter->old_spte) > ret = RET_PF_SPURIOUS; > @@ -959,7 +1068,8 @@ static int tdp_mmu_map_handle_target_level(struct kvm_vcpu *vcpu, > } > > static bool tdp_mmu_populate_nonleaf( > - struct kvm_vcpu *vcpu, struct tdp_iter *iter, bool account_nx) > + struct kvm_vcpu *vcpu, struct tdp_iter *iter, bool is_private, > + bool account_nx) > { > struct kvm_mmu_page *sp; > u64 *child_pt; > @@ -968,7 +1078,7 @@ static bool tdp_mmu_populate_nonleaf( > WARN_ON(is_shadow_present_pte(iter->old_spte)); > WARN_ON(is_removed_spte(iter->old_spte)); > > - sp = alloc_tdp_mmu_page(vcpu, iter->gfn, iter->level - 1); > + sp = alloc_tdp_mmu_page(vcpu, iter->gfn, iter->level - 1, is_private); > child_pt = sp->spt; > > new_spte = make_nonleaf_spte(child_pt, !shadow_accessed_mask); > @@ -991,6 +1101,8 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) > { > struct kvm_mmu *mmu = vcpu->arch.mmu; > struct tdp_iter iter; > + gfn_t raw_gfn; > + bool is_private; > int ret; > > kvm_mmu_hugepage_adjust(vcpu, fault); > @@ -999,7 +1111,17 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) > > rcu_read_lock(); > > - tdp_mmu_for_each_pte(iter, mmu, fault->gfn, fault->gfn + 1) { > + raw_gfn = gpa_to_gfn(fault->addr); > + is_private = kvm_is_private_gfn(vcpu->kvm, raw_gfn); > + > + if (is_error_noslot_pfn(fault->pfn) || kvm_is_reserved_pfn(fault->pfn)) { > + if (is_private) { > + rcu_read_unlock(); > + return -EFAULT; > + } > + } > + > + tdp_mmu_for_each_pte(iter, mmu, is_private, raw_gfn, raw_gfn + 1) { > if (fault->nx_huge_page_workaround_enabled) > disallowed_hugepage_adjust(fault, iter.old_spte, iter.level); > > @@ -1015,6 +1137,12 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) > is_large_pte(iter.old_spte)) { > if (!tdp_mmu_zap_spte_atomic(vcpu->kvm, &iter)) > break; > + /* > + * TODO: large page support. > + * Doesn't support large page for TDX now > + */ > + WARN_ON(is_private_spte(&iter.old_spte)); The above line is causing a null ptr dereferencing when running the KVM unit tests. It should be is_private_spte(iter.sptep) instead of is_private_spte(&iter.old_spte) While old_spte holds a snapshot of the value pointed to by sptep, &old_spte is not equivalent to sptep. > > + > > > /* > * The iter must explicitly re-read the spte here > @@ -1037,7 +1165,8 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) > > account_nx = fault->huge_page_disallowed && > fault->req_level >= iter.level; > - if (!tdp_mmu_populate_nonleaf(vcpu, &iter, account_nx)) > + if (!tdp_mmu_populate_nonleaf( > + vcpu, &iter, is_private, account_nx)) > break; > } > } > @@ -1058,9 +1187,12 @@ bool kvm_tdp_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range, > { > struct kvm_mmu_page *root; > > - for_each_tdp_mmu_root_yield_safe(kvm, root, range->slot->as_id, false) > + for_each_tdp_mmu_root_yield_safe(kvm, root, range->slot->as_id, false) { > + if (is_private_sp(root)) > + continue; > flush = zap_gfn_range(kvm, root, range->start, range->end, > - range->may_block, flush, false); > + range->may_block, flush, false); > + } > > return flush; > } > @@ -1513,10 +1645,14 @@ int kvm_tdp_mmu_get_walk(struct kvm_vcpu *vcpu, u64 addr, u64 *sptes, > struct kvm_mmu *mmu = vcpu->arch.mmu; > gfn_t gfn = addr >> PAGE_SHIFT; > int leaf = -1; > + bool is_private = kvm_is_private_gfn(vcpu->kvm, gfn); > > *root_level = vcpu->arch.mmu->shadow_root_level; > > - tdp_mmu_for_each_pte(iter, mmu, gfn, gfn + 1) { > + if (WARN_ON(is_private)) > + return leaf; > + > + tdp_mmu_for_each_pte(iter, mmu, false, gfn, gfn + 1) { > leaf = iter.level; > sptes[leaf] = iter.old_spte; > } > @@ -1542,12 +1678,16 @@ u64 *kvm_tdp_mmu_fast_pf_get_last_sptep(struct kvm_vcpu *vcpu, u64 addr, > struct kvm_mmu *mmu = vcpu->arch.mmu; > gfn_t gfn = addr >> PAGE_SHIFT; > tdp_ptep_t sptep = NULL; > + bool is_private = kvm_is_private_gfn(vcpu->kvm, gfn); > > - tdp_mmu_for_each_pte(iter, mmu, gfn, gfn + 1) { > + if (is_private) > + goto out; > + > + tdp_mmu_for_each_pte(iter, mmu, false, gfn, gfn + 1) { > *spte = iter.old_spte; > sptep = iter.sptep; > } > - > +out: > /* > * Perform the rcu_dereference to get the raw spte pointer value since > * we are passing it up to fast_page_fault, which is shared with the > diff --git a/arch/x86/kvm/mmu/tdp_mmu.h b/arch/x86/kvm/mmu/tdp_mmu.h > index 3899004a5d91..7c62f694a465 100644 > --- a/arch/x86/kvm/mmu/tdp_mmu.h > +++ b/arch/x86/kvm/mmu/tdp_mmu.h > @@ -5,7 +5,7 @@ > > #include > > -hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu); > +hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu, bool private); > > __must_check static inline bool kvm_tdp_mmu_get_root(struct kvm *kvm, > struct kvm_mmu_page *root) > @@ -20,11 +20,14 @@ void kvm_tdp_mmu_put_root(struct kvm *kvm, struct kvm_mmu_page *root, > bool shared); > > bool __kvm_tdp_mmu_zap_gfn_range(struct kvm *kvm, int as_id, gfn_t start, > - gfn_t end, bool can_yield, bool flush); > + gfn_t end, bool can_yield, bool flush, > + bool zap_private); > static inline bool kvm_tdp_mmu_zap_gfn_range(struct kvm *kvm, int as_id, > - gfn_t start, gfn_t end, bool flush) > + gfn_t start, gfn_t end, bool flush, > + bool zap_private) > { > - return __kvm_tdp_mmu_zap_gfn_range(kvm, as_id, start, end, true, flush); > + return __kvm_tdp_mmu_zap_gfn_range(kvm, as_id, start, end, true, flush, > + zap_private); > } > static inline bool kvm_tdp_mmu_zap_sp(struct kvm *kvm, struct kvm_mmu_page *sp) > { > @@ -41,7 +44,7 @@ static inline bool kvm_tdp_mmu_zap_sp(struct kvm *kvm, struct kvm_mmu_page *sp) > */ > lockdep_assert_held_write(&kvm->mmu_lock); > return __kvm_tdp_mmu_zap_gfn_range(kvm, kvm_mmu_page_as_id(sp), > - sp->gfn, end, false, false); > + sp->gfn, end, false, false, false); > } > > void kvm_tdp_mmu_zap_all(struct kvm *kvm); > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index ae3bf553f215..d4e117f5b5b9 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -190,6 +190,7 @@ bool kvm_is_reserved_pfn(kvm_pfn_t pfn) > > return true; > } > +EXPORT_SYMBOL_GPL(kvm_is_reserved_pfn); > > /* > * Switches to specified vcpu, until a matching vcpu_put() > -- > 2.25.1 > Sagi