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 X-Spam-Level: X-Spam-Status: No, score=-16.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1DFB0C10F13 for ; Mon, 8 Apr 2019 18:07:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D7C712084C for ; Mon, 8 Apr 2019 18:07:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="UyTnAltH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728482AbfDHSHf (ORCPT ); Mon, 8 Apr 2019 14:07:35 -0400 Received: from mail-qt1-f201.google.com ([209.85.160.201]:42264 "EHLO mail-qt1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726670AbfDHSHf (ORCPT ); Mon, 8 Apr 2019 14:07:35 -0400 Received: by mail-qt1-f201.google.com with SMTP id n10so13525348qtk.9 for ; Mon, 08 Apr 2019 11:07:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=ES2zAQGSNfaYNAwsHBWULJd1GrSpuTxtPfE2KFSdaTw=; b=UyTnAltHA84Ko6ppxdtK0fzShlCMKU3AyTCq9g5FVZhMZig6NUZyhpUpH2fBvLViEy a/q4L3qHXEcWNu6618ov2hIyHXvMZpj0QgL20f5IEHaqecg4AwKPtTQ7SSAkGnxt18Pn 74jrzL+2DIzJDbRSCd/kaOvl+GQbGhtxGPVyJmnXXqBYmtlnYVqcTo+JDqdtIyvDeQlm odqk1BykkToNdXSlNGbZPUyPJjQxCTOK67j519DIP4rlbdL7DvCirFmqb9w1Ql7TFJ4D WUHP1rdHhrkM26h1Ay8Alipb1KFBAF1yYGphx2L9KqvGAjz+S0MRuURXglVY85ReApAc 4pnw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=ES2zAQGSNfaYNAwsHBWULJd1GrSpuTxtPfE2KFSdaTw=; b=Rtc+YH9Ae0Oj5rGLzaTjEey8vxzaDaUiWFAN8RctLumUbctuKjRt8ai5EWv1JDAOB8 heg+9SdriubpBEEaqGb5vwsR0sc+DSKGL8JFSBdOKXdGKLZFPea729+vcd3HF64d0yr+ LKQWsUpyUv0A3nXGbhmNNy3hYhNLm5opgfRTbyS1at2cnMCh/ark+0Q7jEk9nIXBOU5g nAfmHSRW73yx1yTb3S9TX3TOhRvcK2Lp7IAjfZ8CWcl9gsAtxLHE3NOn/Co/IUjTvwbV yL63Scoyz/PmBECe3cnza5TTwIZipJIHcCznB+PpNKaBlfA+awiZXEmwIdweVDjSkcuQ jKSQ== X-Gm-Message-State: APjAAAVBNrXAeP2NmEwIKSViW0JdlrIWJX8OS2o2ofXn6a+OaGwF2szG k0Jfc7GlCggML6C+CEmoZHuPd5ItQCvu X-Google-Smtp-Source: APXvYqz36RL4wjMkN4GkrJ+NGDLhRNAcZZA2FEUnMkZF9RTNxhPnItrUWUCW39yjF6r5nrI83fAtmrIL2NQC X-Received: by 2002:a0c:9254:: with SMTP id 20mr3920586qvz.62.1554746854369; Mon, 08 Apr 2019 11:07:34 -0700 (PDT) Date: Mon, 8 Apr 2019 11:07:30 -0700 Message-Id: <20190408180730.226619-1-bgardon@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.21.0.392.gf8f6787159e-goog Subject: [PATCH v2] kvm: mmu: Fix overflow on kvm mmu page limit calculation From: Ben Gardon To: Paolo Bonzini , Sean Christopherson , "=?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?=" Cc: Peter Feiner , Junaid Shahid , kvm@vger.kernel.org, Ben Gardon Content-Type: text/plain; charset="UTF-8" Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org KVM bases its memory usage limits on the total number of guest pages across all memslots. However, those limits, and the calculations to produce, them use 32 bit unsigned integers. This can result in overflow if a VM has more guest pages that can be represented by a u32. As a result of this overflow, KVM can use a low limit on the number of MMU pages it will allocate. This makes KVM unable to map all of guest memory at once, prompting spurious faults. Tested: Ran all kvm-unit-tests on an Intel Haswell machine. This patch introduced no new failures. Signed-off-by: Ben Gardon --- arch/x86/include/asm/kvm_host.h | 12 ++++++------ arch/x86/kvm/mmu.c | 13 ++++++------- arch/x86/kvm/mmu.h | 2 +- arch/x86/kvm/x86.c | 4 ++-- 4 files changed, 15 insertions(+), 16 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 159b5988292f3..9b7b731a00321 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -126,7 +126,7 @@ static inline gfn_t gfn_to_index(gfn_t gfn, gfn_t base_gfn, int level) } #define KVM_PERMILLE_MMU_PAGES 20 -#define KVM_MIN_ALLOC_MMU_PAGES 64 +#define KVM_MIN_ALLOC_MMU_PAGES 64UL #define KVM_MMU_HASH_SHIFT 12 #define KVM_NUM_MMU_PAGES (1 << KVM_MMU_HASH_SHIFT) #define KVM_MIN_FREE_MMU_PAGES 5 @@ -844,9 +844,9 @@ enum kvm_irqchip_mode { }; struct kvm_arch { - unsigned int n_used_mmu_pages; - unsigned int n_requested_mmu_pages; - unsigned int n_max_mmu_pages; + unsigned long n_used_mmu_pages; + unsigned long n_requested_mmu_pages; + unsigned long n_max_mmu_pages; unsigned int indirect_shadow_pages; struct hlist_head mmu_page_hash[KVM_NUM_MMU_PAGES]; /* @@ -1256,8 +1256,8 @@ void kvm_mmu_clear_dirty_pt_masked(struct kvm *kvm, gfn_t gfn_offset, unsigned long mask); void kvm_mmu_zap_all(struct kvm *kvm); void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm, u64 gen); -unsigned int kvm_mmu_calculate_default_mmu_pages(struct kvm *kvm); -void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int kvm_nr_mmu_pages); +unsigned long kvm_mmu_calculate_default_mmu_pages(struct kvm *kvm); +void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned long kvm_nr_mmu_pages); int load_pdptrs(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, unsigned long cr3); bool pdptrs_changed(struct kvm_vcpu *vcpu); diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index eee455a8a612d..bd07270196744 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -2007,7 +2007,7 @@ static int is_empty_shadow_page(u64 *spt) * aggregate version in order to make the slab shrinker * faster */ -static inline void kvm_mod_used_mmu_pages(struct kvm *kvm, int nr) +static inline void kvm_mod_used_mmu_pages(struct kvm *kvm, unsigned long nr) { kvm->arch.n_used_mmu_pages += nr; percpu_counter_add(&kvm_total_used_mmu_pages, nr); @@ -2763,7 +2763,7 @@ static bool prepare_zap_oldest_mmu_page(struct kvm *kvm, * Changing the number of mmu pages allocated to the vm * Note: if goal_nr_mmu_pages is too small, you will get dead lock */ -void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned int goal_nr_mmu_pages) +void kvm_mmu_change_mmu_pages(struct kvm *kvm, unsigned long goal_nr_mmu_pages) { LIST_HEAD(invalid_list); @@ -6031,10 +6031,10 @@ int kvm_mmu_module_init(void) /* * Calculate mmu pages needed for kvm. */ -unsigned int kvm_mmu_calculate_default_mmu_pages(struct kvm *kvm) +unsigned long kvm_mmu_calculate_default_mmu_pages(struct kvm *kvm) { - unsigned int nr_mmu_pages; - unsigned int nr_pages = 0; + unsigned long nr_mmu_pages; + unsigned long nr_pages = 0; struct kvm_memslots *slots; struct kvm_memory_slot *memslot; int i; @@ -6047,8 +6047,7 @@ unsigned int kvm_mmu_calculate_default_mmu_pages(struct kvm *kvm) } nr_mmu_pages = nr_pages * KVM_PERMILLE_MMU_PAGES / 1000; - nr_mmu_pages = max(nr_mmu_pages, - (unsigned int) KVM_MIN_ALLOC_MMU_PAGES); + nr_mmu_pages = max(nr_mmu_pages, KVM_MIN_ALLOC_MMU_PAGES); return nr_mmu_pages; } diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h index bbdc60f2fae89..54c2a377795be 100644 --- a/arch/x86/kvm/mmu.h +++ b/arch/x86/kvm/mmu.h @@ -64,7 +64,7 @@ bool kvm_can_do_async_pf(struct kvm_vcpu *vcpu); int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 error_code, u64 fault_address, char *insn, int insn_len); -static inline unsigned int kvm_mmu_available_pages(struct kvm *kvm) +static inline unsigned long kvm_mmu_available_pages(struct kvm *kvm) { if (kvm->arch.n_max_mmu_pages > kvm->arch.n_used_mmu_pages) return kvm->arch.n_max_mmu_pages - diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 099b851dabafd..455f156f56ede 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4270,7 +4270,7 @@ static int kvm_vm_ioctl_set_identity_map_addr(struct kvm *kvm, } static int kvm_vm_ioctl_set_nr_mmu_pages(struct kvm *kvm, - u32 kvm_nr_mmu_pages) + unsigned long kvm_nr_mmu_pages) { if (kvm_nr_mmu_pages < KVM_MIN_ALLOC_MMU_PAGES) return -EINVAL; @@ -4284,7 +4284,7 @@ static int kvm_vm_ioctl_set_nr_mmu_pages(struct kvm *kvm, return 0; } -static int kvm_vm_ioctl_get_nr_mmu_pages(struct kvm *kvm) +static unsigned long kvm_vm_ioctl_get_nr_mmu_pages(struct kvm *kvm) { return kvm->arch.n_max_mmu_pages; } -- 2.21.0.392.gf8f6787159e-goog