From patchwork Wed Sep 11 18:50:37 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 11141813 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5720913BD for ; Wed, 11 Sep 2019 18:54:39 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 30E6220578 for ; Wed, 11 Sep 2019 18:54:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="mcx0twCr" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 30E6220578 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=8Pb8MdlQu6A8pb8K7N86qKRnS4ArFapXJ6vRDgTC5DY=; b=mcx0twCr8dI24J one5Z+z8Kw5UbaPl02ZdOxwrQucN8zpEAvXJy0a8ahJNyyIQNdcMkf9oaSkKpsN3/FDS3Td4913S9 v+rPcAGh5RG1AObvWeNIeES50b5EetwCBKBDk++0ta8bZGs5LqHnDFT4d+RxpLsvQwCRu4rhjQwpI QfsqBq5Kz3bFZACUCqETdYwQEh/1ErrVZxzBAO6pOrIjNvDmljnOFls4prbrkwD1sVaWtDRKDqihy gU5X1bfzunlDGnsGE5jNqdVRsADxTC9AmT0BeisJFYodzXz22bdSOtBfPQLwgq9OH0cg1bqo0uvid yAvRrxehAdoIQMTiX+Yw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.2 #3 (Red Hat Linux)) id 1i87l9-0001qd-8C; Wed, 11 Sep 2019 18:54:31 +0000 Received: from mga11.intel.com ([192.55.52.93]) by bombadil.infradead.org with esmtps (Exim 4.92.2 #3 (Red Hat Linux)) id 1i87hb-0007FB-Ds for linux-arm-kernel@lists.infradead.org; Wed, 11 Sep 2019 18:50:53 +0000 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 11 Sep 2019 11:50:41 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,492,1559545200"; d="scan'208";a="196980900" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.41]) by orsmga002.jf.intel.com with ESMTP; 11 Sep 2019 11:50:41 -0700 From: Sean Christopherson To: James Hogan , Paul Mackerras , Christian Borntraeger , Janosch Frank , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , Marc Zyngier Subject: [PATCH 12/13] KVM: Terminate memslot walks via used_slots Date: Wed, 11 Sep 2019 11:50:37 -0700 Message-Id: <20190911185038.24341-13-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190911185038.24341-1-sean.j.christopherson@intel.com> References: <20190911185038.24341-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190911_115052_106468_640C7B68 X-CRM114-Status: GOOD ( 23.19 ) X-Spam-Score: -5.0 (-----) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (-5.0 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at https://www.dnswl.org/, high trust [192.55.52.93 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Julien Thierry , Wanpeng Li , kvm@vger.kernel.org, David Hildenbrand , linux-arm-kernel@lists.infradead.org, Joerg Roedel , Cornelia Huck , linux-mips@vger.kernel.org, Sean Christopherson , linux-kernel@vger.kernel.org, James Morse , kvm-ppc@vger.kernel.org, Vitaly Kuznetsov , kvmarm@lists.cs.columbia.edu, Suzuki K Pouloze , Jim Mattson Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org Refactor memslot handling to treat the number of used slots as the de facto size of the memslot array, e.g. return NULL from id_to_memslot() when an invalid index is provided instead of relying on npages==0 to detect an invalid memslot. Rework the sorting and walking of memslots in advance of dynamically sizing memslots to aid bisection and debug, e.g. with luck, a bug in the refactoring will bisect here and/or hit a WARN instead of randomly corrupting memory. Alternatively, a global null/invalid memslot could be returned, i.e. so callers of id_to_memslot() don't have to explicitly check for a NULL memslot, but that approach runs the risk of introducing difficult-to- debug issues, e.g. if the global null slot is modified. Constifying the return from id_to_memslot() to combat such issues is possible, but would require a massive refactoring of arch specific code and would still be susceptible to casting shenanigans. Add function comments to update_memslots() and search_memslots() to explicitly (and loudly) state how memslots are sorted. No functional change intended. Signed-off-by: Sean Christopherson --- arch/powerpc/kvm/book3s_hv.c | 2 +- arch/x86/kvm/x86.c | 14 ++-- include/linux/kvm_host.h | 18 +++-- virt/kvm/arm/mmu.c | 9 ++- virt/kvm/kvm_main.c | 145 ++++++++++++++++++++++------------- 5 files changed, 117 insertions(+), 71 deletions(-) diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 931091fac52c..f1c07e705d4a 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -4377,7 +4377,7 @@ static int kvm_vm_ioctl_get_dirty_log_hv(struct kvm *kvm, slots = kvm_memslots(kvm); memslot = id_to_memslot(slots, log->slot); r = -ENOENT; - if (!memslot->dirty_bitmap) + if (!memslot || !memslot->dirty_bitmap) goto out; /* diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 7bf54eccb6d4..5167a22e4648 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -9320,9 +9320,9 @@ void kvm_arch_sync_events(struct kvm *kvm) int __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size) { int i, r; - unsigned long hva; + unsigned long hva, uninitialized_var(old_npages); struct kvm_memslots *slots = kvm_memslots(kvm); - struct kvm_memory_slot *slot, old; + struct kvm_memory_slot *slot; /* Called with kvm->slots_lock held. */ if (WARN_ON(id >= KVM_MEM_SLOTS_NUM)) @@ -9330,7 +9330,7 @@ int __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size) slot = id_to_memslot(slots, id); if (size) { - if (slot->npages) + if (slot && slot->npages) return -EEXIST; /* @@ -9342,13 +9342,13 @@ int __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size) if (IS_ERR((void *)hva)) return PTR_ERR((void *)hva); } else { - if (!slot->npages) + if (!slot || !slot->npages) return 0; - hva = 0; + hva = slot->userspace_addr; + old_npages = slot->npages; } - old = *slot; for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { struct kvm_userspace_memory_region m; @@ -9363,7 +9363,7 @@ int __x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size) } if (!size) - vm_munmap(old.userspace_addr, old.npages * PAGE_SIZE); + vm_munmap(hva, old_npages * PAGE_SIZE); return 0; } diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 049e20876b8f..40ea5df50faa 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -580,10 +580,11 @@ static inline int kvm_vcpu_get_idx(struct kvm_vcpu *vcpu) BUG(); } -#define kvm_for_each_memslot(memslot, slots) \ - for (memslot = &slots->memslots[0]; \ - memslot < slots->memslots + KVM_MEM_SLOTS_NUM && memslot->npages;\ - memslot++) +#define kvm_for_each_memslot(memslot, slots) \ + for (memslot = &slots->memslots[0]; \ + memslot < slots->memslots + slots->used_slots; memslot++) \ + if (WARN_ON_ONCE(!memslot->npages)) { \ + } else int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id); void kvm_vcpu_uninit(struct kvm_vcpu *vcpu); @@ -643,12 +644,15 @@ static inline struct kvm_memslots *kvm_vcpu_memslots(struct kvm_vcpu *vcpu) return __kvm_memslots(vcpu->kvm, as_id); } -static inline struct kvm_memory_slot * -id_to_memslot(struct kvm_memslots *slots, int id) +static inline +struct kvm_memory_slot *id_to_memslot(struct kvm_memslots *slots, int id) { int index = slots->id_to_index[id]; struct kvm_memory_slot *slot; + if (index < 0) + return NULL; + slot = &slots->memslots[index]; WARN_ON(slot->id != id); @@ -993,6 +997,8 @@ bool kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args); * used in non-modular code in arch/powerpc/kvm/book3s_hv_rm_mmu.c. * gfn_to_memslot() itself isn't here as an inline because that would * bloat other code too much. + * + * IMPORTANT: Slots are sorted from highest GFN to lowest GFN! */ static inline struct kvm_memory_slot * search_memslots(struct kvm_memslots *slots, gfn_t gfn) diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c index f3241b268d49..7ea3321cabb8 100644 --- a/virt/kvm/arm/mmu.c +++ b/virt/kvm/arm/mmu.c @@ -1536,8 +1536,13 @@ void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot) { struct kvm_memslots *slots = kvm_memslots(kvm); struct kvm_memory_slot *memslot = id_to_memslot(slots, slot); - phys_addr_t start = memslot->base_gfn << PAGE_SHIFT; - phys_addr_t end = (memslot->base_gfn + memslot->npages) << PAGE_SHIFT; + phys_addr_t start, end; + + if (WARN_ON_ONCE(!memslot)) + return; + + start = memslot->base_gfn << PAGE_SHIFT; + end = (memslot->base_gfn + memslot->npages) << PAGE_SHIFT; spin_lock(&kvm->mmu_lock); stage2_wp_range(kvm, start, end); diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 11b130e9f223..e2571a9ccfc4 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -535,7 +535,7 @@ static struct kvm_memslots *kvm_alloc_memslots(void) return NULL; for (i = 0; i < KVM_MEM_SLOTS_NUM; i++) - slots->id_to_index[i] = slots->memslots[i].id = i; + slots->id_to_index[i] = slots->memslots[i].id = -1; return slots; } @@ -793,64 +793,94 @@ static int kvm_create_dirty_bitmap(struct kvm_memory_slot *memslot) return 0; } +static inline void kvm_shift_memslots_deleted(struct kvm_memslots *slots, + struct kvm_memory_slot *new) +{ + struct kvm_memory_slot *mslots = slots->memslots; + int i; + + if (WARN_ON(slots->id_to_index[new->id] == -1)) + return; + + slots->used_slots--; + + for (i = slots->id_to_index[new->id]; i < slots->used_slots; i++) { + mslots[i] = mslots[i + 1]; + slots->id_to_index[mslots[i].id] = i; + } + mslots[i] = *new; + slots->id_to_index[new->id] = -1; +} + +static inline int kvm_shift_memslots_forward(struct kvm_memslots *slots, + struct kvm_memory_slot *new) +{ + struct kvm_memory_slot *mslots = slots->memslots; + int i; + + if (WARN_ON_ONCE(slots->id_to_index[new->id] == -1) || + WARN_ON_ONCE(!slots->used_slots)) + return -1; + + for (i = slots->id_to_index[new->id]; i < slots->used_slots - 1; i++) { + if (new->base_gfn > mslots[i + 1].base_gfn) + break; + + WARN_ON_ONCE(new->base_gfn == mslots[i + 1].base_gfn); + + /* Shift the next memslot forward one and update its index. */ + mslots[i] = mslots[i + 1]; + slots->id_to_index[mslots[i].id] = i; + } + return i; +} + +static inline int kvm_shift_memslots_back(struct kvm_memslots *slots, + struct kvm_memory_slot *new, + int start) +{ + struct kvm_memory_slot *mslots = slots->memslots; + int i; + + for (i = start; i > 0; i--) { + if (new->base_gfn < mslots[i - 1].base_gfn) + break; + + WARN_ON_ONCE(new->base_gfn == mslots[i - 1].base_gfn); + + /* Shift the next memslot back one and update its index. */ + mslots[i] = mslots[i - 1]; + slots->id_to_index[mslots[i].id] = i; + } + return i; +} + /* * Insert memslot and re-sort memslots based on their GFN, * so binary search could be used to lookup GFN. * Sorting algorithm takes advantage of having initially * sorted array and known changed memslot position. + * + * IMPORTANT: Slots are sorted from highest GFN to lowest GFN! */ static void update_memslots(struct kvm_memslots *slots, struct kvm_memory_slot *new, enum kvm_mr_change change) { - int id = new->id; - int i = slots->id_to_index[id]; - struct kvm_memory_slot *mslots = slots->memslots; - - WARN_ON(mslots[i].id != id); - switch (change) { - case KVM_MR_CREATE: - slots->used_slots++; - WARN_ON(mslots[i].npages || !new->npages); - break; - case KVM_MR_DELETE: - slots->used_slots--; - WARN_ON(new->npages || !mslots[i].npages); - break; - default: - break; - } - - while (i < KVM_MEM_SLOTS_NUM - 1 && - new->base_gfn <= mslots[i + 1].base_gfn) { - if (!mslots[i + 1].npages) - break; - mslots[i] = mslots[i + 1]; - slots->id_to_index[mslots[i].id] = i; - i++; + int i; + + if (change == KVM_MR_DELETE) { + kvm_shift_memslots_deleted(slots, new); + } else { + if (change == KVM_MR_CREATE) + i = slots->used_slots++; + else + i = kvm_shift_memslots_forward(slots, new); + i = kvm_shift_memslots_back(slots, new, i); + + slots->memslots[i] = *new; + slots->id_to_index[new->id] = i; } - - /* - * The ">=" is needed when creating a slot with base_gfn == 0, - * so that it moves before all those with base_gfn == npages == 0. - * - * On the other hand, if new->npages is zero, the above loop has - * already left i pointing to the beginning of the empty part of - * mslots, and the ">=" would move the hole backwards in this - * case---which is wrong. So skip the loop when deleting a slot. - */ - if (new->npages) { - while (i > 0 && - new->base_gfn >= mslots[i - 1].base_gfn) { - mslots[i] = mslots[i - 1]; - slots->id_to_index[mslots[i].id] = i; - i--; - } - } else - WARN_ON_ONCE(i != slots->used_slots); - - mslots[i] = *new; - slots->id_to_index[mslots[i].id] = i; } static int check_memory_region_flags(const struct kvm_userspace_memory_region *mem) @@ -1029,8 +1059,13 @@ int __kvm_set_memory_region(struct kvm *kvm, * when the memslots are re-sorted by update_memslots(). */ tmp = id_to_memslot(__kvm_memslots(kvm, as_id), id); - old = *tmp; - tmp = NULL; + if (tmp) { + old = *tmp; + tmp = NULL; + } else { + memset(&old, 0, sizeof(old)); + old.id = id; + } if (!mem->memory_size) return kvm_delete_memslot(kvm, mem, &old, as_id); @@ -1148,7 +1183,7 @@ int kvm_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log, slots = __kvm_memslots(kvm, as_id); *memslot = id_to_memslot(slots, id); - if (!(*memslot)->dirty_bitmap) + if (!(*memslot) || !(*memslot)->dirty_bitmap) return -ENOENT; kvm_arch_sync_dirty_log(kvm, *memslot); @@ -1206,10 +1241,10 @@ static int kvm_get_dirty_log_protect(struct kvm *kvm, struct kvm_dirty_log *log) slots = __kvm_memslots(kvm, as_id); memslot = id_to_memslot(slots, id); + if (!memslot || !memslot->dirty_bitmap) + return -ENOENT; dirty_bitmap = memslot->dirty_bitmap; - if (!dirty_bitmap) - return -ENOENT; kvm_arch_sync_dirty_log(kvm, memslot); @@ -1317,10 +1352,10 @@ static int kvm_clear_dirty_log_protect(struct kvm *kvm, slots = __kvm_memslots(kvm, as_id); memslot = id_to_memslot(slots, id); + if (!memslot || !memslot->dirty_bitmap) + return -ENOENT; dirty_bitmap = memslot->dirty_bitmap; - if (!dirty_bitmap) - return -ENOENT; n = ALIGN(log->num_pages, BITS_PER_LONG) / 8;