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[23.128.96.18]) by mx.google.com with ESMTP id dp16si25055574ejc.760.2021.09.20.20.06.36; Mon, 20 Sep 2021 20:07:02 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344409AbhITVn5 (ORCPT + 99 others); Mon, 20 Sep 2021 17:43:57 -0400 Received: from vps-vb.mhejs.net ([37.28.154.113]:45610 "EHLO vps-vb.mhejs.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239670AbhITVln (ORCPT ); Mon, 20 Sep 2021 17:41:43 -0400 Received: from MUA by vps-vb.mhejs.net with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1mSR11-0006Se-AP; Mon, 20 Sep 2021 23:39:55 +0200 From: "Maciej S. Szmigiero" To: Paolo Bonzini , Vitaly Kuznetsov Cc: Sean Christopherson , Wanpeng Li , Jim Mattson , Igor Mammedov , Marc Zyngier , James Morse , Julien Thierry , Suzuki K Poulose , Huacai Chen , Aleksandar Markovic , Paul Mackerras , Christian Borntraeger , Janosch Frank , David Hildenbrand , Cornelia Huck , Claudio Imbrenda , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v5 09/13] KVM: Use interval tree to do fast hva lookup in memslots Date: Mon, 20 Sep 2021 23:38:57 +0200 Message-Id: <89deea791ff7a5f4faa535edb9956e9863a564b8.1632171479.git.maciej.szmigiero@oracle.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Maciej S. Szmigiero" The current memslots implementation only allows quick binary search by gfn, quick lookup by hva is not possible - the implementation has to do a linear scan of the whole memslots array, even though the operation being performed might apply just to a single memslot. This significantly hurts performance of per-hva operations with higher memslot counts. Since hva ranges can overlap between memslots an interval tree is needed for tracking them. Signed-off-by: Maciej S. Szmigiero --- arch/arm64/kvm/Kconfig | 1 + arch/mips/kvm/Kconfig | 1 + arch/powerpc/kvm/Kconfig | 1 + arch/s390/kvm/Kconfig | 1 + arch/x86/kvm/Kconfig | 1 + include/linux/kvm_host.h | 3 +++ virt/kvm/kvm_main.c | 48 ++++++++++++++++++++++++++++++++++------ 7 files changed, 49 insertions(+), 7 deletions(-) diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig index d7eec0b43744..42185dcc9596 100644 --- a/arch/arm64/kvm/Kconfig +++ b/arch/arm64/kvm/Kconfig @@ -38,6 +38,7 @@ menuconfig KVM select HAVE_KVM_IRQ_BYPASS select HAVE_KVM_VCPU_RUN_PID_CHANGE select SCHED_INFO + select INTERVAL_TREE help Support hosting virtualized guest machines. diff --git a/arch/mips/kvm/Kconfig b/arch/mips/kvm/Kconfig index a77297480f56..91d197bee9c0 100644 --- a/arch/mips/kvm/Kconfig +++ b/arch/mips/kvm/Kconfig @@ -27,6 +27,7 @@ config KVM select KVM_MMIO select MMU_NOTIFIER select SRCU + select INTERVAL_TREE help Support for hosting Guest kernels. diff --git a/arch/powerpc/kvm/Kconfig b/arch/powerpc/kvm/Kconfig index ff581d70f20c..e4c24f524ba8 100644 --- a/arch/powerpc/kvm/Kconfig +++ b/arch/powerpc/kvm/Kconfig @@ -26,6 +26,7 @@ config KVM select KVM_VFIO select IRQ_BYPASS_MANAGER select HAVE_KVM_IRQ_BYPASS + select INTERVAL_TREE config KVM_BOOK3S_HANDLER bool diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig index 67a8e770e369..2e84d3922f7c 100644 --- a/arch/s390/kvm/Kconfig +++ b/arch/s390/kvm/Kconfig @@ -33,6 +33,7 @@ config KVM select HAVE_KVM_NO_POLL select SRCU select KVM_VFIO + select INTERVAL_TREE help Support hosting paravirtualized guest machines using the SIE virtualization capability on the mainframe. This should work diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig index ac69894eab88..572325ec8085 100644 --- a/arch/x86/kvm/Kconfig +++ b/arch/x86/kvm/Kconfig @@ -43,6 +43,7 @@ config KVM select KVM_GENERIC_DIRTYLOG_READ_PROTECT select KVM_VFIO select SRCU + select INTERVAL_TREE select HAVE_KVM_PM_NOTIFIER if PM help Support hosting fully virtualized guest machines using hardware diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index d2acc00a6472..068877af9756 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -30,6 +30,7 @@ #include #include #include +#include #include #include @@ -428,6 +429,7 @@ static inline int kvm_vcpu_exiting_guest_mode(struct kvm_vcpu *vcpu) struct kvm_memory_slot { struct hlist_node id_node; + struct interval_tree_node hva_node; gfn_t base_gfn; unsigned long npages; unsigned long *dirty_bitmap; @@ -529,6 +531,7 @@ static inline int kvm_arch_vcpu_memslots_id(struct kvm_vcpu *vcpu) */ struct kvm_memslots { u64 generation; + struct rb_root_cached hva_tree; /* The mapping table from slot id to the index in memslots[]. */ DECLARE_HASHTABLE(id_hash, 7); atomic_t last_used_slot; diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 50597608d085..7ed780996910 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -472,6 +472,12 @@ static void kvm_null_fn(void) } #define IS_KVM_NULL_FN(fn) ((fn) == (void *)kvm_null_fn) +/* Iterate over each memslot intersecting [start, last] (inclusive) range */ +#define kvm_for_each_memslot_in_hva_range(node, slots, start, last) \ + for (node = interval_tree_iter_first(&slots->hva_tree, start, last); \ + node; \ + node = interval_tree_iter_next(node, start, last)) \ + static __always_inline int __kvm_handle_hva_range(struct kvm *kvm, const struct kvm_hva_range *range) { @@ -481,6 +487,9 @@ static __always_inline int __kvm_handle_hva_range(struct kvm *kvm, struct kvm_memslots *slots; int i, idx; + if (WARN_ON_ONCE(range->end <= range->start)) + return 0; + /* A null handler is allowed if and only if on_lock() is provided. */ if (WARN_ON_ONCE(IS_KVM_NULL_FN(range->on_lock) && IS_KVM_NULL_FN(range->handler))) @@ -489,15 +498,17 @@ static __always_inline int __kvm_handle_hva_range(struct kvm *kvm, idx = srcu_read_lock(&kvm->srcu); for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { + struct interval_tree_node *node; + slots = __kvm_memslots(kvm, i); - kvm_for_each_memslot(slot, slots) { + kvm_for_each_memslot_in_hva_range(node, slots, + range->start, range->end - 1) { unsigned long hva_start, hva_end; + slot = container_of(node, struct kvm_memory_slot, hva_node); hva_start = max(range->start, slot->userspace_addr); hva_end = min(range->end, slot->userspace_addr + (slot->npages << PAGE_SHIFT)); - if (hva_start >= hva_end) - continue; /* * To optimize for the likely case where the address @@ -833,6 +844,7 @@ static struct kvm_memslots *kvm_alloc_memslots(void) if (!slots) return NULL; + slots->hva_tree = RB_ROOT_CACHED; hash_init(slots->id_hash); return slots; @@ -1252,10 +1264,14 @@ static inline void kvm_memslot_delete(struct kvm_memslots *slots, atomic_set(&slots->last_used_slot, 0); for (i = oldslot - mslots; i < slots->used_slots; i++) { + interval_tree_remove(&mslots[i].hva_node, &slots->hva_tree); hash_del(&mslots[i].id_node); + mslots[i] = mslots[i + 1]; + interval_tree_insert(&mslots[i].hva_node, &slots->hva_tree); hash_add(slots->id_hash, &mslots[i].id_node, mslots[i].id); } + interval_tree_remove(&mslots[i].hva_node, &slots->hva_tree); hash_del(&mslots[i].id_node); mslots[i] = *memslot; } @@ -1275,7 +1291,8 @@ static inline int kvm_memslot_insert_back(struct kvm_memslots *slots) * itself is not preserved in the array, i.e. not swapped at this time, only * its new index into the array is tracked. Returns the changed memslot's * current index into the memslots array. - * The memslot at the returned index will not be in @slots->id_hash by then. + * The memslot at the returned index will not be in @slots->hva_tree or + * @slots->id_hash by then. * @memslot is a detached struct with desired final data of the changed slot. */ static inline int kvm_memslot_move_backward(struct kvm_memslots *slots, @@ -1298,6 +1315,7 @@ static inline int kvm_memslot_move_backward(struct kvm_memslots *slots, * That's why the memslot has to be first removed from the hash table * here. */ + interval_tree_remove(&mmemslot->hva_node, &slots->hva_tree); hash_del(&mmemslot->id_node); /* @@ -1312,8 +1330,11 @@ static inline int kvm_memslot_move_backward(struct kvm_memslots *slots, WARN_ON_ONCE(memslot->base_gfn == mslots[i + 1].base_gfn); /* Shift the next memslot forward one and update its index. */ + interval_tree_remove(&mslots[i + 1].hva_node, &slots->hva_tree); hash_del(&mslots[i + 1].id_node); + mslots[i] = mslots[i + 1]; + interval_tree_insert(&mslots[i].hva_node, &slots->hva_tree); hash_add(slots->id_hash, &mslots[i].id_node, mslots[i].id); } return i; @@ -1325,10 +1346,12 @@ static inline int kvm_memslot_move_backward(struct kvm_memslots *slots, * is not preserved in the array, i.e. not swapped at this time, only its new * index into the array is tracked. Returns the changed memslot's final index * into the memslots array. - * The memslot at the returned index will not be in @slots->id_hash by then. + * The memslot at the returned index will not be in @slots->hva_tree or + * @slots->id_hash by then. * @memslot is a detached struct with desired final data of the new or * changed slot. - * Assumes that the memslot at @start index is not in @slots->id_hash. + * Assumes that the memslot at @start index is not in @slots->hva_tree or + * @slots->id_hash. */ static inline int kvm_memslot_move_forward(struct kvm_memslots *slots, struct kvm_memory_slot *memslot, @@ -1344,8 +1367,11 @@ static inline int kvm_memslot_move_forward(struct kvm_memslots *slots, WARN_ON_ONCE(memslot->base_gfn == mslots[i - 1].base_gfn); /* Shift the next memslot back one and update its index. */ + interval_tree_remove(&mslots[i - 1].hva_node, &slots->hva_tree); hash_del(&mslots[i - 1].id_node); + mslots[i] = mslots[i - 1]; + interval_tree_insert(&mslots[i].hva_node, &slots->hva_tree); hash_add(slots->id_hash, &mslots[i].id_node, mslots[i].id); } return i; @@ -1418,6 +1444,11 @@ static void update_memslots(struct kvm_memslots *slots, * its index accordingly. */ slots->memslots[i] = *memslot; + slots->memslots[i].hva_node.start = memslot->userspace_addr; + slots->memslots[i].hva_node.last = memslot->userspace_addr + + (memslot->npages << PAGE_SHIFT) - 1; + interval_tree_insert(&slots->memslots[i].hva_node, + &slots->hva_tree); hash_add(slots->id_hash, &slots->memslots[i].id_node, memslot->id); } @@ -1540,9 +1571,12 @@ static struct kvm_memslots *kvm_dup_memslots(struct kvm_memslots *old, kvm_copy_memslots(slots, old); + slots->hva_tree = RB_ROOT_CACHED; hash_init(slots->id_hash); - kvm_for_each_memslot(memslot, slots) + kvm_for_each_memslot(memslot, slots) { + interval_tree_insert(&memslot->hva_node, &slots->hva_tree); hash_add(slots->id_hash, &memslot->id_node, memslot->id); + } return slots; }