From patchwork Fri May 13 20:28:18 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Matlack X-Patchwork-Id: 12849457 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 B22F9C433EF for ; Fri, 13 May 2022 20:29:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1384267AbiEMU3h (ORCPT ); Fri, 13 May 2022 16:29:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60380 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1384389AbiEMU3Z (ORCPT ); Fri, 13 May 2022 16:29:25 -0400 Received: from mail-oa1-x4a.google.com (mail-oa1-x4a.google.com [IPv6:2001:4860:4864:20::4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 063277A45E for ; Fri, 13 May 2022 13:29:14 -0700 (PDT) Received: by mail-oa1-x4a.google.com with SMTP id 586e51a60fabf-e90d2b84b5so5326707fac.9 for ; Fri, 13 May 2022 13:29:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=ZyvfrK7t/fkygj9zlxm8w55qXC1vVKrQ2xyo5XqoD9o=; b=DL516FtaapUVCGp13HuBwL9ZgRTufCd+erUTZh0MFlzfT5BJUIae4XKJr06r6QSQv0 OOiO5/wTUCt7+JP6EAEU576dKU1Cpr1Oh74S8hsW6FPFuOoM3BTzhi4xRjbTqAUlHqLW DX58FLXtjKWaS1tk5AEf2kQZBHcz37mLjToCwOGnqR2J+In4CDMV2TnPzD0AqToSk5+8 tZR6VfS/fkEV1QI4k8K/owPThJWAE38+GgNMBWoftHMy+x7PiDPu8EZJqSEABD/EwnPy 8RlvTaaLlsJOD3yiJ0U3saqlH2qAaDN+5K61+hESjXWNvJNtzDqZzDA6nlbDOGOGpGX3 POqg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=ZyvfrK7t/fkygj9zlxm8w55qXC1vVKrQ2xyo5XqoD9o=; b=kMii0e33x0aMlFaI6NWbOs5qojGk9qCDNH6GPH8CAh8VmIg+z0oRkOx8EOz5KeNqBN EQcZgx/rnp/lNdUtzRjKTGG8tA7FBmlXfxq5RIJAq9meqRXcv9SnNYfEXx+YrwH+D1T3 vYpx3ORb76EAXkeRKJiQCW/Oows4tqfelMZ67Xpgtu9KAJ9+xvgI648qGYfRAW7/Uyxj M7tzLqljO3Qd1Du5+mCjR4SWRKjmu8Vqv+ksK92b0+Kaao8TA5a7yV6hXW3KDm8zEiDO L5PEgS0R28Xnx8HaeJ0eDnk+OKGqHK11F4efNrSjjKifREn8tDTSe/d5TfWFl3ETBnXs zdpA== X-Gm-Message-State: AOAM531Z7LuwVbuVpxn79EvP5iXnM6Ll8n6ZCPjV+DiZLzv+FPOJWV8T 6AiBiY7RQdRB7rVaS4uoOniiEi8+cDYXgw== X-Google-Smtp-Source: ABdhPJyg/a9CLCdubsuKSWJnUZ/D7bZKr4vuTeYAyZWCYyeeDiVsSB2L6tE+iwttyipU70ZlFf/dDPbmtnOOZQ== X-Received: from dmatlack-heavy.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:19cd]) (user=dmatlack job=sendgmr) by 2002:a05:6808:211e:b0:326:7b4b:1563 with SMTP id r30-20020a056808211e00b003267b4b1563mr3199889oiw.49.1652473745118; Fri, 13 May 2022 13:29:05 -0700 (PDT) Date: Fri, 13 May 2022 20:28:18 +0000 In-Reply-To: <20220513202819.829591-1-dmatlack@google.com> Message-Id: <20220513202819.829591-21-dmatlack@google.com> Mime-Version: 1.0 References: <20220513202819.829591-1-dmatlack@google.com> X-Mailer: git-send-email 2.36.0.550.gb090851708-goog Subject: [PATCH v5 20/21] KVM: Allow for different capacities in kvm_mmu_memory_cache structs From: David Matlack To: Paolo Bonzini Cc: Marc Zyngier , Huacai Chen , Aleksandar Markovic , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Sean Christopherson , Andrew Jones , Ben Gardon , Peter Xu , maciej.szmigiero@oracle.com, "moderated list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" , "open list:KERNEL VIRTUAL MACHINE FOR RISC-V (KVM/riscv)" , Peter Feiner , Lai Jiangshan , David Matlack Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Allow the capacity of the kvm_mmu_memory_cache struct to be chosen at declaration time rather than being fixed for all declarations. This will be used in a follow-up commit to declare an cache in x86 with a capacity of 512+ objects without having to increase the capacity of all caches in KVM. This change requires each cache now specify its capacity at runtime, since the cache struct itself no longer has a fixed capacity known at compile time. To protect against someone accidentally defining a kvm_mmu_memory_cache struct directly (without the extra storage), this commit includes a WARN_ON() in kvm_mmu_topup_memory_cache(). In order to support different capacities, this commit changes the objects pointer array to be dynamically allocated the first time the cache is topped-up. An alternative would be to lay out the objects array after the kvm_mmu_memory_cache struct, which can be done at compile time. But that change, unfortunately, adds some grottiness to arm64 and riscv, which uses a function-local (i.e. stack-allocated) kvm_mmu_memory_cache struct. Since C does not allow anonymous structs in functions, the new wrapper struct that contains kvm_mmu_memory_cache and the objects pointer array, must be named, which means dealing with an outer and inner struct. The outer struct can't be dropped since then there would be no guarantee the kvm_mmu_memory_cache struct and objects array would be laid out consecutively on the stack. No functional change intended. Signed-off-by: David Matlack Reviewed-by: Marc Zyngier --- arch/arm64/kvm/arm.c | 1 + arch/arm64/kvm/mmu.c | 5 ++++- arch/mips/kvm/mips.c | 2 ++ arch/riscv/kvm/mmu.c | 8 ++++---- arch/riscv/kvm/vcpu.c | 1 + arch/x86/kvm/mmu/mmu.c | 9 +++++++++ include/linux/kvm_types.h | 9 +++++++-- virt/kvm/kvm_main.c | 20 ++++++++++++++++++-- 8 files changed, 46 insertions(+), 9 deletions(-) diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 7fceb855fa71..aa1e0c1659d4 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -320,6 +320,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) vcpu->arch.target = -1; bitmap_zero(vcpu->arch.features, KVM_VCPU_MAX_FEATURES); + vcpu->arch.mmu_page_cache.capacity = KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE; vcpu->arch.mmu_page_cache.gfp_zero = __GFP_ZERO; /* Set up the timer */ diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 53ae2c0640bc..2f2ef6b60ff4 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -764,7 +764,10 @@ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa, { phys_addr_t addr; int ret = 0; - struct kvm_mmu_memory_cache cache = { 0, __GFP_ZERO, NULL, }; + struct kvm_mmu_memory_cache cache = { + .capacity = KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE, + .gfp_zero = __GFP_ZERO, + }; struct kvm_pgtable *pgt = kvm->arch.mmu.pgt; enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_DEVICE | KVM_PGTABLE_PROT_R | diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c index a25e0b73ee70..45c7179144dc 100644 --- a/arch/mips/kvm/mips.c +++ b/arch/mips/kvm/mips.c @@ -387,6 +387,8 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) if (err) goto out_free_gebase; + vcpu->arch.mmu_page_cache.capacity = KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE; + return 0; out_free_gebase: diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c index f80a34fbf102..8c2338ecc246 100644 --- a/arch/riscv/kvm/mmu.c +++ b/arch/riscv/kvm/mmu.c @@ -347,10 +347,10 @@ static int stage2_ioremap(struct kvm *kvm, gpa_t gpa, phys_addr_t hpa, int ret = 0; unsigned long pfn; phys_addr_t addr, end; - struct kvm_mmu_memory_cache pcache; - - memset(&pcache, 0, sizeof(pcache)); - pcache.gfp_zero = __GFP_ZERO; + struct kvm_mmu_memory_cache pcache = { + .capacity = KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE, + .gfp_zero = __GFP_ZERO, + }; end = (gpa + size + PAGE_SIZE - 1) & PAGE_MASK; pfn = __phys_to_pfn(hpa); diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index 6785aef4cbd4..bbcb9d4a04fb 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -94,6 +94,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu) /* Mark this VCPU never ran */ vcpu->arch.ran_atleast_once = false; + vcpu->arch.mmu_page_cache.capacity = KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE; vcpu->arch.mmu_page_cache.gfp_zero = __GFP_ZERO; /* Setup ISA features available to VCPU */ diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 4b40fa2e27eb..dad7e19ef8ed 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -5803,12 +5803,21 @@ int kvm_mmu_create(struct kvm_vcpu *vcpu) { int ret; + vcpu->arch.mmu_pte_list_desc_cache.capacity = + KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE; vcpu->arch.mmu_pte_list_desc_cache.kmem_cache = pte_list_desc_cache; vcpu->arch.mmu_pte_list_desc_cache.gfp_zero = __GFP_ZERO; + vcpu->arch.mmu_page_header_cache.capacity = + KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE; vcpu->arch.mmu_page_header_cache.kmem_cache = mmu_page_header_cache; vcpu->arch.mmu_page_header_cache.gfp_zero = __GFP_ZERO; + vcpu->arch.mmu_shadowed_info_cache.capacity = + KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE; + + vcpu->arch.mmu_shadow_page_cache.capacity = + KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE; vcpu->arch.mmu_shadow_page_cache.gfp_zero = __GFP_ZERO; vcpu->arch.mmu = &vcpu->arch.root_mmu; diff --git a/include/linux/kvm_types.h b/include/linux/kvm_types.h index ac1ebb37a0ff..549103a4f7bc 100644 --- a/include/linux/kvm_types.h +++ b/include/linux/kvm_types.h @@ -83,14 +83,19 @@ struct gfn_to_pfn_cache { * MMU flows is problematic, as is triggering reclaim, I/O, etc... while * holding MMU locks. Note, these caches act more like prefetch buffers than * classical caches, i.e. objects are not returned to the cache on being freed. + * + * The storage for the cache object pointers is allocated dynamically when the + * cache is topped-up. The capacity field defines the number of object pointers + * available after the struct. */ struct kvm_mmu_memory_cache { int nobjs; + int capacity; gfp_t gfp_zero; struct kmem_cache *kmem_cache; - void *objects[KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE]; + void **objects; }; -#endif +#endif /* KVM_ARCH_NR_OBJS_PER_MEMORY_CACHE */ #define HALT_POLL_HIST_COUNT 32 diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index e089db822c12..264e4107e06f 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -371,12 +371,23 @@ static inline void *mmu_memory_cache_alloc_obj(struct kvm_mmu_memory_cache *mc, int kvm_mmu_topup_memory_cache(struct kvm_mmu_memory_cache *mc, int min) { + gfp_t gfp = GFP_KERNEL_ACCOUNT; void *obj; if (mc->nobjs >= min) return 0; - while (mc->nobjs < ARRAY_SIZE(mc->objects)) { - obj = mmu_memory_cache_alloc_obj(mc, GFP_KERNEL_ACCOUNT); + + if (WARN_ON(mc->capacity == 0)) + return -EINVAL; + + if (!mc->objects) { + mc->objects = kvmalloc_array(sizeof(void *), mc->capacity, gfp); + if (!mc->objects) + return -ENOMEM; + } + + while (mc->nobjs < mc->capacity) { + obj = mmu_memory_cache_alloc_obj(mc, gfp); if (!obj) return mc->nobjs >= min ? 0 : -ENOMEM; mc->objects[mc->nobjs++] = obj; @@ -397,6 +408,11 @@ void kvm_mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc) else free_page((unsigned long)mc->objects[--mc->nobjs]); } + + kvfree(mc->objects); + + /* Note, must set to NULL to avoid use-after-free in the next top-up. */ + mc->objects = NULL; } void *kvm_mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)