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Thu, 23 Feb 2023 09:13:59 -0800 (PST) Date: Thu, 23 Feb 2023 09:13:58 -0800 In-Reply-To: <20230217041230.2417228-2-yuzhao@google.com> Mime-Version: 1.0 References: <20230217041230.2417228-1-yuzhao@google.com> <20230217041230.2417228-2-yuzhao@google.com> Message-ID: Subject: Re: [PATCH mm-unstable v1 1/5] mm/kvm: add mmu_notifier_test_clear_young() From: Sean Christopherson To: Yu Zhao Cc: Andrew Morton , Paolo Bonzini , Jonathan Corbet , Michael Larabel , kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-mm@google.com Content-Type: text/plain; charset="us-ascii" X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 830BE40026 X-Stat-Signature: wc3du9i58tpw5wfym7ufrg94t7ipyykt X-HE-Tag: 1677172440-981618 X-HE-Meta: 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 RSZfxOQm SkdS5/Rx/Obe3LoUqop2M6gexuz33r4MJHrGtTemgpyCXriqQ01YIWyY0+kT+sC09Ma17cpe9s7Y8vBNYNmF1h5CjbSpubFUVwiW1LTcNrXuBfTEIGcS/xuvPxxOrsqXMdn0OXp/YEvel9muQ+7iVwBVz80UT4XTIlba6bqgxDETkHWsM4BHiUIC2AHGnRnkpezO75uUHRc9kD3vZxkyzisX3TPnoeLr5qyyj+Ho/YOjnouAvwIl8TMMVetakiaGaIOasPXde8BZwCQ1+JJTE71M1OgsHcXH+xlDxkm3ICdgdqxFBEmffN8cxlb2ZpPpU+mN68sZPbxokuzewv5N5mvISl9KAUwz85kSmLuFfAdAkMXpG5CPHA235ZZhdxYiQm3/Y46XOAE4o8u5e5fL3+o2S3Yrbb4zyLkCbdRCrsE+NCLv2T3sbyYRkRcakA/XaIZmFTn9hKqb6RHSfKOq/XO2pGATnJyU8OgocdkWZyw4+2ITYzMLRE1MYcUaobDR8luYoMXVYCQY/kYLlXQ50rhGu19/cIsPIK90bCKuTXHE3AD58XKV6KgsFbj7fqG3dx/Cf4bai1LQzmZ5mKofclJz0UNkwr1bF8kNt0RCbLk/d84t71RSWdzvEPaFY3miEmBF22WGLCLr4cgIZ7ah4V9+YZQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Feb 16, 2023, Yu Zhao wrote: > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 9c60384b5ae0..1b465df4a93d 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -875,6 +875,63 @@ static int kvm_mmu_notifier_clear_young(struct mmu_notifier *mn, > return kvm_handle_hva_range_no_flush(mn, start, end, kvm_age_gfn); > } > > +static bool kvm_test_clear_young(struct kvm *kvm, unsigned long start, > + unsigned long end, unsigned long *bitmap) > +{ > + int i; > + int key; > + bool success = true; > + > + trace_kvm_age_hva(start, end); > + > + key = srcu_read_lock(&kvm->srcu); > + > + for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) { > + struct interval_tree_node *node; > + struct kvm_memslots *slots = __kvm_memslots(kvm, i); > + > + kvm_for_each_memslot_in_hva_range(node, slots, start, end - 1) { > + gfn_t lsb_gfn; > + unsigned long hva_start, hva_end; > + struct kvm_gfn_range range = { > + .slot = container_of(node, struct kvm_memory_slot, > + hva_node[slots->node_idx]), > + }; > + > + hva_start = max(start, range.slot->userspace_addr); > + hva_end = min(end - 1, range.slot->userspace_addr + > + range.slot->npages * PAGE_SIZE - 1); > + > + range.start = hva_to_gfn_memslot(hva_start, range.slot); > + range.end = hva_to_gfn_memslot(hva_end, range.slot) + 1; > + > + if (WARN_ON_ONCE(range.end <= range.start)) > + continue; Extend __kvm_handle_hva_range() instead of copy-pasting. At a very quick glance, I believe all that is needed is (minus sanity checks): diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index d255964ec331..3296ae2cf6fa 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -544,6 +544,7 @@ struct kvm_hva_range { hva_handler_t handler; on_lock_fn_t on_lock; on_unlock_fn_t on_unlock; + bool lockless; bool flush_on_ret; bool may_block; }; @@ -616,7 +617,7 @@ static __always_inline int __kvm_handle_hva_range(struct kvm *kvm, gfn_range.end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, slot); gfn_range.slot = slot; - if (!locked) { + if (!range->lockless && !locked) { locked = true; KVM_MMU_LOCK(kvm); if (!IS_KVM_NULL_FN(range->on_lock)) > + > + /* see the comments on the generic kvm_arch_has_test_clear_young() */ > + lsb_gfn = hva_to_gfn_memslot(end - 1, range.slot); > + > + success = kvm_arch_test_clear_young(kvm, &range, lsb_gfn, bitmap); > + if (!success) > + break; > + } > + } > + > + srcu_read_unlock(&kvm->srcu, key); > + > + return success; > +}