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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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254272ce65
There are many KVM kernel memory allocations which are tied to the life of the VM process and should be charged to the VM process's cgroup. If the allocations aren't tied to the process, the OOM killer will not know that killing the process will free the associated kernel memory. Add __GFP_ACCOUNT flags to many of the allocations which are not yet being charged to the VM process's cgroup. Tested: Ran all kvm-unit-tests on a 64 bit Haswell machine, the patch introduced no new failures. Ran a kernel memory accounting test which creates a VM to touch memory and then checks that the kernel memory allocated for the process is within certain bounds. With this patch we account for much more of the vmalloc and slab memory allocated for the VM. There remain a few allocations which should be charged to the VM's cgroup but are not. In x86, they include: vcpu->arch.pio_data There allocations are unaccounted in this patch because they are mapped to userspace, and accounting them to a cgroup causes problems. This should be addressed in a future patch. Signed-off-by: Ben Gardon <bgardon@google.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
268 lines
6.7 KiB
C
268 lines
6.7 KiB
C
/*
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* Support KVM gust page tracking
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*
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* This feature allows us to track page access in guest. Currently, only
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* write access is tracked.
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*
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* Copyright(C) 2015 Intel Corporation.
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*
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* Author:
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* Xiao Guangrong <guangrong.xiao@linux.intel.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*/
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#include <linux/kvm_host.h>
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#include <linux/rculist.h>
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#include <asm/kvm_host.h>
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#include <asm/kvm_page_track.h>
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#include "mmu.h"
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void kvm_page_track_free_memslot(struct kvm_memory_slot *free,
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struct kvm_memory_slot *dont)
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{
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int i;
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for (i = 0; i < KVM_PAGE_TRACK_MAX; i++)
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if (!dont || free->arch.gfn_track[i] !=
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dont->arch.gfn_track[i]) {
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kvfree(free->arch.gfn_track[i]);
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free->arch.gfn_track[i] = NULL;
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}
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}
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int kvm_page_track_create_memslot(struct kvm_memory_slot *slot,
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unsigned long npages)
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{
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int i;
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for (i = 0; i < KVM_PAGE_TRACK_MAX; i++) {
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slot->arch.gfn_track[i] =
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kvcalloc(npages, sizeof(*slot->arch.gfn_track[i]),
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GFP_KERNEL_ACCOUNT);
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if (!slot->arch.gfn_track[i])
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goto track_free;
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}
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return 0;
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track_free:
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kvm_page_track_free_memslot(slot, NULL);
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return -ENOMEM;
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}
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static inline bool page_track_mode_is_valid(enum kvm_page_track_mode mode)
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{
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if (mode < 0 || mode >= KVM_PAGE_TRACK_MAX)
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return false;
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return true;
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}
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static void update_gfn_track(struct kvm_memory_slot *slot, gfn_t gfn,
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enum kvm_page_track_mode mode, short count)
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{
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int index, val;
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index = gfn_to_index(gfn, slot->base_gfn, PT_PAGE_TABLE_LEVEL);
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val = slot->arch.gfn_track[mode][index];
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if (WARN_ON(val + count < 0 || val + count > USHRT_MAX))
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return;
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slot->arch.gfn_track[mode][index] += count;
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}
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/*
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* add guest page to the tracking pool so that corresponding access on that
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* page will be intercepted.
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*
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* It should be called under the protection both of mmu-lock and kvm->srcu
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* or kvm->slots_lock.
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*
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* @kvm: the guest instance we are interested in.
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* @slot: the @gfn belongs to.
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* @gfn: the guest page.
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* @mode: tracking mode, currently only write track is supported.
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*/
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void kvm_slot_page_track_add_page(struct kvm *kvm,
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struct kvm_memory_slot *slot, gfn_t gfn,
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enum kvm_page_track_mode mode)
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{
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if (WARN_ON(!page_track_mode_is_valid(mode)))
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return;
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update_gfn_track(slot, gfn, mode, 1);
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/*
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* new track stops large page mapping for the
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* tracked page.
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*/
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kvm_mmu_gfn_disallow_lpage(slot, gfn);
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if (mode == KVM_PAGE_TRACK_WRITE)
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if (kvm_mmu_slot_gfn_write_protect(kvm, slot, gfn))
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kvm_flush_remote_tlbs(kvm);
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}
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EXPORT_SYMBOL_GPL(kvm_slot_page_track_add_page);
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/*
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* remove the guest page from the tracking pool which stops the interception
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* of corresponding access on that page. It is the opposed operation of
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* kvm_slot_page_track_add_page().
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*
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* It should be called under the protection both of mmu-lock and kvm->srcu
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* or kvm->slots_lock.
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*
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* @kvm: the guest instance we are interested in.
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* @slot: the @gfn belongs to.
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* @gfn: the guest page.
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* @mode: tracking mode, currently only write track is supported.
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*/
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void kvm_slot_page_track_remove_page(struct kvm *kvm,
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struct kvm_memory_slot *slot, gfn_t gfn,
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enum kvm_page_track_mode mode)
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{
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if (WARN_ON(!page_track_mode_is_valid(mode)))
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return;
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update_gfn_track(slot, gfn, mode, -1);
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/*
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* allow large page mapping for the tracked page
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* after the tracker is gone.
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*/
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kvm_mmu_gfn_allow_lpage(slot, gfn);
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}
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EXPORT_SYMBOL_GPL(kvm_slot_page_track_remove_page);
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/*
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* check if the corresponding access on the specified guest page is tracked.
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*/
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bool kvm_page_track_is_active(struct kvm_vcpu *vcpu, gfn_t gfn,
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enum kvm_page_track_mode mode)
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{
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struct kvm_memory_slot *slot;
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int index;
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if (WARN_ON(!page_track_mode_is_valid(mode)))
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return false;
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slot = kvm_vcpu_gfn_to_memslot(vcpu, gfn);
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if (!slot)
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return false;
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index = gfn_to_index(gfn, slot->base_gfn, PT_PAGE_TABLE_LEVEL);
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return !!READ_ONCE(slot->arch.gfn_track[mode][index]);
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}
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void kvm_page_track_cleanup(struct kvm *kvm)
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{
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struct kvm_page_track_notifier_head *head;
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head = &kvm->arch.track_notifier_head;
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cleanup_srcu_struct(&head->track_srcu);
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}
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void kvm_page_track_init(struct kvm *kvm)
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{
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struct kvm_page_track_notifier_head *head;
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head = &kvm->arch.track_notifier_head;
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init_srcu_struct(&head->track_srcu);
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INIT_HLIST_HEAD(&head->track_notifier_list);
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}
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/*
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* register the notifier so that event interception for the tracked guest
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* pages can be received.
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*/
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void
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kvm_page_track_register_notifier(struct kvm *kvm,
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struct kvm_page_track_notifier_node *n)
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{
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struct kvm_page_track_notifier_head *head;
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head = &kvm->arch.track_notifier_head;
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spin_lock(&kvm->mmu_lock);
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hlist_add_head_rcu(&n->node, &head->track_notifier_list);
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spin_unlock(&kvm->mmu_lock);
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}
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EXPORT_SYMBOL_GPL(kvm_page_track_register_notifier);
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/*
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* stop receiving the event interception. It is the opposed operation of
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* kvm_page_track_register_notifier().
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*/
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void
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kvm_page_track_unregister_notifier(struct kvm *kvm,
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struct kvm_page_track_notifier_node *n)
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{
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struct kvm_page_track_notifier_head *head;
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head = &kvm->arch.track_notifier_head;
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spin_lock(&kvm->mmu_lock);
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hlist_del_rcu(&n->node);
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spin_unlock(&kvm->mmu_lock);
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synchronize_srcu(&head->track_srcu);
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}
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EXPORT_SYMBOL_GPL(kvm_page_track_unregister_notifier);
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/*
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* Notify the node that write access is intercepted and write emulation is
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* finished at this time.
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*
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* The node should figure out if the written page is the one that node is
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* interested in by itself.
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*/
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void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new,
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int bytes)
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{
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struct kvm_page_track_notifier_head *head;
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struct kvm_page_track_notifier_node *n;
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int idx;
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head = &vcpu->kvm->arch.track_notifier_head;
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if (hlist_empty(&head->track_notifier_list))
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return;
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idx = srcu_read_lock(&head->track_srcu);
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hlist_for_each_entry_rcu(n, &head->track_notifier_list, node)
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if (n->track_write)
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n->track_write(vcpu, gpa, new, bytes, n);
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srcu_read_unlock(&head->track_srcu, idx);
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}
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/*
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* Notify the node that memory slot is being removed or moved so that it can
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* drop write-protection for the pages in the memory slot.
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*
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* The node should figure out it has any write-protected pages in this slot
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* by itself.
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*/
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void kvm_page_track_flush_slot(struct kvm *kvm, struct kvm_memory_slot *slot)
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{
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struct kvm_page_track_notifier_head *head;
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struct kvm_page_track_notifier_node *n;
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int idx;
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head = &kvm->arch.track_notifier_head;
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if (hlist_empty(&head->track_notifier_list))
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return;
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idx = srcu_read_lock(&head->track_srcu);
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hlist_for_each_entry_rcu(n, &head->track_notifier_list, node)
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if (n->track_flush_slot)
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n->track_flush_slot(kvm, slot, n);
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srcu_read_unlock(&head->track_srcu, idx);
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}
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