2023-07-29 09:35:27 +08:00
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/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __KVM_X86_PAGE_TRACK_H
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#define __KVM_X86_PAGE_TRACK_H
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#include <linux/kvm_host.h>
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#include <asm/kvm_page_track.h>
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bool kvm_page_track_write_tracking_enabled(struct kvm *kvm);
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int kvm_page_track_write_tracking_alloc(struct kvm_memory_slot *slot);
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void kvm_page_track_free_memslot(struct kvm_memory_slot *slot);
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int kvm_page_track_create_memslot(struct kvm *kvm,
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struct kvm_memory_slot *slot,
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unsigned long npages);
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bool kvm_slot_page_track_is_active(struct kvm *kvm,
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KVM: x86/mmu: Drop infrastructure for multiple page-track modes
Drop "support" for multiple page-track modes, as there is no evidence
that array-based and refcounted metadata is the optimal solution for
other modes, nor is there any evidence that other use cases, e.g. for
access-tracking, will be a good fit for the page-track machinery in
general.
E.g. one potential use case of access-tracking would be to prevent guest
access to poisoned memory (from the guest's perspective). In that case,
the number of poisoned pages is likely to be a very small percentage of
the guest memory, and there is no need to reference count the number of
access-tracking users, i.e. expanding gfn_track[] for a new mode would be
grossly inefficient. And for poisoned memory, host userspace would also
likely want to trap accesses, e.g. to inject #MC into the guest, and that
isn't currently supported by the page-track framework.
A better alternative for that poisoned page use case is likely a
variation of the proposed per-gfn attributes overlay (linked), which
would allow efficiently tracking the sparse set of poisoned pages, and by
default would exit to userspace on access.
Link: https://lore.kernel.org/all/Y2WB48kD0J4VGynX@google.com
Cc: Ben Gardon <bgardon@google.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-24-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-07-29 09:35:29 +08:00
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const struct kvm_memory_slot *slot, gfn_t gfn);
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2023-07-29 09:35:27 +08:00
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2023-07-29 09:35:28 +08:00
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#ifdef CONFIG_KVM_EXTERNAL_WRITE_TRACKING
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int kvm_page_track_init(struct kvm *kvm);
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void kvm_page_track_cleanup(struct kvm *kvm);
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void __kvm_page_track_write(struct kvm *kvm, gpa_t gpa, const u8 *new, int bytes);
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2023-07-29 09:35:27 +08:00
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void kvm_page_track_delete_slot(struct kvm *kvm, struct kvm_memory_slot *slot);
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static inline bool kvm_page_track_has_external_user(struct kvm *kvm)
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{
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return !hlist_empty(&kvm->arch.track_notifier_head.track_notifier_list);
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}
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2023-07-29 09:35:28 +08:00
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#else
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static inline int kvm_page_track_init(struct kvm *kvm) { return 0; }
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static inline void kvm_page_track_cleanup(struct kvm *kvm) { }
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static inline void __kvm_page_track_write(struct kvm *kvm, gpa_t gpa,
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const u8 *new, int bytes) { }
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static inline void kvm_page_track_delete_slot(struct kvm *kvm,
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struct kvm_memory_slot *slot) { }
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static inline bool kvm_page_track_has_external_user(struct kvm *kvm) { return false; }
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#endif /* CONFIG_KVM_EXTERNAL_WRITE_TRACKING */
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static inline void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa,
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const u8 *new, int bytes)
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{
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__kvm_page_track_write(vcpu->kvm, gpa, new, bytes);
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kvm_mmu_track_write(vcpu, gpa, new, bytes);
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}
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2023-07-29 09:35:27 +08:00
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#endif /* __KVM_X86_PAGE_TRACK_H */
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