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ARM64 needs to dirty memory outside of a VCPU context when VGIC/ITS is enabled. It's conflicting with that ring-based dirty page tracking always requires a running VCPU context. Introduce a new flavor of dirty ring that requires the use of both VCPU dirty rings and a dirty bitmap. The expectation is that for non-VCPU sources of dirty memory (such as the VGIC/ITS on arm64), KVM writes to the dirty bitmap. Userspace should scan the dirty bitmap before migrating the VM to the target. Use an additional capability to advertise this behavior. The newly added capability (KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP) can't be enabled before KVM_CAP_DIRTY_LOG_RING_ACQ_REL on ARM64. In this way, the newly added capability is treated as an extension of KVM_CAP_DIRTY_LOG_RING_ACQ_REL. Suggested-by: Marc Zyngier <maz@kernel.org> Suggested-by: Peter Xu <peterx@redhat.com> Co-developed-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Signed-off-by: Gavin Shan <gshan@redhat.com> Acked-by: Peter Xu <peterx@redhat.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110104914.31280-4-gshan@redhat.com
101 lines
2.7 KiB
C
101 lines
2.7 KiB
C
#ifndef KVM_DIRTY_RING_H
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#define KVM_DIRTY_RING_H
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#include <linux/kvm.h>
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/**
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* kvm_dirty_ring: KVM internal dirty ring structure
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*
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* @dirty_index: free running counter that points to the next slot in
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* dirty_ring->dirty_gfns, where a new dirty page should go
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* @reset_index: free running counter that points to the next dirty page
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* in dirty_ring->dirty_gfns for which dirty trap needs to
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* be reenabled
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* @size: size of the compact list, dirty_ring->dirty_gfns
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* @soft_limit: when the number of dirty pages in the list reaches this
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* limit, vcpu that owns this ring should exit to userspace
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* to allow userspace to harvest all the dirty pages
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* @dirty_gfns: the array to keep the dirty gfns
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* @index: index of this dirty ring
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*/
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struct kvm_dirty_ring {
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u32 dirty_index;
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u32 reset_index;
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u32 size;
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u32 soft_limit;
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struct kvm_dirty_gfn *dirty_gfns;
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int index;
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};
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#ifndef CONFIG_HAVE_KVM_DIRTY_RING
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/*
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* If CONFIG_HAVE_HVM_DIRTY_RING not defined, kvm_dirty_ring.o should
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* not be included as well, so define these nop functions for the arch.
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*/
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static inline u32 kvm_dirty_ring_get_rsvd_entries(void)
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{
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return 0;
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}
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static inline bool kvm_use_dirty_bitmap(struct kvm *kvm)
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{
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return true;
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}
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static inline int kvm_dirty_ring_alloc(struct kvm_dirty_ring *ring,
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int index, u32 size)
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{
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return 0;
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}
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static inline int kvm_dirty_ring_reset(struct kvm *kvm,
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struct kvm_dirty_ring *ring)
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{
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return 0;
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}
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static inline void kvm_dirty_ring_push(struct kvm_vcpu *vcpu,
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u32 slot, u64 offset)
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{
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}
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static inline struct page *kvm_dirty_ring_get_page(struct kvm_dirty_ring *ring,
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u32 offset)
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{
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return NULL;
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}
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static inline void kvm_dirty_ring_free(struct kvm_dirty_ring *ring)
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{
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}
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#else /* CONFIG_HAVE_KVM_DIRTY_RING */
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int kvm_cpu_dirty_log_size(void);
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bool kvm_use_dirty_bitmap(struct kvm *kvm);
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bool kvm_arch_allow_write_without_running_vcpu(struct kvm *kvm);
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u32 kvm_dirty_ring_get_rsvd_entries(void);
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int kvm_dirty_ring_alloc(struct kvm_dirty_ring *ring, int index, u32 size);
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/*
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* called with kvm->slots_lock held, returns the number of
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* processed pages.
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*/
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int kvm_dirty_ring_reset(struct kvm *kvm, struct kvm_dirty_ring *ring);
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/*
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* returns =0: successfully pushed
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* <0: unable to push, need to wait
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*/
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void kvm_dirty_ring_push(struct kvm_vcpu *vcpu, u32 slot, u64 offset);
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bool kvm_dirty_ring_check_request(struct kvm_vcpu *vcpu);
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/* for use in vm_operations_struct */
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struct page *kvm_dirty_ring_get_page(struct kvm_dirty_ring *ring, u32 offset);
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void kvm_dirty_ring_free(struct kvm_dirty_ring *ring);
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#endif /* CONFIG_HAVE_KVM_DIRTY_RING */
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#endif /* KVM_DIRTY_RING_H */
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