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KVM: Document KVM_SET_USER_MEMORY_REGION
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Avi Kivity <avi@redhat.com>
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@ -749,6 +749,51 @@ Writes debug registers into the vcpu.
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See KVM_GET_DEBUGREGS for the data structure. The flags field is unused
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yet and must be cleared on entry.
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4.34 KVM_SET_USER_MEMORY_REGION
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Capability: KVM_CAP_USER_MEM
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Architectures: all
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Type: vm ioctl
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Parameters: struct kvm_userspace_memory_region (in)
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Returns: 0 on success, -1 on error
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struct kvm_userspace_memory_region {
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__u32 slot;
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__u32 flags;
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__u64 guest_phys_addr;
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__u64 memory_size; /* bytes */
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__u64 userspace_addr; /* start of the userspace allocated memory */
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};
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/* for kvm_memory_region::flags */
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#define KVM_MEM_LOG_DIRTY_PAGES 1UL
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This ioctl allows the user to create or modify a guest physical memory
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slot. When changing an existing slot, it may be moved in the guest
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physical memory space, or its flags may be modified. It may not be
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resized. Slots may not overlap in guest physical address space.
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Memory for the region is taken starting at the address denoted by the
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field userspace_addr, which must point at user addressable memory for
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the entire memory slot size. Any object may back this memory, including
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anonymous memory, ordinary files, and hugetlbfs.
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It is recommended that the lower 21 bits of guest_phys_addr and userspace_addr
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be identical. This allows large pages in the guest to be backed by large
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pages in the host.
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The flags field supports just one flag, KVM_MEM_LOG_DIRTY_PAGES, which
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instructs kvm to keep track of writes to memory within the slot. See
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the KVM_GET_DIRTY_LOG ioctl.
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When the KVM_CAP_SYNC_MMU capability, changes in the backing of the memory
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region are automatically reflected into the guest. For example, an mmap()
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that affects the region will be made visible immediately. Another example
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is madvise(MADV_DROP).
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It is recommended to use this API instead of the KVM_SET_MEMORY_REGION ioctl.
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The KVM_SET_MEMORY_REGION does not allow fine grained control over memory
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allocation and is deprecated.
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5. The kvm_run structure
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