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authorAvi Kivity <avi@redhat.com>2010-03-25 12:16:48 +0200
committerAvi Kivity <avi@redhat.com>2010-05-17 12:16:46 +0300
commit0f2d8f4dd0663defff8c1738d33478c1fb65a4f5 (patch)
treec013f378ae0dc27192bd6349f690ed507b7f6b04 /Documentation/kvm
parent84b0c8c6a6f87b62bca93727dee12ec59e32e597 (diff)
KVM: Document KVM_SET_USER_MEMORY_REGION
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'Documentation/kvm')
-rw-r--r--Documentation/kvm/api.txt45
1 files changed, 45 insertions, 0 deletions
diff --git a/Documentation/kvm/api.txt b/Documentation/kvm/api.txt
index d170cb43554..9d6e64753d2 100644
--- a/Documentation/kvm/api.txt
+++ b/Documentation/kvm/api.txt
@@ -749,6 +749,51 @@ Writes debug registers into the vcpu.
See KVM_GET_DEBUGREGS for the data structure. The flags field is unused
yet and must be cleared on entry.
+4.34 KVM_SET_USER_MEMORY_REGION
+
+Capability: KVM_CAP_USER_MEM
+Architectures: all
+Type: vm ioctl
+Parameters: struct kvm_userspace_memory_region (in)
+Returns: 0 on success, -1 on error
+
+struct kvm_userspace_memory_region {
+ __u32 slot;
+ __u32 flags;
+ __u64 guest_phys_addr;
+ __u64 memory_size; /* bytes */
+ __u64 userspace_addr; /* start of the userspace allocated memory */
+};
+
+/* for kvm_memory_region::flags */
+#define KVM_MEM_LOG_DIRTY_PAGES 1UL
+
+This ioctl allows the user to create or modify a guest physical memory
+slot. When changing an existing slot, it may be moved in the guest
+physical memory space, or its flags may be modified. It may not be
+resized. Slots may not overlap in guest physical address space.
+
+Memory for the region is taken starting at the address denoted by the
+field userspace_addr, which must point at user addressable memory for
+the entire memory slot size. Any object may back this memory, including
+anonymous memory, ordinary files, and hugetlbfs.
+
+It is recommended that the lower 21 bits of guest_phys_addr and userspace_addr
+be identical. This allows large pages in the guest to be backed by large
+pages in the host.
+
+The flags field supports just one flag, KVM_MEM_LOG_DIRTY_PAGES, which
+instructs kvm to keep track of writes to memory within the slot. See
+the KVM_GET_DIRTY_LOG ioctl.
+
+When the KVM_CAP_SYNC_MMU capability, changes in the backing of the memory
+region are automatically reflected into the guest. For example, an mmap()
+that affects the region will be made visible immediately. Another example
+is madvise(MADV_DROP).
+
+It is recommended to use this API instead of the KVM_SET_MEMORY_REGION ioctl.
+The KVM_SET_MEMORY_REGION does not allow fine grained control over memory
+allocation and is deprecated.
5. The kvm_run structure