main/syscalls/vmar_unmap.md

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# zx_vmar_unmap

## Summary

Unmap virtual memory pages.

## Declaration

```c
#include <zircon/syscalls.h>

zx_status_t zx_vmar_unmap(zx_handle_t handle, zx_vaddr_t addr, size_t len);
```

## Description

`zx_vmar_unmap()` unmaps all VMO mappings and destroys (as if [`zx_vmar_destroy()`]
were called) all sub-regions within the absolute range including *addr* and ending
before exclusively at `addr + len`.  Any sub-region that is in the range must
be fully in the range (i.e. partial overlaps are an error).  If a mapping is
only partially in the range, the mapping is split and the requested portion is
unmapped.

*len* must be page-aligned.

## Rights

TODO(https://fxbug.dev/42107318)

## Return value

`zx_vmar_unmap()` returns `ZX_OK` on success.

## Errors

`ZX_ERR_BAD_HANDLE`  *handle* is not a valid handle.

`ZX_ERR_WRONG_TYPE`  *handle* is not a VMAR handle.

`ZX_ERR_INVALID_ARGS`  *addr* is not page-aligned, *len* is 0 or not page-aligned,
or the requested range partially overlaps a sub-region, or the requested range overlapped
a sub-region and *handle* did not have `ZX_RIGHT_OP_CHILDREN`.

`ZX_ERR_BAD_STATE`  *handle* refers to a destroyed handle.

`ZX_ERR_NOT_FOUND`  Could not find the requested mapping.

## Notes

## See also

 - [`zx_vmar_allocate()`]
 - [`zx_vmar_destroy()`]
 - [`zx_vmar_map()`]
 - [`zx_vmar_protect()`]

[`zx_vmar_allocate()`]: vmar_allocate.md
[`zx_vmar_destroy()`]: vmar_destroy.md
[`zx_vmar_map()`]: vmar_map.md
[`zx_vmar_protect()`]: vmar_protect.md