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# VZVirtioSharedMemoryRegion

A class that represents a Virtio shared memory region for a custom Virtio device in a virtual machine.

```
class VZVirtioSharedMemoryRegion
```

## Overview

Don’t instantiate a `VZVirtioSharedMemoryRegion` directly.

Virtio shared memory regions are first configured on the [`VZCustomVirtioDeviceConfiguration`](/documentation/Virtualization/VZCustomVirtioDeviceConfiguration) through [`VZVirtioSharedMemoryRegionConfiguration`](/documentation/Virtualization/VZVirtioSharedMemoryRegionConfiguration).
When you create a [`VZCustomVirtioDevice`](/documentation/Virtualization/VZCustomVirtioDevice), the shared memory region is available through the [`sharedMemoryRegions`](/documentation/Virtualization/VZCustomVirtioDevice/sharedMemoryRegions) property.

Use this class to manage the shared memory region during virtual machine runtime to map and unmap host memory into and from the shared memory region.

## Topics

### Instance Properties

[`var regionID: UInt8`](/documentation/Virtualization/VZVirtioSharedMemoryRegion/regionID)

The shared memory region ID.

[`var size: UInt64`](/documentation/Virtualization/VZVirtioSharedMemoryRegion/size)

The size of the shared memory region.

### Instance Methods

[`func mapMemory(UnsafeMutableRawPointer, atOffset: UInt64, size: UInt64, completionHandler: ((any Error)?) -> Void)`](/documentation/Virtualization/VZVirtioSharedMemoryRegion/mapMemory(_:atOffset:size:completionHandler:))

Maps a chunk of host memory into the shared memory region.

[`func unmapMemory(atOffset: UInt64, size: UInt64, completionHandler: ((any Error)?) -> Void)`](/documentation/Virtualization/VZVirtioSharedMemoryRegion/unmapMemory(atOffset:size:completionHandler:))

Unmaps a chunk of host memory from the shared memory region.

## See Also

[`class VZVirtioSharedMemoryRegionConfiguration`](/documentation/Virtualization/VZVirtioSharedMemoryRegionConfiguration)

The configuration of a Virtio shared memory region.

[`class VZCustomVirtioDevice`](/documentation/Virtualization/VZCustomVirtioDevice)

An interface that represents a custom Virtio device that you provide the implementation for.

## Relationships

### Conforms To

[`Hashable`](/documentation/Swift/Hashable)

[`CustomDebugStringConvertible`](/documentation/Swift/CustomDebugStringConvertible)

[`NSObjectProtocol`](/documentation/ObjectiveC/NSObjectProtocol)

[`CustomStringConvertible`](/documentation/Swift/CustomStringConvertible)

[`CVarArg`](/documentation/Swift/CVarArg)

[`Equatable`](/documentation/Swift/Equatable)

### Inherits From

[`NSObject-swift.class`](/documentation/ObjectiveC/NSObject-swift.class)

---

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