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vmo_create_physical.md

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zx_vmo_create_physical

SUMMARY

Create a VM object referring to a specific contiguous range of physical memory.

DECLARATION

#include <zircon/syscalls.h>

zx_status_t zx_vmo_create_physical(zx_handle_t resource,
                                   zx_paddr_t paddr,
                                   size_t size,
                                   zx_handle_t* out);

DESCRIPTION

zx_vmo_create_physical() creates a new virtual memory object (VMO), which represents the size bytes of physical memory beginning at physical address paddr.

The content size of the VMO will be initialized to the given (unrounded) size. Use zx_object_get_property() with ZX_PROP_VMO_CONTENT_SIZE to read the content size of the VMO. Use zx_object_set_property() with ZX_PROP_VMO_CONTENT_SIZE to set the content size of the VMO without actually resizing the VMO.

One handle is returned on success, representing an object with the requested size.

The following rights will be set on the handle by default:

  • ZX_RIGHT_DUPLICATE - The handle may be duplicated.

  • ZX_RIGHT_TRANSFER - The handle may be transferred to another process.

  • ZX_RIGHT_READ - May be read from or mapped with read permissions.

  • ZX_RIGHT_WRITE - May be written to or mapped with write permissions.

  • ZX_RIGHT_EXECUTE - May be mapped with execute permissions.

  • ZX_RIGHT_MAP - May be mapped.

  • ZX_RIGHT_GET_PROPERTY - May get its properties using zx_object_get_property().

  • ZX_RIGHT_SET_PROPERTY - May set its properties using zx_object_set_property().

The ZX_VMO_ZERO_CHILDREN signal is active on a newly created VMO. It becomes inactive whenever a child of the VMO is created and becomes active again when all children have been destroyed and no mappings of those children into address spaces exist.

NOTES

The VMOs created by this syscall are not usable with zx_vmo_read() and zx_vmo_write().

RIGHTS

resource must have resource kind ZX_RSRC_KIND_MMIO.

RETURN VALUE

zx_vmo_create_physical() returns ZX_OK on success. In the event of failure, a negative error value is returned.

ERRORS

ZER_ERR_WRONG_TYPE resource is not a handle to a Resource object.

ZER_ERR_ACCESS_DENIED resource does not grant access to the requested range of memory.

ZX_ERR_INVALID_ARGS out is an invalid pointer or NULL, or paddr or size are not page-aligned.

ZX_ERR_NO_MEMORY Failure due to lack of memory. There is no good way for userspace to handle this (unlikely) error. In a future build this error will no longer occur.

ZX_ERR_OUT_OF_RANGE Requested size is too large.

SEE ALSO