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DXGKARG_GETBACKINGRESOURCE structure (dispmprt.h)

  • Article

Arguments used to get backing resources for the virtual device MMIO (memory mapped input output) bars.

Syntax

typedef struct _DXGKARG_GETBACKINGRESOURCE {
  ULONG                           VirtualFunctionIndex;
  USHORT                          ResourceIndex;
  PCM_PARTIAL_RESOURCE_DESCRIPTOR Resource;
  PMDL                            pMdl;
} DXGKARG_GETBACKINGRESOURCE, *PDXGKARG_GETBACKINGRESOURCE;

Members

VirtualFunctionIndex

The particular Virtual function to query security.

ResourceIndex

The resource index.

Resource

The return resource descriptor, containing the host base address and resource length.

pMdl

Pointer to an MDL (memory descriptor list).

Alternative to returning a Resource, the driver can return an already created MDL to use as a backing resource. Any MDL returned must point to contiguous physical RAM or MMIO space, with no offset into the first page, along with a length divisible by PAGE_SIZE.

Remarks

Note that the backing resource is currently limited to MAX_FLEXIO_RESOURCES (32) ranges. These resources are then used by the scatter/gather mechanism present in the MMIO mappings to build up full guest bars. If a physical device does not use a resource at a specific Index, the device should set all return values and return STATUS_SUCCESS.

Requirements

Requirement Value
Minimum supported client Windows 10, version 1809
Header dispmprt.h