_EXT_IOMMU_RESERVED_MEMORY_REGION

Windows 10 | 2016 2104 21H1 (May 2021 Update) x64
Windows 10 | 2016 2110 21H2 (November 2021 Update) x64
Windows 10 | 2016 2210 22H2 (May 2023 Update) x64
Sorry, but such structure doesn't exist in chosen version of the kernel.