1.libhsakmt里的vm是什么1.1.GPUVM这里的vm是指GPUVM，来看AMD给出的官方解释。* GPUVM is the MMU functionality provided on the GPU. * GPUVM is similar to the legacy GART on older asics, however * rather than there being a single global GART table * for the entire GPU, there can be multiple GPUVM page tables active * at any given time. The GPUVM page tables can contain a mix * VRAM pages and system pages (both memory and MMIO) and system pages * can be mapped as snooped (cached system pages) or unsnooped * (uncached system pages). * * Each active GPUVM has an ID associated with it and there is a page table * linked with each VMID. When executing a command buffer, * the kernel tells the engine what VMID to use for that command * buff