On Thu, Sep 26, 2024 at 04:50:46PM +0800, Yi Liu wrote: > On 2024/8/28 00:59, Nicolin Chen wrote: > > Now a VIOMMU can wrap a shareable nested parent HWPT. So, it can act like > > a nested parent HWPT to allocate a nested HWPT. > > > > Support that in the IOMMU_HWPT_ALLOC ioctl handler, and update its kdoc. > > > > Also, associate a viommu to an allocating nested HWPT. > > it still not quite clear to me what vIOMMU obj stands for. Here, it is a > wrapper of s2 hpwt IIUC. But in the cover letter, vIOMMU obj can instanced > per the vIOMMU units in VM. Yea, the implementation in this version is merely a wrapper. I had a general introduction of vIOMMU in the other reply. And I will put something similar in the next version of the series, so the idea would be bigger than a wrapper. > Does it mean each vIOMMU of VM can only have > one s2 HWPT? Giving some examples here: - If a VM has 1 vIOMMU, there will be 1 vIOMMU object in the kernel holding one S2 HWPT. - If a VM has 2 vIOMMUs, there will be 2 vIOMMU objects in the kernel that can hold two different S2 HWPTs, or share one S2 HWPT (saving memory). Thanks Nic
