Hi Eric, > From: Auger Eric < eric.auger@xxxxxxxxxx> > Sent: Tuesday, March 31, 2020 1:23 AM > To: Liu, Yi L <yi.l.liu@xxxxxxxxx>; qemu-devel@xxxxxxxxxx; > Subject: Re: [PATCH v2 04/22] hw/iommu: introduce HostIOMMUContext > > Yi, > > On 3/30/20 6:24 AM, Liu Yi L wrote: > > Currently, many platform vendors provide the capability of dual stage > > DMA address translation in hardware. For example, nested translation > > on Intel VT-d scalable mode, nested stage translation on ARM SMMUv3, > > and etc. In dual stage DMA address translation, there are two stages > > address translation, stage-1 (a.k.a first-level) and stage-2 (a.k.a > > second-level) translation structures. Stage-1 translation results are > > also subjected to stage-2 translation structures. Take vSVA (Virtual > > Shared Virtual Addressing) as an example, guest IOMMU driver owns > > stage-1 translation structures (covers GVA->GPA translation), and host > > IOMMU driver owns stage-2 translation structures (covers GPA->HPA > > translation). VMM is responsible to bind stage-1 translation structures > > to host, thus hardware could achieve GVA->GPA and then GPA->HPA > > translation. For more background on SVA, refer the below links. > > - https://www.youtube.com/watch?v=Kq_nfGK5MwQ > > - https://events19.lfasiallc.com/wp-content/uploads/2017/11/\ > > Shared-Virtual-Memory-in-KVM_Yi-Liu.pdf > > [...] > > +void host_iommu_ctx_init(void *_iommu_ctx, size_t instance_size, > > + const char *mrtypename, > > + uint64_t flags) > > +{ > > + HostIOMMUContext *iommu_ctx; > > + > > + object_initialize(_iommu_ctx, instance_size, mrtypename); > > + iommu_ctx = HOST_IOMMU_CONTEXT(_iommu_ctx); > > + iommu_ctx->flags = flags; > > + iommu_ctx->initialized = true; > > +} > > + > > +static const TypeInfo host_iommu_context_info = { > > + .parent = TYPE_OBJECT, > > + .name = TYPE_HOST_IOMMU_CONTEXT, > > + .class_size = sizeof(HostIOMMUContextClass), > > + .instance_size = sizeof(HostIOMMUContext), > > + .abstract = true, > Can't we use the usual .instance_init and .instance_finalize? sorry, I somehow missed this comment. In prior patch, .instace_init was used, but the current major init method is via host_iommu_ctx_init(), so .instance_init is not really necessary. https://www.spinics.net/lists/kvm/msg210878.html Regards, Yi Liu
