On 16/07/2015 12:51, Ефимов Василий wrote: > The rest of code looks up destination or source region or child region > offset in memory sub-tree which root is PCI or RAM region provided on > PAM creation. We cannon use common address_space_translate because it > searches from address space root and will return current PAM region. > To summarize, I suggest to move the code to exec.c. It is generic > enough.
All these mechanism are extremely low level. They are encapsulated within exec.c, and copying code to pam.c is not a good idea because you already have all the AddressSpaces and RAM MemoryRegions you need. >> Could you use an IOMMU memory region instead? Then a single region can >> be used to implement all four modes, and you don't hit the "trying to >> execute code outside RAM or RAM". > Did you mean MemoryRegion.iommu_ops ? The feature does not allow to > change destination memory region. It does. You're right about this: > exec.c: address_space_translate_for_iotlb: > assert(!section->mr->iommu_ops); ... but an IOMMU region is not needed, and I think you can do everything without touching exec.c at all. + /* Read from RAM and write to PCI */ + memory_region_init_io(&pam->region[1], OBJECT(dev), &pam_ops, pam, + "pam-r-ram-w-pci", size); This can be done with memory_region_set_readonly on the RAM region. You need to set mr->ops in order to point to pam_ops; for a first proof of concept you can just set the field directly. Writes to the PCI memory space can use the PCI address space, with address_space_st*. + /* Read from PCI and write to RAM */ + memory_region_init_io(&pam->region[2], OBJECT(dev), &pam_ops, pam, + "pam-r-pci-w-ram", size); Here you cannot run code from ROM, so it can be a pure MMIO region. Reads can use address_space_ld*, while writes can use memory_region_get_ram_ptr. Paolo
