Hi Valmiki, On 03/12/17 13:56, valmiki wrote: > Hi Jean, > > In PASID flow arm_smmu_atc_inv_master_all is called where size and iova > of arm_smmu_atc_inv_to_cmd are zero and no address is being filled in > struct arm_smmu_cmdq_ent->atc.addr. > So how will smmu hardware know if there are any ats translations > requested or not ? > How invalidation are carried out in PASID flow w.r.t address and size? arm_smmu_atc_inv_master_all() is used to invalidate the whole address space, for example when unbinding a process address space from the master. The encoding is a bit special: when addr and size are 0, arm_smmu_atc_inv_to_cmd() sets cmd->atc.size to 52, which according to the SMMUv3 spec corresponds to a 2^64 byte span, meaning invalidate all. The SMMU then converts this command into a PCIe ATC invalidation (with bits 62:12 all 1b and bit 63 = 0b, according to the ATS spec 2.3.2) Smaller invalidations will go via arm_smmu_atc_inv_domain(), and arm_smmu_atc_inv_to_cmd() will compute the appropriate range that covers the requested address and size. In more details, when a range is unmapped from a process (with munmap() for example), the MMU notifier calls our invalidate_range() callback, which calls arm_smmu_atc_inv_domain() with the right PASID. When a process exits or unbind() is called, we use arm_smmu_atc_inv_master_all() with its PASID. Thanks, Jean
