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[34.168.149.56]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2ccc9bf92bfsm1175875ad.28.2026.07.06.15.17.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 06 Jul 2026 15:17:30 -0700 (PDT) Date: Mon, 6 Jul 2026 22:17:27 +0000 From: David Matlack To: Narayana Murty N Cc: alex@shazbot.org, shuah@kernel.org, amastro@fb.com, rananta@google.com, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, vaibhav@linux.ibm.com, sbhat@linux.ibm.com, harshpb@linux.ibm.com Subject: Re: [RFC PATCH 3/6] selftests/vfio: add sPAPR TCE v2 DMA window helpers Message-ID: References: <20260703032806.40946-1-nnmlinux@linux.ibm.com> <20260703032806.40946-4-nnmlinux@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260703032806.40946-4-nnmlinux@linux.ibm.com> On 2026-07-02 11:28 PM, Narayana Murty N wrote: > Add helper support for sPAPR TCE v2 DMA windows in the VFIO selftest > library. > > Track the platform default DMA window separately from selftest-created > dynamic DMA windows. The default window is discovered with > VFIO_IOMMU_SPAPR_TCE_GET_INFO and is not removed during cleanup. > > Add helpers to create and remove DDWs, return the active IOVA range, and > register/unregister memory around DMA map/unmap operations. Window > selection is done before IOVA allocation; the map path only validates, > registers memory, and calls VFIO_IOMMU_MAP_DMA. > > Signed-off-by: Narayana Murty N > +static int spapr_tce_read_default_window(struct iommu *iommu) Please add vfio_iommu_*() prefix to these routines that wrap VFIO_IOMMU_* ioctls. e.g. spapr_tce_read_default_window() -> vfio_iommu_spapr_tce_get_default() spapr_tce_create_ddw() -> vfio_iommu_spapr_tce_create_window() spapr_tce_remove_ddw() -> vfio_iommu_spapr_tce_remove_window() spapr_register_memory() -> vfio_iommu_spapr_register_memory() spapr_unregister_memory() -> vfio_iommu_spapr_unregister_memory() This helps with readability since it makes it clear these functions are interacting with the VFIO IOMMU driver. > +{ > + struct vfio_iommu_spapr_tce_info info = { > + .argsz = sizeof(info), > + }; > + > + if (iommu->default_window.valid) > + return 0; > + > + if (ioctl(iommu->container_fd, VFIO_IOMMU_SPAPR_TCE_GET_INFO, &info)) > + return -errno; > + > + iommu->default_window.start = info.dma32_window_start; > + iommu->default_window.size = info.dma32_window_size; > + iommu->default_window.page_shift = page_size_to_shift(getpagesize()); > + iommu->default_window.valid = true; > + iommu->default_window.dynamic = false; > + iommu->default_window.remove_on_cleanup = false; > + > + return 0; > +} > + > +static int spapr_tce_create_ddw(struct iommu *iommu, u64 min_size, u32 page_shift) > +{ > + struct vfio_iommu_spapr_tce_create create = { > + .argsz = sizeof(create), > + .page_shift = page_shift, > + .levels = 1, > + .window_size = min_size, > + }; > + > + if (ioctl(iommu->container_fd, VFIO_IOMMU_SPAPR_TCE_CREATE, &create)) > + return -errno; > + > + iommu->ddw_window.start = create.start_addr; > + iommu->ddw_window.size = create.window_size; > + iommu->ddw_window.page_shift = page_shift; > + iommu->ddw_window.valid = true; > + iommu->ddw_window.dynamic = true; > + iommu->ddw_window.remove_on_cleanup = true; > + > + return 0; > +} > + > +static int spapr_tce_remove_window(struct iommu *iommu, struct spapr_tce_window *window) > +{ > + struct vfio_iommu_spapr_tce_remove remove = { > + .argsz = sizeof(remove), > + .start_addr = window->start, > + }; > + > + if (!window->valid || !window->remove_on_cleanup) > + return 0; > + > + if (ioctl(iommu->container_fd, VFIO_IOMMU_SPAPR_TCE_REMOVE, &remove)) > + return -errno; > + > + window->valid = false; > + return 0; > +}