On 2026-07-06 10:33 PM, David Matlack wrote:
> On 2026-07-02 11:28 PM, Narayana Murty N wrote:
> > Prepare the DMA window before IOVA allocation in the DMA mapping tests.
> >
> > Anonymous mappings use the default sPAPR DMA window. HugeTLB mappings force
> > a DDW with the requested page size, allowing the test to exercise DDW
> > creation, mapping, unmapping, and cleanup.
> >
> > Skip gracefully when hugepage allocation fails or when the platform does
> > not support the requested DDW characteristics. Also skip unmap-all when
> > the backend cannot pair it with the sPAPR memory unregister flow.
> >
> > Signed-off-by: Narayana Murty N <[email protected]>
> > ---
> > .../selftests/vfio/vfio_dma_mapping_test.c | 22 +++++++++++++++++++
> > 1 file changed, 22 insertions(+)
> >
> > diff --git a/tools/testing/selftests/vfio/vfio_dma_mapping_test.c
> > b/tools/testing/selftests/vfio/vfio_dma_mapping_test.c
> > index 7d0de8c79de1..4411fdbd56da 100644
> > --- a/tools/testing/selftests/vfio/vfio_dma_mapping_test.c
> > +++ b/tools/testing/selftests/vfio/vfio_dma_mapping_test.c
> > @@ -1,5 +1,6 @@
> > // SPDX-License-Identifier: GPL-2.0-only
> > #include <stdio.h>
> > +#include <string.h>
> > #include <sys/mman.h>
> > #include <unistd.h>
> >
> > @@ -119,8 +120,19 @@
> > FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES(anonymous_hugetlb_1gb, SZ_1G,
> > MAP_HUGETLB |
> >
> > FIXTURE_SETUP(vfio_dma_mapping_test)
> > {
> > + const u64 page_size = variant->size ?: getpagesize();
> > + const bool force_dynamic = !!variant->size;
>
> This is kind of arbitrary right? Should we add explicit variants for
> dynamic/default windows (see below). But we need some way to skip the dynamic
> window tests on non-spapr iommus...
Maybe the flow can be something like this:
iommu = iommu_init(); /* sets up default window */
if (variant->dynamic_window) {
ret = iommu_dma_window_create(...); /* always fails on non-sapr
iommus */
if (ret)
SKIP(...);
}
Then I think you also want to add some call to gracefully skip tests if
the current window does not support the desired mapping. e.g.
if (!iommu_dma_window_fits(region)) /* always succeeds on non-spapr iommus */
SKIP(...);
>
> diff --git a/tools/testing/selftests/vfio/vfio_dma_mapping_test.c
> b/tools/testing/selftests/vfio/vfio_dma_mapping_test.c
> index cd2d3276a46c..b54c529ebedb 100644
> --- a/tools/testing/selftests/vfio/vfio_dma_mapping_test.c
> +++ b/tools/testing/selftests/vfio/vfio_dma_mapping_test.c
> @@ -103,15 +103,21 @@ FIXTURE_VARIANT(vfio_dma_mapping_test) {
> const char *iommu_mode;
> u64 size;
> int mmap_flags;
> + bool dynamic_window;
> };
>
> -#define FIXTURE_VARIANT_ADD_IOMMU_MODE(_iommu_mode, _name, _size,
> _mmap_flags) \
> -FIXTURE_VARIANT_ADD(vfio_dma_mapping_test, _iommu_mode ## _ ## _name) {
> \
> - .iommu_mode = #_iommu_mode,
> \
> - .size = (_size),
> \
> - .mmap_flags = MAP_ANONYMOUS | MAP_PRIVATE | (_mmap_flags),
> \
> +#define __FIXTURE_VARIANT_ADD_IOMMU_MODE(_iommu_mode, _name, _size,
> _mmap_flags, _dynamic_window) \
> +FIXTURE_VARIANT_ADD(vfio_dma_mapping_test,_iommu_mode ## _ ## _name) { \
> + .iommu_mode = #_iommu_mode,
> \
> + .size = (_size),
> \
> + .mmap_flags = MAP_ANONYMOUS | MAP_PRIVATE | (_mmap_flags),
> \
> + .dynamic_window = _dynamic_window,
> \
> }
>
> +#define FIXTURE_VARIANT_ADD_IOMMU_MODE(_iommu_mode, _name, _size,
> _mmap_flags) \
> +__FIXTURE_VARIANT_ADD_IOMMU_MODE(_iommu_mode, _name, _size, _mmap_flags,
> false); \
> +__FIXTURE_VARIANT_ADD_IOMMU_MODE(_iommu_mode, _name ## _dynamic_window,
> _size, _mmap_flags, true) \
> +
> FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES(anonymous, 0, 0);
> FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES(anonymous_hugetlb_2mb, SZ_2M,
> MAP_HUGETLB | MAP_HUGE_2MB);
> FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES(anonymous_hugetlb_1gb, SZ_1G,
> MAP_HUGETLB | MAP_HUGE_1GB);
> @@ -121,14 +127,13 @@
> FIXTURE_VARIANT_ADD_ALL_IOMMU_MODES(anonymous_hugetlb_1gb, SZ_1G, MAP_HUGETLB
> |
> FIXTURE_SETUP(vfio_dma_mapping_test)
> {
> const u64 page_size = variant->size ?: getpagesize();
> - const bool force_dynamic = !!variant->size;
> int ret;
>
> self->iommu = iommu_init(variant->iommu_mode);
> self->device = vfio_pci_device_init(device_bdf, self->iommu);
>
> ret = iommu_prepare_dma_window(self->iommu, page_size, page_size,
> - force_dynamic);
> + variant->dynamic_window);
> if (ret)
> SKIP(return, "DMA window unavailable: %s (%d)\n",
> strerror(-ret), -ret);
>
> > + int ret;
> > +
> > self->iommu = iommu_init(variant->iommu_mode);
> > self->device = vfio_pci_device_init(device_bdf, self->iommu);
> > +
> > + ret = iommu_prepare_dma_window(self->iommu, page_size, page_size,
> > + force_dynamic);
> > + if (ret)
> > + SKIP(return, "DMA window unavailable: %s (%d)\n",
> > + strerror(-ret), -ret);
> > +
> > self->iova_allocator = iova_allocator_init(self->iommu);
> > }
> >
> > @@ -227,6 +239,7 @@ FIXTURE_SETUP(vfio_dma_map_limit_test)
> > u64 region_size = getpagesize();
> > iova_t last_iova;
> > u32 nranges;
> > + int ret;
> >
> > /*
> > * Over-allocate mmap by double the size to provide enough backing vaddr
> > @@ -236,6 +249,13 @@ FIXTURE_SETUP(vfio_dma_map_limit_test)
> >
> > self->iommu = iommu_init(variant->iommu_mode);
> > self->device = vfio_pci_device_init(device_bdf, self->iommu);
> > +
> > + ret = iommu_prepare_dma_window(self->iommu, region_size, region_size,
> > + false);
> > + if (ret)
> > + SKIP(return, "DMA window unavailable: %s (%d)\n",
> > + strerror(-ret), -ret);
> > +
> > region->vaddr = mmap(NULL, self->mmap_size, PROT_READ | PROT_WRITE,
> > MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
> > ASSERT_NE(region->vaddr, MAP_FAILED);
> > @@ -277,6 +297,8 @@ TEST_F(vfio_dma_map_limit_test, unmap_all)
> > u64 unmapped;
> > int rc;
> >
> > + if (!iommu_supports_unmap_all(self->iommu))
> > + SKIP(return, "IOMMU backend does not support unmap-all\n");
> > iommu_map(self->iommu, region);
> > ASSERT_EQ(region->iova, to_iova(self->device, region->vaddr));
> >
> > --
> > 2.51.1
> >
