On 24.09.2026 08:07, Aneesh Kumar K.V (Arm) wrote: > This series centralizes swiotlb default-pool selection and sizing, and > simplifies the initialization flags used to describe pool placement. > > The first patch replaces the addressing-limit argument with initialization > flags and introduces explicit policies for the different reasons a default > pool may be needed. Architectures now report DMA addressing constraints with > SWIOTLB_INIT_ADDRESSING_LIMIT, while the core selects the corresponding pool > policy. > > The second patch moves the reduced sizing used when the pool is needed only > for unaligned kmalloc bouncing from arm64 and RISC-V into the swiotlb core. > > The third patch centralizes swiotlb sizing for memory-encrypted systems. It > moves the existing x86 guest-sizing policy into the core. Host memory > encryption retains the normal pool size, and a shared default pool is not > selected solely for guest memory encryption when a restricted DMA pool is > present. > > The fourth patch removes SWIOTLB_ANY. Pool placement is derived directly from > SWIOTLB_INIT_ADDRESSING_LIMIT: pools required for limited DMA addressing are > allocated below the architecture's low address limit, while other pools may > be allocated anywhere in directly mapped memory. Xen continues to request a > pool explicitly with SWIOTLB_INIT_REMAP without imposing a low-address > constraint.
I would like to give this patchset some tests in linux-next and merge this to v7.4-rc1, as this is important continuation of the code already merged to v7.3. Any chance to get some more acks from arch maintainers (especially x86)? Unfortunately I had to reduce the CC list due to my smtp limits... > ... > > Documentation/core-api/swiotlb.rst | 8 +- > arch/arm/mm/init.c | 6 +- > arch/arm/xen/mm.c | 2 +- > arch/arm64/mm/init.c | 14 +- > arch/loongarch/kernel/setup.c | 2 +- > arch/mips/cavium-octeon/dma-octeon.c | 2 +- > arch/mips/loongson64/dma.c | 2 +- > arch/mips/sibyte/common/dma.c | 2 +- > arch/powerpc/kernel/dma-swiotlb.c | 4 +- > arch/powerpc/mm/mem.c | 17 ++- > arch/powerpc/platforms/pseries/svm.c | 10 -- > arch/powerpc/sysdev/fsl_pci.c | 1 + > arch/riscv/mm/init.c | 24 +--- > arch/s390/mm/init.c | 2 +- > arch/x86/include/asm/crash_reserve.h | 4 +- > arch/x86/kernel/pci-dma.c | 23 +++- > arch/x86/mm/mem_encrypt.c | 24 ---- > include/linux/swiotlb.h | 17 ++- > kernel/dma/swiotlb.c | 193 +++++++++++++++++++-------- > 19 files changed, 210 insertions(+), 147 deletions(-) Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland
