Messages in this thread Patch in this message |  | | Date | Wed, 3 Jun 2026 11:05:20 +0000 | | Subject | [PATCH 1/3] arm64/mm: Simplify SWIOTLB setup in arch_mm_preinit() | | From | Mostafa Saleh <> |
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At the moment, arch_mm_preinit() checks if the system has limited addressing or is running under CCA to enable SWIOTLB, only after to be forced to true anyway if it was false due to CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC being unconditionally true for arm64.
Simplify this logic, by making it clear that SWIOTLB is always used but its size depends on the address layout of the system.
Signed-off-by: Mostafa Saleh <smostafa@google.com> --- arch/arm64/mm/init.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index 97987f850a33..fcc9c05a8fe6 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -336,25 +336,22 @@ void __init arch_setup_zero_pages(void) void __init arch_mm_preinit(void) { unsigned int flags = SWIOTLB_VERBOSE; - bool swiotlb = max_pfn > PFN_DOWN(arm64_dma_phys_limit); + bool limited_addressing = max_pfn > PFN_DOWN(arm64_dma_phys_limit); if (is_realm_world()) { - swiotlb = true; flags |= SWIOTLB_FORCE; - } - - if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC) && !swiotlb) { + } else if (!limited_addressing) { /* * If no bouncing needed for ZONE_DMA, reduce the swiotlb * buffer for kmalloc() bouncing to 1MB per 1GB of RAM. */ unsigned long size = DIV_ROUND_UP(memblock_phys_mem_size(), 1024); + swiotlb_adjust_size(min(swiotlb_size_or_default(), size)); - swiotlb = true; } - swiotlb_init(swiotlb, flags); + swiotlb_init(true, flags); /* * Check boundaries twice: Some fundamental inconsistencies can be -- 2.54.0.1032.g2f8565e1d1-goog
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