>From 6d72b98620281984ae778659cedeb369e82af8d8 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 14 Mar 2022 08:02:57 +0100 Subject: swiotlb: provide swiotlb_init variants that remap the buffer To shared more code between swiotlb and xen-swiotlb, offer a swiotlb_init_remap interface and add a remap callback to swiotlb_init_late that will allow Xen to remap the buffer the buffer without duplicating much of the logic. Signed-off-by: Christoph Hellwig --- arch/x86/pci/sta2x11-fixup.c | 2 +- include/linux/swiotlb.h | 5 ++++- kernel/dma/swiotlb.c | 36 +++++++++++++++++++++++++++++++++--- 3 files changed, 38 insertions(+), 5 deletions(-) diff --git a/arch/x86/pci/sta2x11-fixup.c b/arch/x86/pci/sta2x11-fixup.c index c7e6faf59a861..7368afc039987 100644 --- a/arch/x86/pci/sta2x11-fixup.c +++ b/arch/x86/pci/sta2x11-fixup.c @@ -57,7 +57,7 @@ static void sta2x11_new_instance(struct pci_dev *pdev) int size = STA2X11_SWIOTLB_SIZE; /* First instance: register your own swiotlb area */ dev_info(&pdev->dev, "Using SWIOTLB (size %i)\n", size); - if (swiotlb_init_late(size, GFP_DMA)) + if (swiotlb_init_late(size, GFP_DMA, NULL)) dev_emerg(&pdev->dev, "init swiotlb failed\n"); } list_add(&instance->list, &sta2x11_instance_list); diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h index ee655f2e4d28b..7b50c82f84ce9 100644 --- a/include/linux/swiotlb.h +++ b/include/linux/swiotlb.h @@ -36,8 +36,11 @@ struct scatterlist; int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, unsigned int flags); unsigned long swiotlb_size_or_default(void); +void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags, + int (*remap)(void *tlb, unsigned long nslabs)); +int swiotlb_init_late(size_t size, gfp_t gfp_mask, + int (*remap)(void *tlb, unsigned long nslabs)); extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs); -int swiotlb_init_late(size_t size, gfp_t gfp_mask); extern void __init swiotlb_update_mem_attributes(void); phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, phys_addr_t phys, diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 79641c446d284..c37fd3d1c97f7 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -256,9 +256,11 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, * Statically reserve bounce buffer space and initialize bounce buffer data * structures for the software IO TLB used to implement the DMA API. */ -void __init swiotlb_init(bool addressing_limit, unsigned int flags) +void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags, + int (*remap)(void *tlb, unsigned long nslabs)) { - size_t bytes = PAGE_ALIGN(default_nslabs << IO_TLB_SHIFT); + unsigned long nslabs = default_nslabs; + size_t bytes; void *tlb; if (!addressing_limit && !swiotlb_force_bounce) @@ -271,12 +273,23 @@ void __init swiotlb_init(bool addressing_limit, unsigned int flags) * allow to pick a location everywhere for hypervisors with guest * memory encryption. */ +retry: + bytes = PAGE_ALIGN(default_nslabs << IO_TLB_SHIFT); if (flags & SWIOTLB_ANY) tlb = memblock_alloc(bytes, PAGE_SIZE); else tlb = memblock_alloc_low(bytes, PAGE_SIZE); if (!tlb) goto fail; + if (remap && remap(tlb, nslabs) < 0) { + memblock_free(tlb, PAGE_ALIGN(bytes)); + + if (nslabs <= IO_TLB_MIN_SLABS) + panic("%s: Failed to remap %zu bytes\n", + __func__, bytes); + nslabs = max(1024UL, ALIGN(nslabs >> 1, IO_TLB_SEGSIZE)); + goto retry; + } if (swiotlb_init_with_tbl(tlb, default_nslabs, flags)) goto fail_free_mem; return; @@ -287,12 +300,18 @@ void __init swiotlb_init(bool addressing_limit, unsigned int flags) pr_warn("Cannot allocate buffer"); } +void __init swiotlb_init(bool addressing_limit, unsigned int flags) +{ + return swiotlb_init_remap(addressing_limit, flags, NULL); +} + /* * Systems with larger DMA zones (those that don't support ISA) can * initialize the swiotlb later using the slab allocator if needed. * This should be just like above, but with some error catching. */ -int swiotlb_init_late(size_t size, gfp_t gfp_mask) +int swiotlb_init_late(size_t size, gfp_t gfp_mask, + int (*remap)(void *tlb, unsigned long nslabs)) { unsigned long nslabs = ALIGN(size >> IO_TLB_SHIFT, IO_TLB_SEGSIZE); unsigned long bytes; @@ -303,6 +322,7 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask) if (swiotlb_force_disable) return 0; +retry: order = get_order(nslabs << IO_TLB_SHIFT); nslabs = SLABS_PER_PAGE << order; bytes = nslabs << IO_TLB_SHIFT; @@ -323,6 +343,16 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask) (PAGE_SIZE << order) >> 20); nslabs = SLABS_PER_PAGE << order; } + if (remap) + rc = remap(vstart, nslabs); + if (rc) { + free_pages((unsigned long)vstart, order); + + if (IO_TLB_MIN_SLABS <= 1024) + return rc; + nslabs = max(1024UL, ALIGN(nslabs >> 1, IO_TLB_SEGSIZE)); + goto retry; + } rc = swiotlb_late_init_with_tbl(vstart, nslabs); if (rc) free_pages((unsigned long)vstart, order); -- 2.30.2