Re: [PATCH 12/15] swiotlb: provide swiotlb_init variants that remap the buffer
From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Date: 2022-03-14 22:41:32
Also in:
linux-arm-kernel, linux-hyperv, linux-iommu, linux-mips, linux-pci, linux-riscv, linux-s390, xen-devel
On 3/14/22 3:31 AM, Christoph Hellwig wrote:
quoted hunk ↗ jump to hunk
-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 +273,24 @@ 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)); + + /* Min is 2MB */ + if (nslabs <= 1024)
This is IO_TLB_MIN_SLABS, isn't it? (Xen code didn't say so but that's what it meant to say I believe)
quoted hunk ↗ jump to hunk
+ panic("%s: Failed to remap %zu bytes\n", + __func__, bytes); + nslabs = max(1024UL, ALIGN(nslabs >> 1, IO_TLB_SEGSIZE)); + goto retry; + }@@ -303,6 +323,7 @@ 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;@@ -317,6 +338,17 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask) if (!vstart) return -ENOMEM; + if (remap) + rc = remap(vstart, nslabs); + if (rc) { + free_pages((unsigned long)vstart, order); + + /* Min is 2MB */ + if (nslabs <= 1024)
Same here. -boris
+ return rc;
+ nslabs = max(1024UL, ALIGN(nslabs >> 1, IO_TLB_SEGSIZE));
+ goto retry;
+ }
if (order != get_order(bytes)) {
pr_warn("only able to allocate %ld MB\n",