diff options
Diffstat (limited to 'arch/powerpc/kvm/book3s_hv_cma.c')
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv_cma.c | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_cma.c b/arch/powerpc/kvm/book3s_hv_cma.c new file mode 100644 index 000000000000..e04b269b9c5b --- /dev/null +++ b/arch/powerpc/kvm/book3s_hv_cma.c @@ -0,0 +1,227 @@ +/* + * Contiguous Memory Allocator for ppc KVM hash pagetable based on CMA + * for DMA mapping framework + * + * Copyright IBM Corporation, 2013 + * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of the + * License or (at your optional) any later version of the license. + * + */ +#define pr_fmt(fmt) "kvm_cma: " fmt + +#ifdef CONFIG_CMA_DEBUG +#ifndef DEBUG +# define DEBUG +#endif +#endif + +#include <linux/memblock.h> +#include <linux/mutex.h> +#include <linux/sizes.h> +#include <linux/slab.h> + +struct kvm_cma { + unsigned long base_pfn; + unsigned long count; + unsigned long *bitmap; +}; + +static DEFINE_MUTEX(kvm_cma_mutex); +static struct kvm_cma kvm_cma_area; + +/** + * kvm_cma_declare_contiguous() - reserve area for contiguous memory handling + * for kvm hash pagetable + * @size: Size of the reserved memory. + * @alignment: Alignment for the contiguous memory area + * + * This function reserves memory for kvm cma area. It should be + * called by arch code when early allocator (memblock or bootmem) + * is still activate. + */ +long __init kvm_cma_declare_contiguous(phys_addr_t size, phys_addr_t alignment) +{ + long base_pfn; + phys_addr_t addr; + struct kvm_cma *cma = &kvm_cma_area; + + pr_debug("%s(size %lx)\n", __func__, (unsigned long)size); + + if (!size) + return -EINVAL; + /* + * Sanitise input arguments. + * We should be pageblock aligned for CMA. + */ + alignment = max(alignment, (phys_addr_t)(PAGE_SIZE << pageblock_order)); + size = ALIGN(size, alignment); + /* + * Reserve memory + * Use __memblock_alloc_base() since + * memblock_alloc_base() panic()s. + */ + addr = __memblock_alloc_base(size, alignment, 0); + if (!addr) { + base_pfn = -ENOMEM; + goto err; + } else + base_pfn = PFN_DOWN(addr); + + /* + * Each reserved area must be initialised later, when more kernel + * subsystems (like slab allocator) are available. + */ + cma->base_pfn = base_pfn; + cma->count = size >> PAGE_SHIFT; + pr_info("CMA: reserved %ld MiB\n", (unsigned long)size / SZ_1M); + return 0; +err: + pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M); + return base_pfn; +} + +/** + * kvm_alloc_cma() - allocate pages from contiguous area + * @nr_pages: Requested number of pages. + * @align_pages: Requested alignment in number of pages + * + * This function allocates memory buffer for hash pagetable. + */ +struct page *kvm_alloc_cma(unsigned long nr_pages, unsigned long align_pages) +{ + int ret; + struct page *page = NULL; + struct kvm_cma *cma = &kvm_cma_area; + unsigned long mask, pfn, pageno, start = 0; + + + if (!cma || !cma->count) + return NULL; + + pr_debug("%s(cma %p, count %lu, align pages %lu)\n", __func__, + (void *)cma, nr_pages, align_pages); + + if (!nr_pages) + return NULL; + + VM_BUG_ON(!is_power_of_2(align_pages)); + mask = align_pages - 1; + + mutex_lock(&kvm_cma_mutex); + for (;;) { + pageno = bitmap_find_next_zero_area(cma->bitmap, cma->count, + start, nr_pages, mask); + if (pageno >= cma->count) + break; + + pfn = cma->base_pfn + pageno; + ret = alloc_contig_range(pfn, pfn + nr_pages, MIGRATE_CMA); + if (ret == 0) { + bitmap_set(cma->bitmap, pageno, nr_pages); + page = pfn_to_page(pfn); + memset(pfn_to_kaddr(pfn), 0, nr_pages << PAGE_SHIFT); + break; + } else if (ret != -EBUSY) { + break; + } + pr_debug("%s(): memory range at %p is busy, retrying\n", + __func__, pfn_to_page(pfn)); + /* try again with a bit different memory target */ + start = pageno + mask + 1; + } + mutex_unlock(&kvm_cma_mutex); + pr_debug("%s(): returned %p\n", __func__, page); + return page; +} + +/** + * kvm_release_cma() - release allocated pages for hash pagetable + * @pages: Allocated pages. + * @nr_pages: Number of allocated pages. + * + * This function releases memory allocated by kvm_alloc_cma(). + * It returns false when provided pages do not belong to contiguous area and + * true otherwise. + */ +bool kvm_release_cma(struct page *pages, unsigned long nr_pages) +{ + unsigned long pfn; + struct kvm_cma *cma = &kvm_cma_area; + + + if (!cma || !pages) + return false; + + pr_debug("%s(page %p count %lu)\n", __func__, (void *)pages, nr_pages); + + pfn = page_to_pfn(pages); + + if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count) + return false; + + VM_BUG_ON(pfn + nr_pages > cma->base_pfn + cma->count); + + mutex_lock(&kvm_cma_mutex); + bitmap_clear(cma->bitmap, pfn - cma->base_pfn, nr_pages); + free_contig_range(pfn, nr_pages); + mutex_unlock(&kvm_cma_mutex); + + return true; +} + +static int __init kvm_cma_activate_area(unsigned long base_pfn, + unsigned long count) +{ + unsigned long pfn = base_pfn; + unsigned i = count >> pageblock_order; + struct zone *zone; + + WARN_ON_ONCE(!pfn_valid(pfn)); + zone = page_zone(pfn_to_page(pfn)); + do { + unsigned j; + base_pfn = pfn; + for (j = pageblock_nr_pages; j; --j, pfn++) { + WARN_ON_ONCE(!pfn_valid(pfn)); + /* + * alloc_contig_range requires the pfn range + * specified to be in the same zone. Make this + * simple by forcing the entire CMA resv range + * to be in the same zone. + */ + if (page_zone(pfn_to_page(pfn)) != zone) + return -EINVAL; + } + init_cma_reserved_pageblock(pfn_to_page(base_pfn)); + } while (--i); + return 0; +} + +static int __init kvm_cma_init_reserved_areas(void) +{ + int bitmap_size, ret; + struct kvm_cma *cma = &kvm_cma_area; + + pr_debug("%s()\n", __func__); + if (!cma->count) + return 0; + + bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long); + cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL); + if (!cma->bitmap) + return -ENOMEM; + + ret = kvm_cma_activate_area(cma->base_pfn, cma->count); + if (ret) + goto error; + return 0; + +error: + kfree(cma->bitmap); + return ret; +} +core_initcall(kvm_cma_init_reserved_areas); |