text: /*
   * Copyright 2011 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License, version 2, as
   * published by the Free Software Foundation.
   */
  
  #include <linux/kvm_host.h>
  #include <linux/preempt.h>
  #include <linux/export.h>
  #include <linux/sched.h>
  #include <linux/spinlock.h>
  #include <linux/bootmem.h>
  #include <linux/init.h>
  #include <linux/memblock.h>
  #include <linux/sizes.h>
  
  #include <asm/cputable.h>
  #include <asm/kvm_ppc.h>
  #include <asm/kvm_book3s.h>
  
  #include "book3s_hv_cma.h"
  /*
   * Hash page table alignment on newer cpus(CPU_FTR_ARCH_206)
   * should be power of 2.
   */
  #define HPT_ALIGN_PAGES		((1 << 18) >> PAGE_SHIFT) /* 256k */
  /*
   * By default we reserve 5% of memory for hash pagetable allocation.
   */
  static unsigned long kvm_cma_resv_ratio = 5;
  /*
   * We allocate RMAs (real mode areas) for KVM guests from the KVM CMA area.
   * Each RMA has to be physically contiguous and of a size that the
   * hardware supports.  PPC970 and POWER7 support 64MB, 128MB and 256MB,
   * and other larger sizes.  Since we are unlikely to be allocate that
   * much physically contiguous memory after the system is up and running,
   * we preallocate a set of RMAs in early boot using CMA.
   * should be power of 2.
   */
  unsigned long kvm_rma_pages = (1 << 27) >> PAGE_SHIFT;	/* 128MB */
  EXPORT_SYMBOL_GPL(kvm_rma_pages);
  
  /* Work out RMLS (real mode limit selector) field value for a given RMA size.
     Assumes POWER7 or PPC970. */
  static inline int lpcr_rmls(unsigned long rma_size)
  {
  	switch (rma_size) {
  	case 32ul << 20:	/* 32 MB */
  		if (cpu_has_feature(CPU_FTR_ARCH_206))
  			return 8;	/* only supported on POWER7 */
  		return -1;
  	case 64ul << 20:	/* 64 MB */
  		return 3;
  	case 128ul << 20:	/* 128 MB */
  		return 7;
  	case 256ul << 20:	/* 256 MB */
  		return 4;
  	case 1ul << 30:		/* 1 GB */
  		return 2;
  	case 16ul << 30:	/* 16 GB */
  		return 1;
  	case 256ul << 30:	/* 256 GB */
  		return 0;
  	default:
  		return -1;
  	}
  }
  
  static int __init early_parse_rma_size(char *p)
  {
  	unsigned long kvm_rma_size;
  
  	pr_debug("%s(%s)\n", __func__, p);
  	if (!p)
  		return -EINVAL;
  	kvm_rma_size = memparse(p, &p);
  	/*
  	 * Check that the requested size is one supported in hardware
  	 */
  	if (lpcr_rmls(kvm_rma_size) < 0) {
  		pr_err("RMA size of 0x%lx not supported\n", kvm_rma_size);
  		return -EINVAL;
  	}
  	kvm_rma_pages = kvm_rma_size >> PAGE_SHIFT;
  	return 0;
  }
  early_param("kvm_rma_size", early_parse_rma_size);
  
  struct kvm_rma_info *kvm_alloc_rma()
  {
  	struct page *page;
  	struct kvm_rma_info *ri;
  
  	ri = kmalloc(sizeof(struct kvm_rma_info), GFP_KERNEL);
  	if (!ri)
  		return NULL;
  	page = kvm_alloc_cma(kvm_rma_pages, kvm_rma_pages);
  	if (!page)
  		goto err_out;
  	atomic_set(&ri->use_count, 1);
  	ri->base_pfn = page_to_pfn(page);
  	return ri;
  err_out:
  	kfree(ri);
  	return NULL;
  }
  EXPORT_SYMBOL_GPL(kvm_alloc_rma);
  
  void kvm_release_rma(struct kvm_rma_info *ri)
  {
  	if (atomic_dec_and_test(&ri->use_count)) {
  		kvm_release_cma(pfn_to_page(ri->base_pfn), kvm_rma_pages);
  		kfree(ri);
  	}
  }
  EXPORT_SYMBOL_GPL(kvm_release_rma);
  
  static int __init early_parse_kvm_cma_resv(char *p)
  {
  	pr_debug("%s(%s)\n", __func__, p);
  	if (!p)
  		return -EINVAL;
  	return kstrtoul(p, 0, &kvm_cma_resv_ratio);
  }
  early_param("kvm_cma_resv_ratio", early_parse_kvm_cma_resv);
  
  struct page *kvm_alloc_hpt(unsigned long nr_pages)
  {
  	unsigned long align_pages = HPT_ALIGN_PAGES;
  
  	/* Old CPUs require HPT aligned on a multiple of its size */
  	if (!cpu_has_feature(CPU_FTR_ARCH_206))
  		align_pages = nr_pages;
  	return kvm_alloc_cma(nr_pages, align_pages);
  }
  EXPORT_SYMBOL_GPL(kvm_alloc_hpt);
  
  void kvm_release_hpt(struct page *page, unsigned long nr_pages)
  {
  	kvm_release_cma(page, nr_pages);
  }
  EXPORT_SYMBOL_GPL(kvm_release_hpt);
  
  /**
   * kvm_cma_reserve() - reserve area for kvm hash pagetable
   *
   * This function reserves memory from early allocator. It should be
   * called by arch specific code once the early allocator (memblock or bootmem)
   * has been activated and all other subsystems have already allocated/reserved
   * memory.
   */
  void __init kvm_cma_reserve(void)
  {
  	unsigned long align_size;
  	struct memblock_region *reg;
  	phys_addr_t selected_size = 0;
  
  	/*
  	 * We need CMA reservation only when we are in HV mode
  	 */
  	if (!cpu_has_feature(CPU_FTR_HVMODE))
  		return;
  	/*
  	 * We cannot use memblock_phys_mem_size() here, because
  	 * memblock_analyze() has not been called yet.
  	 */
  	for_each_memblock(memory, reg)
  		selected_size += memblock_region_memory_end_pfn(reg) -
  				 memblock_region_memory_base_pfn(reg);
  
  	selected_size = (selected_size * kvm_cma_resv_ratio / 100) << PAGE_SHIFT;
  	if (selected_size) {
  		pr_debug("%s: reserving %ld MiB for global area\n", __func__,
  			 (unsigned long)selected_size / SZ_1M);
  		/*
  		 * Old CPUs require HPT aligned on a multiple of its size. So for them
  		 * make the alignment as max size we could request.
  		 */
  		if (!cpu_has_feature(CPU_FTR_ARCH_206))
  			align_size = __rounddown_pow_of_two(selected_size);
  		else
  			align_size = HPT_ALIGN_PAGES << PAGE_SHIFT;
  
  		align_size = max(kvm_rma_pages << PAGE_SHIFT, align_size);
  		kvm_cma_declare_contiguous(selected_size, align_size);
  	}
  }
  