1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2020 - Google LLC
4 * Author: Quentin Perret <qperret@google.com>
5 */
6
7 #include <linux/kvm_host.h>
8 #include <linux/memblock.h>
9 #include <linux/sort.h>
10
11 #include <asm/kvm_pkvm.h>
12
13 #include "hyp_constants.h"
14
15 static struct memblock_region *hyp_memory = kvm_nvhe_sym(hyp_memory);
16 static unsigned int *hyp_memblock_nr_ptr = &kvm_nvhe_sym(hyp_memblock_nr);
17
18 phys_addr_t hyp_mem_base;
19 phys_addr_t hyp_mem_size;
20
cmp_hyp_memblock(const void * p1,const void * p2)21 static int cmp_hyp_memblock(const void *p1, const void *p2)
22 {
23 const struct memblock_region *r1 = p1;
24 const struct memblock_region *r2 = p2;
25
26 return r1->base < r2->base ? -1 : (r1->base > r2->base);
27 }
28
sort_memblock_regions(void)29 static void __init sort_memblock_regions(void)
30 {
31 sort(hyp_memory,
32 *hyp_memblock_nr_ptr,
33 sizeof(struct memblock_region),
34 cmp_hyp_memblock,
35 NULL);
36 }
37
register_memblock_regions(void)38 static int __init register_memblock_regions(void)
39 {
40 struct memblock_region *reg;
41
42 for_each_mem_region(reg) {
43 if (*hyp_memblock_nr_ptr >= HYP_MEMBLOCK_REGIONS)
44 return -ENOMEM;
45
46 hyp_memory[*hyp_memblock_nr_ptr] = *reg;
47 (*hyp_memblock_nr_ptr)++;
48 }
49 sort_memblock_regions();
50
51 return 0;
52 }
53
kvm_hyp_reserve(void)54 void __init kvm_hyp_reserve(void)
55 {
56 u64 nr_pages, prev, hyp_mem_pages = 0;
57 int ret;
58
59 if (!is_hyp_mode_available() || is_kernel_in_hyp_mode())
60 return;
61
62 if (kvm_get_mode() != KVM_MODE_PROTECTED)
63 return;
64
65 ret = register_memblock_regions();
66 if (ret) {
67 *hyp_memblock_nr_ptr = 0;
68 kvm_err("Failed to register hyp memblocks: %d\n", ret);
69 return;
70 }
71
72 hyp_mem_pages += hyp_s1_pgtable_pages();
73 hyp_mem_pages += host_s2_pgtable_pages();
74
75 /*
76 * The hyp_vmemmap needs to be backed by pages, but these pages
77 * themselves need to be present in the vmemmap, so compute the number
78 * of pages needed by looking for a fixed point.
79 */
80 nr_pages = 0;
81 do {
82 prev = nr_pages;
83 nr_pages = hyp_mem_pages + prev;
84 nr_pages = DIV_ROUND_UP(nr_pages * STRUCT_HYP_PAGE_SIZE,
85 PAGE_SIZE);
86 nr_pages += __hyp_pgtable_max_pages(nr_pages);
87 } while (nr_pages != prev);
88 hyp_mem_pages += nr_pages;
89
90 /*
91 * Try to allocate a PMD-aligned region to reduce TLB pressure once
92 * this is unmapped from the host stage-2, and fallback to PAGE_SIZE.
93 */
94 hyp_mem_size = hyp_mem_pages << PAGE_SHIFT;
95 hyp_mem_base = memblock_phys_alloc(ALIGN(hyp_mem_size, PMD_SIZE),
96 PMD_SIZE);
97 if (!hyp_mem_base)
98 hyp_mem_base = memblock_phys_alloc(hyp_mem_size, PAGE_SIZE);
99 else
100 hyp_mem_size = ALIGN(hyp_mem_size, PMD_SIZE);
101
102 if (!hyp_mem_base) {
103 kvm_err("Failed to reserve hyp memory\n");
104 return;
105 }
106
107 kvm_info("Reserved %lld MiB at 0x%llx\n", hyp_mem_size >> 20,
108 hyp_mem_base);
109 }
110