1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/acpi.h>
3 #include <linux/export.h>
4 #include <linux/mm.h>
5
6 #include <xen/hvc-console.h>
7
8 #include <asm/io_apic.h>
9 #include <asm/hypervisor.h>
10 #include <asm/e820/api.h>
11 #include <asm/setup.h>
12
13 #include <xen/xen.h>
14 #include <asm/xen/interface.h>
15 #include <asm/xen/hypercall.h>
16
17 #include <xen/interface/memory.h>
18
19 #include "xen-ops.h"
20
21 /*
22 * PVH variables.
23 *
24 * The variable xen_pvh needs to live in a data segment since it is used
25 * after startup_{32|64} is invoked, which will clear the .bss segment.
26 */
27 bool __ro_after_init xen_pvh;
28 EXPORT_SYMBOL_GPL(xen_pvh);
29
30 /*
31 * Reserve e820 UNUSABLE regions to inflate the memory balloon.
32 *
33 * On PVH dom0 the host memory map is used, RAM regions available to dom0 are
34 * located as the same place as in the native memory map, but since dom0 gets
35 * less memory than the total amount of host RAM the ranges that can't be
36 * populated are converted from RAM -> UNUSABLE. Use such regions (up to the
37 * ratio signaled in EXTRA_MEM_RATIO) in order to inflate the balloon driver at
38 * boot. Doing so prevents the guest (even if just temporary) from using holes
39 * in the memory map in order to map grants or foreign addresses, and
40 * hopefully limits the risk of a clash with a device MMIO region. Ideally the
41 * hypervisor should notify us which memory ranges are suitable for creating
42 * foreign mappings, but that's not yet implemented.
43 */
pvh_reserve_extra_memory(void)44 static void __init pvh_reserve_extra_memory(void)
45 {
46 struct boot_params *bootp = &boot_params;
47 unsigned int i, ram_pages = 0, extra_pages;
48
49 for (i = 0; i < bootp->e820_entries; i++) {
50 struct boot_e820_entry *e = &bootp->e820_table[i];
51
52 if (e->type != E820_TYPE_RAM)
53 continue;
54 ram_pages += PFN_DOWN(e->addr + e->size) - PFN_UP(e->addr);
55 }
56
57 /* Max amount of extra memory. */
58 extra_pages = EXTRA_MEM_RATIO * ram_pages;
59
60 /*
61 * Convert UNUSABLE ranges to RAM and reserve them for foreign mapping
62 * purposes.
63 */
64 for (i = 0; i < bootp->e820_entries && extra_pages; i++) {
65 struct boot_e820_entry *e = &bootp->e820_table[i];
66 unsigned long pages;
67
68 if (e->type != E820_TYPE_UNUSABLE)
69 continue;
70
71 pages = min(extra_pages,
72 PFN_DOWN(e->addr + e->size) - PFN_UP(e->addr));
73
74 if (pages != (PFN_DOWN(e->addr + e->size) - PFN_UP(e->addr))) {
75 struct boot_e820_entry *next;
76
77 if (bootp->e820_entries ==
78 ARRAY_SIZE(bootp->e820_table))
79 /* No space left to split - skip region. */
80 continue;
81
82 /* Split entry. */
83 next = e + 1;
84 memmove(next, e,
85 (bootp->e820_entries - i) * sizeof(*e));
86 bootp->e820_entries++;
87 next->addr = PAGE_ALIGN(e->addr) + PFN_PHYS(pages);
88 e->size = next->addr - e->addr;
89 next->size -= e->size;
90 }
91 e->type = E820_TYPE_RAM;
92 extra_pages -= pages;
93
94 xen_add_extra_mem(PFN_UP(e->addr), pages);
95 }
96 }
97
pvh_arch_setup(void)98 static void __init pvh_arch_setup(void)
99 {
100 pvh_reserve_extra_memory();
101
102 if (xen_initial_domain())
103 xen_add_preferred_consoles();
104 }
105
xen_pvh_init(struct boot_params * boot_params)106 void __init xen_pvh_init(struct boot_params *boot_params)
107 {
108 xen_pvh = 1;
109 xen_domain_type = XEN_HVM_DOMAIN;
110 xen_start_flags = pvh_start_info.flags;
111
112 x86_init.oem.arch_setup = pvh_arch_setup;
113 x86_init.oem.banner = xen_banner;
114
115 xen_efi_init(boot_params);
116
117 if (xen_initial_domain()) {
118 struct xen_platform_op op = {
119 .cmd = XENPF_get_dom0_console,
120 };
121 int ret = HYPERVISOR_platform_op(&op);
122
123 if (ret > 0)
124 xen_init_vga(&op.u.dom0_console,
125 min(ret * sizeof(char),
126 sizeof(op.u.dom0_console)),
127 &boot_params->screen_info);
128 }
129 }
130
mem_map_via_hcall(struct boot_params * boot_params_p)131 void __init mem_map_via_hcall(struct boot_params *boot_params_p)
132 {
133 struct xen_memory_map memmap;
134 int rc;
135
136 memmap.nr_entries = ARRAY_SIZE(boot_params_p->e820_table);
137 set_xen_guest_handle(memmap.buffer, boot_params_p->e820_table);
138 rc = HYPERVISOR_memory_op(XENMEM_memory_map, &memmap);
139 if (rc) {
140 xen_raw_printk("XENMEM_memory_map failed (%d)\n", rc);
141 BUG();
142 }
143 boot_params_p->e820_entries = memmap.nr_entries;
144 }
145