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/bootparam.h>
9 #include <asm/io_apic.h>
10 #include <asm/hypervisor.h>
11 #include <asm/e820/api.h>
12 #include <asm/setup.h>
13
14 #include <xen/xen.h>
15 #include <asm/xen/interface.h>
16 #include <asm/xen/hypercall.h>
17
18 #include <xen/interface/memory.h>
19
20 #include "xen-ops.h"
21
22 /*
23 * PVH variables.
24 *
25 * The variable xen_pvh needs to live in a data segment since it is used
26 * after startup_{32|64} is invoked, which will clear the .bss segment.
27 */
28 bool __ro_after_init xen_pvh;
29 EXPORT_SYMBOL_GPL(xen_pvh);
30
31 /*
32 * Reserve e820 UNUSABLE regions to inflate the memory balloon.
33 *
34 * On PVH dom0 the host memory map is used, RAM regions available to dom0 are
35 * located as the same place as in the native memory map, but since dom0 gets
36 * less memory than the total amount of host RAM the ranges that can't be
37 * populated are converted from RAM -> UNUSABLE. Use such regions (up to the
38 * ratio signaled in EXTRA_MEM_RATIO) in order to inflate the balloon driver at
39 * boot. Doing so prevents the guest (even if just temporary) from using holes
40 * in the memory map in order to map grants or foreign addresses, and
41 * hopefully limits the risk of a clash with a device MMIO region. Ideally the
42 * hypervisor should notify us which memory ranges are suitable for creating
43 * foreign mappings, but that's not yet implemented.
44 */
45 static void __init pvh_reserve_extra_memory(void)
46 {
47 struct boot_params *bootp = &boot_params;
48 unsigned int i, ram_pages = 0, extra_pages;
49
50 for (i = 0; i < bootp->e820_entries; i++) {
51 struct boot_e820_entry *e = &bootp->e820_table[i];
52
53 if (e->type != E820_TYPE_RAM)
54 continue;
55 ram_pages += PFN_DOWN(e->addr + e->size) - PFN_UP(e->addr);
56 }
57
58 /* Max amount of extra memory. */
59 extra_pages = EXTRA_MEM_RATIO * ram_pages;
60
61 /*
62 * Convert UNUSABLE ranges to RAM and reserve them for foreign mapping
63 * purposes.
64 */
65 for (i = 0; i < bootp->e820_entries && extra_pages; i++) {
66 struct boot_e820_entry *e = &bootp->e820_table[i];
67 unsigned long pages;
68
69 if (e->type != E820_TYPE_UNUSABLE)
70 continue;
71
72 pages = min(extra_pages,
73 PFN_DOWN(e->addr + e->size) - PFN_UP(e->addr));
74
75 if (pages != (PFN_DOWN(e->addr + e->size) - PFN_UP(e->addr))) {
76 struct boot_e820_entry *next;
77
78 if (bootp->e820_entries ==
79 ARRAY_SIZE(bootp->e820_table))
80 /* No space left to split - skip region. */
81 continue;
82
83 /* Split entry. */
84 next = e + 1;
85 memmove(next, e,
86 (bootp->e820_entries - i) * sizeof(*e));
87 bootp->e820_entries++;
88 next->addr = PAGE_ALIGN(e->addr) + PFN_PHYS(pages);
89 e->size = next->addr - e->addr;
90 next->size -= e->size;
91 }
92 e->type = E820_TYPE_RAM;
93 extra_pages -= pages;
94
95 xen_add_extra_mem(PFN_UP(e->addr), pages);
96 }
97 }
98
99 static void __init pvh_arch_setup(void)
100 {
101 pvh_reserve_extra_memory();
102
103 if (xen_initial_domain())
104 xen_add_preferred_consoles();
105 }
106
107 void __init xen_pvh_init(struct boot_params *boot_params)
108 {
109 u32 msr;
110 u64 pfn;
111
112 xen_pvh = 1;
113 xen_domain_type = XEN_HVM_DOMAIN;
114 xen_start_flags = pvh_start_info.flags;
115
116 msr = cpuid_ebx(xen_cpuid_base() + 2);
117 pfn = __pa(hypercall_page);
118 wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
119
120 x86_init.oem.arch_setup = pvh_arch_setup;
121 x86_init.oem.banner = xen_banner;
122
123 xen_efi_init(boot_params);
124
125 if (xen_initial_domain()) {
126 struct xen_platform_op op = {
127 .cmd = XENPF_get_dom0_console,
128 };
129 int ret = HYPERVISOR_platform_op(&op);
130
131 if (ret > 0)
132 xen_init_vga(&op.u.dom0_console,
133 min(ret * sizeof(char),
134 sizeof(op.u.dom0_console)),
135 &boot_params->screen_info);
136 }
137 }
138
139 void __init mem_map_via_hcall(struct boot_params *boot_params_p)
140 {
141 struct xen_memory_map memmap;
142 int rc;
143
144 memmap.nr_entries = ARRAY_SIZE(boot_params_p->e820_table);
145 set_xen_guest_handle(memmap.buffer, boot_params_p->e820_table);
146 rc = HYPERVISOR_memory_op(XENMEM_memory_map, &memmap);
147 if (rc) {
148 xen_raw_printk("XENMEM_memory_map failed (%d)\n", rc);
149 BUG();
150 }
151 boot_params_p->e820_entries = memmap.nr_entries;
152 }
153
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