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