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