xref: /openbmc/linux/arch/x86/xen/enlighten_pvh.c (revision d2ba09c1)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/acpi.h>
3 
4 #include <xen/hvc-console.h>
5 
6 #include <asm/io_apic.h>
7 #include <asm/hypervisor.h>
8 #include <asm/e820/api.h>
9 #include <asm/x86_init.h>
10 
11 #include <asm/xen/interface.h>
12 #include <asm/xen/hypercall.h>
13 
14 #include <xen/interface/memory.h>
15 #include <xen/interface/hvm/start_info.h>
16 
17 /*
18  * PVH variables.
19  *
20  * xen_pvh pvh_bootparams and pvh_start_info need to live in data segment
21  * since they are used after startup_{32|64}, which clear .bss, are invoked.
22  */
23 bool xen_pvh __attribute__((section(".data"))) = 0;
24 struct boot_params pvh_bootparams __attribute__((section(".data")));
25 struct hvm_start_info pvh_start_info __attribute__((section(".data")));
26 
27 unsigned int pvh_start_info_sz = sizeof(pvh_start_info);
28 
29 static u64 pvh_get_root_pointer(void)
30 {
31 	return pvh_start_info.rsdp_paddr;
32 }
33 
34 static void __init init_pvh_bootparams(void)
35 {
36 	struct xen_memory_map memmap;
37 	int rc;
38 
39 	memset(&pvh_bootparams, 0, sizeof(pvh_bootparams));
40 
41 	memmap.nr_entries = ARRAY_SIZE(pvh_bootparams.e820_table);
42 	set_xen_guest_handle(memmap.buffer, pvh_bootparams.e820_table);
43 	rc = HYPERVISOR_memory_op(XENMEM_memory_map, &memmap);
44 	if (rc) {
45 		xen_raw_printk("XENMEM_memory_map failed (%d)\n", rc);
46 		BUG();
47 	}
48 	pvh_bootparams.e820_entries = memmap.nr_entries;
49 
50 	if (pvh_bootparams.e820_entries < E820_MAX_ENTRIES_ZEROPAGE - 1) {
51 		pvh_bootparams.e820_table[pvh_bootparams.e820_entries].addr =
52 			ISA_START_ADDRESS;
53 		pvh_bootparams.e820_table[pvh_bootparams.e820_entries].size =
54 			ISA_END_ADDRESS - ISA_START_ADDRESS;
55 		pvh_bootparams.e820_table[pvh_bootparams.e820_entries].type =
56 			E820_TYPE_RESERVED;
57 		pvh_bootparams.e820_entries++;
58 	} else
59 		xen_raw_printk("Warning: Can fit ISA range into e820\n");
60 
61 	pvh_bootparams.hdr.cmd_line_ptr =
62 		pvh_start_info.cmdline_paddr;
63 
64 	/* The first module is always ramdisk. */
65 	if (pvh_start_info.nr_modules) {
66 		struct hvm_modlist_entry *modaddr =
67 			__va(pvh_start_info.modlist_paddr);
68 		pvh_bootparams.hdr.ramdisk_image = modaddr->paddr;
69 		pvh_bootparams.hdr.ramdisk_size = modaddr->size;
70 	}
71 
72 	/*
73 	 * See Documentation/x86/boot.txt.
74 	 *
75 	 * Version 2.12 supports Xen entry point but we will use default x86/PC
76 	 * environment (i.e. hardware_subarch 0).
77 	 */
78 	pvh_bootparams.hdr.version = 0x212;
79 	pvh_bootparams.hdr.type_of_loader = (9 << 4) | 0; /* Xen loader */
80 
81 	x86_init.acpi.get_root_pointer = pvh_get_root_pointer;
82 }
83 
84 /*
85  * This routine (and those that it might call) should not use
86  * anything that lives in .bss since that segment will be cleared later.
87  */
88 void __init xen_prepare_pvh(void)
89 {
90 	u32 msr;
91 	u64 pfn;
92 
93 	if (pvh_start_info.magic != XEN_HVM_START_MAGIC_VALUE) {
94 		xen_raw_printk("Error: Unexpected magic value (0x%08x)\n",
95 				pvh_start_info.magic);
96 		BUG();
97 	}
98 
99 	xen_pvh = 1;
100 
101 	msr = cpuid_ebx(xen_cpuid_base() + 2);
102 	pfn = __pa(hypercall_page);
103 	wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
104 
105 	init_pvh_bootparams();
106 }
107