xref: /openbmc/linux/arch/x86/xen/apic.c (revision 0c6dfa75)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/init.h>
3 #include <linux/thread_info.h>
4 
5 #include <asm/x86_init.h>
6 #include <asm/apic.h>
7 #include <asm/io_apic.h>
8 #include <asm/xen/hypercall.h>
9 
10 #include <xen/xen.h>
11 #include <xen/interface/physdev.h>
12 #include "xen-ops.h"
13 #include "pmu.h"
14 #include "smp.h"
15 
16 static unsigned int xen_io_apic_read(unsigned apic, unsigned reg)
17 {
18 	struct physdev_apic apic_op;
19 	int ret;
20 
21 	apic_op.apic_physbase = mpc_ioapic_addr(apic);
22 	apic_op.reg = reg;
23 	ret = HYPERVISOR_physdev_op(PHYSDEVOP_apic_read, &apic_op);
24 	if (!ret)
25 		return apic_op.value;
26 
27 	/* fallback to return an emulated IO_APIC values */
28 	if (reg == 0x1)
29 		return 0x00170020;
30 	else if (reg == 0x0)
31 		return apic << 24;
32 
33 	return 0xfd;
34 }
35 
36 static u32 xen_set_apic_id(unsigned int x)
37 {
38 	WARN_ON(1);
39 	return x;
40 }
41 
42 static unsigned int xen_get_apic_id(unsigned long x)
43 {
44 	return ((x)>>24) & 0xFFu;
45 }
46 
47 static u32 xen_apic_read(u32 reg)
48 {
49 	struct xen_platform_op op = {
50 		.cmd = XENPF_get_cpuinfo,
51 		.interface_version = XENPF_INTERFACE_VERSION,
52 		.u.pcpu_info.xen_cpuid = 0,
53 	};
54 	int ret;
55 
56 	/* Shouldn't need this as APIC is turned off for PV, and we only
57 	 * get called on the bootup processor. But just in case. */
58 	if (!xen_initial_domain() || smp_processor_id())
59 		return 0;
60 
61 	if (reg == APIC_LVR)
62 		return 0x14;
63 	if (reg != APIC_ID)
64 		return 0;
65 
66 	ret = HYPERVISOR_platform_op(&op);
67 	if (ret)
68 		op.u.pcpu_info.apic_id = BAD_APICID;
69 
70 	return op.u.pcpu_info.apic_id << 24;
71 }
72 
73 static void xen_apic_write(u32 reg, u32 val)
74 {
75 	if (reg == APIC_LVTPC) {
76 		(void)pmu_apic_update(reg);
77 		return;
78 	}
79 
80 	/* Warn to see if there's any stray references */
81 	WARN(1,"register: %x, value: %x\n", reg, val);
82 }
83 
84 static void xen_apic_eoi(void)
85 {
86 	WARN_ON_ONCE(1);
87 }
88 
89 static u64 xen_apic_icr_read(void)
90 {
91 	return 0;
92 }
93 
94 static void xen_apic_icr_write(u32 low, u32 id)
95 {
96 	/* Warn to see if there's any stray references */
97 	WARN_ON(1);
98 }
99 
100 static int xen_apic_probe_pv(void)
101 {
102 	if (xen_pv_domain())
103 		return 1;
104 
105 	return 0;
106 }
107 
108 static int xen_madt_oem_check(char *oem_id, char *oem_table_id)
109 {
110 	return xen_pv_domain();
111 }
112 
113 static int xen_phys_pkg_id(int initial_apic_id, int index_msb)
114 {
115 	return initial_apic_id >> index_msb;
116 }
117 
118 static int xen_cpu_present_to_apicid(int cpu)
119 {
120 	if (cpu_present(cpu))
121 		return cpu_data(cpu).apicid;
122 	else
123 		return BAD_APICID;
124 }
125 
126 static struct apic xen_pv_apic __ro_after_init = {
127 	.name				= "Xen PV",
128 	.probe				= xen_apic_probe_pv,
129 	.acpi_madt_oem_check		= xen_madt_oem_check,
130 
131 	/* .delivery_mode and .dest_mode_logical not used by XENPV */
132 
133 	.disable_esr			= 0,
134 
135 	.cpu_present_to_apicid		= xen_cpu_present_to_apicid,
136 	.phys_pkg_id			= xen_phys_pkg_id, /* detect_ht */
137 
138 	.max_apic_id			= UINT_MAX,
139 	.get_apic_id			= xen_get_apic_id,
140 	.set_apic_id			= xen_set_apic_id,
141 
142 	.calc_dest_apicid		= apic_flat_calc_apicid,
143 
144 #ifdef CONFIG_SMP
145 	.send_IPI_mask			= xen_send_IPI_mask,
146 	.send_IPI_mask_allbutself	= xen_send_IPI_mask_allbutself,
147 	.send_IPI_allbutself		= xen_send_IPI_allbutself,
148 	.send_IPI_all			= xen_send_IPI_all,
149 	.send_IPI_self			= xen_send_IPI_self,
150 #endif
151 	.read				= xen_apic_read,
152 	.write				= xen_apic_write,
153 	.eoi				= xen_apic_eoi,
154 
155 	.icr_read			= xen_apic_icr_read,
156 	.icr_write			= xen_apic_icr_write,
157 };
158 apic_driver(xen_pv_apic);
159 
160 void __init xen_init_apic(void)
161 {
162 	x86_apic_ops.io_apic_read = xen_io_apic_read;
163 }
164