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Oleksandr Andrushchenko48654412020-08-06 12:42:48 +03001// SPDX-License-Identifier: MIT License
2/*
3 * hypervisor.c
4 *
5 * Communication to/from hypervisor.
6 *
7 * Copyright (c) 2002-2003, K A Fraser
8 * Copyright (c) 2005, Grzegorz Milos, gm281@cam.ac.uk,Intel Research Cambridge
9 * Copyright (c) 2020, EPAM Systems Inc.
10 */
11#include <common.h>
12#include <cpu_func.h>
13#include <log.h>
14#include <memalign.h>
15
16#include <asm/io.h>
17#include <asm/armv8/mmu.h>
18#include <asm/xen/system.h>
19
20#include <linux/bug.h>
21
22#include <xen/hvm.h>
Oleksandr Andrushchenko673fd822020-08-06 12:42:49 +030023#include <xen/events.h>
Oleksandr Andrushchenkoc8506742020-08-06 12:42:54 +030024#include <xen/gnttab.h>
Oleksandr Andrushchenko60e49ff2020-08-06 12:42:53 +030025#include <xen/xenbus.h>
Oleksandr Andrushchenko48654412020-08-06 12:42:48 +030026#include <xen/interface/memory.h>
27
28#define active_evtchns(cpu, sh, idx) \
29 ((sh)->evtchn_pending[idx] & \
30 ~(sh)->evtchn_mask[idx])
31
32int in_callback;
33
34/*
35 * Shared page for communicating with the hypervisor.
36 * Events flags go here, for example.
37 */
38struct shared_info *HYPERVISOR_shared_info;
39
40static const char *param_name(int op)
41{
42#define PARAM(x)[HVM_PARAM_##x] = #x
43 static const char *const names[] = {
44 PARAM(CALLBACK_IRQ),
45 PARAM(STORE_PFN),
46 PARAM(STORE_EVTCHN),
47 PARAM(PAE_ENABLED),
48 PARAM(IOREQ_PFN),
49 PARAM(VPT_ALIGN),
50 PARAM(CONSOLE_PFN),
51 PARAM(CONSOLE_EVTCHN),
52 };
53#undef PARAM
54
55 if (op >= ARRAY_SIZE(names))
56 return "unknown";
57
58 if (!names[op])
59 return "reserved";
60
61 return names[op];
62}
63
64/**
65 * hvm_get_parameter_maintain_dcache - function to obtain a HVM
66 * parameter value.
67 * @idx: HVM parameter index
68 * @value: Value to fill in
69 *
70 * According to Xen on ARM ABI (xen/include/public/arch-arm.h):
71 * all memory which is shared with other entities in the system
72 * (including the hypervisor and other guests) must reside in memory
73 * which is mapped as Normal Inner Write-Back Outer Write-Back
74 * Inner-Shareable.
75 *
76 * Thus, page attributes must be equally set for all the entities
77 * working with that page.
78 *
79 * Before MMU setup the data cache is turned off, so it means that
80 * manual data cache maintenance is required, because of the
81 * difference of page attributes.
82 */
83int hvm_get_parameter_maintain_dcache(int idx, uint64_t *value)
84{
85 struct xen_hvm_param xhv;
86 int ret;
87
88 invalidate_dcache_range((unsigned long)&xhv,
89 (unsigned long)&xhv + sizeof(xhv));
90 xhv.domid = DOMID_SELF;
91 xhv.index = idx;
92 invalidate_dcache_range((unsigned long)&xhv,
93 (unsigned long)&xhv + sizeof(xhv));
94
95 ret = HYPERVISOR_hvm_op(HVMOP_get_param, &xhv);
96 if (ret < 0) {
97 pr_err("Cannot get hvm parameter %s (%d): %d!\n",
98 param_name(idx), idx, ret);
99 BUG();
100 }
101 invalidate_dcache_range((unsigned long)&xhv,
102 (unsigned long)&xhv + sizeof(xhv));
103
104 *value = xhv.value;
105
106 return ret;
107}
108
109int hvm_get_parameter(int idx, uint64_t *value)
110{
111 struct xen_hvm_param xhv;
112 int ret;
113
114 xhv.domid = DOMID_SELF;
115 xhv.index = idx;
116 ret = HYPERVISOR_hvm_op(HVMOP_get_param, &xhv);
117 if (ret < 0) {
118 pr_err("Cannot get hvm parameter %s (%d): %d!\n",
119 param_name(idx), idx, ret);
120 BUG();
121 }
122
123 *value = xhv.value;
124
125 return ret;
126}
127
128struct shared_info *map_shared_info(void *p)
129{
130 struct xen_add_to_physmap xatp;
131
132 HYPERVISOR_shared_info = (struct shared_info *)memalign(PAGE_SIZE,
133 PAGE_SIZE);
134 if (!HYPERVISOR_shared_info)
135 BUG();
136
137 xatp.domid = DOMID_SELF;
138 xatp.idx = 0;
139 xatp.space = XENMAPSPACE_shared_info;
140 xatp.gpfn = virt_to_pfn(HYPERVISOR_shared_info);
141 if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp) != 0)
142 BUG();
143
144 return HYPERVISOR_shared_info;
145}
146
147void do_hypervisor_callback(struct pt_regs *regs)
148{
149 unsigned long l1, l2, l1i, l2i;
150 unsigned int port;
151 int cpu = 0;
152 struct shared_info *s = HYPERVISOR_shared_info;
153 struct vcpu_info *vcpu_info = &s->vcpu_info[cpu];
154
155 in_callback = 1;
156
157 vcpu_info->evtchn_upcall_pending = 0;
158 l1 = xchg(&vcpu_info->evtchn_pending_sel, 0);
159
160 while (l1 != 0) {
161 l1i = __ffs(l1);
162 l1 &= ~(1UL << l1i);
163
164 while ((l2 = active_evtchns(cpu, s, l1i)) != 0) {
165 l2i = __ffs(l2);
166 l2 &= ~(1UL << l2i);
167
168 port = (l1i * (sizeof(unsigned long) * 8)) + l2i;
Oleksandr Andrushchenko673fd822020-08-06 12:42:49 +0300169 do_event(port, regs);
Oleksandr Andrushchenko48654412020-08-06 12:42:48 +0300170 }
171 }
172
173 in_callback = 0;
174}
175
176void force_evtchn_callback(void)
177{
178#ifdef XEN_HAVE_PV_UPCALL_MASK
179 int save;
180#endif
181 struct vcpu_info *vcpu;
182
183 vcpu = &HYPERVISOR_shared_info->vcpu_info[smp_processor_id()];
184#ifdef XEN_HAVE_PV_UPCALL_MASK
185 save = vcpu->evtchn_upcall_mask;
186#endif
187
188 while (vcpu->evtchn_upcall_pending) {
189#ifdef XEN_HAVE_PV_UPCALL_MASK
190 vcpu->evtchn_upcall_mask = 1;
191#endif
192 do_hypervisor_callback(NULL);
193#ifdef XEN_HAVE_PV_UPCALL_MASK
194 vcpu->evtchn_upcall_mask = save;
195#endif
196 };
197}
198
199void mask_evtchn(uint32_t port)
200{
201 struct shared_info *s = HYPERVISOR_shared_info;
202
203 synch_set_bit(port, &s->evtchn_mask[0]);
204}
205
206void unmask_evtchn(uint32_t port)
207{
208 struct shared_info *s = HYPERVISOR_shared_info;
209 struct vcpu_info *vcpu_info = &s->vcpu_info[smp_processor_id()];
210
211 synch_clear_bit(port, &s->evtchn_mask[0]);
212
213 /*
214 * Just like a real IO-APIC we 'lose the interrupt edge' if the
215 * channel is masked.
216 */
217 if (synch_test_bit(port, &s->evtchn_pending[0]) &&
218 !synch_test_and_set_bit(port / (sizeof(unsigned long) * 8),
219 &vcpu_info->evtchn_pending_sel)) {
220 vcpu_info->evtchn_upcall_pending = 1;
221#ifdef XEN_HAVE_PV_UPCALL_MASK
222 if (!vcpu_info->evtchn_upcall_mask)
223#endif
224 force_evtchn_callback();
225 }
226}
227
228void clear_evtchn(uint32_t port)
229{
230 struct shared_info *s = HYPERVISOR_shared_info;
231
232 synch_clear_bit(port, &s->evtchn_pending[0]);
233}
234
Ovidiu Panaiteb2825b2020-11-28 10:43:14 +0200235int xen_init(void)
Oleksandr Andrushchenko48654412020-08-06 12:42:48 +0300236{
237 debug("%s\n", __func__);
238
239 map_shared_info(NULL);
Oleksandr Andrushchenko673fd822020-08-06 12:42:49 +0300240 init_events();
Oleksandr Andrushchenko60e49ff2020-08-06 12:42:53 +0300241 init_xenbus();
Oleksandr Andrushchenkoc8506742020-08-06 12:42:54 +0300242 init_gnttab();
Ovidiu Panaiteb2825b2020-11-28 10:43:14 +0200243
244 return 0;
Oleksandr Andrushchenko48654412020-08-06 12:42:48 +0300245}
246
Oleksandr Andrushchenkod17f6692020-08-06 12:43:00 +0300247void xen_fini(void)
248{
249 debug("%s\n", __func__);
250
251 fini_gnttab();
252 fini_xenbus();
253 fini_events();
254}