trivial: replace last usages of __FUNCTION__ in kernel
[linux-2.6-block.git] / drivers / lguest / hypercalls.c
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1/*P:500 Just as userspace programs request kernel operations through a system
2 * call, the Guest requests Host operations through a "hypercall". You might
3 * notice this nomenclature doesn't really follow any logic, but the name has
4 * been around for long enough that we're stuck with it. As you'd expect, this
5 * code is basically a one big switch statement. :*/
6
7/* Copyright (C) 2006 Rusty Russell IBM Corporation
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8
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 2 of the License, or
12 (at your option) any later version.
13
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
18
19 You should have received a copy of the GNU General Public License
20 along with this program; if not, write to the Free Software
21 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22*/
23#include <linux/uaccess.h>
24#include <linux/syscalls.h>
25#include <linux/mm.h>
ca94f2bd 26#include <linux/ktime.h>
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27#include <asm/page.h>
28#include <asm/pgtable.h>
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29#include "lg.h"
30
b410e7b1 31/*H:120 This is the core hypercall routine: where the Guest gets what it wants.
a6bd8e13 32 * Or gets killed. Or, in the case of LHCALL_SHUTDOWN, both. */
73044f05 33static void do_hcall(struct lg_cpu *cpu, struct hcall_args *args)
d7e28ffe 34{
b410e7b1 35 switch (args->arg0) {
d7e28ffe 36 case LHCALL_FLUSH_ASYNC:
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37 /* This call does nothing, except by breaking out of the Guest
38 * it makes us process all the asynchronous hypercalls. */
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39 break;
40 case LHCALL_LGUEST_INIT:
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41 /* You can't get here unless you're already initialized. Don't
42 * do that. */
382ac6b3 43 kill_guest(cpu, "already have lguest_data");
d7e28ffe 44 break;
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45 case LHCALL_SHUTDOWN: {
46 /* Shutdown is such a trivial hypercall that we do it in four
bff672e6 47 * lines right here. */
d7e28ffe 48 char msg[128];
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49 /* If the lgread fails, it will call kill_guest() itself; the
50 * kill_guest() with the message will be ignored. */
382ac6b3 51 __lgread(cpu, msg, args->arg1, sizeof(msg));
d7e28ffe 52 msg[sizeof(msg)-1] = '\0';
382ac6b3 53 kill_guest(cpu, "CRASH: %s", msg);
ec04b13f 54 if (args->arg2 == LGUEST_SHUTDOWN_RESTART)
382ac6b3 55 cpu->lg->dead = ERR_PTR(-ERESTART);
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56 break;
57 }
58 case LHCALL_FLUSH_TLB:
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59 /* FLUSH_TLB comes in two flavors, depending on the
60 * argument: */
b410e7b1 61 if (args->arg1)
4665ac8e 62 guest_pagetable_clear_all(cpu);
d7e28ffe 63 else
1713608f 64 guest_pagetable_flush_user(cpu);
d7e28ffe 65 break;
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66
67 /* All these calls simply pass the arguments through to the right
68 * routines. */
d7e28ffe 69 case LHCALL_NEW_PGTABLE:
4665ac8e 70 guest_new_pagetable(cpu, args->arg1);
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71 break;
72 case LHCALL_SET_STACK:
4665ac8e 73 guest_set_stack(cpu, args->arg1, args->arg2, args->arg3);
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74 break;
75 case LHCALL_SET_PTE:
382ac6b3 76 guest_set_pte(cpu, args->arg1, args->arg2, __pte(args->arg3));
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77 break;
78 case LHCALL_SET_PMD:
382ac6b3 79 guest_set_pmd(cpu->lg, args->arg1, args->arg2);
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80 break;
81 case LHCALL_SET_CLOCKEVENT:
ad8d8f3b 82 guest_set_clockevent(cpu, args->arg1);
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83 break;
84 case LHCALL_TS:
bff672e6 85 /* This sets the TS flag, as we saw used in run_guest(). */
4665ac8e 86 cpu->ts = args->arg1;
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87 break;
88 case LHCALL_HALT:
bff672e6 89 /* Similarly, this sets the halted flag for run_guest(). */
66686c2a 90 cpu->halted = 1;
d7e28ffe 91 break;
15045275 92 case LHCALL_NOTIFY:
5e232f4f 93 cpu->pending_notify = args->arg1;
15045275 94 break;
d7e28ffe 95 default:
e1e72965 96 /* It should be an architecture-specific hypercall. */
73044f05 97 if (lguest_arch_do_hcall(cpu, args))
382ac6b3 98 kill_guest(cpu, "Bad hypercall %li\n", args->arg0);
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99 }
100}
b410e7b1 101/*:*/
d7e28ffe 102
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103/*H:124 Asynchronous hypercalls are easy: we just look in the array in the
104 * Guest's "struct lguest_data" to see if any new ones are marked "ready".
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105 *
106 * We are careful to do these in order: obviously we respect the order the
107 * Guest put them in the ring, but we also promise the Guest that they will
108 * happen before any normal hypercall (which is why we check this before
109 * checking for a normal hcall). */
73044f05 110static void do_async_hcalls(struct lg_cpu *cpu)
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111{
112 unsigned int i;
113 u8 st[LHCALL_RING_SIZE];
114
bff672e6 115 /* For simplicity, we copy the entire call status array in at once. */
382ac6b3 116 if (copy_from_user(&st, &cpu->lg->lguest_data->hcall_status, sizeof(st)))
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117 return;
118
bff672e6 119 /* We process "struct lguest_data"s hcalls[] ring once. */
d7e28ffe 120 for (i = 0; i < ARRAY_SIZE(st); i++) {
b410e7b1 121 struct hcall_args args;
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122 /* We remember where we were up to from last time. This makes
123 * sure that the hypercalls are done in the order the Guest
124 * places them in the ring. */
73044f05 125 unsigned int n = cpu->next_hcall;
d7e28ffe 126
bff672e6 127 /* 0xFF means there's no call here (yet). */
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128 if (st[n] == 0xFF)
129 break;
130
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131 /* OK, we have hypercall. Increment the "next_hcall" cursor,
132 * and wrap back to 0 if we reach the end. */
73044f05
GOC
133 if (++cpu->next_hcall == LHCALL_RING_SIZE)
134 cpu->next_hcall = 0;
d7e28ffe 135
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136 /* Copy the hypercall arguments into a local copy of
137 * the hcall_args struct. */
382ac6b3 138 if (copy_from_user(&args, &cpu->lg->lguest_data->hcalls[n],
b410e7b1 139 sizeof(struct hcall_args))) {
382ac6b3 140 kill_guest(cpu, "Fetching async hypercalls");
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141 break;
142 }
143
bff672e6 144 /* Do the hypercall, same as a normal one. */
73044f05 145 do_hcall(cpu, &args);
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146
147 /* Mark the hypercall done. */
382ac6b3
GOC
148 if (put_user(0xFF, &cpu->lg->lguest_data->hcall_status[n])) {
149 kill_guest(cpu, "Writing result for async hypercall");
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150 break;
151 }
152
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153 /* Stop doing hypercalls if they want to notify the Launcher:
154 * it needs to service this first. */
5e232f4f 155 if (cpu->pending_notify)
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156 break;
157 }
158}
159
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160/* Last of all, we look at what happens first of all. The very first time the
161 * Guest makes a hypercall, we end up here to set things up: */
73044f05 162static void initialize(struct lg_cpu *cpu)
d7e28ffe 163{
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164 /* You can't do anything until you're initialized. The Guest knows the
165 * rules, so we're unforgiving here. */
73044f05 166 if (cpu->hcall->arg0 != LHCALL_LGUEST_INIT) {
382ac6b3 167 kill_guest(cpu, "hypercall %li before INIT", cpu->hcall->arg0);
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168 return;
169 }
170
73044f05 171 if (lguest_arch_init_hypercalls(cpu))
382ac6b3 172 kill_guest(cpu, "bad guest page %p", cpu->lg->lguest_data);
3c6b5bfa 173
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174 /* The Guest tells us where we're not to deliver interrupts by putting
175 * the range of addresses into "struct lguest_data". */
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176 if (get_user(cpu->lg->noirq_start, &cpu->lg->lguest_data->noirq_start)
177 || get_user(cpu->lg->noirq_end, &cpu->lg->lguest_data->noirq_end))
178 kill_guest(cpu, "bad guest page %p", cpu->lg->lguest_data);
d7e28ffe 179
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180 /* We write the current time into the Guest's data page once so it can
181 * set its clock. */
382ac6b3 182 write_timestamp(cpu);
6c8dca5d 183
47436aa4 184 /* page_tables.c will also do some setup. */
382ac6b3 185 page_table_guest_data_init(cpu);
47436aa4 186
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187 /* This is the one case where the above accesses might have been the
188 * first write to a Guest page. This may have caused a copy-on-write
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189 * fault, but the old page might be (read-only) in the Guest
190 * pagetable. */
4665ac8e 191 guest_pagetable_clear_all(cpu);
d7e28ffe 192}
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193/*:*/
194
195/*M:013 If a Guest reads from a page (so creates a mapping) that it has never
196 * written to, and then the Launcher writes to it (ie. the output of a virtual
197 * device), the Guest will still see the old page. In practice, this never
198 * happens: why would the Guest read a page which it has never written to? But
199 * a similar scenario might one day bite us, so it's worth mentioning. :*/
d7e28ffe 200
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201/*H:100
202 * Hypercalls
203 *
204 * Remember from the Guest, hypercalls come in two flavors: normal and
205 * asynchronous. This file handles both of types.
206 */
73044f05 207void do_hypercalls(struct lg_cpu *cpu)
d7e28ffe 208{
cc6d4fbc 209 /* Not initialized yet? This hypercall must do it. */
73044f05 210 if (unlikely(!cpu->lg->lguest_data)) {
cc6d4fbc 211 /* Set up the "struct lguest_data" */
73044f05 212 initialize(cpu);
cc6d4fbc 213 /* Hcall is done. */
73044f05 214 cpu->hcall = NULL;
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215 return;
216 }
217
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218 /* The Guest has initialized.
219 *
220 * Look in the hypercall ring for the async hypercalls: */
73044f05 221 do_async_hcalls(cpu);
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222
223 /* If we stopped reading the hypercall ring because the Guest did a
15045275 224 * NOTIFY to the Launcher, we want to return now. Otherwise we do
cc6d4fbc 225 * the hypercall. */
5e232f4f 226 if (!cpu->pending_notify) {
73044f05 227 do_hcall(cpu, cpu->hcall);
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228 /* Tricky point: we reset the hcall pointer to mark the
229 * hypercall as "done". We use the hcall pointer rather than
230 * the trap number to indicate a hypercall is pending.
231 * Normally it doesn't matter: the Guest will run again and
232 * update the trap number before we come back here.
233 *
e1e72965 234 * However, if we are signalled or the Guest sends I/O to the
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235 * Launcher, the run_guest() loop will exit without running the
236 * Guest. When it comes back it would try to re-run the
a6bd8e13 237 * hypercall. Finding that bug sucked. */
73044f05 238 cpu->hcall = NULL;
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239 }
240}
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241
242/* This routine supplies the Guest with time: it's used for wallclock time at
243 * initial boot and as a rough time source if the TSC isn't available. */
382ac6b3 244void write_timestamp(struct lg_cpu *cpu)
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245{
246 struct timespec now;
247 ktime_get_real_ts(&now);
382ac6b3
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248 if (copy_to_user(&cpu->lg->lguest_data->time,
249 &now, sizeof(struct timespec)))
250 kill_guest(cpu, "Writing timestamp");
6c8dca5d 251}