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Rusty Russellf938d2c2007-07-26 10:41:02 -07001/*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
Rusty Russelld7e28ff2007-07-19 01:49:23 -07008
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>
Glauber de Oliveira Costaca94f2b2008-01-18 23:59:07 -020026#include <linux/ktime.h>
Rusty Russelld7e28ff2007-07-19 01:49:23 -070027#include <asm/page.h>
28#include <asm/pgtable.h>
Rusty Russelld7e28ff2007-07-19 01:49:23 -070029#include "lg.h"
30
Jes Sorensenb410e7b2007-10-22 11:03:31 +100031/*H:120 This is the core hypercall routine: where the Guest gets what it wants.
Rusty Russella6bd8e12008-03-28 11:05:53 -050032 * Or gets killed. Or, in the case of LHCALL_SHUTDOWN, both. */
Glauber de Oliveira Costa73044f02008-01-07 11:05:27 -020033static void do_hcall(struct lg_cpu *cpu, struct hcall_args *args)
Rusty Russelld7e28ff2007-07-19 01:49:23 -070034{
Jes Sorensenb410e7b2007-10-22 11:03:31 +100035 switch (args->arg0) {
Rusty Russelld7e28ff2007-07-19 01:49:23 -070036 case LHCALL_FLUSH_ASYNC:
Rusty Russellbff672e2007-07-26 10:41:04 -070037 /* This call does nothing, except by breaking out of the Guest
38 * it makes us process all the asynchronous hypercalls. */
Rusty Russelld7e28ff2007-07-19 01:49:23 -070039 break;
40 case LHCALL_LGUEST_INIT:
Rusty Russellbff672e2007-07-26 10:41:04 -070041 /* You can't get here unless you're already initialized. Don't
42 * do that. */
Glauber de Oliveira Costa382ac6b2008-01-17 19:19:42 -020043 kill_guest(cpu, "already have lguest_data");
Rusty Russelld7e28ff2007-07-19 01:49:23 -070044 break;
Balaji Raoec04b132007-12-28 14:26:24 +053045 case LHCALL_SHUTDOWN: {
46 /* Shutdown is such a trivial hypercall that we do it in four
Rusty Russellbff672e2007-07-26 10:41:04 -070047 * lines right here. */
Rusty Russelld7e28ff2007-07-19 01:49:23 -070048 char msg[128];
Rusty Russellbff672e2007-07-26 10:41:04 -070049 /* If the lgread fails, it will call kill_guest() itself; the
50 * kill_guest() with the message will be ignored. */
Glauber de Oliveira Costa382ac6b2008-01-17 19:19:42 -020051 __lgread(cpu, msg, args->arg1, sizeof(msg));
Rusty Russelld7e28ff2007-07-19 01:49:23 -070052 msg[sizeof(msg)-1] = '\0';
Glauber de Oliveira Costa382ac6b2008-01-17 19:19:42 -020053 kill_guest(cpu, "CRASH: %s", msg);
Balaji Raoec04b132007-12-28 14:26:24 +053054 if (args->arg2 == LGUEST_SHUTDOWN_RESTART)
Glauber de Oliveira Costa382ac6b2008-01-17 19:19:42 -020055 cpu->lg->dead = ERR_PTR(-ERESTART);
Rusty Russelld7e28ff2007-07-19 01:49:23 -070056 break;
57 }
58 case LHCALL_FLUSH_TLB:
Rusty Russellbff672e2007-07-26 10:41:04 -070059 /* FLUSH_TLB comes in two flavors, depending on the
60 * argument: */
Jes Sorensenb410e7b2007-10-22 11:03:31 +100061 if (args->arg1)
Glauber de Oliveira Costa4665ac8e2008-01-07 11:05:35 -020062 guest_pagetable_clear_all(cpu);
Rusty Russelld7e28ff2007-07-19 01:49:23 -070063 else
Glauber de Oliveira Costa17136082008-01-07 11:05:37 -020064 guest_pagetable_flush_user(cpu);
Rusty Russelld7e28ff2007-07-19 01:49:23 -070065 break;
Rusty Russellbff672e2007-07-26 10:41:04 -070066
67 /* All these calls simply pass the arguments through to the right
68 * routines. */
Rusty Russelld7e28ff2007-07-19 01:49:23 -070069 case LHCALL_NEW_PGTABLE:
Glauber de Oliveira Costa4665ac8e2008-01-07 11:05:35 -020070 guest_new_pagetable(cpu, args->arg1);
Rusty Russelld7e28ff2007-07-19 01:49:23 -070071 break;
72 case LHCALL_SET_STACK:
Glauber de Oliveira Costa4665ac8e2008-01-07 11:05:35 -020073 guest_set_stack(cpu, args->arg1, args->arg2, args->arg3);
Rusty Russelld7e28ff2007-07-19 01:49:23 -070074 break;
75 case LHCALL_SET_PTE:
Glauber de Oliveira Costa382ac6b2008-01-17 19:19:42 -020076 guest_set_pte(cpu, args->arg1, args->arg2, __pte(args->arg3));
Rusty Russelld7e28ff2007-07-19 01:49:23 -070077 break;
78 case LHCALL_SET_PMD:
Glauber de Oliveira Costa382ac6b2008-01-17 19:19:42 -020079 guest_set_pmd(cpu->lg, args->arg1, args->arg2);
Rusty Russelld7e28ff2007-07-19 01:49:23 -070080 break;
81 case LHCALL_SET_CLOCKEVENT:
Glauber de Oliveira Costaad8d8f32008-01-07 11:05:28 -020082 guest_set_clockevent(cpu, args->arg1);
Rusty Russelld7e28ff2007-07-19 01:49:23 -070083 break;
84 case LHCALL_TS:
Rusty Russellbff672e2007-07-26 10:41:04 -070085 /* This sets the TS flag, as we saw used in run_guest(). */
Glauber de Oliveira Costa4665ac8e2008-01-07 11:05:35 -020086 cpu->ts = args->arg1;
Rusty Russelld7e28ff2007-07-19 01:49:23 -070087 break;
88 case LHCALL_HALT:
Rusty Russellbff672e2007-07-26 10:41:04 -070089 /* Similarly, this sets the halted flag for run_guest(). */
Glauber de Oliveira Costa66686c22008-01-07 11:05:34 -020090 cpu->halted = 1;
Rusty Russelld7e28ff2007-07-19 01:49:23 -070091 break;
Rusty Russell15045272007-10-22 11:24:10 +100092 case LHCALL_NOTIFY:
Glauber de Oliveira Costa5e232f42008-01-07 11:05:36 -020093 cpu->pending_notify = args->arg1;
Rusty Russell15045272007-10-22 11:24:10 +100094 break;
Rusty Russelld7e28ff2007-07-19 01:49:23 -070095 default:
Rusty Russelle1e72962007-10-25 15:02:50 +100096 /* It should be an architecture-specific hypercall. */
Glauber de Oliveira Costa73044f02008-01-07 11:05:27 -020097 if (lguest_arch_do_hcall(cpu, args))
Glauber de Oliveira Costa382ac6b2008-01-17 19:19:42 -020098 kill_guest(cpu, "Bad hypercall %li\n", args->arg0);
Rusty Russelld7e28ff2007-07-19 01:49:23 -070099 }
100}
Jes Sorensenb410e7b2007-10-22 11:03:31 +1000101/*:*/
Rusty Russelld7e28ff2007-07-19 01:49:23 -0700102
Jes Sorensenb410e7b2007-10-22 11:03:31 +1000103/*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".
Rusty Russellbff672e2007-07-26 10:41:04 -0700105 *
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). */
Glauber de Oliveira Costa73044f02008-01-07 11:05:27 -0200110static void do_async_hcalls(struct lg_cpu *cpu)
Rusty Russelld7e28ff2007-07-19 01:49:23 -0700111{
112 unsigned int i;
113 u8 st[LHCALL_RING_SIZE];
114
Rusty Russellbff672e2007-07-26 10:41:04 -0700115 /* For simplicity, we copy the entire call status array in at once. */
Glauber de Oliveira Costa382ac6b2008-01-17 19:19:42 -0200116 if (copy_from_user(&st, &cpu->lg->lguest_data->hcall_status, sizeof(st)))
Rusty Russelld7e28ff2007-07-19 01:49:23 -0700117 return;
118
Rusty Russellbff672e2007-07-26 10:41:04 -0700119 /* We process "struct lguest_data"s hcalls[] ring once. */
Rusty Russelld7e28ff2007-07-19 01:49:23 -0700120 for (i = 0; i < ARRAY_SIZE(st); i++) {
Jes Sorensenb410e7b2007-10-22 11:03:31 +1000121 struct hcall_args args;
Rusty Russellbff672e2007-07-26 10:41:04 -0700122 /* 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. */
Glauber de Oliveira Costa73044f02008-01-07 11:05:27 -0200125 unsigned int n = cpu->next_hcall;
Rusty Russelld7e28ff2007-07-19 01:49:23 -0700126
Rusty Russellbff672e2007-07-26 10:41:04 -0700127 /* 0xFF means there's no call here (yet). */
Rusty Russelld7e28ff2007-07-19 01:49:23 -0700128 if (st[n] == 0xFF)
129 break;
130
Rusty Russellbff672e2007-07-26 10:41:04 -0700131 /* OK, we have hypercall. Increment the "next_hcall" cursor,
132 * and wrap back to 0 if we reach the end. */
Glauber de Oliveira Costa73044f02008-01-07 11:05:27 -0200133 if (++cpu->next_hcall == LHCALL_RING_SIZE)
134 cpu->next_hcall = 0;
Rusty Russelld7e28ff2007-07-19 01:49:23 -0700135
Jes Sorensenb410e7b2007-10-22 11:03:31 +1000136 /* Copy the hypercall arguments into a local copy of
137 * the hcall_args struct. */
Glauber de Oliveira Costa382ac6b2008-01-17 19:19:42 -0200138 if (copy_from_user(&args, &cpu->lg->lguest_data->hcalls[n],
Jes Sorensenb410e7b2007-10-22 11:03:31 +1000139 sizeof(struct hcall_args))) {
Glauber de Oliveira Costa382ac6b2008-01-17 19:19:42 -0200140 kill_guest(cpu, "Fetching async hypercalls");
Rusty Russelld7e28ff2007-07-19 01:49:23 -0700141 break;
142 }
143
Rusty Russellbff672e2007-07-26 10:41:04 -0700144 /* Do the hypercall, same as a normal one. */
Glauber de Oliveira Costa73044f02008-01-07 11:05:27 -0200145 do_hcall(cpu, &args);
Rusty Russellbff672e2007-07-26 10:41:04 -0700146
147 /* Mark the hypercall done. */
Glauber de Oliveira Costa382ac6b2008-01-17 19:19:42 -0200148 if (put_user(0xFF, &cpu->lg->lguest_data->hcall_status[n])) {
149 kill_guest(cpu, "Writing result for async hypercall");
Rusty Russelld7e28ff2007-07-19 01:49:23 -0700150 break;
151 }
152
Rusty Russell15045272007-10-22 11:24:10 +1000153 /* Stop doing hypercalls if they want to notify the Launcher:
154 * it needs to service this first. */
Glauber de Oliveira Costa5e232f42008-01-07 11:05:36 -0200155 if (cpu->pending_notify)
Rusty Russelld7e28ff2007-07-19 01:49:23 -0700156 break;
157 }
158}
159
Rusty Russellbff672e2007-07-26 10:41:04 -0700160/* 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: */
Glauber de Oliveira Costa73044f02008-01-07 11:05:27 -0200162static void initialize(struct lg_cpu *cpu)
Rusty Russelld7e28ff2007-07-19 01:49:23 -0700163{
Rusty Russellbff672e2007-07-26 10:41:04 -0700164 /* You can't do anything until you're initialized. The Guest knows the
165 * rules, so we're unforgiving here. */
Glauber de Oliveira Costa73044f02008-01-07 11:05:27 -0200166 if (cpu->hcall->arg0 != LHCALL_LGUEST_INIT) {
Glauber de Oliveira Costa382ac6b2008-01-17 19:19:42 -0200167 kill_guest(cpu, "hypercall %li before INIT", cpu->hcall->arg0);
Rusty Russelld7e28ff2007-07-19 01:49:23 -0700168 return;
169 }
170
Glauber de Oliveira Costa73044f02008-01-07 11:05:27 -0200171 if (lguest_arch_init_hypercalls(cpu))
Glauber de Oliveira Costa382ac6b2008-01-17 19:19:42 -0200172 kill_guest(cpu, "bad guest page %p", cpu->lg->lguest_data);
Rusty Russell3c6b5bf2007-10-22 11:03:26 +1000173
Rusty Russellbff672e2007-07-26 10:41:04 -0700174 /* The Guest tells us where we're not to deliver interrupts by putting
175 * the range of addresses into "struct lguest_data". */
Glauber de Oliveira Costa382ac6b2008-01-17 19:19:42 -0200176 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);
Rusty Russelld7e28ff2007-07-19 01:49:23 -0700179
Rusty Russelle1e72962007-10-25 15:02:50 +1000180 /* We write the current time into the Guest's data page once so it can
181 * set its clock. */
Glauber de Oliveira Costa382ac6b2008-01-17 19:19:42 -0200182 write_timestamp(cpu);
Rusty Russell6c8dca52007-07-27 13:42:52 +1000183
Rusty Russell47436aa2007-10-22 11:03:36 +1000184 /* page_tables.c will also do some setup. */
Glauber de Oliveira Costa382ac6b2008-01-17 19:19:42 -0200185 page_table_guest_data_init(cpu);
Rusty Russell47436aa2007-10-22 11:03:36 +1000186
Rusty Russellbff672e2007-07-26 10:41:04 -0700187 /* 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
Rusty Russelle1e72962007-10-25 15:02:50 +1000189 * fault, but the old page might be (read-only) in the Guest
190 * pagetable. */
Glauber de Oliveira Costa4665ac8e2008-01-07 11:05:35 -0200191 guest_pagetable_clear_all(cpu);
Rusty Russelld7e28ff2007-07-19 01:49:23 -0700192}
Rusty Russella6bd8e12008-03-28 11:05:53 -0500193/*:*/
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. :*/
Rusty Russelld7e28ff2007-07-19 01:49:23 -0700200
Rusty Russellbff672e2007-07-26 10:41:04 -0700201/*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 */
Glauber de Oliveira Costa73044f02008-01-07 11:05:27 -0200207void do_hypercalls(struct lg_cpu *cpu)
Rusty Russelld7e28ff2007-07-19 01:49:23 -0700208{
Rusty Russellcc6d4fb2007-10-22 11:03:30 +1000209 /* Not initialized yet? This hypercall must do it. */
Glauber de Oliveira Costa73044f02008-01-07 11:05:27 -0200210 if (unlikely(!cpu->lg->lguest_data)) {
Rusty Russellcc6d4fb2007-10-22 11:03:30 +1000211 /* Set up the "struct lguest_data" */
Glauber de Oliveira Costa73044f02008-01-07 11:05:27 -0200212 initialize(cpu);
Rusty Russellcc6d4fb2007-10-22 11:03:30 +1000213 /* Hcall is done. */
Glauber de Oliveira Costa73044f02008-01-07 11:05:27 -0200214 cpu->hcall = NULL;
Rusty Russelld7e28ff2007-07-19 01:49:23 -0700215 return;
216 }
217
Rusty Russellbff672e2007-07-26 10:41:04 -0700218 /* The Guest has initialized.
219 *
220 * Look in the hypercall ring for the async hypercalls: */
Glauber de Oliveira Costa73044f02008-01-07 11:05:27 -0200221 do_async_hcalls(cpu);
Rusty Russellbff672e2007-07-26 10:41:04 -0700222
223 /* If we stopped reading the hypercall ring because the Guest did a
Rusty Russell15045272007-10-22 11:24:10 +1000224 * NOTIFY to the Launcher, we want to return now. Otherwise we do
Rusty Russellcc6d4fb2007-10-22 11:03:30 +1000225 * the hypercall. */
Glauber de Oliveira Costa5e232f42008-01-07 11:05:36 -0200226 if (!cpu->pending_notify) {
Glauber de Oliveira Costa73044f02008-01-07 11:05:27 -0200227 do_hcall(cpu, cpu->hcall);
Rusty Russellcc6d4fb2007-10-22 11:03:30 +1000228 /* 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 *
Rusty Russelle1e72962007-10-25 15:02:50 +1000234 * However, if we are signalled or the Guest sends I/O to the
Rusty Russellcc6d4fb2007-10-22 11:03:30 +1000235 * Launcher, the run_guest() loop will exit without running the
236 * Guest. When it comes back it would try to re-run the
Rusty Russella6bd8e12008-03-28 11:05:53 -0500237 * hypercall. Finding that bug sucked. */
Glauber de Oliveira Costa73044f02008-01-07 11:05:27 -0200238 cpu->hcall = NULL;
Rusty Russelld7e28ff2007-07-19 01:49:23 -0700239 }
240}
Rusty Russell6c8dca52007-07-27 13:42:52 +1000241
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. */
Glauber de Oliveira Costa382ac6b2008-01-17 19:19:42 -0200244void write_timestamp(struct lg_cpu *cpu)
Rusty Russell6c8dca52007-07-27 13:42:52 +1000245{
246 struct timespec now;
247 ktime_get_real_ts(&now);
Glauber de Oliveira Costa382ac6b2008-01-17 19:19:42 -0200248 if (copy_to_user(&cpu->lg->lguest_data->time,
249 &now, sizeof(struct timespec)))
250 kill_guest(cpu, "Writing timestamp");
Rusty Russell6c8dca52007-07-27 13:42:52 +1000251}