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authorRusty Russell <rusty@rustcorp.com.au>2007-07-19 04:49:23 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-19 13:04:52 -0400
commitd7e28ffe6c74416b54345d6004fd0964c115b12c (patch)
tree844beb4f400d5400098538e0c1e5f12d20a9504a /drivers/lguest/hypercalls.c
parent07ad157f6e5d228be78acd5cea0291e5d0360398 (diff)
lguest: the host code
This is the code for the "lg.ko" module, which allows lguest guests to be launched. [akpm@linux-foundation.org: update for futex-new-private-futexes] [akpm@linux-foundation.org: build fix] [jmorris@namei.org: lguest: use hrtimers] [akpm@linux-foundation.org: x86_64 build fix] Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Andi Kleen <ak@suse.de> Cc: Eric Dumazet <dada1@cosmosbay.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/lguest/hypercalls.c')
-rw-r--r--drivers/lguest/hypercalls.c192
1 files changed, 192 insertions, 0 deletions
diff --git a/drivers/lguest/hypercalls.c b/drivers/lguest/hypercalls.c
new file mode 100644
index 000000000000..ea52ca451f74
--- /dev/null
+++ b/drivers/lguest/hypercalls.c
@@ -0,0 +1,192 @@
1/* Actual hypercalls, which allow guests to actually do something.
2 Copyright (C) 2006 Rusty Russell IBM Corporation
3
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
17*/
18#include <linux/uaccess.h>
19#include <linux/syscalls.h>
20#include <linux/mm.h>
21#include <asm/page.h>
22#include <asm/pgtable.h>
23#include <irq_vectors.h>
24#include "lg.h"
25
26static void do_hcall(struct lguest *lg, struct lguest_regs *regs)
27{
28 switch (regs->eax) {
29 case LHCALL_FLUSH_ASYNC:
30 break;
31 case LHCALL_LGUEST_INIT:
32 kill_guest(lg, "already have lguest_data");
33 break;
34 case LHCALL_CRASH: {
35 char msg[128];
36 lgread(lg, msg, regs->edx, sizeof(msg));
37 msg[sizeof(msg)-1] = '\0';
38 kill_guest(lg, "CRASH: %s", msg);
39 break;
40 }
41 case LHCALL_FLUSH_TLB:
42 if (regs->edx)
43 guest_pagetable_clear_all(lg);
44 else
45 guest_pagetable_flush_user(lg);
46 break;
47 case LHCALL_GET_WALLCLOCK: {
48 struct timespec ts;
49 ktime_get_real_ts(&ts);
50 regs->eax = ts.tv_sec;
51 break;
52 }
53 case LHCALL_BIND_DMA:
54 regs->eax = bind_dma(lg, regs->edx, regs->ebx,
55 regs->ecx >> 8, regs->ecx & 0xFF);
56 break;
57 case LHCALL_SEND_DMA:
58 send_dma(lg, regs->edx, regs->ebx);
59 break;
60 case LHCALL_LOAD_GDT:
61 load_guest_gdt(lg, regs->edx, regs->ebx);
62 break;
63 case LHCALL_LOAD_IDT_ENTRY:
64 load_guest_idt_entry(lg, regs->edx, regs->ebx, regs->ecx);
65 break;
66 case LHCALL_NEW_PGTABLE:
67 guest_new_pagetable(lg, regs->edx);
68 break;
69 case LHCALL_SET_STACK:
70 guest_set_stack(lg, regs->edx, regs->ebx, regs->ecx);
71 break;
72 case LHCALL_SET_PTE:
73 guest_set_pte(lg, regs->edx, regs->ebx, mkgpte(regs->ecx));
74 break;
75 case LHCALL_SET_PMD:
76 guest_set_pmd(lg, regs->edx, regs->ebx);
77 break;
78 case LHCALL_LOAD_TLS:
79 guest_load_tls(lg, regs->edx);
80 break;
81 case LHCALL_SET_CLOCKEVENT:
82 guest_set_clockevent(lg, regs->edx);
83 break;
84 case LHCALL_TS:
85 lg->ts = regs->edx;
86 break;
87 case LHCALL_HALT:
88 lg->halted = 1;
89 break;
90 default:
91 kill_guest(lg, "Bad hypercall %li\n", regs->eax);
92 }
93}
94
95/* We always do queued calls before actual hypercall. */
96static void do_async_hcalls(struct lguest *lg)
97{
98 unsigned int i;
99 u8 st[LHCALL_RING_SIZE];
100
101 if (copy_from_user(&st, &lg->lguest_data->hcall_status, sizeof(st)))
102 return;
103
104 for (i = 0; i < ARRAY_SIZE(st); i++) {
105 struct lguest_regs regs;
106 unsigned int n = lg->next_hcall;
107
108 if (st[n] == 0xFF)
109 break;
110
111 if (++lg->next_hcall == LHCALL_RING_SIZE)
112 lg->next_hcall = 0;
113
114 if (get_user(regs.eax, &lg->lguest_data->hcalls[n].eax)
115 || get_user(regs.edx, &lg->lguest_data->hcalls[n].edx)
116 || get_user(regs.ecx, &lg->lguest_data->hcalls[n].ecx)
117 || get_user(regs.ebx, &lg->lguest_data->hcalls[n].ebx)) {
118 kill_guest(lg, "Fetching async hypercalls");
119 break;
120 }
121
122 do_hcall(lg, &regs);
123 if (put_user(0xFF, &lg->lguest_data->hcall_status[n])) {
124 kill_guest(lg, "Writing result for async hypercall");
125 break;
126 }
127
128 if (lg->dma_is_pending)
129 break;
130 }
131}
132
133static void initialize(struct lguest *lg)
134{
135 u32 tsc_speed;
136
137 if (lg->regs->eax != LHCALL_LGUEST_INIT) {
138 kill_guest(lg, "hypercall %li before LGUEST_INIT",
139 lg->regs->eax);
140 return;
141 }
142
143 /* We only tell the guest to use the TSC if it's reliable. */
144 if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC) && !check_tsc_unstable())
145 tsc_speed = tsc_khz;
146 else
147 tsc_speed = 0;
148
149 lg->lguest_data = (struct lguest_data __user *)lg->regs->edx;
150 /* We check here so we can simply copy_to_user/from_user */
151 if (!lguest_address_ok(lg, lg->regs->edx, sizeof(*lg->lguest_data))) {
152 kill_guest(lg, "bad guest page %p", lg->lguest_data);
153 return;
154 }
155 if (get_user(lg->noirq_start, &lg->lguest_data->noirq_start)
156 || get_user(lg->noirq_end, &lg->lguest_data->noirq_end)
157 /* We reserve the top pgd entry. */
158 || put_user(4U*1024*1024, &lg->lguest_data->reserve_mem)
159 || put_user(tsc_speed, &lg->lguest_data->tsc_khz)
160 || put_user(lg->guestid, &lg->lguest_data->guestid))
161 kill_guest(lg, "bad guest page %p", lg->lguest_data);
162
163 /* This is the one case where the above accesses might have
164 * been the first write to a Guest page. This may have caused
165 * a copy-on-write fault, but the Guest might be referring to
166 * the old (read-only) page. */
167 guest_pagetable_clear_all(lg);
168}
169
170/* Even if we go out to userspace and come back, we don't want to do
171 * the hypercall again. */
172static void clear_hcall(struct lguest *lg)
173{
174 lg->regs->trapnum = 255;
175}
176
177void do_hypercalls(struct lguest *lg)
178{
179 if (unlikely(!lg->lguest_data)) {
180 if (lg->regs->trapnum == LGUEST_TRAP_ENTRY) {
181 initialize(lg);
182 clear_hcall(lg);
183 }
184 return;
185 }
186
187 do_async_hcalls(lg);
188 if (!lg->dma_is_pending && lg->regs->trapnum == LGUEST_TRAP_ENTRY) {
189 do_hcall(lg, lg->regs);
190 clear_hcall(lg);
191 }
192}