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d7e28ffe RR |
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 | ||
26 | static 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. */ | |
96 | static 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, ®s); | |
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 | ||
133 | static 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. */ | |
172 | static void clear_hcall(struct lguest *lg) | |
173 | { | |
174 | lg->regs->trapnum = 255; | |
175 | } | |
176 | ||
177 | void 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 | } |