1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
|
#ifndef _LGUEST_H
#define _LGUEST_H
#ifndef __ASSEMBLY__
#include <linux/types.h>
#include <linux/init.h>
#include <linux/stringify.h>
#include <linux/lguest.h>
#include <linux/lguest_launcher.h>
#include <linux/wait.h>
#include <linux/hrtimer.h>
#include <linux/err.h>
#include <asm/lguest.h>
void free_pagetables(void);
int init_pagetables(struct page **switcher_page, unsigned int pages);
struct pgdir
{
unsigned long gpgdir;
pgd_t *pgdir;
};
/* We have two pages shared with guests, per cpu. */
struct lguest_pages
{
/* This is the stack page mapped rw in guest */
char spare[PAGE_SIZE - sizeof(struct lguest_regs)];
struct lguest_regs regs;
/* This is the host state & guest descriptor page, ro in guest */
struct lguest_ro_state state;
} __attribute__((aligned(PAGE_SIZE)));
#define CHANGED_IDT 1
#define CHANGED_GDT 2
#define CHANGED_GDT_TLS 4 /* Actually a subset of CHANGED_GDT */
#define CHANGED_ALL 3
struct lguest;
struct lg_cpu {
unsigned int id;
struct lguest *lg;
struct task_struct *tsk;
struct mm_struct *mm; /* == tsk->mm, but that becomes NULL on exit */
u32 cr2;
int ts;
u32 esp1;
u8 ss1;
/* Bitmap of what has changed: see CHANGED_* above. */
int changed;
unsigned long pending_notify; /* pfn from LHCALL_NOTIFY */
/* At end of a page shared mapped over lguest_pages in guest. */
unsigned long regs_page;
struct lguest_regs *regs;
struct lguest_pages *last_pages;
int cpu_pgd; /* which pgd this cpu is currently using */
/* If a hypercall was asked for, this points to the arguments. */
struct hcall_args *hcall;
u32 next_hcall;
/* Virtual clock device */
struct hrtimer hrt;
/* Do we need to stop what we're doing and return to userspace? */
int break_out;
wait_queue_head_t break_wq;
int halted;
/* Pending virtual interrupts */
DECLARE_BITMAP(irqs_pending, LGUEST_IRQS);
struct lg_cpu_arch arch;
};
/* The private info the thread maintains about the guest. */
struct lguest
{
struct lguest_data __user *lguest_data;
struct lg_cpu cpus[NR_CPUS];
unsigned int nr_cpus;
u32 pfn_limit;
/* This provides the offset to the base of guest-physical
* memory in the Launcher. */
void __user *mem_base;
unsigned long kernel_address;
struct pgdir pgdirs[4];
unsigned long noirq_start, noirq_end;
unsigned int stack_pages;
u32 tsc_khz;
/* Dead? */
const char *dead;
};
extern struct mutex lguest_lock;
/* core.c: */
bool lguest_address_ok(const struct lguest *lg,
unsigned long addr, unsigned long len);
void __lgread(struct lg_cpu *, void *, unsigned long, unsigned);
void __lgwrite(struct lg_cpu *, unsigned long, const void *, unsigned);
/*H:035 Using memory-copy operations like that is usually inconvient, so we
* have the following helper macros which read and write a specific type (often
* an unsigned long).
*
* This reads into a variable of the given type then returns that. */
#define lgread(cpu, addr, type) \
({ type _v; __lgread((cpu), &_v, (addr), sizeof(_v)); _v; })
/* This checks that the variable is of the given type, then writes it out. */
#define lgwrite(cpu, addr, type, val) \
do { \
typecheck(type, val); \
__lgwrite((cpu), (addr), &(val), sizeof(val)); \
} while(0)
/* (end of memory access helper routines) :*/
int run_guest(struct lg_cpu *cpu, unsigned long __user *user);
/* Helper macros to obtain the first 12 or the last 20 bits, this is only the
* first step in the migration to the kernel types. pte_pfn is already defined
* in the kernel. */
#define pgd_flags(x) (pgd_val(x) & ~PAGE_MASK)
#define pgd_pfn(x) (pgd_val(x) >> PAGE_SHIFT)
/* interrupts_and_traps.c: */
void maybe_do_interrupt(struct lg_cpu *cpu);
bool deliver_trap(struct lg_cpu *cpu, unsigned int num);
void load_guest_idt_entry(struct lg_cpu *cpu, unsigned int i,
u32 low, u32 hi);
void guest_set_stack(struct lg_cpu *cpu, u32 seg, u32 esp, unsigned int pages);
void pin_stack_pages(struct lg_cpu *cpu);
void setup_default_idt_entries(struct lguest_ro_state *state,
const unsigned long *def);
void copy_traps(const struct lg_cpu *cpu, struct desc_struct *idt,
const unsigned long *def);
void guest_set_clockevent(struct lg_cpu *cpu, unsigned long delta);
void init_clockdev(struct lg_cpu *cpu);
bool check_syscall_vector(struct lguest *lg);
int init_interrupts(void);
void free_interrupts(void);
/* segments.c: */
void setup_default_gdt_entries(struct lguest_ro_state *state);
void setup_guest_gdt(struct lg_cpu *cpu);
void load_guest_gdt_entry(struct lg_cpu *cpu, unsigned int i,
u32 low, u32 hi);
void guest_load_tls(struct lg_cpu *cpu, unsigned long tls_array);
void copy_gdt(const struct lg_cpu *cpu, struct desc_struct *gdt);
void copy_gdt_tls(const struct lg_cpu *cpu, struct desc_struct *gdt);
/* page_tables.c: */
int init_guest_pagetable(struct lguest *lg);
void free_guest_pagetable(struct lguest *lg);
void guest_new_pagetable(struct lg_cpu *cpu, unsigned long pgtable);
void guest_set_pmd(struct lguest *lg, unsigned long gpgdir, u32 i);
void guest_pagetable_clear_all(struct lg_cpu *cpu);
void guest_pagetable_flush_user(struct lg_cpu *cpu);
void guest_set_pte(struct lg_cpu *cpu, unsigned long gpgdir,
unsigned long vaddr, pte_t val);
void map_switcher_in_guest(struct lg_cpu *cpu, struct lguest_pages *pages);
bool demand_page(struct lg_cpu *cpu, unsigned long cr2, int errcode);
void pin_page(struct lg_cpu *cpu, unsigned long vaddr);
unsigned long guest_pa(struct lg_cpu *cpu, unsigned long vaddr);
void page_table_guest_data_init(struct lg_cpu *cpu);
/* <arch>/core.c: */
void lguest_arch_host_init(void);
void lguest_arch_host_fini(void);
void lguest_arch_run_guest(struct lg_cpu *cpu);
void lguest_arch_handle_trap(struct lg_cpu *cpu);
int lguest_arch_init_hypercalls(struct lg_cpu *cpu);
int lguest_arch_do_hcall(struct lg_cpu *cpu, struct hcall_args *args);
void lguest_arch_setup_regs(struct lg_cpu *cpu, unsigned long start);
/* <arch>/switcher.S: */
extern char start_switcher_text[], end_switcher_text[], switch_to_guest[];
/* lguest_user.c: */
int lguest_device_init(void);
void lguest_device_remove(void);
/* hypercalls.c: */
void do_hypercalls(struct lg_cpu *cpu);
void write_timestamp(struct lg_cpu *cpu);
/*L:035
* Let's step aside for the moment, to study one important routine that's used
* widely in the Host code.
*
* There are many cases where the Guest can do something invalid, like pass crap
* to a hypercall. Since only the Guest kernel can make hypercalls, it's quite
* acceptable to simply terminate the Guest and give the Launcher a nicely
* formatted reason. It's also simpler for the Guest itself, which doesn't
* need to check most hypercalls for "success"; if you're still running, it
* succeeded.
*
* Once this is called, the Guest will never run again, so most Host code can
* call this then continue as if nothing had happened. This means many
* functions don't have to explicitly return an error code, which keeps the
* code simple.
*
* It also means that this can be called more than once: only the first one is
* remembered. The only trick is that we still need to kill the Guest even if
* we can't allocate memory to store the reason. Linux has a neat way of
* packing error codes into invalid pointers, so we use that here.
*
* Like any macro which uses an "if", it is safely wrapped in a run-once "do {
* } while(0)".
*/
#define kill_guest(cpu, fmt...) \
do { \
if (!(cpu)->lg->dead) { \
(cpu)->lg->dead = kasprintf(GFP_ATOMIC, fmt); \
if (!(cpu)->lg->dead) \
(cpu)->lg->dead = ERR_PTR(-ENOMEM); \
} \
} while(0)
/* (End of aside) :*/
#endif /* __ASSEMBLY__ */
#endif /* _LGUEST_H */
|
