Line data Source code
1 : #ifndef HEADER_fd_src_flamenco_vm_fd_vm_h
2 : #define HEADER_fd_src_flamenco_vm_fd_vm_h
3 :
4 : #include "fd_vm_base.h"
5 : #include "../../ballet/sha256/fd_sha256.h"
6 :
7 : /* A fd_vm_t is an opaque handle of a virtual machine that can execute
8 : sBPF programs. */
9 :
10 : struct fd_vm;
11 : typedef struct fd_vm fd_vm_t;
12 :
13 : /**********************************************************************/
14 : /* FIXME: MOVE TO FD_VM_PRIVATE WHEN CONSTRUCTORS READY */
15 :
16 : /* A fd_vm_shadow_t holds stack frame information not accessible from
17 : within a program. */
18 :
19 : struct fd_vm_shadow { ulong r6; ulong r7; ulong r8; ulong r9; ulong r10; ulong pc; };
20 : typedef struct fd_vm_shadow fd_vm_shadow_t;
21 :
22 : /* fd_vm_input_region_t holds information about fragmented memory regions
23 : within the larger input region. */
24 :
25 : struct __attribute__((aligned(8UL))) fd_vm_input_region {
26 : ulong vaddr_offset; /* Represents offset from the start of the input region. */
27 : ulong haddr; /* Host address corresponding to the start of the mem region. */
28 : uint region_sz; /* Size of the memory region. */
29 : ulong address_space_reserved; /* The amount of address space reserved for the region. */
30 : uchar is_writable; /* If the region can be written to or is read-only */
31 : ulong acc_region_meta_idx; /* Index of the acc_region_meta_t struct for the account corresponding to this region. */
32 : };
33 : typedef struct fd_vm_input_region fd_vm_input_region_t;
34 :
35 : /* fd_vm_acc_region_meta_t holds metadata about a given account. An array of these
36 : structs will map an instruction account index to its respective input memory
37 : region location. */
38 :
39 : struct __attribute((aligned(8UL))) fd_vm_acc_region_meta {
40 : uint region_idx;
41 : /* FIXME: We can get rid of this field once DM is activated. This is
42 : only a hack to make the non-DM code path happy. When DM is
43 : activated, we could query the input_mem_region array for the
44 : original data len. */
45 : ulong original_data_len;
46 : /* The transaction account corresponding to this account. */
47 : fd_txn_account_t * acct;
48 : /* The expected virtual offsets of the serialized pubkey, lamports and owner
49 : for the account corresponding to this region. Relative to the start of the
50 : account's input region vaddr.
51 : Used for CPI security checks. */
52 : uint expected_pubkey_offset;
53 : uint expected_lamports_offset;
54 : uint expected_owner_offset;
55 : };
56 : typedef struct fd_vm_acc_region_meta fd_vm_acc_region_meta_t;
57 :
58 : /* In Agave, all the regions are 16-byte aligned in host address space. There is then an alignment check
59 : which is done inside each syscall memory translation, checking if the data is aligned in host address
60 : space. This is a layering violation, as it leaks the host address layout into the consensus model.
61 :
62 : In the future we will change this alignment check in the vm to purely operate on the virtual address space,
63 : taking advantage of the fact that Agave regions are known to be aligned. For now, we align our regions to
64 : either 8 or 16 bytes, as there are no 16-byte alignment translations in the syscalls currently:
65 : stack: 16 byte aligned
66 : heap: 16 byte aligned
67 : input: 8 byte aligned
68 : rodata: 8 byte aligned
69 :
70 : https://github.com/solana-labs/rbpf/blob/cd19a25c17ec474e6fa01a3cc3efa325f44cd111/src/ebpf.rs#L39-L40 */
71 483 : #define FD_VM_HOST_REGION_ALIGN (16UL)
72 :
73 : struct __attribute__((aligned(FD_VM_HOST_REGION_ALIGN))) fd_vm {
74 :
75 : /* VM configuration */
76 :
77 : /* FIXME: suspect these three should be replaced by some kind of VM
78 : enabled feature struct (though syscalls do seem to make additional
79 : non-trivial use of instr_ctx). */
80 :
81 : fd_exec_instr_ctx_t * instr_ctx; /* FIXME: DOCUMENT */
82 :
83 : /* FIXME: frame_max should be run time configurable by compute budget.
84 : If there is no reasonable upper bound on this, shadow and stack
85 : will need to be provided by users. */
86 :
87 : //ulong frame_max; /* Maximum number of stack frames, in [0,FD_VM_STACK_FRAME_MAX] */
88 : ulong heap_max; /* Maximum amount of heap in bytes, in [0,FD_VM_HEAP_MAX] */
89 : ulong entry_cu; /* Initial number of compute units for this program, in [0,FD_VM_COMPUTE_UNIT_LIMIT] */
90 :
91 : /* FIXME: The below are practically an exact match to the
92 : fields of an fd_sbpf_program_t (sans ELF info) */
93 :
94 : uchar const * rodata; /* Program read only data, indexed [0,rodata_sz), aligned 8 */
95 : ulong rodata_sz; /* Program read only data size in bytes, FIXME: BOUNDS? */
96 : ulong const * text; /* Program sBPF words, indexed [0,text_cnt), aligned 8 */
97 : ulong text_cnt; /* Program sBPF word count, all text words are inside the rodata */
98 : ulong text_off; /* ==(ulong)text - (ulong)rodata, relocation offset in bytes we must apply to indirect calls
99 : (callx/CALL_REGs), IMPORTANT SAFETY TIP! THIS IS IN BYTES, NOT WORDS! */
100 : ulong text_sz; /* Program sBPF size in bytes, == text_cnt*8 */
101 :
102 : ulong entry_pc; /* Initial program counter, in [0,text_cnt)
103 : FIXME: MAKE SURE NOT INTO MW INSTRUCTION, MAKE SURE VALID CALLDEST? */
104 : ulong const * calldests; /* Bit vector of local functions that can be called into, bit indexed in [0,text_cnt) */
105 : /* FIXME: ADD BIT VECTOR OF FORBIDDEN BRANCH TARGETS (E.G.
106 : INTO THE MIDDLE OF A MULTIWORD INSTRUCTION) */
107 :
108 : fd_sbpf_syscalls_t const * syscalls; /* The map of syscalls (sharable over multiple concurrently running vm) */
109 :
110 : fd_vm_trace_t * trace; /* Location to stream traces (no tracing if NULL) */
111 :
112 : /* VM execution and syscall state */
113 :
114 : /* These are used to communicate the execution and syscall state to
115 : users and syscalls. These are initialized based on the above when
116 : a program starts executing. When program halts or faults, these
117 : provide precise execution diagnostics to the user (and potential
118 : breakpoint/continue functionality in the future). When the vm
119 : makes a syscall, the vm will set these precisely and, when a
120 : syscall returns, the vm will update its internal execution state
121 : appropriately. */
122 :
123 : /* IMPORTANT SAFETY TIP! THE BEHAVIOR OF THE SYSCALL ALLOCATOR FOR
124 : HEAP_SZ MUST EXACTLY MATCH THE SOLANA VALIDATOR ALLOCATOR:
125 :
126 : https://github.com/solana-labs/solana/blob/v1.17.23/program-runtime/src/invoke_context.rs#L122-L148
127 :
128 : BIT-FOR-BIT AND BUG-FOR-BUG. SEE THE SYSCALL_ALLOC_FREE FOR MORE
129 : DETAILS. */
130 :
131 : ulong pc; /* The current instruction, in [0,text_cnt) in normal execution, may be out of bounds in a fault */
132 : ulong ic; /* The number of instructions which have been executed */
133 : ulong cu; /* The remaining CUs left for the transaction, positive in normal execution, may be zero in a fault */
134 : ulong frame_cnt; /* The current number of stack frames pushed, in [0,frame_max] */
135 :
136 : ulong heap_sz; /* Heap size in bytes, in [0,heap_max] */
137 :
138 : /* VM memory */
139 :
140 : /* The vm classifies the 64-bit vm address space into 6 regions:
141 :
142 : 0 - unmapped lo
143 : 1 - program -> [FD_VM_MEM_MAP_PROGRAM_REGION_START,FD_VM_MEM_MAP_PROGRAM_REGION_START+4GiB)
144 : 2 - stack -> [FD_VM_MEM_MAP_STACK_REGION_START, FD_VM_MEM_MAP_STACK_REGION_START +4GiB)
145 : 3 - heap -> [FD_VM_MEM_MAP_HEAP_REGION_START, FD_VM_MEM_MAP_HEAP_REGION_START +4GiB)
146 : 4 - input -> [FD_VM_MEM_MAP_INPUT_REGION_START, FD_VM_MEM_MAP_INPUT_REGION_START +4GiB)
147 : 5 - unmapped hi
148 :
149 : These mappings are encoded in a software TLB consisting of three
150 : 6-element arrays: region_haddr, region_ld_sz and region_st_sz.
151 :
152 : region_haddr[i] gives the location in host address space of the
153 : first byte in region i. region_{ld,st}_sz[i] gives the number of
154 : mappable bytes in this region for {loads,stores}. Note that
155 : region_{ld,st}_sz[i]<2^32. Further note that
156 : [region_haddr[i],region_haddr[i]+region_{ld,st}_sz[i]) does not
157 : wrap around in host address space and does not overlap with any
158 : other usages.
159 :
160 : region_{ld,st}_sz[0] and region_{ld,st}_sz[5] are zero such that
161 : requests to access data from a positive sz range in these regions
162 : will fail, making regions 0 and 5 unreadable and unwritable. As
163 : such, region_haddr[0] and region_haddr[5] are arbitrary; NULL is
164 : used as the obvious default.
165 :
166 : region_st_sz[1] is also zero such that requests to store data to
167 : any positive sz range in this region will fail, making region 1
168 : unwritable.
169 :
170 : When the direct mapping feature is enabled, the input region will
171 : no longer be a contigious buffer of host memory. Instead
172 : it will compose of several fragmented regions of memory each with
173 : its own read/write privleges and size. Address translation to the
174 : input region will now have to rely on a binary search lookup of the
175 : start of the appropriate area of physical memory. It also involves
176 : doing a check against if the region can be written to. */
177 :
178 : /* FIXME: If accessing memory beyond the end of the current heap
179 : region is not allowed, sol_alloc_free will need to update the tlb
180 : arrays during program execution (this is trivial). At the same
181 : time, given sol_alloc_free is deprecated, this is unlikely to be
182 : the case. */
183 :
184 : ulong region_haddr[6];
185 : uint region_ld_sz[6];
186 : uint region_st_sz[6];
187 :
188 : /* fd_vm_input_region_t and fd_vm_acc_to_mem arrays are passed in by the bpf
189 : loaders into fd_vm_init.
190 : TODO: It might make more sense to allocate space for these in the VM. */
191 : fd_vm_input_region_t * input_mem_regions; /* An array of input mem regions represent the input region.
192 : The virtual addresses of each region are contigiuous and
193 : strictly increasing. */
194 : uint input_mem_regions_cnt;
195 : fd_vm_acc_region_meta_t * acc_region_metas; /* Represents a mapping from the instruction account indicies
196 : from the instruction context to the input memory region index
197 : of the account's data region in the input space. */
198 : uchar is_deprecated; /* The vm requires additional checks in certain CPIs if the
199 : vm's current instance was initialized by a deprecated program. */
200 :
201 : ulong reg [ FD_VM_REG_MAX ]; /* registers, indexed [0,FD_VM_REG_CNT). Note that FD_VM_REG_MAX>FD_VM_REG_CNT.
202 : As such, malformed instructions, which can have src/dst reg index in
203 : [0,FD_VM_REG_MAX), cannot access info outside reg. Aligned 8. */
204 : fd_vm_shadow_t shadow[ FD_VM_STACK_FRAME_MAX ]; /* shadow stack, indexed [0,frame_cnt), if frame_cnt>0, 0/frame_cnt-1 is
205 : bottom/top. Aligned 16. */
206 : uchar stack [ FD_VM_STACK_MAX ]; /* stack, indexed [0,FD_VM_STACK_MAX). Divided into FD_VM_STACK_FRAME_MAX
207 : frames. Each frame has a FD_VM_STACK_GUARD_SZ region followed by a
208 : FD_VM_STACK_FRAME_SZ region. reg[10] gives the offset of the start of the
209 : current stack frame. Aligned 16. */
210 : uchar heap [ FD_VM_HEAP_MAX ]; /* syscall heap, [0,heap_sz) used, [heap_sz,heap_max) free. Aligned 8. */
211 :
212 : fd_sha256_t * sha; /* Pre-joined SHA instance. This should be re-initialised before every use. */
213 :
214 : ulong magic; /* ==FD_VM_MAGIC */
215 :
216 : int direct_mapping; /* If direct mapping feature flag is enabled */
217 : int stricter_abi_and_runtime_constraints; /* If stricter_abi_and_runtime_constraints feature flag is enabled */
218 :
219 : /* Agave uses the segv vaddr in several different cases, including:
220 : - Determining whether or not to return a regular or stack access violation
221 : - (If direct mapping is enabled) determining the instruction error
222 : code to return on store operations. */
223 : ulong segv_vaddr;
224 : ulong segv_access_len;
225 : uchar segv_access_type;
226 :
227 : ulong sbpf_version; /* SBPF version, SIMD-0161 */
228 :
229 : int dump_syscall_to_pb; /* If true, syscalls will be dumped to the specified output directory */
230 : };
231 :
232 : /* FIXME: MOVE ABOVE INTO PRIVATE WHEN CONSTRUCTORS READY */
233 : /**********************************************************************/
234 :
235 : FD_PROTOTYPES_BEGIN
236 :
237 : /* FIXME: FD_VM_T NEEDS PROPER CONSTRUCTORS */
238 :
239 : /* FD_VM_{ALIGN,FOOTPRINT} describe the alignment and footprint needed
240 : for a memory region to hold a fd_vm_t. ALIGN is a positive
241 : integer power of 2. FOOTPRINT is a multiple of align.
242 : These are provided to facilitate compile time declarations. */
243 483 : #define FD_VM_ALIGN FD_VM_HOST_REGION_ALIGN
244 237 : #define FD_VM_FOOTPRINT (527824UL)
245 :
246 : /* fd_vm_{align,footprint} give the needed alignment and footprint
247 : of a memory region suitable to hold an fd_vm_t.
248 : Declaration / aligned_alloc / fd_alloca friendly (e.g. a memory
249 : region declared as "fd_vm_t _vm[1];", or created by
250 : "aligned_alloc(alignof(fd_vm_t),sizeof(fd_vm_t))" or created
251 : by "fd_alloca(alignof(fd_vm_t),sizeof(fd_vm_t))" will all
252 : automatically have the needed alignment and footprint).
253 : fd_vm_{align,footprint} return the same value as
254 : FD_VM_{ALIGN,FOOTPRINT}. */
255 : FD_FN_CONST ulong
256 : fd_vm_align( void );
257 :
258 : FD_FN_CONST ulong
259 : fd_vm_footprint( void );
260 :
261 237 : #define FD_VM_MAGIC (0xF17EDA2CEF0) /* FIREDANCE SBPF V0 */
262 :
263 : /* fd_vm_new formats memory region with suitable alignment and
264 : footprint suitable for holding a fd_vm_t. Assumes
265 : shmem points on the caller to the first byte of the memory region
266 : owned by the caller to use. Returns shmem on success and NULL on
267 : failure (logs details). The memory region will be owned by the state
268 : on successful return. The caller is not joined on return. */
269 :
270 : void *
271 : fd_vm_new( void * shmem );
272 :
273 : /* fd_vm_join joins the caller to a vm.
274 : Assumes shmem points to the first byte of the memory region holding
275 : the vm. Returns a local handle to the join on success (this is
276 : not necessarily a simple cast of the address) and NULL on failure
277 : (logs details). */
278 : fd_vm_t *
279 : fd_vm_join( void * shmem );
280 :
281 : /* fd_vm_init initializes the given fd_vm_t struct, checking that it is
282 : not null and has the correct magic value.
283 :
284 : It modifies the vm object and also returns the object for convenience.
285 :
286 : FIXME: we should split out the memory mapping setup from this function
287 : to handle those errors separately. */
288 : fd_vm_t *
289 : fd_vm_init(
290 : fd_vm_t * vm,
291 : fd_exec_instr_ctx_t *instr_ctx,
292 : ulong heap_max,
293 : ulong entry_cu,
294 : uchar const * rodata,
295 : ulong rodata_sz,
296 : ulong const * text,
297 : ulong text_cnt,
298 : ulong text_off,
299 : ulong text_sz,
300 : ulong entry_pc,
301 : ulong const * calldests,
302 : ulong sbpf_version,
303 : fd_sbpf_syscalls_t * syscalls,
304 : fd_vm_trace_t * trace,
305 : fd_sha256_t * sha,
306 : fd_vm_input_region_t * mem_regions,
307 : uint mem_regions_cnt,
308 : fd_vm_acc_region_meta_t * acc_region_metas,
309 : uchar is_deprecated,
310 : int direct_mapping,
311 : int stricter_abi_and_runtime_constraints,
312 : int dump_syscall_to_pb );
313 :
314 : /* fd_vm_leave leaves the caller's current local join to a vm.
315 : Returns a pointer to the memory region holding the vm on success
316 : (this is not necessarily a simple cast of the
317 : address) and NULL on failure (logs details). The caller is not
318 : joined on successful return. */
319 : void *
320 : fd_vm_leave( fd_vm_t * vm );
321 :
322 : /* fd_vm_delete unformats a memory region that holds a vm.
323 : Assumes shmem points on the caller to the first
324 : byte of the memory region holding the state and that nobody is
325 : joined. Returns a pointer to the memory region on success and NULL
326 : on failure (logs details). The caller has ownership of the memory
327 : region on successful return. */
328 : void *
329 : fd_vm_delete( void * shmem );
330 :
331 : /* fd_vm_validate validates the sBPF program in the given vm. Returns
332 : success or an error code. Called before executing a sBPF program.
333 : FIXME: DOCUMENT BETTER */
334 :
335 : FD_FN_PURE int
336 : fd_vm_validate( fd_vm_t const * vm );
337 :
338 : /* fd_vm_is_check_align_enabled returns 1 if the vm should check alignment
339 : when doing memory translation. */
340 : FD_FN_PURE static inline int
341 309 : fd_vm_is_check_align_enabled( fd_vm_t const * vm ) {
342 309 : return !vm->is_deprecated;
343 309 : }
344 :
345 : /* fd_vm_is_check_size_enabled returns 1 if the vm should check size
346 : when doing memory translation. */
347 : FD_FN_PURE static inline int
348 0 : fd_vm_is_check_size_enabled( fd_vm_t const * vm ) {
349 0 : return !vm->is_deprecated;
350 0 : }
351 :
352 : /* FIXME: make this trace-aware, and move into fd_vm_init
353 : This is a temporary hack to make the fuzz harness work. */
354 : int
355 : fd_vm_setup_state_for_execution( fd_vm_t * vm ) ;
356 :
357 : /* fd_vm_exec runs vm from program start to program halt or program
358 : fault, appending an execution trace if vm is attached to a trace.
359 :
360 : Since this is running from program start, this will init r1 and r10,
361 : pop all stack frames and free all heap allocations.
362 :
363 : IMPORTANT SAFETY TIP! This currently does not zero out any other
364 : registers, the user stack region or the user heap. (FIXME: SHOULD
365 : IT??)
366 :
367 : Returns FD_VM_SUCCESS (0) on success and an FD_VM_ERR code (negative)
368 : on failure. Reasons for failure include:
369 :
370 : INVAL - NULL vm (or, for fd_vm_exec_trace, the vm is not
371 : attached to trace). FIXME: ADD OTHER INPUT ARG CHECKS?
372 :
373 : SIGTEXT - A jump/call set the program counter outside the text
374 : region or the program counter incremented beyond the
375 : text region. pc will be at the out of bounds location.
376 : ic and cu will not include the out of bounds location.
377 : For a call, the call stack frame was allocated.
378 :
379 : SIGSPLIT - A jump/call set the program counter into the middle of
380 : a multiword instruction or a multiword instruction went
381 : past the text region end. pc will be at the split. ic
382 : and cu will not include the split. For a call, the
383 : call stack frame was allocated.
384 :
385 : SIGCALL - A call set the program counter to a non-function
386 : location. pc will be at the non-function location. ic
387 : and cu will include the call but not include the
388 : non-function location. The call stack frame was
389 : allocated.
390 :
391 : SIGSTACK - The call depth limit was exceeded. pc will be at the
392 : call. ic and cu will include the call but not the call
393 : target. The call stack frame was not allocated.
394 :
395 : SIGILL - An invalid instruction was encountered (including an
396 : invalid opcode and an endian swap with an invalid bit
397 : width). pc will be at the invalid instruction. ic and
398 : cu will not include the invalid instruction.
399 :
400 : SIGSEGV - An invalid memory access (outside the program memory
401 : map) was encountered. pc will be at the faulting
402 : instruction. ic and cu will not include the faulting
403 : instruction.
404 :
405 : SIGBUS - An unaligned memory access was encountered. pc will be
406 : at the faulting instruction. ic and cu will not
407 : include the faulting instruction. (Note: currently
408 : mapped to SIGSEGV and then only if check_align is
409 : enabled.)
410 :
411 : SIGRDONLY - A write to read-only memory address was encountered.
412 : pc will be at the faulting instruction. ic and cu will
413 : not include the faulting instruction. (Note: currently
414 : mapped to SIGSEGV.)
415 :
416 : SIGCOST - The compute limit was exceeded. pc will be at the
417 : first non-executed instruction (if pc is a syscall, the
418 : syscall might have been partially executed when it ran
419 : out of budget .. see safety tip below). ic will cover
420 : all executed instructions. cu will be zero.
421 :
422 : This will considers any error returned by a syscall as a fault and
423 : returns the syscall error code here. See syscall documentation for
424 : details here. When a syscall faults, pc will be at the syscall, ic
425 : will include the syscall and cu will include the syscall and any
426 : additional costs the syscall might have incurred up to that point of
427 : the fault.
428 :
429 : IMPORTANT SAFETY TIP! Ideally, a syscall should only modify vm's
430 : state when it knows its overall syscall will be successful.
431 : Unfortunately, this is often not practical (e.g. a syscall starts
432 : processing a list of user provided commands and discovers an error
433 : condition late in the command list that did not exist at syscall
434 : start because the error condition was created by successfully
435 : executed commands earlier in the list). As such, vm's state on a
436 : faulting syscall may not be clean.
437 :
438 : FIXME: SINCE MOST SYSCALLS CAN BE IMPLEMENTED TO HAVE CLEAN FAULTING
439 : BEHAVIOR, PROVIDE A MECHANISM SO USERS CAN EASILY DETECT UNCLEAN
440 : SYSCALL FAULTS?
441 :
442 : For SIGCOST, note that the vm can speculate ahead when processing
443 : instructions. This makes it is possible to have a situation where
444 : a vm faults with, for example, SIGSEGV from a speculatively
445 : executed memory access while a non-speculative execution would have
446 : faulted with SIGCOST on an earlier instruction. In these situations,
447 : pc will be at the faulting speculatively executed instruction, ic
448 : will include all the speculatively executed instructions, cu will be
449 : zero and vm's state will include the impact of all the speculation.
450 :
451 : IMPORTANT SAFETY TIP! While different vm implementations can
452 : disagree on why a program faulted (e.g. SIGCOST versus SIGSEGV in the
453 : example above), they cannot disagree on whether or not a program
454 : faulted. As a result, the specific fault reason must never be
455 : allowed to be part of consensus.
456 :
457 : fd_vm_exec_trace runs with tracing and requires vm to be attached to
458 : a trace. fd_vm_exec_notrace runs without without tracing even if vm
459 : is attached to a trace. */
460 :
461 : int
462 : fd_vm_exec_trace( fd_vm_t * vm );
463 :
464 : int
465 : fd_vm_exec_notrace( fd_vm_t * vm );
466 :
467 : static inline int
468 186 : fd_vm_exec( fd_vm_t * vm ) {
469 186 : if( FD_UNLIKELY( vm->trace ) ) return fd_vm_exec_trace ( vm );
470 186 : else return fd_vm_exec_notrace( vm );
471 186 : }
472 :
473 : FD_PROTOTYPES_END
474 :
475 : #endif /* HEADER_fd_src_flamenco_vm_fd_vm_h */
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