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