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bbssd: add deleted-data-remanence experiment logging #190

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5 changes: 4 additions & 1 deletion femu-scripts/run-blackbox.sh
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Original file line number Diff line number Diff line change
Expand Up @@ -59,7 +59,10 @@ if [[ ! -e "$OSIMGF" ]]; then
exit
fi

sudo ./qemu-system-x86_64 \
sudo FEMU_EXP_LOG=${FEMU_EXP_LOG} \
FEMU_SECRET=${FEMU_SECRET} \
FEMU_DUMP_LPN=${FEMU_DUMP_LPN} \
./qemu-system-x86_64 \
-name "FEMU-BBSSD-VM" \
-enable-kvm \
-cpu host \
Expand Down
158 changes: 157 additions & 1 deletion hw/femu/bbssd/ftl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -539,6 +539,132 @@ static inline bool mapped_ppa(struct ppa *ppa)
return !(ppa->ppa == UNMAPPED_PPA);
}

/* ===== 데이터 잔존성 실험용 debug 헬퍼 (FTL 동작 변경 없음) ===== */
/* stderr 사용: tee 파이프에서도 무버퍼라 즉시 출력됨 */
#define EXP_LOG(fmt, ...) do { \
if (getenv("FEMU_EXP_LOG")) \
fprintf(stderr, "[EXP] " fmt, ## __VA_ARGS__); \
} while (0)

#define PPA_FMT "ch=%u lun=%u pl=%u blk=%u pg=%u"
#define PPA_ARG(p) (unsigned)(p)->g.ch, (unsigned)(p)->g.lun, \
(unsigned)(p)->g.pl, (unsigned)(p)->g.blk, (unsigned)(p)->g.pg

/* backend(DRAM)에서 한 LPN의 실제 바이트를 hex+ascii로 덤프.
* 주의: 데이터는 PPA가 아니라 LBA(=lpn*page_bytes) 위치에 있다. */
static void femu_dbg_dump_lpn(struct ssd *ssd, uint64_t lpn)
{
struct ssdparams *spp = &ssd->sp;
uint64_t page_bytes = (uint64_t)spp->secs_per_pg * spp->secsz; /* 4096 */
uint64_t off = lpn * page_bytes;
struct ppa ppa = get_maptbl_ent(ssd, lpn);
uint8_t *base;

if (!ssd->n || !ssd->n->mbe || !ssd->n->mbe->logical_space) {
fprintf(stderr, "[DUMP] backend not ready\n");
return;
}
if (off + page_bytes > (uint64_t)ssd->n->mbe->size) {
fprintf(stderr, "[DUMP] lpn=%lu out of range\n", lpn);
return;
}
base = (uint8_t *)ssd->n->mbe->logical_space + off;

fprintf(stderr, "[DUMP] lpn=%lu off=0x%lx mapped=%d", lpn, off,
mapped_ppa(&ppa));
if (mapped_ppa(&ppa))
fprintf(stderr, " " PPA_FMT, PPA_ARG(&ppa));
fprintf(stderr, "\n");
for (uint64_t i = 0; i < page_bytes; i += 16) {
fprintf(stderr, " %08lx ", off + i);
for (int j = 0; j < 16; j++)
fprintf(stderr, "%02x ", base[i + j]);
fprintf(stderr, " |");
for (int j = 0; j < 16; j++) {
uint8_t c = base[i + j];
fprintf(stderr, "%c", (c >= 0x20 && c < 0x7f) ? c : '.');
}
fprintf(stderr, "|\n");
}
}

/* backend 전체에서 FEMU_SECRET 문자열을 찾아 어느 LPN에 남아있는지 출력 */
static void femu_dbg_scan_secret(struct ssd *ssd, const char *tag)
{
const char *sec = getenv("FEMU_SECRET");
struct ssdparams *spp = &ssd->sp;
uint64_t page_bytes, size;
uint8_t *buf;
size_t slen;
int hits = 0;

if (!sec || !ssd->n || !ssd->n->mbe || !ssd->n->mbe->logical_space)
return;

page_bytes = (uint64_t)spp->secs_per_pg * spp->secsz;
buf = (uint8_t *)ssd->n->mbe->logical_space;
size = (uint64_t)ssd->n->mbe->size;
slen = strlen(sec);

for (uint64_t i = 0; i + slen <= size; i++) {
if (buf[i] == (uint8_t)sec[0] && memcmp(buf + i, sec, slen) == 0) {
fprintf(stderr, "[SCAN:%s] FOUND '%s' at off=0x%lx lpn=%lu\n",
tag, sec, i, i / page_bytes);
hits++;
i += slen - 1;
}
}
if (!hits)
fprintf(stderr, "[SCAN:%s] '%s' NOT present in backend\n", tag, sec);
}

/* ---- 비밀 문자열을 담은 LPN/블록만 추적해 로그 노이즈 제거 ---- */
#define EXP_MAX_WATCH 256
static uint64_t exp_watch_lpn[EXP_MAX_WATCH];
static int exp_watch_lpn_cnt = 0;
static uint8_t exp_watch_blk[1 << BLK_BITS]; /* blk(line) id -> watched? */

static bool exp_lpn_watched(uint64_t lpn)
{
for (int i = 0; i < exp_watch_lpn_cnt; i++)
if (exp_watch_lpn[i] == lpn)
return true;
return false;
}

static void exp_watch_lpn_add(uint64_t lpn)
{
if (exp_lpn_watched(lpn))
return;
if (exp_watch_lpn_cnt < EXP_MAX_WATCH)
exp_watch_lpn[exp_watch_lpn_cnt++] = lpn;
}

/* 해당 LPN의 backend 페이지에 FEMU_SECRET 이 들어있는지 검사 */
static bool femu_dbg_lpn_has_secret(struct ssd *ssd, uint64_t lpn)
{
const char *sec = getenv("FEMU_SECRET");
struct ssdparams *spp = &ssd->sp;
uint64_t page_bytes, off;
uint8_t *base;
size_t slen;

if (!sec || !getenv("FEMU_EXP_LOG"))
return false;
if (!ssd->n || !ssd->n->mbe || !ssd->n->mbe->logical_space)
return false;
page_bytes = (uint64_t)spp->secs_per_pg * spp->secsz;
off = lpn * page_bytes;
if (off + page_bytes > (uint64_t)ssd->n->mbe->size)
return false;
base = (uint8_t *)ssd->n->mbe->logical_space + off;
slen = strlen(sec);
for (uint64_t i = 0; i + slen <= page_bytes; i++)
if (base[i] == (uint8_t)sec[0] && memcmp(base + i, sec, slen) == 0)
return true;
return false;
}

static inline struct ssd_channel *get_ch(struct ssd *ssd, struct ppa *ppa)
{
return &(ssd->ch[ppa->g.ch]);
Expand Down Expand Up @@ -732,6 +858,9 @@ static void mark_block_free(struct ssd *ssd, struct ppa *ppa)
blk->ipc = 0;
blk->vpc = 0;
blk->erase_cnt++;
if (exp_watch_blk[ppa->g.blk])
EXP_LOG("[ERASE] " PPA_FMT " erase_cnt=%d (vpc/ipc reset)\n",
PPA_ARG(ppa), blk->erase_cnt);
}

static void gc_read_page(struct ssd *ssd, struct ppa *ppa)
Expand Down Expand Up @@ -759,6 +888,11 @@ static uint64_t gc_write_page(struct ssd *ssd, struct ppa *old_ppa)
set_maptbl_ent(ssd, lpn, &new_ppa);
/* update rmap */
set_rmap_ent(ssd, lpn, &new_ppa);
if (exp_lpn_watched(lpn)) {
exp_watch_blk[new_ppa.g.blk] = 1; /* 새 블록도 추적 대상에 추가 */
EXP_LOG("[GC_MOVE] lpn=%lu " PPA_FMT " -> " PPA_FMT "\n",
lpn, PPA_ARG(old_ppa), PPA_ARG(&new_ppa));
}

mark_page_valid(ssd, &new_ppa);

Expand Down Expand Up @@ -904,6 +1038,11 @@ static uint64_t ssd_read(struct ssd *ssd, NvmeRequest *req)

/* normal IO read path */
for (lpn = start_lpn; lpn <= end_lpn; lpn++) {
/* 환경변수 FEMU_DUMP_LPN 으로 지정한 LPN을 read할 때마다 덤프 */
const char *dl = getenv("FEMU_DUMP_LPN");
if (dl && lpn == strtoull(dl, NULL, 0))
femu_dbg_dump_lpn(ssd, lpn);

ppa = get_maptbl_ent(ssd, lpn);
if (!mapped_ppa(&ppa) || !valid_ppa(ssd, &ppa)) {
//printf("%s,lpn(%" PRId64 ") not mapped to valid ppa\n", ssd->ssdname, lpn);
Expand Down Expand Up @@ -950,6 +1089,9 @@ static uint64_t ssd_write(struct ssd *ssd, NvmeRequest *req)
ppa = get_maptbl_ent(ssd, lpn);
if (mapped_ppa(&ppa)) {
/* update old page information first */
if (exp_lpn_watched(lpn))
EXP_LOG("[INVALIDATE:overwrite] lpn=%lu old " PPA_FMT "\n",
lpn, PPA_ARG(&ppa));
mark_page_invalid(ssd, &ppa);
set_rmap_ent(ssd, INVALID_LPN, &ppa);
}
Expand All @@ -962,6 +1104,13 @@ static uint64_t ssd_write(struct ssd *ssd, NvmeRequest *req)
set_rmap_ent(ssd, lpn, &ppa);

mark_page_valid(ssd, &ppa);
/* 비밀 문자열을 담은 페이지만 로그 + 추적 등록 */
if (femu_dbg_lpn_has_secret(ssd, lpn)) {
exp_watch_lpn_add(lpn);
exp_watch_blk[ppa.g.blk] = 1;
EXP_LOG("[WRITE] lpn=%lu -> " PPA_FMT " (secret)\n",
lpn, PPA_ARG(&ppa));
}

/* need to advance the write pointer here */
ssd_advance_write_pointer(ssd);
Expand Down Expand Up @@ -1030,8 +1179,11 @@ static uint64_t ssd_trim(struct ssd *ssd, NvmeRequest *req)
}

// Invalidate the existing mapped page
if (exp_lpn_watched(lpn))
EXP_LOG("[INVALIDATE:trim] lpn=%lu old " PPA_FMT "\n",
lpn, PPA_ARG(&ppa));
mark_page_invalid(ssd, &ppa);

// Clear reverse mapping
set_rmap_ent(ssd, INVALID_LPN, &ppa);

Expand All @@ -1058,6 +1210,10 @@ static uint64_t ssd_trim(struct ssd *ssd, NvmeRequest *req)
req->dsm_nr_ranges = 0;
req->dsm_attributes = 0;

/* 삭제(TRIM) 직후 backend에 비밀 문자열이 남아있는지 자동 확인 */
if (getenv("FEMU_EXP_LOG"))
femu_dbg_scan_secret(ssd, "after_trim");

return 0; // Assume TRIM operations have no NAND latency
}

Expand Down