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| author | Arthur Hanson Rasmusson <arthur@vgpu.io> | 2026-10-21 22:30:46 -0400 |
|---|---|---|
| committer | Arthur Hanson Rasmusson <arthur@vgpu.io> | 2026-10-21 22:30:46 -0400 |
| commit | e256d3d2eef5c75401d6969ea8b7a44dc5c64933 (patch) | |
| tree | 81dd8e39885af28304e889d23125e089e712c9c1 /kernel | |
| parent | 55a77193c7b3bf3bcebf7e75e79b0c615a3a2fb3 (diff) | |
| download | open-iov-e256d3d2eef5c75401d6969ea8b7a44dc5c64933.tar.gz open-iov-e256d3d2eef5c75401d6969ea8b7a44dc5c64933.zip | |
r441 zero the guest-visible release words on the FIRST attempt too (not only outcome retries): the r439 evidence shows a first attempt breaking its poll on a stale value (qmd_rel=0x5 from the previous launch's engine write, want=6) while the engine never fetched the deposit (sentinel intact) - the host then shipped a completion for a launch that did not run; zeroing forces the poll to wait for this launch's own engine write, so the timeout ladder and the software-authored completion are the honest path and the wedge classification can no longer be satisfied by a stale value
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/gsp_phys_booter.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/kernel/gsp_phys_booter.c b/kernel/gsp_phys_booter.c index b19fa0d..217f4e4 100644 --- a/kernel/gsp_phys_booter.c +++ b/kernel/gsp_phys_booter.c @@ -19897,6 +19897,27 @@ gr_page_unmapped: /* A stale release from a previous submission must not be observed. */ WRITE_ONCE(*(u32 *)sem_va, 0); WRITE_ONCE(*(u32 *)(sem_va + 4), 0); + /* + * r441: zero the GUEST-VISIBLE release words for the first attempt + * too, not only for outcome retries. The r439 evidence shows a first + * attempt whose poll broke on a STALE value (qmd_rel=0x00000005 from + * the previous launch's engine write, want=6) while the engine never + * fetched this launch's deposit (sentinel intact, "engine fetch + * NONE"): the host then shipped a completion for a launch that did + * not run. Zeroing forces the poll to wait for THIS launch's own + * engine write; when the engine does not write it, the timeout ladder + * and the software-authored completion take over (the honest path), + * and the wedge classification stops being satisfiable by a stale + * value. The write guard re-validates the target like the retry path. + */ + if (qmd_rel_hpa && qmd_rel_off < GSP_PHYS_PAGE_SIZE && + gsp_sema_gr_write_guard(req->rel_va, qmd_rel_hpa, + "gr-rel-zero-first")) + WRITE_ONCE(*(u32 *)((u8 *)__va(qmd_rel_hpa) + qmd_rel_off), 0); + if (ch_rel_hpa && ch_rel_off < GSP_PHYS_PAGE_SIZE && + gsp_sema_gr_write_guard(req->rel_va, ch_rel_hpa, + "gr-chrel-zero-first")) + WRITE_ONCE(*(u32 *)((u8 *)__va(ch_rel_hpa) + ch_rel_off), 0); wmb(); /* |