ZC WRITE_ZEROES must zero, not ACK 0 - #88
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The device advertises max_write_zeroes_sectors. ACK-0 without zeroing is guest-visible silent wrong. DISCARD remains an advertised no-op.
DISCARD stays Complete(0) because max_discard_sectors is 0. WRITE_ZEROES follows the FLUSH pattern: deferred, run the same handler as USER_COPY.
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The device advertises
max_write_zeroes_sectors(16 MiB). On the zero-copy pathWRITE_ZEROEScompleted with 0 and never calledhandler.write_zeroes, so the guest saw success and read stale bytes. Two commits: tests that fail on main, then the fix.WRITE_ZEROESruns the handler;DISCARDstays ACK-0 (max_discard_sectorsis 0).write_zeroespath USER_COPY already uses.