dlfeat was changed from 0x9 to 0x1 when PI support was added. It was removed because we can't rely on unmap and have to physically clear it to get the checksums right but that doesnt mean that we do not support the bit.
The spec says that if wzds is enabled, then the controller supports deallocate (DEAC) on write zeroes. But DEAC bit in write zeroes command is only a hint, the controller might choose to physically write zeroes in those areas. As we are sending write zeroes command with BDRV_REQ_MAY_UNMAP to the underlying block device anyway (if the unmap operation is supported), change the dlfeat value back to 0x9. A new flag FALLOC_FL_WRITE_ZEROES has been introduced in linux for fallocate which will use the wzds bit in dlfeat to quickly zeroout extents using unmap operation whenever possible[1]. [1] https://lore.kernel.org/linux-fsdevel/[email protected]/ Fixes: 146f720c55 ("hw/block/nvme: end-to-end data protection") Suggested-by: Klaus Jensen <[email protected]> Signed-off-by: Pankaj Raghav <[email protected]> --- hw/nvme/ns.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/nvme/ns.c b/hw/nvme/ns.c index 38f86a1726..b0106eaa5c 100644 --- a/hw/nvme/ns.c +++ b/hw/nvme/ns.c @@ -75,7 +75,7 @@ static int nvme_ns_init(NvmeNamespace *ns, Error **errp) ns->csi = NVME_CSI_NVM; ns->status = 0x0; - ns->id_ns.dlfeat = 0x1; + ns->id_ns.dlfeat = 0x9; /* support DULBE and I/O optimization fields */ id_ns->nsfeat |= (NVME_ID_NS_NSFEAT_DAE | NVME_ID_NS_NSFEAT_OPTPERF_ALL); -- 2.50.1
