On Jun 8 03:28, Niklas Cassel via wrote: > Hello there, > > considering that Linux v5.19-rc1 is out which includes support for > NVMe TP4084: > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/nvme/host/core.c?id=354201c53e61e493017b15327294b0c8ab522d69 > > I thought that it might be nice to have QEMU support for the same. > > TP4084 adds a new mode, CC.CRIME, that can be used to mark a namespace > as ready independently from the controller. > > When CC.CRIME is 0 (default), things behave as before, all namespaces > are ready when CSTS.RDY gets set to 1. > > Add a new "ready_delay" namespace device parameter, in order to emulate > different ready latencies for namespaces when CC.CRIME is 1. > > The patch series also adds a "crwmt" controller parameter, in order to > be able to expose the worst case timeout that the host should wait for > all namespaces to become ready. > > > Example qemu cmd line for the new options: > > # delay in s (20s) > NS1_DELAY_S=20 > # convert to units of 500ms > NS1_DELAY=$((NS1_DELAY_S*2)) > > # delay in s (60s) > NS2_DELAY_S=60 > # convert to units of 500ms > NS2_DELAY=$((NS2_DELAY_S*2)) > > # timeout in s (120s) > CRWMT_S=120 > # convert to units of 500ms > CRWMT=$((CRWMT_S*2)) > > -device nvme,serial=deadbeef,crwmt=$CRWMT \ > -drive file=$NS1_DATA,id=nvm-1,format=raw,if=none \ > -device nvme-ns,drive=nvm-1,ready_delay=$NS1_DELAY \ > -drive file=$NS2_DATA,id=nvm-2,format=raw,if=none \ > -device nvme-ns,drive=nvm-2,ready_delay=$NS2_DELAY \ > > > Niklas Cassel (4): > hw/nvme: claim NVMe 2.0 compliance > hw/nvme: store a pointer to the NvmeSubsystem in the NvmeNamespace > hw/nvme: add support for ratified TP4084 > hw/nvme: add new never_ready parameter to test the DNR bit > > hw/nvme/ctrl.c | 151 +++++++++++++++++++++++++++++++++++++++++-- > hw/nvme/ns.c | 17 +++++ > hw/nvme/nvme.h | 9 +++ > hw/nvme/trace-events | 1 + > include/block/nvme.h | 60 ++++++++++++++++- > 5 files changed, 233 insertions(+), 5 deletions(-) > > -- > 2.36.1 > >
Hi Niklas, I've been going back and forth on my position on this. I'm not straight up against it, but this only seems useful as a one-off patch to test the kernel support for this. Considering the limitations you state and the limited use case, I fear this is a little bloaty to carry upstream. But I totally acknowledge that this is a horrible complicated behavior to implement on the driver side, so I guess we might all benefit from this. Keith, do you have an opinion on this?
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