On Jun 16 07:57, Keith Busch wrote: > On Thu, Jun 16, 2022 at 12:42:49PM +0200, Klaus Jensen wrote: > > 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? > > There are drivers utilizing the capability, so I think supporting it is fine > despite this environment not having any inherent time-to-ready delays. > > This will probably be another knob that gets lots of use for initial driver > validation, then largely forgotten. But maybe it will be useful for driver > unit > and regression testing in the future.
Alright, sounds good. I'll give it a proper review :)
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