On 21-01-26 09:57:23, Keith Busch wrote: > On Tue, Jan 26, 2021 at 09:52:48AM +0900, Minwoo Im wrote: > > On 21-01-25 10:11:43, Keith Busch wrote: > > > On Mon, Jan 25, 2021 at 07:03:32PM +0100, Klaus Jensen wrote: > > > > On Jan 24 11:54, Minwoo Im wrote: > > > > > We have nvme-subsys and nvme devices mapped together. To support > > > > > multi-controller scheme to this setup, controller identifier(id) has > > > > > to > > > > > be managed. Earlier, cntlid(controller id) used to be always 0 > > > > > because > > > > > we didn't have any subsystem scheme that controller id matters. > > > > > > > > > > This patch introduced 'cntlid' attribute to the nvme controller > > > > > instance(NvmeCtrl) and make it allocated by the nvme-subsys device > > > > > mapped to the controller. If nvme-subsys is not given to the > > > > > controller, then it will always be 0 as it was. > > > > > > > > > > Added 'ctrls' array in the nvme-subsys instance to manage attached > > > > > controllers to the subsystem with a limit(32). This patch didn't take > > > > > list for the controllers to make it seamless with nvme-ns device. > > > > > > > > > > Signed-off-by: Minwoo Im <minwoo.im....@gmail.com> > > > > > --- > > > > > hw/block/nvme-subsys.c | 21 +++++++++++++++++++++ > > > > > hw/block/nvme-subsys.h | 4 ++++ > > > > > hw/block/nvme.c | 29 +++++++++++++++++++++++++++++ > > > > > hw/block/nvme.h | 1 + > > > > > 4 files changed, 55 insertions(+) > > > > > > > > > > diff --git a/hw/block/nvme.c b/hw/block/nvme.c > > > > > index b525fca14103..7138389be4bd 100644 > > > > > --- a/hw/block/nvme.c > > > > > +++ b/hw/block/nvme.c > > > > > @@ -4481,6 +4484,10 @@ static void nvme_init_ctrl(NvmeCtrl *n, > > > > > PCIDevice *pci_dev) > > > > > id->psd[0].enlat = cpu_to_le32(0x10); > > > > > id->psd[0].exlat = cpu_to_le32(0x4); > > > > > > > > > > + if (n->subsys) { > > > > > + id->cmic |= NVME_CMIC_MULTI_CTRL; > > > > > + } > > > > > > > > Since multiple controllers show up with a PCIe port of their own, do we > > > > need to set bit 0 (NVME_CMIC_MULTI_PORT?) as well? Or am I > > > > misunderstanding that bit? > > > > > > AIUI, if you report this MULTI_PORT bit, then each PCI device in the > > > subsystem needs to report a different "Port Number" in their PCIe Link > > > Capabilities register. I don't think we can manipulate that value from > > > the nvme "device", but I also don't know what a host should do with this > > > information even if we could. So, I think it's safe to leave it at 0. > > > > AFAIK, If we leave it to 0, kernel will not allocate disk for multi-path > > case (e.g., nvmeXcYnZ). > > Kernel only checks for MULTI_CTRL. It doesn't do anything with MULTI_PORT.
Please forgive me that I took this discussion as MULTI_CTRL rather than MULTI_PORT. Please ignore this noise ;) Thanks!