Hi, On Thu, Jun 16, 2022 at 08:34:07PM +0800, Jinhao Fan wrote: > Implement Doorbel Buffer Config command (Section 5.7 in NVMe Spec 1.3) > and Shadow Doorbel buffer & EventIdx buffer handling logic (Section 7.13 > in NVMe Spec 1.3). For queues created before the Doorbell Buffer Config > command, the nvme_dbbuf_config function tries to associate each existing > SQ and CQ with its Shadow Doorbel buffer and EventIdx buffer address. > Queues created after the Doorbell Buffer Config command will have the > doorbell buffers associated with them when they are initialized. > > In nvme_process_sq and nvme_post_cqe, proactively check for Shadow > Doorbell buffer changes instead of wait for doorbell register changes. > This reduces the number of MMIOs. > > In nvme_process_db(), update the shadow doorbell buffer value with > the doorbell register value if it is the admin queue. This is a hack > since hosts like Linux NVMe driver and SPDK do not use shadow > doorbell buffer for the admin queue. Copying the doorbell register > value to the shadow doorbell buffer allows us to support these hosts > as well as spec-compliant hosts that use shadow doorbell buffer for > the admin queue. > > Signed-off-by: Jinhao Fan <fanjinhao...@ict.ac.cn>
I noticed that I can no longer boot Linux kernels from nvme on riscv64 systems. The problem is seen with qemu v7.1 and qemu v7.2-rc4. The log shows: [ 35.904128] nvme nvme0: I/O 642 (I/O Cmd) QID 1 timeout, aborting [ 35.905000] EXT4-fs (nvme0n1): mounting ext2 file system using the ext4 subsystem [ 66.623863] nvme nvme0: I/O 643 (I/O Cmd) QID 1 timeout, aborting [ 97.343989] nvme nvme0: Abort status: 0x0 [ 97.344355] nvme nvme0: Abort status: 0x0 [ 97.344647] nvme nvme0: I/O 7 QID 0 timeout, reset controller [ 97.350568] nvme nvme0: I/O 644 (I/O Cmd) QID 1 timeout, aborting This is with the mainline Linux kernel (v6.1-rc8). Bisect points to this patch. Reverting this patch and a number of associated patches (to fix conflicts) fixes the problem. 06143d8771 Revert "hw/nvme: Implement shadow doorbell buffer support" acb4443e3a Revert "hw/nvme: Use ioeventfd to handle doorbell updates" d5fd309feb Revert "hw/nvme: do not enable ioeventfd by default" 1ca1e6c47c Revert "hw/nvme: unregister the event notifier handler on the main loop" 2d26abd51e Revert "hw/nvme: skip queue processing if notifier is cleared" 99d411b5a5 Revert "hw/nvme: reenable cqe batching" 2293d3ca6c Revert "hw/nvme: Add trace events for shadow doorbell buffer" Qemu command line: qemu-system-riscv64 -M virt -m 512M \ -kernel arch/riscv/boot/Image -snapshot \ -device nvme,serial=foo,drive=d0 \ -drive file=rootfs.ext2,if=none,format=raw,id=d0 \ -bios default \ -append "root=/dev/nvme0n1 console=ttyS0,115200 earlycon=uart8250,mmio,0x10000000,115200" \ -nographic -monitor none Guenter