On 11/12/19 04:53, Alexey Kardashevskiy wrote: > Hi! > > I am enabling IOMMU for virtio in the pseries firmware (SLOF) and seeing > problems, one of them is SLOF does SCSI bus scan, then it stops the > virtio-scsi by clearing MMIO|IO|BUSMASTER from PCI_COMMAND (as SLOF > stopped using the devices) and when this happens, I see unassigned > memory access (see below) which happens because disabling busmaster > disables IOMMU and QEMU cannot access the rings to do some shutdown. And > when this happens, the device does not come back even if SLOF re-enables it. > > Hacking SLOF to not clear BUSMASTER makes virtio-scsi work but it is > hardly a right fix. > > Is this something expected? Thanks,
Can you perform a virtio reset (write 0 to the virtio-scsi-pci device's virtio status register) in SLOF, before clearing PCI_COMMAND? Thanks, Laszlo > > > Here is the exact command line: > > /home/aik/pbuild/qemu-garrison2-ppc64/ppc64-softmmu/qemu-system-ppc64 \ > > -nodefaults \ > > -chardev stdio,id=STDIO0,signal=off,mux=on \ > > -device spapr-vty,id=svty0,reg=0x71000110,chardev=STDIO0 \ > > -mon id=MON0,chardev=STDIO0,mode=readline \ > > -nographic \ > > -vga none \ > > -enable-kvm \ > -m 2G \ > > -device > virtio-scsi-pci,id=vscsi0,iommu_platform=on,disable-modern=off,disable-legacy=on > \ > -drive id=DRIVE0,if=none,file=img/u1804-64le.qcow2,format=qcow2 \ > > -device scsi-disk,id=scsi-disk0,drive=DRIVE0 \ > > -snapshot \ > > -smp 1 \ > > -machine pseries \ > > -L /home/aik/t/qemu-ppc64-bios/ \ > > -trace events=qemu_trace_events \ > > -d guest_errors \ > > -chardev socket,id=SOCKET0,server,nowait,path=qemu.mon.ssh59518 \ > > -mon chardev=SOCKET0,mode=control > > > > Here is the backtrace: > > Thread 5 "qemu-system-ppc" hit Breakpoint 8, unassigned_mem_accepts > (opaque=0x0, addr=0x5802, size=0x2, is_write=0x0, attrs=...) at /home/ > aik/p/qemu/memory.c:1275 > 1275 return false; > #0 unassigned_mem_accepts (opaque=0x0, addr=0x5802, size=0x2, > is_write=0x0, attrs=...) at /home/aik/p/qemu/memory.c:1275 > #1 0x00000000100a8ac8 in memory_region_access_valid (mr=0x1105c230 > <io_mem_unassigned>, addr=0x5802, size=0x2, is_write=0x0, attrs=...) at > /home/aik/p/qemu/memory.c:1377 > #2 0x00000000100a8c88 in memory_region_dispatch_read (mr=0x1105c230 > <io_mem_unassigned>, addr=0x5802, pval=0x7ffff550d410, op=MO_16, > attrs=...) at /home/aik/p/qemu/memory.c:1418 > #3 0x000000001001cad4 in address_space_lduw_internal_cached_slow > (cache=0x7fff68036fa0, addr=0x2, attrs=..., result=0x0, > endian=DEVICE_LITTLE_ENDIAN) at /home/aik/p/qemu/memory_ldst.inc.c:211 > #4 0x000000001001cc84 in address_space_lduw_le_cached_slow > (cache=0x7fff68036fa0, addr=0x2, attrs=..., result=0x0) at > /home/aik/p/qemu/memory_ldst.inc.c:249 > #5 0x000000001019bd80 in address_space_lduw_le_cached > (cache=0x7fff68036fa0, addr=0x2, attrs=..., result=0x0) at > /home/aik/p/qemu/include/exec/memory_ldst_cached.inc.h:56 > #6 0x000000001019c10c in lduw_le_phys_cached (cache=0x7fff68036fa0, > addr=0x2) at /home/aik/p/qemu/include/exec/memory_ldst_phys.inc.h:91 > #7 0x000000001019d86c in virtio_lduw_phys_cached (vdev=0x118b9110, > cache=0x7fff68036fa0, pa=0x2) at > /home/aik/p/qemu/include/hw/virtio/virtio-access.h:166 > #8 0x000000001019e648 in vring_avail_idx (vq=0x118c2720) at > /home/aik/p/qemu/hw/virtio/virtio.c:302 > #9 0x000000001019f5bc in virtio_queue_split_empty (vq=0x118c2720) at > /home/aik/p/qemu/hw/virtio/virtio.c:581 > #10 0x000000001019f838 in virtio_queue_empty (vq=0x118c2720) at > /home/aik/p/qemu/hw/virtio/virtio.c:612 > #11 0x00000000101a8fa8 in virtio_queue_host_notifier_aio_poll > (opaque=0x118c2798) at /home/aik/p/qemu/hw/virtio/virtio.c:3389 > #12 0x000000001092679c in run_poll_handlers_once (ctx=0x11212e40, > timeout=0x7ffff550d7d8) at /home/aik/p/qemu/util/aio-posix.c:520 > #13 0x0000000010926aec in try_poll_mode (ctx=0x11212e40, > timeout=0x7ffff550d7d8) at /home/aik/p/qemu/util/aio-posix.c:607 > #14 0x0000000010926c2c in aio_poll (ctx=0x11212e40, blocking=0x1) at > /home/aik/p/qemu/util/aio-posix.c:639 > #15 0x000000001091fe0c in aio_wait_bh_oneshot (ctx=0x11212e40, > cb=0x1016f35c <virtio_scsi_dataplane_stop_bh>, opaque=0x118b9110) at > /home/aik/p/qemu/util/aio-wait.c:71 > #16 0x000000001016fa60 in virtio_scsi_dataplane_stop (vdev=0x118b9110) > at /home/aik/p/qemu/hw/scsi/virtio-scsi-dataplane.c:211 > #17 0x0000000010684740 in virtio_bus_stop_ioeventfd (bus=0x118b9098) at > /home/aik/p/qemu/hw/virtio/virtio-bus.c:245 > #18 0x0000000010688290 in virtio_pci_stop_ioeventfd (proxy=0x118b0fa0) > at /home/aik/p/qemu/hw/virtio/virtio-pci.c:292 > #19 0x00000000106891e8 in virtio_write_config (pci_dev=0x118b0fa0, > address=0x4, val=0x100100, len=0x4) at > /home/aik/p/qemu/hw/virtio/virtio-pci.c:613 > #20 0x00000000105b7228 in pci_host_config_write_common > (pci_dev=0x118b0fa0, addr=0x4, limit=0x100, val=0x100100, len=0x4) at > /home/aik/p/qemu/hw/pci/pci_host.c:81 > #21 0x00000000101f7bdc in finish_write_pci_config (spapr=0x11217200, > buid=0x800000020000000, addr=0x4, size=0x4, val=0x100100, > rets=0x7e7533e0) at /home/aik/p/qemu/hw/ppc/spapr_pci.c:192 > #22 0x00000000101f7cec in rtas_ibm_write_pci_config (cpu=0x11540df0, > spapr=0x11217200, token=0x2017, nargs=0x5, args=0x7e7533cc, nret=0x1, > rets=0x7e7533e0) at /home/aik/p/qemu/hw/ppc/spapr_pci.c:216 > #23 0x00000000101f5860 in spapr_rtas_call (cpu=0x11540df0, > spapr=0x11217200, token=0x2017, nargs=0x5, args=0x7e7533cc, nret=0x1, > rets=0x7e7533e0) at /home/aik/p/qemu/hw/ppc/spapr_rtas.c:416 > #24 0x00000000101ee214 in h_rtas (cpu=0x11540df0, spapr=0x11217200, > opcode=0xf000, args=0x7ffff4cf0030) at > /home/aik/p/qemu/hw/ppc/spapr_hcall.c:1214 > #25 0x00000000101f0524 in spapr_hypercall (cpu=0x11540df0, > opcode=0xf000, args=0x7ffff4cf0030) at > /home/aik/p/qemu/hw/ppc/spapr_hcall.c:2014 > #26 0x000000001033bff0 in kvm_arch_handle_exit (cs=0x11540df0, > run=0x7ffff4cf0000) at /home/aik/p/qemu/target/ppc/kvm.c:1684 > #27 0x00000000100cc7c8 in kvm_cpu_exec (cpu=0x11540df0) at > /home/aik/p/qemu/accel/kvm/kvm-all.c:2391 > #28 0x000000001008edf8 in qemu_kvm_cpu_thread_fn (arg=0x11540df0) at > /home/aik/p/qemu/cpus.c:1318 > #29 0x000000001092c704 in qemu_thread_start (args=0x11588d90) at > /home/aik/p/qemu/util/qemu-thread-posix.c:519 > #30 0x00007ffff7b58070 in start_thread (arg=0x7ffff550ebf0) at > pthread_create.c:335 > #31 0x00007ffff7aa3a70 in clone () at > ../sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S:96 > (gdb) >
