| Message ID | 1513246316-56019-3-git-send-email-hare@suse.de (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
On 12/14/2017 11:11 AM, Hannes Reinecke wrote: > When a device announces an 'FC' protocol we should be pulling > in the FC transport class to have the rports etc setup correctly. It took some time for me to understand what this does. It seems to mirror the topology of rports and sdevs that exist under the fc_host on the kvm host side to the virtio-scsi-fc side in the guest. I like the idea. This is also what I've been suggesting users to do if they back virtio-scsi with zfcp on the kvm host side. Primarily to not stall all virtio-scsi I/O on all paths if the guest ever gets into scsi_eh. But also to make it look like an HBA pass through so one can more easily migrate to this once we have FCP pass through. > > Signed-off-by: Hannes Reinecke <hare@suse.com> > --- > drivers/scsi/virtio_scsi.c | 323 ++++++++++++++++++++++++++++++++++++++------- > 1 file changed, 277 insertions(+), 46 deletions(-) > > diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c > index a561e90..f925fbd 100644 > --- a/drivers/scsi/virtio_scsi.c > +++ b/drivers/scsi/virtio_scsi.c > @@ -591,11 +616,25 @@ static int virtscsi_queuecommand_single(struct Scsi_Host *sh, > struct scsi_cmnd *sc) > + if (vscsi->protocol == SCSI_PROTOCOL_FCP) { > + struct fc_rport *rport = > + starget_to_rport(scsi_target(sc->device)); > + if (rport && rport->dd_data) { > + tgt = rport->dd_data; > + target_id = tgt->target_id; > + } > + } else > + tgt = scsi_target(sc->device)->hostdata; > + if (!tgt || tgt->removed) { > @@ -648,16 +687,30 @@ static int virtscsi_queuecommand_multi(struct Scsi_Host *sh, > struct scsi_cmnd *sc) > + if (vscsi->protocol == SCSI_PROTOCOL_FCP) { > + struct fc_rport *rport = > + starget_to_rport(scsi_target(sc->device)); > + if (rport && rport->dd_data) { > + tgt = rport->dd_data; > + target_id = tgt->target_id; > + } > + } else > + tgt = scsi_target(sc->device)->hostdata; > + if (!tgt || tgt->removed) { repeating pattern? > @@ -696,12 +749,27 @@ static int virtscsi_device_reset(struct scsi_cmnd *sc) > { > + if (vscsi->protocol == SCSI_PROTOCOL_FCP) { > + struct fc_rport *rport = > + starget_to_rport(scsi_target(sc->device)); > + if (rport && rport->dd_data ) { > + tgt = rport->dd_data; > + target_id = tgt->target_id; > + } else > + return FAST_IO_FAIL; > + } else { > + tgt = scsi_target(sc->device)->hostdata; > + if (!tgt || tgt->removed) The other patterns have the !tgt check outside of the if else condition. For consistency this might work here, too? > + return FAST_IO_FAIL; > + } > @@ -755,19 +823,34 @@ static int virtscsi_abort(struct scsi_cmnd *sc) > + if (vscsi->protocol == SCSI_PROTOCOL_FCP) { > + struct fc_rport *rport = > + starget_to_rport(scsi_target(sc->device)); > + if (rport && rport->dd_data ) { > + tgt = rport->dd_data; > + target_id = tgt->target_id; > + } else > + return FAST_IO_FAIL; > + } else { > + tgt = scsi_target(sc->device)->hostdata; > + if (!tgt || tgt->removed) > + return FAST_IO_FAIL; > + } dito > @@ -857,27 +970,67 @@ static void virtscsi_rescan_work(struct work_struct *work) > > wait_for_completion(&comp); Waiting in work item .vs. having the response (IRQ) path trigger subsequent processing async ? Or do we need the call chain(s) getting here to be in our own process context via the workqueue anyway? > target_id = virtio32_to_cpu(vscsi->vdev, cmd->resp.rescan.id); > - if (target_id != -1) { > - int transport = virtio32_to_cpu(vscsi->vdev, > - cmd->resp.rescan.transport); > - spin_lock_irq(&vscsi->rescan_lock); > - vscsi->next_target_id = target_id + 1; > - spin_unlock_irq(&vscsi->rescan_lock); > - shost_printk(KERN_INFO, sh, > - "found %s target %d (WWN %*phN)\n", > - transport == SCSI_PROTOCOL_FCP ? "FC" : "SAS", > - target_id, 8, > - cmd->resp.rescan.port_wwn); > - scsi_scan_target(&sh->shost_gendev, 0, target_id, > - SCAN_WILD_CARD, SCSI_SCAN_INITIAL); > - queue_work(system_freezable_wq, &vscsi->rescan_work); > - } else { > + if (target_id == -1) { This boolean if expression was introduced in the previous patch. Why negate it here? It causes a number of potentially unnecessary changed lines making review harder. > + if (transport == SCSI_PROTOCOL_FCP) { > + struct fc_rport_identifiers rport_ids; > + struct fc_rport *rport; > + > + rport_ids.node_name = wwn_to_u64(cmd->resp.rescan.node_wwn); > + rport_ids.port_name = wwn_to_u64(cmd->resp.rescan.port_wwn); > + rport_ids.port_id = (target_id >> 8); Why do you shift target_id by one byte to the right? > + rport = fc_remote_port_add(sh, 0, &rport_ids); > + if (rport) { > + tgt->rport = rport; > + rport->dd_data = tgt; > + fc_remote_port_rolechg(rport, FC_RPORT_ROLE_FCP_TARGET); Is the rolechg to get some event? Otherwise we could have rport_ids.roles = FC_RPORT_ROLE_FCP_TARGET before fc_remote_port_add(). > + } else { > + spin_lock_irq(&vscsi->rescan_lock); > + list_del(&tgt->list); > + spin_unlock_irq(&vscsi->rescan_lock); > + kfree(tgt); > + tgt = NULL; > + } > + } else { > + scsi_scan_target(&sh->shost_gendev, 0, tgt->target_id, > + SCAN_WILD_CARD, SCSI_SCAN_INITIAL); > + } > + queue_work(system_freezable_wq, &vscsi->rescan_work); > +out: > mempool_free(cmd, virtscsi_cmd_pool); > return; > scan_host: > @@ -932,14 +1089,31 @@ static void virtscsi_scan_host(struct virtio_scsi *vscsi) > static void virtscsi_scan_start(struct Scsi_Host *sh) > { > struct virtio_scsi *vscsi = shost_priv(sh); > + struct virtio_scsi_target_state *tgt; > > - virtscsi_scan_host(vscsi); > spin_lock_irq(&vscsi->rescan_lock); > if (vscsi->next_target_id != -1) { > shost_printk(KERN_INFO, sh, "rescan: already running\n"); > spin_unlock_irq(&vscsi->rescan_lock); > return; > } > + if (vscsi->protocol == SCSI_PROTOCOL_FCP) { > + fc_host_node_name(sh) = vscsi->wwnn; > + fc_host_port_name(sh) = vscsi->wwpn; > + fc_host_port_id(sh) = 0x00ff00; > + fc_host_port_type(sh) = FC_PORTTYPE_NPIV; Why is this hardcoded? At least with zfcp, we can have kvm host *v*HBAs without NPIV. > + fc_host_port_state(sh) = FC_PORTSTATE_BLOCKED; > + list_for_each_entry(tgt, &vscsi->target_list, list) { > + if (tgt->rport) { > + fc_remote_port_delete(tgt->rport); I'm not familiar with the scan callbacks, maybe that's why I wonder why you block all rports when scanning the host. Is it so that the subsequent port scans can call the properly paired fc_remote_port_add to potentially update a previously existing rport with new properties we got from the qemu/host side. > + tgt->rport = NULL; > + } > + tgt->removed = true; > + } > + } else { > + list_for_each_entry(tgt, &vscsi->target_list, list) > + tgt->removed = true; > + } > vscsi->next_target_id = 0; > shost_printk(KERN_INFO, sh, "rescan: start\n"); > spin_unlock_irq(&vscsi->rescan_lock); > @@ -954,12 +1128,14 @@ int virtscsi_scan_finished(struct Scsi_Host *sh, unsigned long time) > spin_lock_irq(&vscsi->rescan_lock); > if (vscsi->next_target_id != -1) > ret = 0; > + else if (vscsi->protocol == SCSI_PROTOCOL_FCP) > + fc_host_port_state(sh) = FC_PORTSTATE_ONLINE; > spin_unlock_irq(&vscsi->rescan_lock); > if (!ret) > flush_work(&vscsi->rescan_work); > > - shost_printk(KERN_INFO, sh, "rescan: %s finished\n", > - ret ? "" : "not"); > + shost_printk(KERN_INFO, sh, "rescan: %sfinished\n", > + ret ? "" : "not "); You introduced it in the previous patch, so do the fixup there in the first place? > return ret; > } > > @@ -978,6 +1154,34 @@ static ssize_t virtscsi_host_store_rescan(struct device *dev, > NULL, > }; > > +static int virtscsi_issue_lip(struct Scsi_Host *shost) > +{ > + struct virtio_scsi *vscsi = shost_priv(shost); > + unsigned long start = jiffies; > + struct virtio_scsi_target_state *tgt; > + > + spin_lock_irq(&vscsi->rescan_lock); > + if (vscsi->next_target_id != -1) { > + spin_unlock_irq(&vscsi->rescan_lock); > + return 0; > + } > + fc_host_port_state(shost) = FC_PORTSTATE_BLOCKED; > + list_for_each_entry(tgt, &vscsi->target_list, list) { > + if (tgt->rport) { > + fc_remote_port_delete(tgt->rport); > + tgt->rport = NULL; > + } > + } > + vscsi->next_target_id = 0; I see some code duplication with what's in virtscsi_scan_host(). Not sure if reduction is worth it. > + spin_unlock_irq(&vscsi->rescan_lock); > + queue_work(system_freezable_wq, &vscsi->rescan_work); > + > + while (!virtscsi_scan_finished(shost, jiffies - start)) > + msleep(10); > + > + return 0; > +} > + > static struct scsi_host_template virtscsi_host_template_single = { > .module = THIS_MODULE, > .name = "Virtio SCSI HBA", > @@ -1066,6 +1270,20 @@ static ssize_t virtscsi_host_store_rescan(struct device *dev, > .track_queue_depth = 1, > }; > > +static struct fc_function_template virtscsi_transport_functions = { > + .dd_fcrport_size = sizeof(struct virtio_scsi_target_state *), > + .show_host_node_name = 1, > + .show_host_port_name = 1, > + .show_host_port_id = 1, > + .show_host_port_state = 1, > + .show_host_port_type = 1, > + .show_starget_node_name = 1, > + .show_starget_port_name = 1, > + .show_starget_port_id = 1, > + .show_rport_dev_loss_tmo = 1, > + .issue_fc_host_lip = virtscsi_issue_lip, > +}; > + > #define virtscsi_config_get(vdev, fld) \ > ({ \ > typeof(((struct virtio_scsi_config *)0)->fld) __val; \ > @@ -1193,7 +1411,9 @@ static int virtscsi_probe(struct virtio_device *vdev) > vscsi->num_queues = num_queues; > vdev->priv = shost; > vscsi->next_target_id = -1; > + vscsi->protocol = SCSI_PROTOCOL_SAS; Why is the old/legacy/non-fcp hardcoded SAS? Doesn't the non-fcp virtio-scsi have any real transport at all, i.e. "none"? Maybe I just don't understand semantics of vscsi->protocol well enough. > spin_lock_init(&vscsi->rescan_lock); > + INIT_LIST_HEAD(&vscsi->target_list); > INIT_WORK(&vscsi->rescan_work, virtscsi_rescan_work); > > err = virtscsi_init(vdev, vscsi);
On 12/15/2017 07:08 PM, Steffen Maier wrote: > > On 12/14/2017 11:11 AM, Hannes Reinecke wrote: >> When a device announces an 'FC' protocol we should be pulling >> in the FC transport class to have the rports etc setup correctly. > > It took some time for me to understand what this does. > It seems to mirror the topology of rports and sdevs that exist under the > fc_host on the kvm host side to the virtio-scsi-fc side in the guest. > > I like the idea. This is also what I've been suggesting users to do if > they back virtio-scsi with zfcp on the kvm host side. Primarily to not > stall all virtio-scsi I/O on all paths if the guest ever gets into > scsi_eh. But also to make it look like an HBA pass through so one can > more easily migrate to this once we have FCP pass through. > Thanks for the review. >> >> Signed-off-by: Hannes Reinecke <hare@suse.com> >> --- >> drivers/scsi/virtio_scsi.c | 323 >> ++++++++++++++++++++++++++++++++++++++------- >> 1 file changed, 277 insertions(+), 46 deletions(-) >> >> diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c >> index a561e90..f925fbd 100644 >> --- a/drivers/scsi/virtio_scsi.c >> +++ b/drivers/scsi/virtio_scsi.c > >> @@ -591,11 +616,25 @@ static int virtscsi_queuecommand_single(struct >> Scsi_Host *sh, >> struct scsi_cmnd *sc) > >> + if (vscsi->protocol == SCSI_PROTOCOL_FCP) { >> + struct fc_rport *rport = >> + starget_to_rport(scsi_target(sc->device)); >> + if (rport && rport->dd_data) { >> + tgt = rport->dd_data; >> + target_id = tgt->target_id; >> + } >> + } else >> + tgt = scsi_target(sc->device)->hostdata; >> + if (!tgt || tgt->removed) { > >> @@ -648,16 +687,30 @@ static int virtscsi_queuecommand_multi(struct >> Scsi_Host *sh, >> struct scsi_cmnd *sc) > >> + if (vscsi->protocol == SCSI_PROTOCOL_FCP) { >> + struct fc_rport *rport = >> + starget_to_rport(scsi_target(sc->device)); >> + if (rport && rport->dd_data) { >> + tgt = rport->dd_data; >> + target_id = tgt->target_id; >> + } >> + } else >> + tgt = scsi_target(sc->device)->hostdata; >> + if (!tgt || tgt->removed) { > > repeating pattern? > Yeah, I could probably move that to a separate function. >> @@ -696,12 +749,27 @@ static int virtscsi_device_reset(struct >> scsi_cmnd *sc) >> { >> + if (vscsi->protocol == SCSI_PROTOCOL_FCP) { >> + struct fc_rport *rport = >> + starget_to_rport(scsi_target(sc->device)); >> + if (rport && rport->dd_data ) { >> + tgt = rport->dd_data; >> + target_id = tgt->target_id; >> + } else >> + return FAST_IO_FAIL; >> + } else { >> + tgt = scsi_target(sc->device)->hostdata; >> + if (!tgt || tgt->removed) > > The other patterns have the !tgt check outside of the if else condition. > For consistency this might work here, too? > Possibly. I'll check. >> + return FAST_IO_FAIL; >> + } > > >> @@ -755,19 +823,34 @@ static int virtscsi_abort(struct scsi_cmnd *sc) > >> + if (vscsi->protocol == SCSI_PROTOCOL_FCP) { >> + struct fc_rport *rport = >> + starget_to_rport(scsi_target(sc->device)); >> + if (rport && rport->dd_data ) { >> + tgt = rport->dd_data; >> + target_id = tgt->target_id; >> + } else >> + return FAST_IO_FAIL; >> + } else { >> + tgt = scsi_target(sc->device)->hostdata; >> + if (!tgt || tgt->removed) >> + return FAST_IO_FAIL; >> + } > > dito > >> @@ -857,27 +970,67 @@ static void virtscsi_rescan_work(struct >> work_struct *work) >> >> wait_for_completion(&comp); > > Waiting in work item .vs. having the response (IRQ) path trigger > subsequent processing async ? > Or do we need the call chain(s) getting here to be in our own process > context via the workqueue anyway? > Can't see I can parse this sentence, but I'll be looking at the code trying to come up with a clever explanation :-) >> target_id = virtio32_to_cpu(vscsi->vdev, cmd->resp.rescan.id); >> - if (target_id != -1) { >> - int transport = virtio32_to_cpu(vscsi->vdev, >> - cmd->resp.rescan.transport); >> - spin_lock_irq(&vscsi->rescan_lock); >> - vscsi->next_target_id = target_id + 1; >> - spin_unlock_irq(&vscsi->rescan_lock); >> - shost_printk(KERN_INFO, sh, >> - "found %s target %d (WWN %*phN)\n", >> - transport == SCSI_PROTOCOL_FCP ? "FC" : "SAS", >> - target_id, 8, >> - cmd->resp.rescan.port_wwn); >> - scsi_scan_target(&sh->shost_gendev, 0, target_id, >> - SCAN_WILD_CARD, SCSI_SCAN_INITIAL); >> - queue_work(system_freezable_wq, &vscsi->rescan_work); >> - } else { >> + if (target_id == -1) { > > This boolean if expression was introduced in the previous patch. > Why negate it here? > It causes a number of potentially unnecessary changed lines making > review harder. > True. Will be fixing it up. > >> + if (transport == SCSI_PROTOCOL_FCP) { >> + struct fc_rport_identifiers rport_ids; >> + struct fc_rport *rport; >> + >> + rport_ids.node_name = wwn_to_u64(cmd->resp.rescan.node_wwn); >> + rport_ids.port_name = wwn_to_u64(cmd->resp.rescan.port_wwn); >> + rport_ids.port_id = (target_id >> 8); > > Why do you shift target_id by one byte to the right? > Because with the original setup virtio_scsi guest would pass in the target_id, and the host would be selecting the device based on that information. With virtio-vfc we pass in the wwpn, but still require the target ID to be compliant with things like event notification etc. So I've shifted the target id onto the port ID (which is 24 bit anyway). I could've used a bitfield here, but then I wasn't quite sure about the endianness of which. >> + rport = fc_remote_port_add(sh, 0, &rport_ids); >> + if (rport) { >> + tgt->rport = rport; >> + rport->dd_data = tgt; >> + fc_remote_port_rolechg(rport, FC_RPORT_ROLE_FCP_TARGET); > > Is the rolechg to get some event? Otherwise we could have > rport_ids.roles = FC_RPORT_ROLE_FCP_TARGET before fc_remote_port_add(). > That's how the 'normal' transport classes do it; but I'll check if this can be rolled into the call to fc_remote_port_add(). >> + } else { >> + spin_lock_irq(&vscsi->rescan_lock); >> + list_del(&tgt->list); >> + spin_unlock_irq(&vscsi->rescan_lock); >> + kfree(tgt); >> + tgt = NULL; >> + } >> + } else { >> + scsi_scan_target(&sh->shost_gendev, 0, tgt->target_id, >> + SCAN_WILD_CARD, SCSI_SCAN_INITIAL); >> + } >> + queue_work(system_freezable_wq, &vscsi->rescan_work); >> +out: >> mempool_free(cmd, virtscsi_cmd_pool); >> return; >> scan_host: > >> @@ -932,14 +1089,31 @@ static void virtscsi_scan_host(struct >> virtio_scsi *vscsi) >> static void virtscsi_scan_start(struct Scsi_Host *sh) >> { >> struct virtio_scsi *vscsi = shost_priv(sh); >> + struct virtio_scsi_target_state *tgt; >> >> - virtscsi_scan_host(vscsi); >> spin_lock_irq(&vscsi->rescan_lock); >> if (vscsi->next_target_id != -1) { >> shost_printk(KERN_INFO, sh, "rescan: already running\n"); >> spin_unlock_irq(&vscsi->rescan_lock); >> return; >> } >> + if (vscsi->protocol == SCSI_PROTOCOL_FCP) { >> + fc_host_node_name(sh) = vscsi->wwnn; >> + fc_host_port_name(sh) = vscsi->wwpn; >> + fc_host_port_id(sh) = 0x00ff00; >> + fc_host_port_type(sh) = FC_PORTTYPE_NPIV; > > Why is this hardcoded? > > At least with zfcp, we can have kvm host *v*HBAs without NPIV. > For the simple fact that I don't have fields to transfer this information; plus it's not _actually_ used anywhere. Unless you have a strict need why this information is required? >> + fc_host_port_state(sh) = FC_PORTSTATE_BLOCKED; >> + list_for_each_entry(tgt, &vscsi->target_list, list) { >> + if (tgt->rport) { >> + fc_remote_port_delete(tgt->rport); > > I'm not familiar with the scan callbacks, maybe that's why I wonder why > you block all rports when scanning the host. Is it so that the > subsequent port scans can call the properly paired fc_remote_port_add to > potentially update a previously existing rport with new properties we > got from the qemu/host side. > The 'scan' code here is the equivalent of an RSCN for FC-AL, ie we will be updating the rport state (and existence) during scanning. As we cannot guess the rport state during this operation (in fact, we can't even tell if the rport is still alive) we set all ports to BLOCKED here, and let the FC transport class handle the state transition of the rports via fc_remove_port_add() or dev_loss_tmo firing. >> + tgt->rport = NULL; >> + } >> + tgt->removed = true; >> + } >> + } else { >> + list_for_each_entry(tgt, &vscsi->target_list, list) >> + tgt->removed = true; >> + } >> vscsi->next_target_id = 0; >> shost_printk(KERN_INFO, sh, "rescan: start\n"); >> spin_unlock_irq(&vscsi->rescan_lock); >> @@ -954,12 +1128,14 @@ int virtscsi_scan_finished(struct Scsi_Host >> *sh, unsigned long time) >> spin_lock_irq(&vscsi->rescan_lock); >> if (vscsi->next_target_id != -1) >> ret = 0; >> + else if (vscsi->protocol == SCSI_PROTOCOL_FCP) >> + fc_host_port_state(sh) = FC_PORTSTATE_ONLINE; >> spin_unlock_irq(&vscsi->rescan_lock); >> if (!ret) >> flush_work(&vscsi->rescan_work); >> >> - shost_printk(KERN_INFO, sh, "rescan: %s finished\n", >> - ret ? "" : "not"); >> + shost_printk(KERN_INFO, sh, "rescan: %sfinished\n", >> + ret ? "" : "not "); > > You introduced it in the previous patch, so do the fixup there in the > first place? > Yeah, will be cleaning it up. >> return ret; >> } >> >> @@ -978,6 +1154,34 @@ static ssize_t virtscsi_host_store_rescan(struct >> device *dev, >> NULL, >> }; >> >> +static int virtscsi_issue_lip(struct Scsi_Host *shost) >> +{ >> + struct virtio_scsi *vscsi = shost_priv(shost); >> + unsigned long start = jiffies; >> + struct virtio_scsi_target_state *tgt; >> + >> + spin_lock_irq(&vscsi->rescan_lock); >> + if (vscsi->next_target_id != -1) { >> + spin_unlock_irq(&vscsi->rescan_lock); >> + return 0; >> + } > >> + fc_host_port_state(shost) = FC_PORTSTATE_BLOCKED; >> + list_for_each_entry(tgt, &vscsi->target_list, list) { >> + if (tgt->rport) { >> + fc_remote_port_delete(tgt->rport); >> + tgt->rport = NULL; >> + } >> + } >> + vscsi->next_target_id = 0; > > I see some code duplication with what's in virtscsi_scan_host(). > Not sure if reduction is worth it. > Possibly not :-) >> + spin_unlock_irq(&vscsi->rescan_lock); >> + queue_work(system_freezable_wq, &vscsi->rescan_work); >> + >> + while (!virtscsi_scan_finished(shost, jiffies - start)) >> + msleep(10); >> + >> + return 0; >> +} >> + >> static struct scsi_host_template virtscsi_host_template_single = { >> .module = THIS_MODULE, >> .name = "Virtio SCSI HBA", >> @@ -1066,6 +1270,20 @@ static ssize_t >> virtscsi_host_store_rescan(struct device *dev, >> .track_queue_depth = 1, >> }; >> >> +static struct fc_function_template virtscsi_transport_functions = { >> + .dd_fcrport_size = sizeof(struct virtio_scsi_target_state *), >> + .show_host_node_name = 1, >> + .show_host_port_name = 1, >> + .show_host_port_id = 1, >> + .show_host_port_state = 1, >> + .show_host_port_type = 1, >> + .show_starget_node_name = 1, >> + .show_starget_port_name = 1, >> + .show_starget_port_id = 1, >> + .show_rport_dev_loss_tmo = 1, >> + .issue_fc_host_lip = virtscsi_issue_lip, >> +}; >> + >> #define virtscsi_config_get(vdev, fld) \ >> ({ \ >> typeof(((struct virtio_scsi_config *)0)->fld) __val; \ >> @@ -1193,7 +1411,9 @@ static int virtscsi_probe(struct virtio_device >> *vdev) >> vscsi->num_queues = num_queues; >> vdev->priv = shost; >> vscsi->next_target_id = -1; >> + vscsi->protocol = SCSI_PROTOCOL_SAS; > > Why is the old/legacy/non-fcp hardcoded SAS? > Doesn't the non-fcp virtio-scsi have any real transport at all, i.e. > "none"? > Maybe I just don't understand semantics of vscsi->protocol well enough. > The original virtio-scsi code _claimed_ to the a SAS HBA (look for the VPD page 83 emulation). So to get the compatible output there we need to set the protocol to 'SAS'. Using 'none' would just add another layer of complexity (as I would need to differentiate between 'none' and 'real' SAS), which gives not benefit ATM as there _is_ not real SAS implementation. Cheers, Hannes
On 12/18/2017 09:31 AM, Hannes Reinecke wrote: > On 12/15/2017 07:08 PM, Steffen Maier wrote: >> On 12/14/2017 11:11 AM, Hannes Reinecke wrote: >>> When a device announces an 'FC' protocol we should be pulling >>> in the FC transport class to have the rports etc setup correctly. >> >> It took some time for me to understand what this does. >> It seems to mirror the topology of rports and sdevs that exist under the >> fc_host on the kvm host side to the virtio-scsi-fc side in the guest. >> >> I like the idea. This is also what I've been suggesting users to do if >> they back virtio-scsi with zfcp on the kvm host side. Primarily to not >> stall all virtio-scsi I/O on all paths if the guest ever gets into >> scsi_eh. But also to make it look like an HBA pass through so one can >> more easily migrate to this once we have FCP pass through. On second thought, I like the idea for virtio-scsi. For the future virtio-(v)fc case, see below. >>> @@ -755,19 +823,34 @@ static int virtscsi_abort(struct scsi_cmnd *sc) >> >>> + if (vscsi->protocol == SCSI_PROTOCOL_FCP) { >>> + struct fc_rport *rport = >>> + starget_to_rport(scsi_target(sc->device)); >>> + if (rport && rport->dd_data ) { >>> + tgt = rport->dd_data; >>> + target_id = tgt->target_id; >>> + } else >>> + return FAST_IO_FAIL; >>> + } else { >>> + tgt = scsi_target(sc->device)->hostdata; >>> + if (!tgt || tgt->removed) >>> + return FAST_IO_FAIL; >>> + } >> >> dito >> >>> @@ -857,27 +970,67 @@ static void virtscsi_rescan_work(struct >>> work_struct *work) >>> >>> wait_for_completion(&comp); >> >> Waiting in work item .vs. having the response (IRQ) path trigger >> subsequent processing async ? >> Or do we need the call chain(s) getting here to be in our own process >> context via the workqueue anyway? >> > Can't see I can parse this sentence, but I'll be looking at the code > trying to come up with a clever explanation :-) Sorry, meanwhile I have a hard time understanding my own words, too. I think I wondered if the effort of a work item is really necessary, especially considering that it does block on the completion and thus could delay other queued work items (even though Concurrency Managed Workqueues can often hide this delay). Couldn't we just return asynchronously after having sent the request. And then later on, simply have the response (IRQ) path trigger whatever processing is necessary (after the work item variant woke up from the wait_for_completion) in some asynchronuous fashion? Of course, this could also be a work item which just does necessary remaining processing after we got a response. Just a wild guess, without knowing the environmental requirements. >>> + if (transport == SCSI_PROTOCOL_FCP) { >>> + struct fc_rport_identifiers rport_ids; >>> + struct fc_rport *rport; >>> + >>> + rport_ids.node_name = wwn_to_u64(cmd->resp.rescan.node_wwn); >>> + rport_ids.port_name = wwn_to_u64(cmd->resp.rescan.port_wwn); >>> + rport_ids.port_id = (target_id >> 8); >> >> Why do you shift target_id by one byte to the right? >> > Because with the original setup virtio_scsi guest would pass in the > target_id, and the host would be selecting the device based on that > information. > With virtio-vfc we pass in the wwpn, but still require the target ID to > be compliant with things like event notification etc. Don't we need the true N_Port-ID, then? That's what an fc_rport.port_id usually contains. It's also a simple way to lookup resources on a SAN switch for problem determination. Or did I misunderstand the content/semantics of the variable target_id, assuming it's a SCSI target ID, i.e. the 3rd part of a HCTL 4-tuple? > So I've shifted the target id onto the port ID (which is 24 bit anyway). > I could've used a bitfield here, but then I wasn't quite sure about the > endianness of which. >>> + rport = fc_remote_port_add(sh, 0, &rport_ids); >>> + if (rport) { >>> + tgt->rport = rport; >>> + rport->dd_data = tgt; >>> + fc_remote_port_rolechg(rport, FC_RPORT_ROLE_FCP_TARGET); >> >> Is the rolechg to get some event? Otherwise we could have >> rport_ids.roles = FC_RPORT_ROLE_FCP_TARGET before fc_remote_port_add(). >> > That's how the 'normal' transport classes do it; but I'll check if this > can be rolled into the call to fc_remote_port_add(). My idea was just based on how zfcp does it. Do you think I need to check if zfcp should do it via rolechg (even though zfcp never changes an rport role since it can only open targets)? >>> @@ -932,14 +1089,31 @@ static void virtscsi_scan_host(struct >>> virtio_scsi *vscsi) >>> static void virtscsi_scan_start(struct Scsi_Host *sh) >>> { >>> + if (vscsi->protocol == SCSI_PROTOCOL_FCP) { >>> + fc_host_node_name(sh) = vscsi->wwnn; >>> + fc_host_port_name(sh) = vscsi->wwpn; >>> + fc_host_port_id(sh) = 0x00ff00; >>> + fc_host_port_type(sh) = FC_PORTTYPE_NPIV; >> >> Why is this hardcoded? >> >> At least with zfcp, we can have kvm host *v*HBAs without NPIV. >> > For the simple fact that I don't have fields to transfer this > information; plus it's not _actually_ used anywhere. It might not be used in this code, but it is exported to user space via sysfs. If I understood things correctly, you newly introduce virtio-scsi commands in patch 1 and are free to add more fields to struct virtio_scsi_rescan_resp (maybe within some max size limit)? To me, this raises the question which properties of the host's FC (driver core) objects should be mirrored to the guest. Ideally all (and that's a lot). This in turn makes me wonder if mirroring is really desirable (e.g. considering the effort) or if only the guest should have its own FC object hierarchy which does _not_ exist on the KVM host in case an fc_host is passed through with virtio-(v)fc. > Unless you have a strict need why this information is required? In general, I would wish that virtio-(v)fc has no hard requirement for creating real vports on the KVM host. From a zfcp perspective, it would be nice if already existing fc_hosts of any type (vport or not) could be configured for virtio-vfc pass through. A selection key could e.g. be fc_host.port_name which is the (NPIV) WWPN of the initiator. Rationale: A 1st level hypervisor manages physical devices. A 1st level hypervisor can pass through devices to a 1st level guest. On x86, the 1st level hypervisor is KVM. It can pass through PCI devices (physical or virtual functions). It can create vports (defining the NPIV WWPN) to pass through with virtio-vfc. From your presentation [1] I derived and as quite surprised that there does not seem to be a thing that combines a VF and vport (actually no VFs for HBAs at all), because then x86 would already have everything needed: Just PCI pass through a vport-VF and be done. If I understood your slides correctly "mediated device passthrough" would be a software "workaround" because the hardware does not provide vport-VFs. (The following assumes an FCP channel / zfcp perspective.) On s390, the 1st level hypervisor is PR/SM providing LPARs. The PR/SM ecosystem defines virtual function equivalents [2, slide 15]. They can either use NPIV (kind of a vport) or not (FCP channel hardware virtualization was there before NPIV). Admittedly, the latter case is probably of no(t so much) importance for a virtio-vfc use case {it would be more like virtio-fc, i.e. without the 'v' as in NPIV}. For the NPIV case, we have something like a vport and VF combined into a device, that we can sense on the system bus CCW (would be PCI on x86). The PR/SM ecosystem also defines the virtual NPIV WWPN for such initiator. An LPAR only sees an equivalent of virtual functions; it does not get access to a PF equivalent. Hence, zfcp can hardly reasonably implement the vport creation interface of scsi_transport_fc; it only fakes the fc_host.port_type but otherwise all zfcp fc_hosts are "real", i.e. non-vport. KVM as a 2nd level hypervisor sees the VF equivalents of the LPAR it runs in. Hence, KVM can only take whatever devices are there, HBA LLDDs in that KVM cannot create vports themselves. (BTW, in case of z/VM as 2nd level hypervisor, it supports live guest migration with zfcp devices passed through the 1st and the 2nd level hypervisor.) IOW, it would be nice if virtio-vfc could support nested KVM as 2nd level hypervisor just seeing already existing VFs or vports, which are in turn managed, defined and passed through by some 1st level hypervisor. A few more thoughts on your presentation [1]: "Devices on the vport will not be visible on the host" I could not agree more to the design point that devices (or at least their descendant object subtree) passed through to a guest should not appear on the host! With virtio-blk or virtio-scsi, we have SCSI devices and thus disks visible in the host, which needlessly scans partitions, or even worse automatically scans for LVM and maybe even activates PVs/VGs/LVs. It's hard for a KVM host admin to suppress this (and not break the devices the host needs itself). If we mirror the host's scsi_transport_fc tree including fc_rports and thus SCSI devices etc., we would have the same problems? Even more so, dev_loss_tmo and fast_io_fail_tmo would run independently on the host and in the guest on the same mirrored scsi_transport_fc object tree. I can envision user confusion having configured timeouts on the "wrong" side (host vs. guest). Also we would still need a mechanism to mirror fc_rport (un)block from host to guest for proper transport recovery. In zfcp we try to recover on transport rather than scsi_eh whenever possible because it is so much smoother. "Towards virtio-fc?" Using the FCP_CMND_IU (instead of just a plain SCB as with virtio-scsi) sounds promising to me as starting point. A listener from the audience asked if you would also do ELS/CT in the guest and you replied that this would not be good. Why is that? Based on above starting point, doing ELS/CT (and basic aborts and maybe a few other functions such as open/close ports or metadata transfer commands) in the guest is exactly what I would have expected. An HBA LLDD on the KVM host would implement such API and for all fc_hosts, passed through this way, it would *not* establish any scsi_transport_fc tree on the host. Instead the one virtio-vfc implementation in the guest would do this indendently of which HBA LLDD provides the passed through fc_host in the KVM host. ELS/CT pass through is maybe even for free via FC_BSG for those LLDDs that already implement it. Rport open/close is just the analogon of slave_alloc()/slave_destroy(). A new tricky part would be how to "unbind" an fc_host on the KVM host to be able to pass it through. (At least on x86) we have a vport and thus would not have a system bus (PCI) device we could unbind and then bind to the virtio-vfc equivalent of VFIO for pass through. A virtio-vfc API with sysfs interface for HBA LLDDs on the host could provide something similar on an fc_host level. Even better would be if an HBA LLDD would already know at probe time which of its fc_hosts are planned for pass through so it would not even start establishing the whole FC transport object tree with port discovery and the implied SCSI target scan. A late unbind would, at least with zfcp, cause the object tree to linger with fc_rports transitioning to "not present" state eventually (because zfcp uses the default FC_TGTID_BIND_BY_WWPN and the fc_host lives long until module unload or system shutdown, so fc_remote_port_delete() does not really delete rports from sysfs) and SCSI devices transitioning to "transport-offline" eventually. What do you think? REFERENCES [1] https://www.youtube.com/watch?v=ME1IdbtaU5E , https://events.static.linuxfound.org/sites/events/files/slides/kvmforum17-npiv.pdf [2] http://www-05.ibm.com/de/events/linux-on-z/pdf/day2/4_Steffen_Maier_zfcp-best-practices-2015.pdf
On 01/26/2018 05:54 PM, Steffen Maier wrote: > On 12/18/2017 09:31 AM, Hannes Reinecke wrote: >> On 12/15/2017 07:08 PM, Steffen Maier wrote: >>> On 12/14/2017 11:11 AM, Hannes Reinecke wrote: >>>> When a device announces an 'FC' protocol we should be pulling >>>> in the FC transport class to have the rports etc setup correctly. >>> >>> It took some time for me to understand what this does. >>> It seems to mirror the topology of rports and sdevs that exist under the >>> fc_host on the kvm host side to the virtio-scsi-fc side in the guest. >>> >>> I like the idea. This is also what I've been suggesting users to do if >>> they back virtio-scsi with zfcp on the kvm host side. Primarily to not >>> stall all virtio-scsi I/O on all paths if the guest ever gets into >>> scsi_eh. But also to make it look like an HBA pass through so one can >>> more easily migrate to this once we have FCP pass through. > > On second thought, I like the idea for virtio-scsi. > > For the future virtio-(v)fc case, see below. > >>>> @@ -755,19 +823,34 @@ static int virtscsi_abort(struct scsi_cmnd *sc) >>> >>>> + if (vscsi->protocol == SCSI_PROTOCOL_FCP) { >>>> + struct fc_rport *rport = >>>> + starget_to_rport(scsi_target(sc->device)); >>>> + if (rport && rport->dd_data ) { >>>> + tgt = rport->dd_data; >>>> + target_id = tgt->target_id; >>>> + } else >>>> + return FAST_IO_FAIL; >>>> + } else { >>>> + tgt = scsi_target(sc->device)->hostdata; >>>> + if (!tgt || tgt->removed) >>>> + return FAST_IO_FAIL; >>>> + } >>> >>> dito >>> >>>> @@ -857,27 +970,67 @@ static void virtscsi_rescan_work(struct >>>> work_struct *work) >>>> >>>> wait_for_completion(&comp); >>> >>> Waiting in work item .vs. having the response (IRQ) path trigger >>> subsequent processing async ? >>> Or do we need the call chain(s) getting here to be in our own process >>> context via the workqueue anyway? >>> >> Can't see I can parse this sentence, but I'll be looking at the code >> trying to come up with a clever explanation :-) > > Sorry, meanwhile I have a hard time understanding my own words, too. > > I think I wondered if the effort of a work item is really necessary, > especially considering that it does block on the completion and thus > could delay other queued work items (even though Concurrency Managed > Workqueues can often hide this delay). > > Couldn't we just return asynchronously after having sent the request. > And then later on, simply have the response (IRQ) path trigger whatever > processing is necessary (after the work item variant woke up from the > wait_for_completion) in some asynchronuous fashion? Of course, this > could also be a work item which just does necessary remaining processing > after we got a response. > Just a wild guess, without knowing the environmental requirements. > The main point here was that we get off the irq-completion handler; if we were to trigger this directly we would be running in an interrupt context, which then will make things like spin_lock, mutex et al tricky. Plus it's not really time critical; during rescanning all I/O should be blocked, so we shouldn't have anything else going on. >>>> + if (transport == SCSI_PROTOCOL_FCP) { >>>> + struct fc_rport_identifiers rport_ids; >>>> + struct fc_rport *rport; >>>> + >>>> + rport_ids.node_name = wwn_to_u64(cmd->resp.rescan.node_wwn); >>>> + rport_ids.port_name = wwn_to_u64(cmd->resp.rescan.port_wwn); >>>> + rport_ids.port_id = (target_id >> 8); >>> >>> Why do you shift target_id by one byte to the right? >>> >> Because with the original setup virtio_scsi guest would pass in the >> target_id, and the host would be selecting the device based on that >> information. >> With virtio-vfc we pass in the wwpn, but still require the target ID to >> be compliant with things like event notification etc. > > Don't we need the true N_Port-ID, then? That's what an fc_rport.port_id > usually contains. It's also a simple way to lookup resources on a SAN > switch for problem determination. Or did I misunderstand the > content/semantics of the variable target_id, assuming it's a SCSI target > ID, i.e. the 3rd part of a HCTL 4-tuple? > Yes, that was the idea. I've now modified the code so that we can pick up the port id for both, target and host port. That should satisfy the needs here. >> So I've shifted the target id onto the port ID (which is 24 bit anyway). >> I could've used a bitfield here, but then I wasn't quite sure about the >> endianness of which. > >>>> + rport = fc_remote_port_add(sh, 0, &rport_ids); >>>> + if (rport) { >>>> + tgt->rport = rport; >>>> + rport->dd_data = tgt; >>>> + fc_remote_port_rolechg(rport, FC_RPORT_ROLE_FCP_TARGET); >>> >>> Is the rolechg to get some event? Otherwise we could have >>> rport_ids.roles = FC_RPORT_ROLE_FCP_TARGET before fc_remote_port_add(). >>> >> That's how the 'normal' transport classes do it; but I'll check if this >> can be rolled into the call to fc_remote_port_add(). > > My idea was just based on how zfcp does it. Do you think I need to check > if zfcp should do it via rolechg (even though zfcp never changes an > rport role since it can only open targets)? > Yeah, modified that with the next version. >>>> @@ -932,14 +1089,31 @@ static void virtscsi_scan_host(struct >>>> virtio_scsi *vscsi) >>>> static void virtscsi_scan_start(struct Scsi_Host *sh) >>>> { > >>>> + if (vscsi->protocol == SCSI_PROTOCOL_FCP) { >>>> + fc_host_node_name(sh) = vscsi->wwnn; >>>> + fc_host_port_name(sh) = vscsi->wwpn; >>>> + fc_host_port_id(sh) = 0x00ff00; >>>> + fc_host_port_type(sh) = FC_PORTTYPE_NPIV; >>> >>> Why is this hardcoded? >>> >>> At least with zfcp, we can have kvm host *v*HBAs without NPIV. >>> >> For the simple fact that I don't have fields to transfer this >> information; plus it's not _actually_ used anywhere. > > It might not be used in this code, but it is exported to user space via > sysfs. If I understood things correctly, you newly introduce virtio-scsi > commands in patch 1 and are free to add more fields to struct > virtio_scsi_rescan_resp (maybe within some max size limit)? > To me, this raises the question which properties of the host's FC > (driver core) objects should be mirrored to the guest. Ideally all (and > that's a lot). > This in turn makes me wonder if mirroring is really desirable (e.g. > considering the effort) or if only the guest should have its own FC > object hierarchy which does _not_ exist on the KVM host in case an > fc_host is passed through with virtio-(v)fc. > The original idea here was to pass in NPIV hosts only; otherwise it might be simpler to use device passthrough and have the full device assigned to the guest. >> Unless you have a strict need why this information is required? > > In general, I would wish that virtio-(v)fc has no hard requirement for > creating real vports on the KVM host. From a zfcp perspective, it would > be nice if already existing fc_hosts of any type (vport or not) could be > configured for virtio-vfc pass through. A selection key could e.g. be > fc_host.port_name which is the (NPIV) WWPN of the initiator. > > Rationale: > > A 1st level hypervisor manages physical devices. > A 1st level hypervisor can pass through devices to a 1st level guest. > > On x86, the 1st level hypervisor is KVM. > It can pass through PCI devices (physical or virtual functions). > It can create vports (defining the NPIV WWPN) to pass through with > virtio-vfc. > From your presentation [1] I derived and as quite surprised that there > does not seem to be a thing that combines a VF and vport (actually no > VFs for HBAs at all), because then x86 would already have everything > needed: Just PCI pass through a vport-VF and be done. > If I understood your slides correctly "mediated device passthrough" > would be a software "workaround" because the hardware does not provide > vport-VFs. > Yeah, sort of. > (The following assumes an FCP channel / zfcp perspective.) > On s390, the 1st level hypervisor is PR/SM providing LPARs. > The PR/SM ecosystem defines virtual function equivalents [2, slide 15]. > They can either use NPIV (kind of a vport) or not (FCP channel hardware > virtualization was there before NPIV). Admittedly, the latter case is > probably of no(t so much) importance for a virtio-vfc use case {it would > be more like virtio-fc, i.e. without the 'v' as in NPIV}. > For the NPIV case, we have something like a vport and VF combined into a > device, that we can sense on the system bus CCW (would be PCI on x86). > The PR/SM ecosystem also defines the virtual NPIV WWPN for such initiator. > An LPAR only sees an equivalent of virtual functions; it does not get > access to a PF equivalent. > Hence, zfcp can hardly reasonably implement the vport creation interface > of scsi_transport_fc; it only fakes the fc_host.port_type but otherwise > all zfcp fc_hosts are "real", i.e. non-vport. > KVM as a 2nd level hypervisor sees the VF equivalents of the LPAR it > runs in. Hence, KVM can only take whatever devices are there, HBA LLDDs > in that KVM cannot create vports themselves. > (BTW, in case of z/VM as 2nd level hypervisor, it supports live guest > migration with zfcp devices passed through the 1st and the 2nd level > hypervisor.) > > IOW, it would be nice if virtio-vfc could support nested KVM as 2nd > level hypervisor just seeing already existing VFs or vports, which are > in turn managed, defined and passed through by some 1st level hypervisor. > As mentioned, there is nothing in the code which requires NPIV. It works happily with any FC HBA (or emulated devices, or whatever). From the guest side I just have exposed the port_id, wwpn, and wwnn, as this was the only fields I found a use-case for (like keeping lsscsi -t happy). If you have a need to for additional information we sure can add them. > > A few more thoughts on your presentation [1]: > > "Devices on the vport will not be visible on the host" > I could not agree more to the design point that devices (or at least > their descendant object subtree) passed through to a guest should not > appear on the host! > With virtio-blk or virtio-scsi, we have SCSI devices and thus disks > visible in the host, which needlessly scans partitions, or even worse > automatically scans for LVM and maybe even activates PVs/VGs/LVs. It's > hard for a KVM host admin to suppress this (and not break the devices > the host needs itself). > If we mirror the host's scsi_transport_fc tree including fc_rports and > thus SCSI devices etc., we would have the same problems? > Even more so, dev_loss_tmo and fast_io_fail_tmo would run independently > on the host and in the guest on the same mirrored scsi_transport_fc > object tree. I can envision user confusion having configured timeouts on > the "wrong" side (host vs. guest). Also we would still need a mechanism > to mirror fc_rport (un)block from host to guest for proper transport > recovery. In zfcp we try to recover on transport rather than scsi_eh > whenever possible because it is so much smoother. > As similar thing can be achieved event today, by setting the 'no_uld_attach' parameter when scanning the scsi device (that's what some RAID HBAs do). However, there currently is no way of modifying it from user-space, and certainly not to change the behaviour for existing devices. It should be relatively simple to set this flag whenever the host is exposed to a VM; we would still see the scsi devices, but the 'sd' driver won't be attached so nothing will scan the device on the host. > "Towards virtio-fc?" > Using the FCP_CMND_IU (instead of just a plain SCB as with virtio-scsi) > sounds promising to me as starting point. > A listener from the audience asked if you would also do ELS/CT in the > guest and you replied that this would not be good. Why is that? > Based on above starting point, doing ELS/CT (and basic aborts and maybe > a few other functions such as open/close ports or metadata transfer > commands) in the guest is exactly what I would have expected. An HBA > LLDD on the KVM host would implement such API and for all fc_hosts, > passed through this way, it would *not* establish any scsi_transport_fc > tree on the host. Instead the one virtio-vfc implementation in the guest > would do this indendently of which HBA LLDD provides the passed through > fc_host in the KVM host. > ELS/CT pass through is maybe even for free via FC_BSG for those LLDDs > that already implement it. > Rport open/close is just the analogon of slave_alloc()/slave_destroy(). > I'm not convinced that moving to full virtio-fc is something we want or even can do. Neither qla2xxx nor lpfc allow for direct FC frame access; so one would need to reformat the FC frames into something the driver understands, just so that the hardware can transform it back into FC frames. Another thing is xid management; some drivers have to do their own xid management, based on hardware capabilities etc. So the FC frames would need to re-write the xids, making it hard if not impossible to match things up when the response comes in. And, more importantly, what's the gain here? Which feature do we miss? > A new tricky part would be how to "unbind" an fc_host on the KVM host to > be able to pass it through. (At least on x86) we have a vport and thus > would not have a system bus (PCI) device we could unbind and then bind > to the virtio-vfc equivalent of VFIO for pass through. A virtio-vfc API > with sysfs interface for HBA LLDDs on the host could provide something > similar on an fc_host level. > Even better would be if an HBA LLDD would already know at probe time > which of its fc_hosts are planned for pass through so it would not even > start establishing the whole FC transport object tree with port > discovery and the implied SCSI target scan. A late unbind would, at > least with zfcp, cause the object tree to linger with fc_rports > transitioning to "not present" state eventually (because zfcp uses the > default FC_TGTID_BIND_BY_WWPN and the fc_host lives long until module > unload or system shutdown, so fc_remote_port_delete() does not really > delete rports from sysfs) and SCSI devices transitioning to > "transport-offline" eventually. > Hehe. That's one unresolved problem; the FC vendors have a hard time already figuring out how to bind to the various modes (FC inintiator, FC target, NVMe initiator, NVMe target, and all the combinations thereof). Not sure if we can solve it generically. Cheers, Hannes
On 02/02/2018 05:00 PM, Hannes Reinecke wrote: > On 01/26/2018 05:54 PM, Steffen Maier wrote: >> On 12/18/2017 09:31 AM, Hannes Reinecke wrote: >>> On 12/15/2017 07:08 PM, Steffen Maier wrote: >>>> On 12/14/2017 11:11 AM, Hannes Reinecke wrote: >> To me, this raises the question which properties of the host's FC >> (driver core) objects should be mirrored to the guest. Ideally all (and >> that's a lot). >> This in turn makes me wonder if mirroring is really desirable (e.g. >> considering the effort) or if only the guest should have its own FC >> object hierarchy which does _not_ exist on the KVM host in case an >> fc_host is passed through with virtio-(v)fc. >> A few more thoughts on your presentation [1]: >> >> "Devices on the vport will not be visible on the host" >> I could not agree more to the design point that devices (or at least >> their descendant object subtree) passed through to a guest should not >> appear on the host! >> With virtio-blk or virtio-scsi, we have SCSI devices and thus disks >> visible in the host, which needlessly scans partitions, or even worse >> automatically scans for LVM and maybe even activates PVs/VGs/LVs. It's >> hard for a KVM host admin to suppress this (and not break the devices >> the host needs itself). >> If we mirror the host's scsi_transport_fc tree including fc_rports and >> thus SCSI devices etc., we would have the same problems? >> Even more so, dev_loss_tmo and fast_io_fail_tmo would run independently >> on the host and in the guest on the same mirrored scsi_transport_fc >> object tree. I can envision user confusion having configured timeouts on >> the "wrong" side (host vs. guest). Also we would still need a mechanism >> to mirror fc_rport (un)block from host to guest for proper transport >> recovery. In zfcp we try to recover on transport rather than scsi_eh >> whenever possible because it is so much smoother. >> > As similar thing can be achieved event today, by setting the > 'no_uld_attach' parameter when scanning the scsi device > (that's what some RAID HBAs do). > However, there currently is no way of modifying it from user-space, and > certainly not to change the behaviour for existing devices. > It should be relatively simple to set this flag whenever the host is > exposed to a VM; we would still see the scsi devices, but the 'sd' > driver won't be attached so nothing will scan the device on the host. Ah, nice, didn't know that. It would solve the undesired I/O problem in the host. But it would not solve the so far somewhat unsynchronized state transitions of fc_rports on the host and their mirrors in the guest? I would be very interested in how you intend to do transport recovery. >> "Towards virtio-fc?" >> Using the FCP_CMND_IU (instead of just a plain SCB as with virtio-scsi) >> sounds promising to me as starting point. >> A listener from the audience asked if you would also do ELS/CT in the >> guest and you replied that this would not be good. Why is that? >> Based on above starting point, doing ELS/CT (and basic aborts and maybe >> a few other functions such as open/close ports or metadata transfer >> commands) in the guest is exactly what I would have expected. An HBA >> LLDD on the KVM host would implement such API and for all fc_hosts, >> passed through this way, it would *not* establish any scsi_transport_fc >> tree on the host. Instead the one virtio-vfc implementation in the guest >> would do this indendently of which HBA LLDD provides the passed through >> fc_host in the KVM host. >> ELS/CT pass through is maybe even for free via FC_BSG for those LLDDs >> that already implement it. >> Rport open/close is just the analogon of slave_alloc()/slave_destroy(). >> > I'm not convinced that moving to full virtio-fc is something we want or > even can do. > Neither qla2xxx nor lpfc allow for direct FC frame access; so one would > need to reformat the FC frames into something the driver understands, > just so that the hardware can transform it back into FC frames. I thought of a more high level para-virtualized FCP HBA interface, than FC frames (which did exist in kernel v2.4 under drivers/fc4/ but no longer as it seems). Just like large parts of today's FCP LLDDs handle scatter gather lists and framing is done by the hardware. > Another thing is xid management; some drivers have to do their own xid > management, based on hardware capabilities etc. > So the FC frames would need to re-write the xids, making it hard if not > impossible to match things up when the response comes in. For such things, where the hardware exposes more details (than, say, zfcp sees) I thought the LLDD on the KVM host would handle such details internally and only expose the higher level interface to virtio-fc. Maybe something roughly like the basic transport protocol part of ibmvfc/ibmvscsi (not the other end in the firmware and not the cross partition DMA part), if I understood its overall design correctly by quickly looking at the code. I somewhat had the impression that zfcp isn't too far from the overall operations style. As seem qla2xxx or lpfc to me, they just see and need to handle some more low-level FC details. Conceptually replace CRQ/RDMA or QDIO with virtio. (And for ibmvscsi also: SRP => FCP because it uses a different SCSI transport.) > And, more importantly, what's the gain here? > Which feature do we miss? Pros: Full transport_fc tree in guest (only) and reliable fc_rport state transitions done in the guest, where I would expect them as user for a passed through fc_host. No effort needed for transport tree mirroring and trying to get (mirrored) rport state transitions right. Cons: Of course such virtio-fc protocol/API would be a bit more than just FCP_CMND_IU and FCP_RSP_IU. It's also: abort, open/close port, open/close LUN, ELS, CT, get HBA metadata, and a mechanism for unsolicited notifications from the HBA LLDD on the KVM host side mainly for link up/down. And any host LLDD interested in supporting it would need some modifications to implement such API. Admittedly, with your currently limited transport tree property mirroring it is likely less effort to get a first working virtio-vfc. However, I would not call it fc_host pass through. To me it currently more looks like a bit of a "faked" (no offense) transport tree in the guest and the rest is close to today's virtio-scsi? I'm just trying to understand where this would be going, in order to get a conceptual impression or classification in my brain.
On 02/02/2018 06:39 PM, Steffen Maier wrote: > > On 02/02/2018 05:00 PM, Hannes Reinecke wrote: >> On 01/26/2018 05:54 PM, Steffen Maier wrote: >>> On 12/18/2017 09:31 AM, Hannes Reinecke wrote: >>>> On 12/15/2017 07:08 PM, Steffen Maier wrote: >>>>> On 12/14/2017 11:11 AM, Hannes Reinecke wrote: > >>> To me, this raises the question which properties of the host's FC >>> (driver core) objects should be mirrored to the guest. Ideally all (and >>> that's a lot). >>> This in turn makes me wonder if mirroring is really desirable (e.g. >>> considering the effort) or if only the guest should have its own FC >>> object hierarchy which does _not_ exist on the KVM host in case an >>> fc_host is passed through with virtio-(v)fc. > >>> A few more thoughts on your presentation [1]: >>> >>> "Devices on the vport will not be visible on the host" >>> I could not agree more to the design point that devices (or at least >>> their descendant object subtree) passed through to a guest should not >>> appear on the host! >>> With virtio-blk or virtio-scsi, we have SCSI devices and thus disks >>> visible in the host, which needlessly scans partitions, or even worse >>> automatically scans for LVM and maybe even activates PVs/VGs/LVs. It's >>> hard for a KVM host admin to suppress this (and not break the devices >>> the host needs itself). >>> If we mirror the host's scsi_transport_fc tree including fc_rports and >>> thus SCSI devices etc., we would have the same problems? >>> Even more so, dev_loss_tmo and fast_io_fail_tmo would run independently >>> on the host and in the guest on the same mirrored scsi_transport_fc >>> object tree. I can envision user confusion having configured timeouts on >>> the "wrong" side (host vs. guest). Also we would still need a mechanism >>> to mirror fc_rport (un)block from host to guest for proper transport >>> recovery. In zfcp we try to recover on transport rather than scsi_eh >>> whenever possible because it is so much smoother. >>> >> As similar thing can be achieved event today, by setting the >> 'no_uld_attach' parameter when scanning the scsi device >> (that's what some RAID HBAs do). >> However, there currently is no way of modifying it from user-space, and >> certainly not to change the behaviour for existing devices. >> It should be relatively simple to set this flag whenever the host is >> exposed to a VM; we would still see the scsi devices, but the 'sd' >> driver won't be attached so nothing will scan the device on the host. > > Ah, nice, didn't know that. It would solve the undesired I/O problem in > the host. > But it would not solve the so far somewhat unsynchronized state > transitions of fc_rports on the host and their mirrors in the guest? > > I would be very interested in how you intend to do transport recovery. > So am I :-) Current plan is to check fc-transport events; probably implementing a listener which then will manage the interface to the guest. Also I'm looking at implementing a new block device, which just gets a WWPN as input and manages all associated scsi (sg) devices. But that still needs some more work to be done. >>> "Towards virtio-fc?" [ .. ] >> I'm not convinced that moving to full virtio-fc is something we want or >> even can do. >> Neither qla2xxx nor lpfc allow for direct FC frame access; so one would >> need to reformat the FC frames into something the driver understands, >> just so that the hardware can transform it back into FC frames. > > I thought of a more high level para-virtualized FCP HBA interface, than > FC frames (which did exist in kernel v2.4 under drivers/fc4/ but no > longer as it seems). Just like large parts of today's FCP LLDDs handle > scatter gather lists and framing is done by the hardware. > But that would amount to yet another abstraction layer; not sure if it's worth the trouble... >> Another thing is xid management; some drivers have to do their own xid >> management, based on hardware capabilities etc. >> So the FC frames would need to re-write the xids, making it hard if not >> impossible to match things up when the response comes in. > > For such things, where the hardware exposes more details (than, say, > zfcp sees) I thought the LLDD on the KVM host would handle such details > internally and only expose the higher level interface to virtio-fc. > Yes; but that's what I'm aiming for with my virtio-vfc thingie already :-) > Maybe something roughly like the basic transport protocol part of > ibmvfc/ibmvscsi (not the other end in the firmware and not the cross > partition DMA part), if I understood its overall design correctly by > quickly looking at the code. > I somewhat had the impression that zfcp isn't too far from the overall > operations style. As seem qla2xxx or lpfc to me, they just see and need > to handle some more low-level FC details. > Conceptually replace CRQ/RDMA or QDIO with virtio. > (And for ibmvscsi also: SRP => FCP because it uses a different SCSI > transport.) > This is actually a different project; we're looking at extending libfc to cover ibmvfc, too. But that's even further down the line. >> And, more importantly, what's the gain here? >> Which feature do we miss? > > Pros: Full transport_fc tree in guest (only) and reliable fc_rport state > transitions done in the guest, where I would expect them as user for a > passed through fc_host. No effort needed for transport tree mirroring > and trying to get (mirrored) rport state transitions right. > > Cons: Of course such virtio-fc protocol/API would be a bit more than > just FCP_CMND_IU and FCP_RSP_IU. It's also: abort, open/close port, > open/close LUN, ELS, CT, get HBA metadata, and a mechanism for > unsolicited notifications from the HBA LLDD on the KVM host side mainly > for link up/down. And any host LLDD interested in supporting it would > need some modifications to implement such API. > > Admittedly, with your currently limited transport tree property > mirroring it is likely less effort to get a first working virtio-vfc. > However, I would not call it fc_host pass through. To me it currently > more looks like a bit of a "faked" (no offense) transport tree in the > guest and the rest is close to today's virtio-scsi? > I'm just trying to understand where this would be going, in order to get > a conceptual impression or classification in my brain. > Oh, it certainly is not fc_host pass through; indeed it _is_ a faked transport tree. vfc is just a better name; less degrading :-) And the overall idea here was to provide a _minimal_ emulation for virtio to simulate an FC host in the KVM guest. Basically, let's see if we can make it to work without having to reinvent yet another protocol, and layer it on top of the existing virtio scsi transport. Cheers, Hannes
diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c index a561e90..f925fbd 100644 --- a/drivers/scsi/virtio_scsi.c +++ b/drivers/scsi/virtio_scsi.c @@ -25,11 +25,13 @@ #include <linux/virtio_scsi.h> #include <linux/cpu.h> #include <linux/blkdev.h> +#include <linux/delay.h> #include <scsi/scsi_host.h> #include <scsi/scsi_device.h> #include <scsi/scsi_cmnd.h> #include <scsi/scsi_tcq.h> #include <scsi/scsi_devinfo.h> +#include <scsi/scsi_transport_fc.h> #include <linux/seqlock.h> #include <linux/blk-mq-virtio.h> @@ -91,6 +93,12 @@ struct virtio_scsi_vq { * an atomic_t. */ struct virtio_scsi_target_state { + struct list_head list; + struct fc_rport *rport; + struct virtio_scsi *vscsi; + int target_id; + bool removed; + seqcount_t tgt_seq; /* Count of outstanding requests. */ @@ -117,8 +125,12 @@ struct virtio_scsi { /* Protected by event_vq lock */ bool stop_events; + int protocol; int next_target_id; + u64 wwnn; + u64 wwpn; struct work_struct rescan_work; + struct list_head target_list; spinlock_t rescan_lock; struct virtio_scsi_vq ctrl_vq; @@ -128,6 +140,7 @@ struct virtio_scsi { static struct kmem_cache *virtscsi_cmd_cache; static mempool_t *virtscsi_cmd_pool; +static struct scsi_transport_template *virtio_transport_template; static inline struct Scsi_Host *virtio_scsi_host(struct virtio_device *vdev) { @@ -156,15 +169,21 @@ static void virtscsi_compute_resid(struct scsi_cmnd *sc, u32 resid) static void virtscsi_complete_cmd(struct virtio_scsi *vscsi, void *buf) { struct virtio_scsi_cmd *cmd = buf; + struct fc_rport *rport; struct scsi_cmnd *sc = cmd->sc; struct virtio_scsi_cmd_resp *resp = &cmd->resp.cmd; - struct virtio_scsi_target_state *tgt = - scsi_target(sc->device)->hostdata; + struct virtio_scsi_target_state *tgt; dev_dbg(&sc->device->sdev_gendev, "cmd %p response %u status %#02x sense_len %u\n", sc, resp->response, resp->status, resp->sense_len); + rport = starget_to_rport(scsi_target(sc->device)); + if (!rport) + tgt = scsi_target(sc->device)->hostdata; + else + tgt = rport->dd_data; + sc->result = resp->status; virtscsi_compute_resid(sc, virtio32_to_cpu(vscsi->vdev, resp->resid)); switch (resp->response) { @@ -502,10 +521,11 @@ static int virtscsi_kick_cmd(struct virtio_scsi_vq *vq, static void virtio_scsi_init_hdr(struct virtio_device *vdev, struct virtio_scsi_cmd_req *cmd, + int target_id, struct scsi_cmnd *sc) { cmd->lun[0] = 1; - cmd->lun[1] = sc->device->id; + cmd->lun[1] = target_id; cmd->lun[2] = (sc->device->lun >> 8) | 0x40; cmd->lun[3] = sc->device->lun & 0xff; cmd->tag = cpu_to_virtio64(vdev, (unsigned long)sc); @@ -517,12 +537,14 @@ static void virtio_scsi_init_hdr(struct virtio_device *vdev, #ifdef CONFIG_BLK_DEV_INTEGRITY static void virtio_scsi_init_hdr_pi(struct virtio_device *vdev, struct virtio_scsi_cmd_req_pi *cmd_pi, + int target_id, struct scsi_cmnd *sc) { struct request *rq = sc->request; struct blk_integrity *bi; - virtio_scsi_init_hdr(vdev, (struct virtio_scsi_cmd_req *)cmd_pi, sc); + virtio_scsi_init_hdr(vdev, (struct virtio_scsi_cmd_req *)cmd_pi, + target_id, sc); if (!rq || !scsi_prot_sg_count(sc)) return; @@ -542,6 +564,7 @@ static void virtio_scsi_init_hdr_pi(struct virtio_device *vdev, static int virtscsi_queuecommand(struct virtio_scsi *vscsi, struct virtio_scsi_vq *req_vq, + int target_id, struct scsi_cmnd *sc) { struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev); @@ -564,13 +587,15 @@ static int virtscsi_queuecommand(struct virtio_scsi *vscsi, #ifdef CONFIG_BLK_DEV_INTEGRITY if (virtio_has_feature(vscsi->vdev, VIRTIO_SCSI_F_T10_PI)) { - virtio_scsi_init_hdr_pi(vscsi->vdev, &cmd->req.cmd_pi, sc); + virtio_scsi_init_hdr_pi(vscsi->vdev, &cmd->req.cmd_pi, + target_id, sc); memcpy(cmd->req.cmd_pi.cdb, sc->cmnd, sc->cmd_len); req_size = sizeof(cmd->req.cmd_pi); } else #endif { - virtio_scsi_init_hdr(vscsi->vdev, &cmd->req.cmd, sc); + virtio_scsi_init_hdr(vscsi->vdev, &cmd->req.cmd, + target_id, sc); memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len); req_size = sizeof(cmd->req.cmd); } @@ -591,11 +616,25 @@ static int virtscsi_queuecommand_single(struct Scsi_Host *sh, struct scsi_cmnd *sc) { struct virtio_scsi *vscsi = shost_priv(sh); - struct virtio_scsi_target_state *tgt = - scsi_target(sc->device)->hostdata; - + struct virtio_scsi_target_state *tgt = NULL; + int target_id = sc->device->id; + + if (vscsi->protocol == SCSI_PROTOCOL_FCP) { + struct fc_rport *rport = + starget_to_rport(scsi_target(sc->device)); + if (rport && rport->dd_data) { + tgt = rport->dd_data; + target_id = tgt->target_id; + } + } else + tgt = scsi_target(sc->device)->hostdata; + if (!tgt || tgt->removed) { + sc->result = DID_NO_CONNECT << 16; + sc->scsi_done(sc); + return 0; + } atomic_inc(&tgt->reqs); - return virtscsi_queuecommand(vscsi, &vscsi->req_vqs[0], sc); + return virtscsi_queuecommand(vscsi, &vscsi->req_vqs[0], target_id, sc); } static struct virtio_scsi_vq *virtscsi_pick_vq_mq(struct virtio_scsi *vscsi, @@ -648,16 +687,30 @@ static int virtscsi_queuecommand_multi(struct Scsi_Host *sh, struct scsi_cmnd *sc) { struct virtio_scsi *vscsi = shost_priv(sh); - struct virtio_scsi_target_state *tgt = - scsi_target(sc->device)->hostdata; + struct virtio_scsi_target_state *tgt = NULL; struct virtio_scsi_vq *req_vq; - + int target_id = sc->device->id; + + if (vscsi->protocol == SCSI_PROTOCOL_FCP) { + struct fc_rport *rport = + starget_to_rport(scsi_target(sc->device)); + if (rport && rport->dd_data) { + tgt = rport->dd_data; + target_id = tgt->target_id; + } + } else + tgt = scsi_target(sc->device)->hostdata; + if (!tgt || tgt->removed) { + sc->result = DID_NO_CONNECT << 16; + sc->scsi_done(sc); + return 0; + } if (shost_use_blk_mq(sh)) req_vq = virtscsi_pick_vq_mq(vscsi, sc); else req_vq = virtscsi_pick_vq(vscsi, tgt); - return virtscsi_queuecommand(vscsi, req_vq, sc); + return virtscsi_queuecommand(vscsi, req_vq, target_id, sc); } static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd) @@ -696,12 +749,27 @@ static int virtscsi_device_reset(struct scsi_cmnd *sc) { struct virtio_scsi *vscsi = shost_priv(sc->device->host); struct virtio_scsi_cmd *cmd; + struct virtio_scsi_target_state *tgt = NULL; + int target_id = sc->device->id; sdev_printk(KERN_INFO, sc->device, "device reset\n"); cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO); if (!cmd) return FAILED; + if (vscsi->protocol == SCSI_PROTOCOL_FCP) { + struct fc_rport *rport = + starget_to_rport(scsi_target(sc->device)); + if (rport && rport->dd_data ) { + tgt = rport->dd_data; + target_id = tgt->target_id; + } else + return FAST_IO_FAIL; + } else { + tgt = scsi_target(sc->device)->hostdata; + if (!tgt || tgt->removed) + return FAST_IO_FAIL; + } memset(cmd, 0, sizeof(*cmd)); cmd->sc = sc; cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){ @@ -709,7 +777,7 @@ static int virtscsi_device_reset(struct scsi_cmnd *sc) .subtype = cpu_to_virtio32(vscsi->vdev, VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET), .lun[0] = 1, - .lun[1] = sc->device->id, + .lun[1] = target_id, .lun[2] = (sc->device->lun >> 8) | 0x40, .lun[3] = sc->device->lun & 0xff, }; @@ -755,19 +823,34 @@ static int virtscsi_abort(struct scsi_cmnd *sc) { struct virtio_scsi *vscsi = shost_priv(sc->device->host); struct virtio_scsi_cmd *cmd; + struct virtio_scsi_target_state *tgt = NULL; + int target_id = sc->device->id; scmd_printk(KERN_INFO, sc, "abort\n"); cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO); if (!cmd) return FAILED; + if (vscsi->protocol == SCSI_PROTOCOL_FCP) { + struct fc_rport *rport = + starget_to_rport(scsi_target(sc->device)); + if (rport && rport->dd_data ) { + tgt = rport->dd_data; + target_id = tgt->target_id; + } else + return FAST_IO_FAIL; + } else { + tgt = scsi_target(sc->device)->hostdata; + if (!tgt || tgt->removed) + return FAST_IO_FAIL; + } memset(cmd, 0, sizeof(*cmd)); cmd->sc = sc; cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){ .type = VIRTIO_SCSI_T_TMF, .subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK, .lun[0] = 1, - .lun[1] = sc->device->id, + .lun[1] = target_id, .lun[2] = (sc->device->lun >> 8) | 0x40, .lun[3] = sc->device->lun & 0xff, .tag = cpu_to_virtio64(vscsi->vdev, (unsigned long)sc), @@ -777,25 +860,54 @@ static int virtscsi_abort(struct scsi_cmnd *sc) static int virtscsi_target_alloc(struct scsi_target *starget) { - struct Scsi_Host *sh = dev_to_shost(starget->dev.parent); - struct virtio_scsi *vscsi = shost_priv(sh); - - struct virtio_scsi_target_state *tgt = - kmalloc(sizeof(*tgt), GFP_KERNEL); - if (!tgt) - return -ENOMEM; - + struct Scsi_Host *sh; + struct virtio_scsi *vscsi; + struct fc_rport *rport; + struct virtio_scsi_target_state *tgt; + + rport = starget_to_rport(starget); + if (rport) { + tgt = rport->dd_data; + sh = rport_to_shost(rport); + vscsi = shost_priv(sh); + } else { + sh = dev_to_shost(starget->dev.parent); + vscsi = shost_priv(sh); + spin_lock_irq(&vscsi->rescan_lock); + list_for_each_entry(tgt, &vscsi->target_list, list) { + if (tgt->target_id == starget->id) { + starget->hostdata = tgt; + break; + } + } + spin_unlock_irq(&vscsi->rescan_lock); + if (!starget->hostdata) + return -ENOMEM; + tgt = starget->hostdata; + } seqcount_init(&tgt->tgt_seq); atomic_set(&tgt->reqs, 0); tgt->req_vq = &vscsi->req_vqs[0]; - - starget->hostdata = tgt; + tgt->vscsi = vscsi; return 0; } static void virtscsi_target_destroy(struct scsi_target *starget) { - struct virtio_scsi_target_state *tgt = starget->hostdata; + struct fc_rport *rport; + struct virtio_scsi_target_state *tgt; + + rport = starget_to_rport(starget); + if (rport) { + tgt = rport->dd_data; + rport->dd_data = NULL; + } else { + tgt = starget->hostdata; + starget->hostdata = NULL; + } + spin_lock_irq(&tgt->vscsi->rescan_lock); + list_del_init(&tgt->list); + spin_unlock_irq(&tgt->vscsi->rescan_lock); kfree(tgt); } @@ -821,8 +933,9 @@ static void virtscsi_rescan_work(struct work_struct *work) struct virtio_scsi *vscsi = container_of(work, struct virtio_scsi, rescan_work); struct Scsi_Host *sh = virtio_scsi_host(vscsi->vdev); - int target_id, ret; + int target_id, ret, transport; struct virtio_scsi_cmd *cmd; + struct virtio_scsi_target_state *tgt, *tmp, *old; DECLARE_COMPLETION_ONSTACK(comp); spin_lock_irq(&vscsi->rescan_lock); @@ -857,27 +970,67 @@ static void virtscsi_rescan_work(struct work_struct *work) wait_for_completion(&comp); target_id = virtio32_to_cpu(vscsi->vdev, cmd->resp.rescan.id); - if (target_id != -1) { - int transport = virtio32_to_cpu(vscsi->vdev, - cmd->resp.rescan.transport); - spin_lock_irq(&vscsi->rescan_lock); - vscsi->next_target_id = target_id + 1; - spin_unlock_irq(&vscsi->rescan_lock); - shost_printk(KERN_INFO, sh, - "found %s target %d (WWN %*phN)\n", - transport == SCSI_PROTOCOL_FCP ? "FC" : "SAS", - target_id, 8, - cmd->resp.rescan.port_wwn); - scsi_scan_target(&sh->shost_gendev, 0, target_id, - SCAN_WILD_CARD, SCSI_SCAN_INITIAL); - queue_work(system_freezable_wq, &vscsi->rescan_work); - } else { + if (target_id == -1) { shost_printk(KERN_INFO, sh, "rescan: no more targets\n"); spin_lock_irq(&vscsi->rescan_lock); vscsi->next_target_id = -1; spin_unlock_irq(&vscsi->rescan_lock); + goto out; + } + transport = virtio32_to_cpu(vscsi->vdev, cmd->resp.rescan.transport); + shost_printk(KERN_INFO, sh, + "found %s target %d (WWN %*phN)\n", + transport == SCSI_PROTOCOL_FCP ? "FC" : "SAS", + target_id, 8, cmd->resp.rescan.port_wwn); + + tgt = kmalloc(sizeof(*tgt), GFP_KERNEL); + if (!tgt) { + shost_printk(KERN_WARNING, sh, + "rescan: out of memory for rport\n"); + goto out; + } + tgt->target_id = (target_id & 0xff) + tgt->removed = false; + spin_lock_irq(&vscsi->rescan_lock); + vscsi->next_target_id = tgt->target_id + 1; + list_for_each_entry(tmp, &vscsi->target_list, list) { + if (tgt->target_id == tmp->target_id) { + old = tmp; + break; + } } + if (old) { + kfree(tgt); + tgt = old; + } else + list_add_tail(&tgt->list, &vscsi->target_list); + spin_unlock_irq(&vscsi->rescan_lock); + if (transport == SCSI_PROTOCOL_FCP) { + struct fc_rport_identifiers rport_ids; + struct fc_rport *rport; + + rport_ids.node_name = wwn_to_u64(cmd->resp.rescan.node_wwn); + rport_ids.port_name = wwn_to_u64(cmd->resp.rescan.port_wwn); + rport_ids.port_id = (target_id >> 8); + rport = fc_remote_port_add(sh, 0, &rport_ids); + if (rport) { + tgt->rport = rport; + rport->dd_data = tgt; + fc_remote_port_rolechg(rport, FC_RPORT_ROLE_FCP_TARGET); + } else { + spin_lock_irq(&vscsi->rescan_lock); + list_del(&tgt->list); + spin_unlock_irq(&vscsi->rescan_lock); + kfree(tgt); + tgt = NULL; + } + } else { + scsi_scan_target(&sh->shost_gendev, 0, tgt->target_id, + SCAN_WILD_CARD, SCSI_SCAN_INITIAL); + } + queue_work(system_freezable_wq, &vscsi->rescan_work); +out: mempool_free(cmd, virtscsi_cmd_pool); return; scan_host: @@ -920,11 +1073,15 @@ static void virtscsi_scan_host(struct virtio_scsi *vscsi) if (cmd->resp.rescan.id == -1) { int transport = virtio32_to_cpu(vscsi->vdev, cmd->resp.rescan.transport); + shost_printk(KERN_INFO, sh, "%s host wwnn %*phN wwpn %*phN\n", transport == SCSI_PROTOCOL_FCP ? "FC" : "SAS", 8, cmd->resp.rescan.node_wwn, 8, cmd->resp.rescan.port_wwn); + vscsi->protocol = transport; + vscsi->wwnn = wwn_to_u64(cmd->resp.rescan.node_wwn); + vscsi->wwpn = wwn_to_u64(cmd->resp.rescan.port_wwn); } mempool_free(cmd, virtscsi_cmd_pool); } @@ -932,14 +1089,31 @@ static void virtscsi_scan_host(struct virtio_scsi *vscsi) static void virtscsi_scan_start(struct Scsi_Host *sh) { struct virtio_scsi *vscsi = shost_priv(sh); + struct virtio_scsi_target_state *tgt; - virtscsi_scan_host(vscsi); spin_lock_irq(&vscsi->rescan_lock); if (vscsi->next_target_id != -1) { shost_printk(KERN_INFO, sh, "rescan: already running\n"); spin_unlock_irq(&vscsi->rescan_lock); return; } + if (vscsi->protocol == SCSI_PROTOCOL_FCP) { + fc_host_node_name(sh) = vscsi->wwnn; + fc_host_port_name(sh) = vscsi->wwpn; + fc_host_port_id(sh) = 0x00ff00; + fc_host_port_type(sh) = FC_PORTTYPE_NPIV; + fc_host_port_state(sh) = FC_PORTSTATE_BLOCKED; + list_for_each_entry(tgt, &vscsi->target_list, list) { + if (tgt->rport) { + fc_remote_port_delete(tgt->rport); + tgt->rport = NULL; + } + tgt->removed = true; + } + } else { + list_for_each_entry(tgt, &vscsi->target_list, list) + tgt->removed = true; + } vscsi->next_target_id = 0; shost_printk(KERN_INFO, sh, "rescan: start\n"); spin_unlock_irq(&vscsi->rescan_lock); @@ -954,12 +1128,14 @@ int virtscsi_scan_finished(struct Scsi_Host *sh, unsigned long time) spin_lock_irq(&vscsi->rescan_lock); if (vscsi->next_target_id != -1) ret = 0; + else if (vscsi->protocol == SCSI_PROTOCOL_FCP) + fc_host_port_state(sh) = FC_PORTSTATE_ONLINE; spin_unlock_irq(&vscsi->rescan_lock); if (!ret) flush_work(&vscsi->rescan_work); - shost_printk(KERN_INFO, sh, "rescan: %s finished\n", - ret ? "" : "not"); + shost_printk(KERN_INFO, sh, "rescan: %sfinished\n", + ret ? "" : "not "); return ret; } @@ -978,6 +1154,34 @@ static ssize_t virtscsi_host_store_rescan(struct device *dev, NULL, }; +static int virtscsi_issue_lip(struct Scsi_Host *shost) +{ + struct virtio_scsi *vscsi = shost_priv(shost); + unsigned long start = jiffies; + struct virtio_scsi_target_state *tgt; + + spin_lock_irq(&vscsi->rescan_lock); + if (vscsi->next_target_id != -1) { + spin_unlock_irq(&vscsi->rescan_lock); + return 0; + } + fc_host_port_state(shost) = FC_PORTSTATE_BLOCKED; + list_for_each_entry(tgt, &vscsi->target_list, list) { + if (tgt->rport) { + fc_remote_port_delete(tgt->rport); + tgt->rport = NULL; + } + } + vscsi->next_target_id = 0; + spin_unlock_irq(&vscsi->rescan_lock); + queue_work(system_freezable_wq, &vscsi->rescan_work); + + while (!virtscsi_scan_finished(shost, jiffies - start)) + msleep(10); + + return 0; +} + static struct scsi_host_template virtscsi_host_template_single = { .module = THIS_MODULE, .name = "Virtio SCSI HBA", @@ -1066,6 +1270,20 @@ static ssize_t virtscsi_host_store_rescan(struct device *dev, .track_queue_depth = 1, }; +static struct fc_function_template virtscsi_transport_functions = { + .dd_fcrport_size = sizeof(struct virtio_scsi_target_state *), + .show_host_node_name = 1, + .show_host_port_name = 1, + .show_host_port_id = 1, + .show_host_port_state = 1, + .show_host_port_type = 1, + .show_starget_node_name = 1, + .show_starget_port_name = 1, + .show_starget_port_id = 1, + .show_rport_dev_loss_tmo = 1, + .issue_fc_host_lip = virtscsi_issue_lip, +}; + #define virtscsi_config_get(vdev, fld) \ ({ \ typeof(((struct virtio_scsi_config *)0)->fld) __val; \ @@ -1193,7 +1411,9 @@ static int virtscsi_probe(struct virtio_device *vdev) vscsi->num_queues = num_queues; vdev->priv = shost; vscsi->next_target_id = -1; + vscsi->protocol = SCSI_PROTOCOL_SAS; spin_lock_init(&vscsi->rescan_lock); + INIT_LIST_HEAD(&vscsi->target_list); INIT_WORK(&vscsi->rescan_work, virtscsi_rescan_work); err = virtscsi_init(vdev, vscsi); @@ -1228,6 +1448,10 @@ static int virtscsi_probe(struct virtio_device *vdev) } #endif + virtscsi_scan_host(vscsi); + if (vscsi->protocol == SCSI_PROTOCOL_FCP) + shost->transportt = virtio_transport_template; + err = scsi_add_host(shost, &vdev->dev); if (err) goto scsi_add_host_failed; @@ -1332,6 +1556,10 @@ static int __init init(void) pr_err("mempool_create() for virtscsi_cmd_pool failed\n"); goto error; } + virtio_transport_template = + fc_attach_transport(&virtscsi_transport_functions); + if (!virtio_transport_template) + goto error; ret = register_virtio_driver(&virtio_scsi_driver); if (ret < 0) goto error; @@ -1339,6 +1567,8 @@ static int __init init(void) return 0; error: + if (virtio_transport_template) + fc_release_transport(virtio_transport_template); if (virtscsi_cmd_pool) { mempool_destroy(virtscsi_cmd_pool); virtscsi_cmd_pool = NULL; @@ -1352,6 +1582,7 @@ static int __init init(void) static void __exit fini(void) { + fc_release_transport(virtio_transport_template); unregister_virtio_driver(&virtio_scsi_driver); mempool_destroy(virtscsi_cmd_pool); kmem_cache_destroy(virtscsi_cmd_cache);
When a device announces an 'FC' protocol we should be pulling in the FC transport class to have the rports etc setup correctly. Signed-off-by: Hannes Reinecke <hare@suse.com> --- drivers/scsi/virtio_scsi.c | 323 ++++++++++++++++++++++++++++++++++++++------- 1 file changed, 277 insertions(+), 46 deletions(-)