Commit 93d16d81 authored by Yi Min Zhao's avatar Yi Min Zhao Committed by Cornelia Huck
Browse files

s390x/pci: make hot-unplug handler smoother 



The current implementation of hot-unplug handler is abrupt. Any pci
operation will be just rejected if pci device is unconfigured. Thus a
pci device can not be reset or destroyed in a right, smooth and safe
way.

Improve this as follows:
- Notify the guest via a HP_EVENT_DECONFIGURE_REQUEST(0x303) event in
  the unplug handler, giving it a chance to deconfigure the device via
  sclp and allowing us to continue hot-unplug afterwards.
- Set up a timer that will generate the HP_EVENT_CONFIGURE_TO_STBRES
  (0x304) event as before if the guest did not react after an adequate
  time.

Signed-off-by: default avatarYi Min Zhao <zyimin@linux.vnet.ibm.com>
Reviewed-by: default avatarPierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
parent cdd85eb2

hw/s390x/s390-pci-bus.c

+34 −1
Original line number Diff line number Diff line
@@ -192,6 +192,10 @@ void s390_pci_sclp_deconfigure(SCCB *sccb) 
        }

        pbdev->state = ZPCI_FS_STANDBY;

        rc = SCLP_RC_NORMAL_COMPLETION;



        if (pbdev->release_timer) {

            qdev_unplug(DEVICE(pbdev->pdev), NULL);

        }

    }

out:

    psccb->header.response_code = cpu_to_be16(rc);
@@ -679,6 +683,23 @@ static void s390_pcihost_hot_plug(HotplugHandler *hotplug_dev, 
    }

}



static void s390_pcihost_timer_cb(void *opaque)

{

    S390PCIBusDevice *pbdev = opaque;



    if (pbdev->summary_ind) {

        pci_dereg_irqs(pbdev);

    }

    if (pbdev->iommu_enabled) {

        pci_dereg_ioat(pbdev);

    }



    pbdev->state = ZPCI_FS_STANDBY;

    s390_pci_generate_plug_event(HP_EVENT_CONFIGURED_TO_STBRES,

                                 pbdev->fh, pbdev->fid);

    qdev_unplug(DEVICE(pbdev), NULL);

}



static void s390_pcihost_hot_unplug(HotplugHandler *hotplug_dev,

                                    DeviceState *dev, Error **errp)

{
@@ -712,8 +733,20 @@ static void s390_pcihost_hot_unplug(HotplugHandler *hotplug_dev, 
    case ZPCI_FS_STANDBY:

        break;

    default:

        s390_pci_generate_plug_event(HP_EVENT_CONFIGURED_TO_STBRES,

        s390_pci_generate_plug_event(HP_EVENT_DECONFIGURE_REQUEST,

                                     pbdev->fh, pbdev->fid);

        pbdev->release_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,

                                            s390_pcihost_timer_cb,

                                            pbdev);

        timer_mod(pbdev->release_timer,

                  qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + HOT_UNPLUG_TIMEOUT);

        return;

    }



    if (pbdev->release_timer && timer_pending(pbdev->release_timer)) {

        timer_del(pbdev->release_timer);

        timer_free(pbdev->release_timer);

        pbdev->release_timer = NULL;

    }



    s390_pci_generate_plug_event(HP_EVENT_STANDBY_TO_RESERVED,

hw/s390x/s390-pci-bus.h

+3 −0
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ 
#define ZPCI_MAX_UID 0xffff

#define UID_UNDEFINED 0

#define UID_CHECKING_ENABLED 0x01

#define HOT_UNPLUG_TIMEOUT (NANOSECONDS_PER_SECOND * 60 * 5)



#define S390_PCI_HOST_BRIDGE(obj) \

    OBJECT_CHECK(S390pciState, (obj), TYPE_S390_PCI_HOST_BRIDGE)
@@ -44,6 +45,7 @@ 


#define HP_EVENT_TO_CONFIGURED        0x0301

#define HP_EVENT_RESERVED_TO_STANDBY  0x0302

#define HP_EVENT_DECONFIGURE_REQUEST  0x0303

#define HP_EVENT_CONFIGURED_TO_STBRES 0x0304

#define HP_EVENT_STANDBY_TO_RESERVED  0x0308
@@ -283,6 +285,7 @@ typedef struct S390PCIBusDevice { 
    MemoryRegion iommu_mr;

    IndAddr *summary_ind;

    IndAddr *indicator;

    QEMUTimer *release_timer;

} S390PCIBusDevice;



typedef struct S390PCIBus {