From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [PATCH v1 1/2] vfio-ccw: Set subchannel state STANDBY on open References: <1557148270-19901-1-git-send-email-pmorel@linux.ibm.com> <1557148270-19901-2-git-send-email-pmorel@linux.ibm.com> From: Farhan Ali Date: Tue, 7 May 2019 15:44:54 -0400 MIME-Version: 1.0 In-Reply-To: <1557148270-19901-2-git-send-email-pmorel@linux.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Message-Id: <3a55983d-c304-ec7e-f53d-8380576b9a42@linux.ibm.com> Sender: kvm-owner@vger.kernel.org List-Archive: List-Post: To: Pierre Morel , cohuck@redhat.com Cc: pasic@linux.vnet.ibm.com, farman@linux.ibm.com, linux-s390@vger.kernel.org, kvm@vger.kernel.org List-ID: On 05/06/2019 09:11 AM, Pierre Morel wrote: > When no guest is associated with the mediated device, > i.e. the mediated device is not opened, the state of > the mediated device is VFIO_CCW_STATE_NOT_OPER. > > The subchannel enablement and the according setting to the > VFIO_CCW_STATE_STANDBY state should only be done when all > parts of the VFIO mediated device have been initialized > i.e. after the mediated device has been successfully opened. > > Let's stay in VFIO_CCW_STATE_NOT_OPER until the mediated > device has been opened. > > When the mediated device is closed, disable the sub channel > by calling vfio_ccw_sch_quiesce() no reset needs to be done > the mediated devce will be enable on next open. s/devce/device > > Signed-off-by: Pierre Morel > --- > drivers/s390/cio/vfio_ccw_drv.c | 10 +--------- > drivers/s390/cio/vfio_ccw_ops.c | 36 ++++++++++++++++++------------------ > 2 files changed, 19 insertions(+), 27 deletions(-) > > diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c > index ee8767f..a95b6c7 100644 > --- a/drivers/s390/cio/vfio_ccw_drv.c > +++ b/drivers/s390/cio/vfio_ccw_drv.c > @@ -143,26 +143,18 @@ static int vfio_ccw_sch_probe(struct subchannel *sch) > dev_set_drvdata(&sch->dev, private); > mutex_init(&private->io_mutex); > > - spin_lock_irq(sch->lock); > private->state = VFIO_CCW_STATE_NOT_OPER; > sch->isc = VFIO_CCW_ISC; > - ret = cio_enable_subchannel(sch, (u32)(unsigned long)sch); > - spin_unlock_irq(sch->lock); > - if (ret) > - goto out_free; > > INIT_WORK(&private->io_work, vfio_ccw_sch_io_todo); > atomic_set(&private->avail, 1); > - private->state = VFIO_CCW_STATE_STANDBY; > > ret = vfio_ccw_mdev_reg(sch); > if (ret) > - goto out_disable; > + goto out_free; > > return 0; > > -out_disable: > - cio_disable_subchannel(sch); > out_free: > dev_set_drvdata(&sch->dev, NULL); > if (private->cmd_region) > diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c > index 5eb6111..497419c 100644 > --- a/drivers/s390/cio/vfio_ccw_ops.c > +++ b/drivers/s390/cio/vfio_ccw_ops.c > @@ -115,14 +115,10 @@ static int vfio_ccw_mdev_create(struct kobject *kobj, struct mdev_device *mdev) > struct vfio_ccw_private *private = > dev_get_drvdata(mdev_parent_dev(mdev)); > > - if (private->state == VFIO_CCW_STATE_NOT_OPER) > - return -ENODEV; > - > if (atomic_dec_if_positive(&private->avail) < 0) > return -EPERM; > > private->mdev = mdev; > - private->state = VFIO_CCW_STATE_IDLE; > > return 0; > } > @@ -132,12 +128,7 @@ static int vfio_ccw_mdev_remove(struct mdev_device *mdev) > struct vfio_ccw_private *private = > dev_get_drvdata(mdev_parent_dev(mdev)); > > - if ((private->state != VFIO_CCW_STATE_NOT_OPER) && > - (private->state != VFIO_CCW_STATE_STANDBY)) { > - if (!vfio_ccw_sch_quiesce(private->sch)) > - private->state = VFIO_CCW_STATE_STANDBY; > - /* The state will be NOT_OPER on error. */ > - } > + vfio_ccw_sch_quiesce(private->sch); > > cp_free(&private->cp); > private->mdev = NULL; > @@ -151,6 +142,7 @@ static int vfio_ccw_mdev_open(struct mdev_device *mdev) > struct vfio_ccw_private *private = > dev_get_drvdata(mdev_parent_dev(mdev)); > unsigned long events = VFIO_IOMMU_NOTIFY_DMA_UNMAP; > + struct subchannel *sch = private->sch; > int ret; > > private->nb.notifier_call = vfio_ccw_mdev_notifier; > @@ -165,6 +157,20 @@ static int vfio_ccw_mdev_open(struct mdev_device *mdev) > vfio_unregister_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY, > &private->nb); > return ret; > + > + spin_lock_irq(private->sch->lock); > + if (cio_enable_subchannel(sch, (u32)(unsigned long)sch)) > + goto error; > + > + private->state = VFIO_CCW_STATE_STANDBY; I don't think we should set the state to STANDBY here, because with just this patch applied, any VFIO_CCW_EVENT_IO_REQ will return an error (due to fsm_io_error). It might be safe to set it to IDLE in this patch. > + spin_unlock_irq(sch->lock); > + return 0; > + > +error: > + spin_unlock_irq(sch->lock); > + vfio_unregister_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY, > + &private->nb); > + return -EFAULT; > } > > static void vfio_ccw_mdev_release(struct mdev_device *mdev) > @@ -173,20 +179,14 @@ static void vfio_ccw_mdev_release(struct mdev_device *mdev) > dev_get_drvdata(mdev_parent_dev(mdev)); > int i; > > - if ((private->state != VFIO_CCW_STATE_NOT_OPER) && > - (private->state != VFIO_CCW_STATE_STANDBY)) { > - if (!vfio_ccw_mdev_reset(mdev)) > - private->state = VFIO_CCW_STATE_STANDBY; > - /* The state will be NOT_OPER on error. */ > - } > - > - cp_free(&private->cp); > + vfio_ccw_sch_quiesce(private->sch); > vfio_unregister_notifier(mdev_dev(mdev), VFIO_IOMMU_NOTIFY, > &private->nb); > > for (i = 0; i < private->num_regions; i++) > private->region[i].ops->release(private, &private->region[i]); > > + cp_free(&private->cp); > private->num_regions = 0; > kfree(private->region); > private->region = NULL; >