linux-kernel - Re: [PATCH v2 1/2] vfio : resume notifier

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Date:	Fri, 29 Jul 2016 11:11:58 -0600
From:	Alex Williamson <alex.williamson@...hat.com>
To:	Zhou Jie <zhoujie2011@...fujitsu.com>
Cc:	<linux-kernel@...r.kernel.org>, <qemu-devel@...gnu.org>,
	<izumi.taku@...fujitsu.com>, <fan.chen@...ystack.cn>,
	Chen Fan <chen.fan.fnst@...fujitsu.com>
Subject: Re: [PATCH v2 1/2] vfio : resume notifier

On Tue, 19 Jul 2016 15:52:45 +0800
Zhou Jie <zhoujie2011@...fujitsu.com> wrote:

> From: Chen Fan <chen.fan.fnst@...fujitsu.com>

An empty commit log is unacceptable for all but the most trivial
patches.

There's also no sign-off on this patch.

I also don't know why we need this since you previously found that for
QEMU, ordering of error versus resume notifications is not guaranteed,
which is why I thought we went with a status flag within the struct
vfio_device_info.  I'm not adding an interrupt to the user that has
no users.  This was not part of the most recent discussion we had about
this, so I'm lost why this patch exists. Thanks,

Alex

> ---
>  drivers/vfio/pci/vfio_pci.c         | 28 +++++++++++++++++++++++++++-
>  drivers/vfio/pci/vfio_pci_intrs.c   | 18 ++++++++++++++++++
>  drivers/vfio/pci/vfio_pci_private.h |  1 +
>  include/uapi/linux/vfio.h           |  1 +
>  4 files changed, 47 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
> index 188b1ff..2d12b03 100644
> --- a/drivers/vfio/pci/vfio_pci.c
> +++ b/drivers/vfio/pci/vfio_pci.c
> @@ -363,7 +363,8 @@ static int vfio_pci_get_irq_count(struct vfio_pci_device *vdev, int irq_type)
>  
>  			return (flags & PCI_MSIX_FLAGS_QSIZE) + 1;
>  		}
> -	} else if (irq_type == VFIO_PCI_ERR_IRQ_INDEX) {
> +	} else if (irq_type == VFIO_PCI_ERR_IRQ_INDEX ||
> +		   irq_type == VFIO_PCI_RESUME_IRQ_INDEX) {
>  		if (pci_is_pcie(vdev->pdev))
>  			return 1;
>  	} else if (irq_type == VFIO_PCI_REQ_IRQ_INDEX) {
> @@ -731,6 +732,7 @@ static long vfio_pci_ioctl(void *device_data,
>  		case VFIO_PCI_REQ_IRQ_INDEX:
>  			break;
>  		case VFIO_PCI_ERR_IRQ_INDEX:
> +		case VFIO_PCI_RESUME_IRQ_INDEX:
>  			if (pci_is_pcie(vdev->pdev))
>  				break;
>  		/* pass thru to return error */
> @@ -1234,8 +1236,32 @@ static pci_ers_result_t vfio_pci_aer_err_detected(struct pci_dev *pdev,
>  	return PCI_ERS_RESULT_CAN_RECOVER;
>  }
>  
> +static void vfio_pci_aer_resume(struct pci_dev *pdev)
> +{
> +	struct vfio_pci_device *vdev;
> +	struct vfio_device *device;
> +
> +	device = vfio_device_get_from_dev(&pdev->dev);
> +	if (device == NULL)
> +		return;
> +
> +	vdev = vfio_device_data(device);
> +	if (vdev == NULL) {
> +		vfio_device_put(device);
> +		return;
> +	}
> +
> +	mutex_lock(&vdev->igate);
> +	if (vdev->resume_trigger)
> +		eventfd_signal(vdev->resume_trigger, 1);
> +
> +	mutex_unlock(&vdev->igate);
> +	vfio_device_put(device);
> +}
> +
>  static const struct pci_error_handlers vfio_err_handlers = {
>  	.error_detected = vfio_pci_aer_err_detected,
> +	.resume         = vfio_pci_aer_resume,
>  };
>  
>  static struct pci_driver vfio_pci_driver = {
> diff --git a/drivers/vfio/pci/vfio_pci_intrs.c b/drivers/vfio/pci/vfio_pci_intrs.c
> index 15ecfc9..3a01a62 100644
> --- a/drivers/vfio/pci/vfio_pci_intrs.c
> +++ b/drivers/vfio/pci/vfio_pci_intrs.c
> @@ -617,6 +617,16 @@ static int vfio_pci_set_err_trigger(struct vfio_pci_device *vdev,
>  	return vfio_pci_set_ctx_trigger_single(&vdev->err_trigger, flags, data);
>  }
>  
> +static int vfio_pci_set_resume_trigger(struct vfio_pci_device *vdev,
> +				    unsigned index, unsigned start,
> +				    unsigned count, uint32_t flags, void *data)
> +{
> +	if (index != VFIO_PCI_RESUME_IRQ_INDEX)
> +		return -EINVAL;
> +
> +	return vfio_pci_set_ctx_trigger_single(&vdev->resume_trigger, flags, data);
> +}
> +
>  static int vfio_pci_set_req_trigger(struct vfio_pci_device *vdev,
>  				    unsigned index, unsigned start,
>  				    unsigned count, uint32_t flags, void *data)
> @@ -676,6 +686,14 @@ int vfio_pci_set_irqs_ioctl(struct vfio_pci_device *vdev, uint32_t flags,
>  			break;
>  		}
>  		break;
> +	case VFIO_PCI_RESUME_IRQ_INDEX:
> +		switch (flags & VFIO_IRQ_SET_ACTION_TYPE_MASK) {
> +		case VFIO_IRQ_SET_ACTION_TRIGGER:
> +			if (pci_is_pcie(vdev->pdev))
> +				func = vfio_pci_set_resume_trigger;
> +			break;
> +		}
> +		break;
>  	}
>  
>  	if (!func)
> diff --git a/drivers/vfio/pci/vfio_pci_private.h b/drivers/vfio/pci/vfio_pci_private.h
> index 016c14a..80d4ddd 100644
> --- a/drivers/vfio/pci/vfio_pci_private.h
> +++ b/drivers/vfio/pci/vfio_pci_private.h
> @@ -88,6 +88,7 @@ struct vfio_pci_device {
>  	int			refcnt;
>  	struct eventfd_ctx	*err_trigger;
>  	struct eventfd_ctx	*req_trigger;
> +	struct eventfd_ctx	*resume_trigger;
>  };
>  
>  #define is_intx(vdev) (vdev->irq_type == VFIO_PCI_INTX_IRQ_INDEX)
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index 255a211..34ab138 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -433,6 +433,7 @@ enum {
>  	VFIO_PCI_MSIX_IRQ_INDEX,
>  	VFIO_PCI_ERR_IRQ_INDEX,
>  	VFIO_PCI_REQ_IRQ_INDEX,
> +	VFIO_PCI_RESUME_IRQ_INDEX,
>  	VFIO_PCI_NUM_IRQS
>  };
>