2015-04-01 12:23:15

by Eric Auger

[permalink] [raw]
Subject: Re: [RFC v5 06/13] VFIO: platform: add vfio_external_{mask|is_active|set_automasked}

On 03/31/2015 07:20 PM, Alex Williamson wrote:
> On Thu, 2015-03-19 at 15:55 +0100, Eric Auger wrote:
>> Introduces 3 new external functions aimed at doining some actions
>> on VFIO platform devices:
>> - mask a VFIO IRQ
>> - get the active status of a VFIO IRQ (active at interrupt
>> controller level or masked by the level-sensitive automasking).
>> - change the automasked property and the VFIO handler
>>
>> Note there is no way to discriminate between user-space
>> masking and automasked handler masking. As a consequence, is_active
>> will return true in case the IRQ was masked by the user-space.
>>
>> Signed-off-by: Eric Auger <[email protected]>
>>
>> ---
>>
>> V4: creation
>> ---
>> drivers/vfio/platform/vfio_platform_irq.c | 43 +++++++++++++++++++++++++++++++
>> include/linux/vfio.h | 14 ++++++++++
>> 2 files changed, 57 insertions(+)
>>
>> diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
>> index 8eb65c1..49994cb 100644
>> --- a/drivers/vfio/platform/vfio_platform_irq.c
>> +++ b/drivers/vfio/platform/vfio_platform_irq.c
>> @@ -231,6 +231,49 @@ static int vfio_set_trigger(struct vfio_platform_device *vdev, int index,
>> return 0;
>> }
>>
>> +void vfio_external_mask(struct vfio_platform_device *vdev, int index)
>> +{
>> + vfio_platform_mask(&vdev->irqs[index]);
>> +}
>> +EXPORT_SYMBOL_GPL(vfio_external_mask);
>> +
>> +bool vfio_external_is_active(struct vfio_platform_device *vdev, int index)
>> +{
>> + unsigned long flags;
>> + struct vfio_platform_irq *irq = &vdev->irqs[index];
>> + bool active, masked, outstanding;
>> + int ret;
>> +
>> + spin_lock_irqsave(&irq->lock, flags);
>> +
>> + ret = irq_get_irqchip_state(irq->hwirq, IRQCHIP_STATE_ACTIVE, &active);
>> + BUG_ON(ret);
>> + masked = irq->masked;
>> + outstanding = active || masked;
>> +
>> + spin_unlock_irqrestore(&irq->lock, flags);
>> + return outstanding;
>> +}
>> +EXPORT_SYMBOL_GPL(vfio_external_is_active);
>> +
>> +void vfio_external_set_automasked(struct vfio_platform_device *vdev,
>> + int index, bool automasked)
>> +{
>> + unsigned long flags;
>> + struct vfio_platform_irq *irq = &vdev->irqs[index];
>> +
>> + spin_lock_irqsave(&irq->lock, flags);
>> + if (automasked) {
>> + irq->flags |= VFIO_IRQ_INFO_AUTOMASKED;
>> + irq->handler = vfio_automasked_irq_handler;
>> + } else {
>> + irq->flags &= ~VFIO_IRQ_INFO_AUTOMASKED;
>> + irq->handler = vfio_irq_handler;
>> + }
>> + spin_unlock_irqrestore(&irq->lock, flags);
>> +}
>> +EXPORT_SYMBOL_GPL(vfio_external_set_automasked);
>> +
>
>
> This is where the abstraction breaks down. These are
> vfio_external_foo() interfaces, yet they assume a specific type of
> device, a vfio platform device. Either the name should reflect that or
> they should be hosted in vfio-core with a callout to the device specific
> implementations. Can we make kvm-vfio deal only in struct vfio_device
> and struct device?

Hi Alex,

I will follow your guidelines and intend to extend vfio_platform_ops to
store those new callbacks. Indeed kvm-vfio should be able to be
vfio_platform_device independent.

Thank you for the review.

Best Regards

Eric
>
>> static int vfio_platform_set_irq_trigger(struct vfio_platform_device *vdev,
>> unsigned index, unsigned start,
>> unsigned count, uint32_t flags,
>> diff --git a/include/linux/vfio.h b/include/linux/vfio.h
>> index b18c38f..7aa6330 100644
>> --- a/include/linux/vfio.h
>> +++ b/include/linux/vfio.h
>> @@ -105,6 +105,20 @@ extern struct vfio_device *vfio_device_get_external_user(struct file *filep);
>> extern void vfio_device_put_external_user(struct vfio_device *vdev);
>> extern struct device *vfio_external_base_device(struct vfio_device *vdev);
>>
>> +struct vfio_platform_device;
>> +extern void vfio_external_mask(struct vfio_platform_device *vdev, int index);
>> +/*
>> + * returns whether the VFIO IRQ is active:
>> + * true if not yet deactivated at interrupt controller level or if
>> + * automasked (level sensitive IRQ). Unfortunately there is no way to
>> + * discriminate between handler auto-masking and user-space masking
>> + */
>> +extern bool vfio_external_is_active(struct vfio_platform_device *vdev,
>> + int index);
>> +
>> +extern void vfio_external_set_automasked(struct vfio_platform_device *vdev,
>> + int index, bool automasked);
>> +
>> struct pci_dev;
>> #ifdef CONFIG_EEH
>> extern void vfio_spapr_pci_eeh_open(struct pci_dev *pdev);
>
>
>