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Message-ID: <e1799597-5de9-9ac9-dd73-4086e56eebb4@redhat.com>
Date: Thu, 10 Sep 2020 10:16:00 +0200
From: Auger Eric <eric.auger@...hat.com>
To: Diana Craciun OSS <diana.craciun@....nxp.com>,
alex.williamson@...hat.com, kvm@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, bharatb.linux@...il.com,
laurentiu.tudor@....com, Bharat Bhushan <Bharat.Bhushan@....com>
Subject: Re: [PATCH v4 08/10] vfio/fsl-mc: trigger an interrupt via eventfd
Hi Diana,
On 9/7/20 4:02 PM, Diana Craciun OSS wrote:
> Hi Eric,
>
> On 9/4/2020 11:02 AM, Auger Eric wrote:
>> Hi Diana,
>>
>> On 8/26/20 11:33 AM, Diana Craciun wrote:
>>> This patch allows to set an eventfd for fsl-mc device interrupts
>>> and also to trigger the interrupt eventfd from userspace for testing.
>>>
>>> All fsl-mc device interrupts are MSIs. The MSIs are allocated from
>>> the MSI domain only once per DPRC and used by all the DPAA2 objects.
>>> The interrupts are managed by the DPRC in a pool of interrupts. Each
>>> device requests interrupts from this pool. The pool is allocated
>>> when the first virtual device is setting the interrupts.
>>> The pool of interrupts is protected by a lock.
>>>
>>> The DPRC has an interrupt of its own which indicates if the DPRC
>>> contents have changed. However, currently, the contents of a DPRC
>>> assigned to the guest cannot be changed at runtime, so this interrupt
>>> is not configured.
>>>
>>> Signed-off-by: Bharat Bhushan <Bharat.Bhushan@....com>
>>> Signed-off-by: Diana Craciun <diana.craciun@....nxp.com>
>>> ---
>>> drivers/vfio/fsl-mc/vfio_fsl_mc.c | 18 ++-
>>> drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c | 160 +++++++++++++++++++++-
>>> drivers/vfio/fsl-mc/vfio_fsl_mc_private.h | 10 ++
>>> 3 files changed, 186 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc.c
>>> b/drivers/vfio/fsl-mc/vfio_fsl_mc.c
>>> index 42014297b484..73834f488a94 100644
>>> --- a/drivers/vfio/fsl-mc/vfio_fsl_mc.c
>>> +++ b/drivers/vfio/fsl-mc/vfio_fsl_mc.c
>>> @@ -147,12 +147,28 @@ static int vfio_fsl_mc_open(void *device_data)
>>> static void vfio_fsl_mc_release(void *device_data)
>>> {
>>> struct vfio_fsl_mc_device *vdev = device_data;
>>> + int ret;
>>> mutex_lock(&vdev->reflck->lock);
>>> - if (!(--vdev->refcnt))
>>> + if (!(--vdev->refcnt)) {
>>> + struct fsl_mc_device *mc_dev = vdev->mc_dev;
>>> + struct device *cont_dev = fsl_mc_cont_dev(&mc_dev->dev);
>>> + struct fsl_mc_device *mc_cont = to_fsl_mc_device(cont_dev);
>>> +
>>> vfio_fsl_mc_regions_cleanup(vdev);
>>> + /* reset the device before cleaning up the interrupts */
>>> + ret = dprc_reset_container(mc_cont->mc_io, 0,
>>> + mc_cont->mc_handle,
>>> + mc_cont->obj_desc.id,
>>> + DPRC_RESET_OPTION_NON_RECURSIVE);
>> shouldn't you test ret?
>>> +
>>> + vfio_fsl_mc_irqs_cleanup(vdev);
>>> +
>>> + fsl_mc_cleanup_irq_pool(mc_cont);
>>> + }
>>> +
>>> mutex_unlock(&vdev->reflck->lock);
>>> module_put(THIS_MODULE);
>>> diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c
>>> b/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c
>>> index 058aa97aa54a..409f3507fcf3 100644
>>> --- a/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c
>>> +++ b/drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c
>>> @@ -29,12 +29,149 @@ static int vfio_fsl_mc_irq_unmask(struct
>>> vfio_fsl_mc_device *vdev,
>>> return -EINVAL;
>>> }
>>> +int vfio_fsl_mc_irqs_allocate(struct vfio_fsl_mc_device *vdev)
>>> +{
>>> + struct fsl_mc_device *mc_dev = vdev->mc_dev;
>>> + struct vfio_fsl_mc_irq *mc_irq;
>>> + int irq_count;
>>> + int ret, i;
>>> +
>>> + /* Device does not support any interrupt */
>> indent needs to be fixed
>>> + if (mc_dev->obj_desc.irq_count == 0)
>>> + return 0;
>>> +
>>> + /* interrupts were already allocated for this device */
>>> + if (vdev->mc_irqs)
>>> + return 0;
>>> +
>>> + irq_count = mc_dev->obj_desc.irq_count;
>>> +
>>> + mc_irq = kcalloc(irq_count, sizeof(*mc_irq), GFP_KERNEL);
>>> + if (!mc_irq)
>>> + return -ENOMEM;
>>> +
>>> + /* Allocate IRQs */
>>> + ret = fsl_mc_allocate_irqs(mc_dev);
>>> + if (ret) {
>>> + kfree(mc_irq);
>>> + return ret;
>>> + }
>>> +
>>> + for (i = 0; i < irq_count; i++) {
>>> + mc_irq[i].count = 1;
>>> + mc_irq[i].flags = VFIO_IRQ_INFO_EVENTFD;
>>> + }
>>> +
>>> + vdev->mc_irqs = mc_irq;
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static irqreturn_t vfio_fsl_mc_irq_handler(int irq_num, void *arg)
>>> +{
>>> + struct vfio_fsl_mc_irq *mc_irq = (struct vfio_fsl_mc_irq *)arg;
>>> +
>>> + eventfd_signal(mc_irq->trigger, 1);
>>> + return IRQ_HANDLED;
>>> +}
>>> +
>>> +static int vfio_set_trigger(struct vfio_fsl_mc_device *vdev,
>>> + int index, int fd)
>>> +{
>>> + struct vfio_fsl_mc_irq *irq = &vdev->mc_irqs[index];
>>> + struct eventfd_ctx *trigger;
>>> + int hwirq;
>>> + int ret;
>>> +
>>> + hwirq = vdev->mc_dev->irqs[index]->msi_desc->irq;
>>> + if (irq->trigger) {
>>> + free_irq(hwirq, irq);
>>> + kfree(irq->name);
>>> + eventfd_ctx_put(irq->trigger);
>>> + irq->trigger = NULL;
>>> + }
>>> +
>>> + if (fd < 0) /* Disable only */
>>> + return 0;
>>> +
>>> + irq->name = kasprintf(GFP_KERNEL, "vfio-irq[%d](%s)",
>>> + hwirq, dev_name(&vdev->mc_dev->dev));
>>> + if (!irq->name)
>>> + return -ENOMEM;
>>> +
>>> + trigger = eventfd_ctx_fdget(fd);
>>> + if (IS_ERR(trigger)) {
>>> + kfree(irq->name);
>>> + return PTR_ERR(trigger);
>>> + }
>>> +
>>> + irq->trigger = trigger;
>>> +
>>> + ret = request_irq(hwirq, vfio_fsl_mc_irq_handler, 0,
>>> + irq->name, irq);
>>> + if (ret) {
>>> + kfree(irq->name);
>>> + eventfd_ctx_put(trigger);
>>> + irq->trigger = NULL;
>>> + return ret;
>>> + }
>>> +
>>> + return 0;
>>> +}
>>> +
>>> static int vfio_fsl_mc_set_irq_trigger(struct vfio_fsl_mc_device
>>> *vdev,
>>> unsigned int index, unsigned int start,
>>> unsigned int count, u32 flags,
>>> void *data)
>>> {
>>> - return -EINVAL;
>>> + struct fsl_mc_device *mc_dev = vdev->mc_dev;
>>> + int ret, hwirq;
>>> + struct vfio_fsl_mc_irq *irq;
>>> + struct device *cont_dev = fsl_mc_cont_dev(&mc_dev->dev);
>>> + struct fsl_mc_device *mc_cont = to_fsl_mc_device(cont_dev);
>>> +
>>> + if (start != 0 || count != 1)
>>> + return -EINVAL;
>>> +
>>> + mutex_lock(&vdev->reflck->lock);
>>> + ret = fsl_mc_populate_irq_pool(mc_cont,
>>> + FSL_MC_IRQ_POOL_MAX_TOTAL_IRQS);
>>> + if (ret)
>>> + goto unlock;
>>> +
>>> + ret = vfio_fsl_mc_irqs_allocate(vdev);
>> any reason the init is done in the set_irq() and not in the open() if
>> !vdev->refcnt?
>
> Actually yes, there is a reason. It comes from the way the MSIs are
> handled.
>
> The DPAA2 devices (the devices that can be assigned to the userspace)
> are organized in a hierarchical way. The DPRC is some kind of container
> (parent) for child devices. Only the DPRC is allocating interrupts (it
> allocates MSIs from the MSI domain). The MSIs cannot be allocated in the
> open() because the MSI setup needs an IOMMU cookie which is set when the
> IOMMU is set with VFIO_SET_IOMMU. But iommu is set later, after open(),
> so the MSIs should be allocated afterwards.
>
> So, the DPRC is allocating a pool of MSIs and each child object will
> request a number of interrupts from that pool. This is what
> vfio_fsl_mc_irqs_allocate does: it requests a number of interrupts from
> the pool.
OK, thank you for the clarifications.
Thanks
Eric
>
>
>>> + if (ret)
>>> + goto unlock;
>>> + mutex_unlock(&vdev->reflck->lock);
>>> +
>>> + if (!count && (flags & VFIO_IRQ_SET_DATA_NONE))
>>> + return vfio_set_trigger(vdev, index, -1);
>>> +
>>> + if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
>>> + s32 fd = *(s32 *)data;
>>> +
>>> + return vfio_set_trigger(vdev, index, fd);
>>> + }
>>> +
>>> + hwirq = vdev->mc_dev->irqs[index]->msi_desc->irq;
>>> +
>>> + irq = &vdev->mc_irqs[index];
>>> +
>>> + if (flags & VFIO_IRQ_SET_DATA_NONE) {
>>> + vfio_fsl_mc_irq_handler(hwirq, irq);
>>> +
>>> + } else if (flags & VFIO_IRQ_SET_DATA_BOOL) {
>>> + u8 trigger = *(u8 *)data;
>>> +
>>> + if (trigger)
>>> + vfio_fsl_mc_irq_handler(hwirq, irq);
>>> + }
>>> +
>>> + return 0;
>>> +
>>> +unlock:
>>> + mutex_unlock(&vdev->reflck->lock);
>>> + return ret;
>>> }
>>> int vfio_fsl_mc_set_irqs_ioctl(struct vfio_fsl_mc_device *vdev,
>>> @@ -61,3 +198,24 @@ int vfio_fsl_mc_set_irqs_ioctl(struct
>>> vfio_fsl_mc_device *vdev,
>>> return ret;
>>> }
>>> +
>>> +/* Free All IRQs for the given MC object */
>>> +void vfio_fsl_mc_irqs_cleanup(struct vfio_fsl_mc_device *vdev)
>>> +{
>>> + struct fsl_mc_device *mc_dev = vdev->mc_dev;
>>> + int irq_count = mc_dev->obj_desc.irq_count;
>>> + int i;
>>> +
>>> + /* Device does not support any interrupt or the interrupts
>>> + * were not configured
>>> + */
>>> + if (mc_dev->obj_desc.irq_count == 0 || !vdev->mc_irqs)
>>> + return;
>>> +
>>> + for (i = 0; i < irq_count; i++)
>>> + vfio_set_trigger(vdev, i, -1);
>>> +
>>> + fsl_mc_free_irqs(mc_dev);
>>> + kfree(vdev->mc_irqs);
>>> + vdev->mc_irqs = NULL;
>>> +}
>>> diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc_private.h
>>> b/drivers/vfio/fsl-mc/vfio_fsl_mc_private.h
>>> index d5b6fe891a48..bbfca8b55f8a 100644
>>> --- a/drivers/vfio/fsl-mc/vfio_fsl_mc_private.h
>>> +++ b/drivers/vfio/fsl-mc/vfio_fsl_mc_private.h
>>> @@ -15,6 +15,13 @@
>>> #define VFIO_FSL_MC_INDEX_TO_OFFSET(index) \
>>> ((u64)(index) << VFIO_FSL_MC_OFFSET_SHIFT)
>>> +struct vfio_fsl_mc_irq {
>>> + u32 flags;
>>> + u32 count;
>>> + struct eventfd_ctx *trigger;
>>> + char *name;
>>> +};
>>> +
>>> struct vfio_fsl_mc_reflck {
>>> struct kref kref;
>>> struct mutex lock;
>>> @@ -35,6 +42,7 @@ struct vfio_fsl_mc_device {
>>> struct vfio_fsl_mc_region *regions;
>>> struct vfio_fsl_mc_reflck *reflck;
>>> struct mutex igate;
>>> + struct vfio_fsl_mc_irq *mc_irqs;
>>> };
>>> extern int vfio_fsl_mc_set_irqs_ioctl(struct vfio_fsl_mc_device
>>> *vdev,
>>> @@ -42,4 +50,6 @@ extern int vfio_fsl_mc_set_irqs_ioctl(struct
>>> vfio_fsl_mc_device *vdev,
>>> unsigned int start, unsigned int count,
>>> void *data);
>>> +void vfio_fsl_mc_irqs_cleanup(struct vfio_fsl_mc_device *vdev);
>>> +
>>> #endif /* VFIO_FSL_MC_PRIVATE_H */
>>>
>> Thanks
>>
>> Eric
>>
>
> Thanks,
> Diana
>
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