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Message-ID: <CAG8rG2zSaKqmZMiEa4W68zvLU4UgW0VHpLxWFqmidPk76FPuaw@mail.gmail.com>
Date: Fri, 26 Sep 2014 17:03:53 +0200
From: Antonios Motakis <a.motakis@...tualopensystems.com>
To: Alex Williamson <alex.williamson@...hat.com>
Cc: kvm-arm <kvmarm@...ts.cs.columbia.edu>,
Linux IOMMU <iommu@...ts.linux-foundation.org>,
VirtualOpenSystems Technical Team <tech@...tualopensystems.com>,
KVM devel mailing list <kvm@...r.kernel.org>,
Christoffer Dall <christoffer.dall@...aro.org>,
Will Deacon <will.deacon@....com>,
Kim Phillips <kim.phillips@...escale.com>,
Eric Auger <eric.auger@...aro.org>,
Marc Zyngier <marc.zyngier@....com>,
open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCHv7 20/26] vfio/platform: trigger an interrupt via eventfd
On Wed, Sep 24, 2014 at 7:00 PM, Alex Williamson
<alex.williamson@...hat.com> wrote:
> On Tue, 2014-09-23 at 16:46 +0200, Antonios Motakis wrote:
>> This patch allows to set an eventfd for a patform device's interrupt,
>> and also to trigger the interrupt eventfd from userspace for testing.
>>
>> Signed-off-by: Antonios Motakis <a.motakis@...tualopensystems.com>
>> ---
>> drivers/vfio/platform/vfio_platform_irq.c | 89 ++++++++++++++++++++++++++-
>> drivers/vfio/platform/vfio_platform_private.h | 2 +
>> 2 files changed, 89 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/vfio/platform/vfio_platform_irq.c b/drivers/vfio/platform/vfio_platform_irq.c
>> index 007b386..25a7825 100644
>> --- a/drivers/vfio/platform/vfio_platform_irq.c
>> +++ b/drivers/vfio/platform/vfio_platform_irq.c
>> @@ -45,11 +45,91 @@ static int vfio_platform_set_irq_unmask(struct vfio_platform_device *vdev,
>> return -EINVAL;
>> }
>>
>> +static irqreturn_t vfio_irq_handler(int irq, void *dev_id)
>> +{
>> + struct vfio_platform_irq *irq_ctx = dev_id;
>> +
>> + eventfd_signal(irq_ctx->trigger, 1);
>> +
>> + return IRQ_HANDLED;
>> +}
>> +
>> +static int vfio_set_trigger(struct vfio_platform_device *vdev,
>> + int index, int fd)
>> +{
>> + struct vfio_platform_irq *irq = &vdev->irqs[index];
>> + struct eventfd_ctx *trigger;
>> + int ret;
>> +
>> + if (irq->trigger) {
>> + free_irq(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)",
>> + irq->hwirq, vdev->name);
>> + 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(irq->hwirq, vfio_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_platform_set_irq_trigger(struct vfio_platform_device *vdev,
>> unsigned index, unsigned start,
>> unsigned count, uint32_t flags, void *data)
>> {
>> - return -EINVAL;
>> + struct vfio_platform_irq *irq = &vdev->irqs[index];
>> + uint8_t irq_bitmap;
>
> Minor nit here and also present in the next patch, I believe when we
> have DATA_BOOL, it's defined to be a u8 array, where each byte is a
> bool, not each bit. So it's not actually a bitmap. The PCI code
> handles any non-zero byte as true, not just bit0. Thanks,
>
Ok, I will correct this. Thanks for the clarification.
> Alex
>
>> + int32_t fd;
>> +
>> + switch (flags & VFIO_IRQ_SET_DATA_TYPE_MASK) {
>> + case VFIO_IRQ_SET_DATA_NONE:
>> + if (count == 0)
>> + return vfio_set_trigger(vdev, index, -1);
>> +
>> + vfio_irq_handler(irq->hwirq, irq);
>> + return 0;
>> +
>> + case VFIO_IRQ_SET_DATA_BOOL:
>> + if (copy_from_user(&irq_bitmap, data, sizeof(uint8_t)))
>> + return -EFAULT;
>> +
>> + if (irq_bitmap == 0x1) {
>> + vfio_irq_handler(irq->hwirq, irq);
>> + return 0;
>> + }
>> +
>> + return -EINVAL;
>> +
>> + case VFIO_IRQ_SET_DATA_EVENTFD:
>> + if (copy_from_user(&fd, data, sizeof(int32_t)))
>> + return -EFAULT;
>> +
>> + return vfio_set_trigger(vdev, index, fd);
>> + }
>> +
>> + return -EFAULT;
>> }
>>
>> int vfio_platform_set_irqs_ioctl(struct vfio_platform_device *vdev,
>> @@ -95,7 +175,7 @@ int vfio_platform_irq_init(struct vfio_platform_device *vdev)
>> if (hwirq < 0)
>> goto err;
>>
>> - vdev->irqs[i].flags = 0;
>> + vdev->irqs[i].flags = VFIO_IRQ_INFO_EVENTFD;
>> vdev->irqs[i].count = 1;
>> vdev->irqs[i].hwirq = hwirq;
>> }
>> @@ -110,6 +190,11 @@ err:
>>
>> void vfio_platform_irq_cleanup(struct vfio_platform_device *vdev)
>> {
>> + int i;
>> +
>> + for (i = 0; i < vdev->num_irqs; i++)
>> + vfio_set_trigger(vdev, i, -1);
>> +
>> vdev->num_irqs = 0;
>> kfree(vdev->irqs);
>> }
>> diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
>> index 4201b94..765b371 100644
>> --- a/drivers/vfio/platform/vfio_platform_private.h
>> +++ b/drivers/vfio/platform/vfio_platform_private.h
>> @@ -28,6 +28,8 @@ struct vfio_platform_irq {
>> u32 flags;
>> u32 count;
>> int hwirq;
>> + char *name;
>> + struct eventfd_ctx *trigger;
>> };
>>
>> struct vfio_platform_region {
>
>
>
--
Antonios Motakis
Virtual Open Systems
--
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