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Message-ID: <6e8b267c-0734-1d9b-d3da-e2e6f44f7847@redhat.com>
Date: Mon, 13 Jul 2020 16:27:08 +0800
From: Jason Wang <jasowang@...hat.com>
To: Zhu Lingshan <lingshan.zhu@...el.com>, mst@...hat.com,
alex.williamson@...hat.com, pbonzini@...hat.com,
sean.j.christopherson@...el.com, wanpengli@...cent.com
Cc: virtualization@...ts.linux-foundation.org, kvm@...r.kernel.org,
netdev@...r.kernel.org, dan.daly@...el.com
Subject: Re: [PATCH 4/7] vDPA: implement IRQ offloading helpers in vDPA core
On 2020/7/12 下午10:49, Zhu Lingshan wrote:
> This commit implements IRQ offloading helpers in vDPA core by
> introducing two couple of functions:
>
> vdpa_alloc_vq_irq() and vdpa_free_vq_irq(): request irq and free
> irq, will setup irq offloading if irq_bypass is enabled.
>
> vdpa_setup_irq() and vdpa_unsetup_irq(): supportive functions,
> will call vhost_vdpa helpers.
>
> Signed-off-by: Zhu Lingshan <lingshan.zhu@...el.com>
This patch should go before patch 3.
> ---
> drivers/vdpa/vdpa.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
> drivers/vhost/Kconfig | 1 +
> drivers/vhost/vdpa.c | 2 ++
> include/linux/vdpa.h | 11 +++++++++++
> 4 files changed, 60 insertions(+)
>
> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
> index ff6562f..d8eba01 100644
> --- a/drivers/vdpa/vdpa.c
> +++ b/drivers/vdpa/vdpa.c
> @@ -163,6 +163,52 @@ void vdpa_unregister_driver(struct vdpa_driver *drv)
> }
> EXPORT_SYMBOL_GPL(vdpa_unregister_driver);
>
> +static void vdpa_setup_irq(struct vdpa_device *vdev, int qid, int irq)
> +{
> + struct vdpa_driver *drv = drv_to_vdpa(vdev->dev.driver);
> +
> +#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
Let's don't do the check here. It's the responsibility of driver to
decide what it should do.
> + if (drv->setup_vq_irq)
> + drv->setup_vq_irq(vdev, qid, irq);
> +#endif
> +}
> +
> +static void vdpa_unsetup_irq(struct vdpa_device *vdev, int qid)
> +{
> + struct vdpa_driver *drv = drv_to_vdpa(vdev->dev.driver);
> +
> +#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
> + if (drv->unsetup_vq_irq)
> + drv->unsetup_vq_irq(vdev, qid);
> +#endif
> +}
> +
> +int vdpa_alloc_vq_irq(struct device *dev, struct vdpa_device *vdev,
> + unsigned int irq, irq_handler_t handler,
> + unsigned long irqflags, const char *devname, void *dev_id,
> + int qid)
> +{
> + int ret;
> +
> + ret = devm_request_irq(dev, irq, handler, irqflags, devname, dev_id);
> + if (ret)
> + dev_err(dev, "Failed to request irq for vq %d\n", qid);
> + else
> + vdpa_setup_irq(vdev, qid, irq);
I'd like to squash the vdpa_setup_irq logic here.
> +
> + return ret;
> +
> +}
> +EXPORT_SYMBOL_GPL(vdpa_alloc_vq_irq);
> +
> +void vdpa_free_vq_irq(struct device *dev, struct vdpa_device *vdev, int irq,
> + int qid, void *dev_id)
> +{
> + devm_free_irq(dev, irq, dev_id);
> + vdpa_unsetup_irq(vdev, qid);
> +}
> +EXPORT_SYMBOL_GPL(vdpa_free_vq_irq);
> +
> static int vdpa_init(void)
> {
> return bus_register(&vdpa_bus);
> diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig
Let squash the vhost patch into patch 3.
> index d3688c6..587fbae 100644
> --- a/drivers/vhost/Kconfig
> +++ b/drivers/vhost/Kconfig
> @@ -65,6 +65,7 @@ config VHOST_VDPA
> tristate "Vhost driver for vDPA-based backend"
> depends on EVENTFD
> select VHOST
> + select IRQ_BYPASS_MANAGER
> depends on VDPA
> help
> This kernel module can be loaded in host kernel to accelerate
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index 92683e4..6e25158 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -1020,6 +1020,8 @@ static void vhost_vdpa_remove(struct vdpa_device *vdpa)
> },
> .probe = vhost_vdpa_probe,
> .remove = vhost_vdpa_remove,
> + .setup_vq_irq = vhost_vdpa_setup_vq_irq,
> + .unsetup_vq_irq = vhost_vdpa_unsetup_vq_irq,
> };
>
> static int __init vhost_vdpa_init(void)
> diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
> index 239db79..9f9b245 100644
> --- a/include/linux/vdpa.h
> +++ b/include/linux/vdpa.h
> @@ -220,17 +220,28 @@ struct vdpa_device *__vdpa_alloc_device(struct device *parent,
>
> int vdpa_register_device(struct vdpa_device *vdev);
> void vdpa_unregister_device(struct vdpa_device *vdev);
> +int vdpa_alloc_vq_irq(struct device *dev, struct vdpa_device *vdev,
> + unsigned int irq, irq_handler_t handler,
> + unsigned long irqflags, const char *devname, void *dev_id,
> + int qid);
> +void vdpa_free_vq_irq(struct device *dev, struct vdpa_device *vdev, int irq,
> + int qid, void *dev_id);
You need to document the devres implications of those two helpers.
> +
>
> /**
> * vdpa_driver - operations for a vDPA driver
> * @driver: underlying device driver
> * @probe: the function to call when a device is found. Returns 0 or -errno.
> * @remove: the function to call when a device is removed.
> + * @setup_vq_irq: setup irq bypass for a vhost_vdpa vq.
> + * @unsetup_vq_irq: unsetup irq bypass for a vhost_vdpa vq.
Though irq bypass is used by vhost-vdpa, it's not necessarily to be true
in the future. So it's better not to mention irqbypass in the doc here.
Thanks
> */
> struct vdpa_driver {
> struct device_driver driver;
> int (*probe)(struct vdpa_device *vdev);
> void (*remove)(struct vdpa_device *vdev);
> + void (*setup_vq_irq)(struct vdpa_device *vdev, int qid, int irq);
> + void (*unsetup_vq_irq)(struct vdpa_device *vdev, int qid);
> };
>
> #define vdpa_register_driver(drv) \
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