diff mbox series

[V2,4/6] vhost_vdpa: implement IRQ offloading in vhost_vdpa

Message ID 1594898629-18790-5-git-send-email-lingshan.zhu@intel.com (mailing list archive)
State New, archived
Headers show
Series IRQ offloading for vDPA | expand

Commit Message

Zhu, Lingshan July 16, 2020, 11:23 a.m. UTC 
This patch introduce a set of functions for setup/unsetup
and update irq offloading respectively by register/unregister
and re-register the irq_bypass_producer.

Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
Suggested-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vhost/Kconfig |  1 +
 drivers/vhost/vdpa.c  | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+)

Comments

Jason Wang July 17, 2020, 5:29 a.m. UTC | #1 
On 2020/7/16 下午7:23, Zhu Lingshan wrote:
> This patch introduce a set of functions for setup/unsetup
> and update irq offloading respectively by register/unregister
> and re-register the irq_bypass_producer.
>
> Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
> Suggested-by: Jason Wang <jasowang@redhat.com>
> ---
>   drivers/vhost/Kconfig |  1 +
>   drivers/vhost/vdpa.c  | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
>   2 files changed, 49 insertions(+)
>
> diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig
> 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 2fcc422..b9078d4 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -115,6 +115,43 @@ static irqreturn_t vhost_vdpa_config_cb(void *private)
>   	return IRQ_HANDLED;
>   }
>   
> +static void vhost_vdpa_setup_vq_irq(struct vdpa_device *dev, int qid, int irq)
> +{
> +	struct vhost_vdpa *v = vdpa_get_drvdata(dev);
> +	struct vhost_virtqueue *vq = &v->vqs[qid];
> +	int ret;
> +
> +	spin_lock(&vq->call_ctx.ctx_lock);
> +	if (!vq->call_ctx.ctx) {
> +		spin_unlock(&vq->call_ctx.ctx_lock);
> +		return;
> +	}


I think we can simply remove this check as what is done in 
vhost_vdpq_update_vq_irq().


> +
> +	vq->call_ctx.producer.token = vq->call_ctx.ctx;
> +	vq->call_ctx.producer.irq = irq;
> +	ret = irq_bypass_register_producer(&vq->call_ctx.producer);
> +	spin_unlock(&vq->call_ctx.ctx_lock);
> +}
> +
> +static void vhost_vdpa_unsetup_vq_irq(struct vdpa_device *dev, int qid)
> +{
> +	struct vhost_vdpa *v = vdpa_get_drvdata(dev);
> +	struct vhost_virtqueue *vq = &v->vqs[qid];
> +
> +	spin_lock(&vq->call_ctx.ctx_lock);
> +	irq_bypass_unregister_producer(&vq->call_ctx.producer);
> +	spin_unlock(&vq->call_ctx.ctx_lock);
> +}
> +
> +static void vhost_vdpa_update_vq_irq(struct vhost_virtqueue *vq)
> +{
> +	spin_lock(&vq->call_ctx.ctx_lock);
> +	irq_bypass_unregister_producer(&vq->call_ctx.producer);
> +	vq->call_ctx.producer.token = vq->call_ctx.ctx;
> +	irq_bypass_register_producer(&vq->call_ctx.producer);
> +	spin_unlock(&vq->call_ctx.ctx_lock);
> +}
> +
>   static void vhost_vdpa_reset(struct vhost_vdpa *v)
>   {
>   	struct vdpa_device *vdpa = v->vdpa;
> @@ -332,6 +369,7 @@ static long vhost_vdpa_set_config_call(struct vhost_vdpa *v, u32 __user *argp)
>   
>   	return 0;
>   }
> +


If you really want to fix coding style issue, it's better to have 
another patch.


>   static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
>   				   void __user *argp)
>   {
> @@ -390,6 +428,14 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
>   			cb.private = NULL;
>   		}
>   		ops->set_vq_cb(vdpa, idx, &cb);
> +		/*
> +		 * if it has a non-zero irq, means there is a
> +		 * previsouly registered irq_bypass_producer,
> +		 * we should update it when ctx (its token)
> +		 * changes.
> +		 */
> +		if (vq->call_ctx.producer.irq)
> +			vhost_vdpa_update_vq_irq(vq);


Is this safe to check producer.irq outside spinlock?

Thanks


>   		break;
>   
>   	case VHOST_SET_VRING_NUM:
> @@ -951,6 +997,8 @@ 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)
kernel test robot July 17, 2020, 10:07 a.m. UTC | #2 
Hi Zhu,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on vhost/linux-next]
[also build test WARNING on kvm/linux-next linus/master v5.8-rc5 next-20200716]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Zhu-Lingshan/IRQ-offloading-for-vDPA/20200716-192910
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git linux-next
config: openrisc-randconfig-r016-20200717 (attached as .config)
compiler: or1k-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=openrisc 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   drivers/vhost/vdpa.c: In function 'vhost_vdpa_setup_vq_irq':
>> drivers/vhost/vdpa.c:122:6: warning: variable 'ret' set but not used [-Wunused-but-set-variable]
     122 |  int ret;
         |      ^~~

vim +/ret +122 drivers/vhost/vdpa.c

   117	
   118	static void vhost_vdpa_setup_vq_irq(struct vdpa_device *dev, int qid, int irq)
   119	{
   120		struct vhost_vdpa *v = vdpa_get_drvdata(dev);
   121		struct vhost_virtqueue *vq = &v->vqs[qid];
 > 122		int ret;
   123	
   124		spin_lock(&vq->call_ctx.ctx_lock);
   125		if (!vq->call_ctx.ctx) {
   126			spin_unlock(&vq->call_ctx.ctx_lock);
   127			return;
   128		}
   129	
   130		vq->call_ctx.producer.token = vq->call_ctx.ctx;
   131		vq->call_ctx.producer.irq = irq;
   132		ret = irq_bypass_register_producer(&vq->call_ctx.producer);
   133		spin_unlock(&vq->call_ctx.ctx_lock);
   134	}
   135	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
diff mbox series

Patch

diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig
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 2fcc422..b9078d4 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -115,6 +115,43 @@  static irqreturn_t vhost_vdpa_config_cb(void *private)
 	return IRQ_HANDLED;
 }
 
+static void vhost_vdpa_setup_vq_irq(struct vdpa_device *dev, int qid, int irq)
+{
+	struct vhost_vdpa *v = vdpa_get_drvdata(dev);
+	struct vhost_virtqueue *vq = &v->vqs[qid];
+	int ret;
+
+	spin_lock(&vq->call_ctx.ctx_lock);
+	if (!vq->call_ctx.ctx) {
+		spin_unlock(&vq->call_ctx.ctx_lock);
+		return;
+	}
+
+	vq->call_ctx.producer.token = vq->call_ctx.ctx;
+	vq->call_ctx.producer.irq = irq;
+	ret = irq_bypass_register_producer(&vq->call_ctx.producer);
+	spin_unlock(&vq->call_ctx.ctx_lock);
+}
+
+static void vhost_vdpa_unsetup_vq_irq(struct vdpa_device *dev, int qid)
+{
+	struct vhost_vdpa *v = vdpa_get_drvdata(dev);
+	struct vhost_virtqueue *vq = &v->vqs[qid];
+
+	spin_lock(&vq->call_ctx.ctx_lock);
+	irq_bypass_unregister_producer(&vq->call_ctx.producer);
+	spin_unlock(&vq->call_ctx.ctx_lock);
+}
+
+static void vhost_vdpa_update_vq_irq(struct vhost_virtqueue *vq)
+{
+	spin_lock(&vq->call_ctx.ctx_lock);
+	irq_bypass_unregister_producer(&vq->call_ctx.producer);
+	vq->call_ctx.producer.token = vq->call_ctx.ctx;
+	irq_bypass_register_producer(&vq->call_ctx.producer);
+	spin_unlock(&vq->call_ctx.ctx_lock);
+}
+
 static void vhost_vdpa_reset(struct vhost_vdpa *v)
 {
 	struct vdpa_device *vdpa = v->vdpa;
@@ -332,6 +369,7 @@  static long vhost_vdpa_set_config_call(struct vhost_vdpa *v, u32 __user *argp)
 
 	return 0;
 }
+
 static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
 				   void __user *argp)
 {
@@ -390,6 +428,14 @@  static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
 			cb.private = NULL;
 		}
 		ops->set_vq_cb(vdpa, idx, &cb);
+		/*
+		 * if it has a non-zero irq, means there is a
+		 * previsouly registered irq_bypass_producer,
+		 * we should update it when ctx (its token)
+		 * changes.
+		 */
+		if (vq->call_ctx.producer.irq)
+			vhost_vdpa_update_vq_irq(vq);
 		break;
 
 	case VHOST_SET_VRING_NUM:
@@ -951,6 +997,8 @@  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)