Jason Wang
2020-Jul-17 05:29 UTC
[PATCH V2 4/6] vhost_vdpa: implement IRQ offloading in vhost_vdpa
On 2020/7/16 ??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 at intel.com> > Suggested-by: Jason Wang <jasowang at 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)