Messages in this thread | | | Date | Tue, 14 Feb 2023 10:05:00 +0800 | Subject | Re: [PATCH v3 2/2] vdpasim: support doorbell mapping | From | "Longpeng (Mike, Cloud Infrastructure Service Product Dept.)" <> |
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在 2023/2/13 20:05, Michael S. Tsirkin 写道: > On Sun, Jan 29, 2023 at 02:19:51PM +0800, Jason Wang wrote: >> On Sun, Jan 29, 2023 at 10:51 AM Longpeng(Mike) <longpeng2@huawei.com> wrote: >>> >>> From: Longpeng <longpeng2@huawei.com> >>> >>> Support doorbell mapping for vdpasim devices, then we can test the notify >>> passthrough feature even if there's no real hardware on hand. >>> >>> Allocates a dummy page which is used to emulate the notify page of the device, >>> all VQs share the same notify register that initiated to 0xffff. A periodic >>> work will check whether there're requests need to process ( the value of the >>> notify register is 0xffff or not ). >>> --- >>> drivers/vdpa/vdpa_sim/vdpa_sim.c | 65 ++++++++++++++++++++++++++++++++ >>> drivers/vdpa/vdpa_sim/vdpa_sim.h | 3 ++ >>> 2 files changed, 68 insertions(+) >>> >>> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c >>> index b071f0d842fb..4fcfeb6e2fb8 100644 >>> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c >>> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c >>> @@ -39,6 +39,8 @@ MODULE_PARM_DESC(max_iotlb_entries, >>> #define VDPASIM_QUEUE_ALIGN PAGE_SIZE >>> #define VDPASIM_QUEUE_MAX 256 >>> #define VDPASIM_VENDOR_ID 0 >>> +#define VDPASIM_VRING_POLL_PERIOD 100 /* ms */ >>> +#define VDPASIM_NOTIFY_DEFVAL 0xffff >>> >>> static struct vdpasim *vdpa_to_sim(struct vdpa_device *vdpa) >>> { >>> @@ -246,6 +248,28 @@ static const struct dma_map_ops vdpasim_dma_ops = { >>> static const struct vdpa_config_ops vdpasim_config_ops; >>> static const struct vdpa_config_ops vdpasim_batch_config_ops; >>> >>> +static void vdpasim_notify_work(struct work_struct *work) >>> +{ >>> + struct vdpasim *vdpasim; >>> + u16 *val; >>> + >>> + vdpasim = container_of(work, struct vdpasim, notify_work.work); >>> + >>> + if (!(vdpasim->status & VIRTIO_CONFIG_S_DRIVER_OK)) >>> + goto out; >>> + >>> + if (!vdpasim->running) >>> + goto out; >>> + >>> + val = (u16 *)vdpasim->notify; >>> + if (xchg(val, VDPASIM_NOTIFY_DEFVAL) != VDPASIM_NOTIFY_DEFVAL) >>> + schedule_work(&vdpasim->work); >>> + >>> +out: >>> + schedule_delayed_work(&vdpasim->notify_work, >>> + msecs_to_jiffies(VDPASIM_VRING_POLL_PERIOD)); >>> +} >>> + >>> struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr, >>> const struct vdpa_dev_set_config *config) >>> { >>> @@ -287,6 +311,13 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr, >>> set_dma_ops(dev, &vdpasim_dma_ops); >>> vdpasim->vdpa.mdev = dev_attr->mgmt_dev; >>> >>> + INIT_DELAYED_WORK(&vdpasim->notify_work, vdpasim_notify_work); >>> + >>> + vdpasim->notify = __get_free_page(GFP_KERNEL | __GFP_ZERO); >>> + if (!vdpasim->notify) >>> + goto err_iommu; >> >> We can simply avoid the advertising notification area in this case. >> >>> + *(u16 *)vdpasim->notify = VDPASIM_NOTIFY_DEFVAL; >> >> WRITE_ONCE()? > > it is just initialization so it should not matter. > I think so.
And WRITE_ONCE seems operate on a variable, but we want write value into a specific memory location here.
>>> + >>> vdpasim->config = kzalloc(dev_attr->config_size, GFP_KERNEL); >>> if (!vdpasim->config) >>> goto err_iommu; >>> @@ -498,16 +529,21 @@ static u8 vdpasim_get_status(struct vdpa_device *vdpa) >>> static void vdpasim_set_status(struct vdpa_device *vdpa, u8 status) >>> { >>> struct vdpasim *vdpasim = vdpa_to_sim(vdpa); >>> + bool started = vdpasim->status & VIRTIO_CONFIG_S_DRIVER_OK; >> >> Do we need to do the check under the vdpasim->lock? >> >>> >>> spin_lock(&vdpasim->lock); >>> vdpasim->status = status; >>> spin_unlock(&vdpasim->lock); >>> + if (!started && (status & VIRTIO_CONFIG_S_DRIVER_OK)) >>> + schedule_delayed_work(&vdpasim->notify_work, >>> + msecs_to_jiffies(VDPASIM_VRING_POLL_PERIOD)); >>> } >>> >>> static int vdpasim_reset(struct vdpa_device *vdpa) >>> { >>> struct vdpasim *vdpasim = vdpa_to_sim(vdpa); >>> >>> + cancel_delayed_work_sync(&vdpasim->notify_work); >> >> Do we need to do this after setting running to zero? Otherwise it's racy. >> >> Thanks >> >>> spin_lock(&vdpasim->lock); >>> vdpasim->status = 0; >>> vdpasim_do_reset(vdpasim); >>> @@ -672,11 +708,34 @@ static int vdpasim_dma_unmap(struct vdpa_device *vdpa, unsigned int asid, >>> return 0; >>> } >>> >>> +static pgprot_t vdpasim_get_vq_notification_pgprot(struct vdpa_device *vdpa, >>> + u16 qid, pgprot_t prot) >>> +{ >>> + /* >>> + * We use normal RAM pages to emulate the vq notification area, so >>> + * just keep the pgprot as it mmaped. >>> + */ >>> + return prot; >>> +} >>> + >>> +static struct vdpa_notification_area >>> +vdpasim_get_vq_notification(struct vdpa_device *vdpa, u16 qid) >>> +{ >>> + struct vdpasim *vdpasim = vdpa_to_sim(vdpa); >>> + struct vdpa_notification_area notify; >>> + >>> + notify.addr = virt_to_phys((void *)vdpasim->notify); >>> + notify.size = PAGE_SIZE; >>> + >>> + return notify; >>> +} >>> + >>> static void vdpasim_free(struct vdpa_device *vdpa) >>> { >>> struct vdpasim *vdpasim = vdpa_to_sim(vdpa); >>> int i; >>> >>> + cancel_delayed_work_sync(&vdpasim->notify_work); >>> cancel_work_sync(&vdpasim->work); >>> >>> for (i = 0; i < vdpasim->dev_attr.nvqs; i++) { >>> @@ -693,6 +752,8 @@ static void vdpasim_free(struct vdpa_device *vdpa) >>> vhost_iotlb_free(vdpasim->iommu); >>> kfree(vdpasim->vqs); >>> kfree(vdpasim->config); >>> + if (vdpasim->notify) >>> + free_page(vdpasim->notify); >>> } >>> >>> static const struct vdpa_config_ops vdpasim_config_ops = { >>> @@ -704,6 +765,8 @@ static const struct vdpa_config_ops vdpasim_config_ops = { >>> .get_vq_ready = vdpasim_get_vq_ready, >>> .set_vq_state = vdpasim_set_vq_state, >>> .get_vq_state = vdpasim_get_vq_state, >>> + .get_vq_notification = vdpasim_get_vq_notification, >>> + .get_vq_notification_pgprot = vdpasim_get_vq_notification_pgprot, >>> .get_vq_align = vdpasim_get_vq_align, >>> .get_vq_group = vdpasim_get_vq_group, >>> .get_device_features = vdpasim_get_device_features, >>> @@ -737,6 +800,8 @@ static const struct vdpa_config_ops vdpasim_batch_config_ops = { >>> .get_vq_ready = vdpasim_get_vq_ready, >>> .set_vq_state = vdpasim_set_vq_state, >>> .get_vq_state = vdpasim_get_vq_state, >>> + .get_vq_notification = vdpasim_get_vq_notification, >>> + .get_vq_notification_pgprot = vdpasim_get_vq_notification_pgprot, >>> .get_vq_align = vdpasim_get_vq_align, >>> .get_vq_group = vdpasim_get_vq_group, >>> .get_device_features = vdpasim_get_device_features, >>> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.h b/drivers/vdpa/vdpa_sim/vdpa_sim.h >>> index 0e78737dcc16..0769ccbd3911 100644 >>> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.h >>> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.h >>> @@ -69,6 +69,9 @@ struct vdpasim { >>> bool running; >>> /* spinlock to synchronize iommu table */ >>> spinlock_t iommu_lock; >>> + /* dummy notify page */ >>> + unsigned long notify; >>> + struct delayed_work notify_work; >>> }; >>> >>> struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *attr, >>> -- >>> 2.23.0 >>> > > .
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