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;
+ *(u16 *)vdpasim->notify = VDPASIM_NOTIFY_DEFVAL;
+
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;
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);
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,
--
2.23.0On 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()?
> +
> 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
>
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.
> > +
> > 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
> >
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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