* [PATCH v5] virtio: add VIRTIO_F_NOTIFICATION_DATA feature support
@ 2023-03-23 8:55 Viktor Prutyanov
2023-03-23 9:00 ` Xuan Zhuo
2023-03-24 3:09 ` Jason Wang
0 siblings, 2 replies; 6+ messages in thread
From: Viktor Prutyanov @ 2023-03-23 8:55 UTC (permalink / raw)
To: mst, jasowang
Cc: cohuck, pasic, farman, linux-s390, kvm, virtualization,
linux-kernel, yan, viktor
According to VirtIO spec v1.2, VIRTIO_F_NOTIFICATION_DATA feature
indicates that the driver passes extra data along with the queue
notifications.
In a split queue case, the extra data is 16-bit available index. In a
packed queue case, the extra data is 1-bit wrap counter and 15-bit
available index.
Add support for this feature for MMIO, channel I/O and modern PCI
transports.
Signed-off-by: Viktor Prutyanov <viktor@daynix.com>
---
v5: replace ternary operator with if-else
v4: remove VP_NOTIFY macro and legacy PCI support, add
virtio_ccw_kvm_notify_with_data to virtio_ccw
v3: support feature in virtio_ccw, remove VM_NOTIFY, use avail_idx_shadow,
remove byte swap, rename to vring_notification_data
v2: reject the feature in virtio_ccw, replace __le32 with u32
Tested with disabled VIRTIO_F_NOTIFICATION_DATA on qemu-system-s390x
(virtio-blk-ccw), qemu-system-riscv64 (virtio-blk-device,
virtio-rng-device), qemu-system-x86_64 (virtio-blk-pci, virtio-net-pci)
to make sure nothing is broken.
Tested with enabled VIRTIO_F_NOTIFICATION_DATA on 64-bit RISC-V Linux
and my hardware implementation of virtio-rng with MMIO.
drivers/s390/virtio/virtio_ccw.c | 22 +++++++++++++++++++---
drivers/virtio/virtio_mmio.c | 18 +++++++++++++++++-
drivers/virtio/virtio_pci_modern.c | 17 ++++++++++++++++-
drivers/virtio/virtio_ring.c | 17 +++++++++++++++++
include/linux/virtio_ring.h | 2 ++
include/uapi/linux/virtio_config.h | 6 ++++++
6 files changed, 77 insertions(+), 5 deletions(-)
diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index 954fc31b4bc7..9a9c5d34454c 100644
--- a/drivers/s390/virtio/virtio_ccw.c
+++ b/drivers/s390/virtio/virtio_ccw.c
@@ -391,7 +391,7 @@ static void virtio_ccw_drop_indicator(struct virtio_ccw_device *vcdev,
ccw_device_dma_free(vcdev->cdev, thinint_area, sizeof(*thinint_area));
}
-static bool virtio_ccw_kvm_notify(struct virtqueue *vq)
+static inline bool virtio_ccw_do_kvm_notify(struct virtqueue *vq, u32 data)
{
struct virtio_ccw_vq_info *info = vq->priv;
struct virtio_ccw_device *vcdev;
@@ -402,12 +402,22 @@ static bool virtio_ccw_kvm_notify(struct virtqueue *vq)
BUILD_BUG_ON(sizeof(struct subchannel_id) != sizeof(unsigned int));
info->cookie = kvm_hypercall3(KVM_S390_VIRTIO_CCW_NOTIFY,
*((unsigned int *)&schid),
- vq->index, info->cookie);
+ data, info->cookie);
if (info->cookie < 0)
return false;
return true;
}
+static bool virtio_ccw_kvm_notify(struct virtqueue *vq)
+{
+ return virtio_ccw_do_kvm_notify(vq, vq->index);
+}
+
+static bool virtio_ccw_kvm_notify_with_data(struct virtqueue *vq)
+{
+ return virtio_ccw_do_kvm_notify(vq, vring_notification_data(vq));
+}
+
static int virtio_ccw_read_vq_conf(struct virtio_ccw_device *vcdev,
struct ccw1 *ccw, int index)
{
@@ -501,6 +511,12 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
u64 queue;
unsigned long flags;
bool may_reduce;
+ bool (*notify)(struct virtqueue *vq);
+
+ if (__virtio_test_bit(vdev, VIRTIO_F_NOTIFICATION_DATA))
+ notify = virtio_ccw_kvm_notify_with_data;
+ else
+ notify = virtio_ccw_kvm_notify;
/* Allocate queue. */
info = kzalloc(sizeof(struct virtio_ccw_vq_info), GFP_KERNEL);
@@ -524,7 +540,7 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
may_reduce = vcdev->revision > 0;
vq = vring_create_virtqueue(i, info->num, KVM_VIRTIO_CCW_RING_ALIGN,
vdev, true, may_reduce, ctx,
- virtio_ccw_kvm_notify, callback, name);
+ notify, callback, name);
if (!vq) {
/* For now, we fail if we can't get the requested size. */
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index 3ff746e3f24a..7e87f745f68d 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -285,6 +285,16 @@ static bool vm_notify(struct virtqueue *vq)
return true;
}
+static bool vm_notify_with_data(struct virtqueue *vq)
+{
+ struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
+ u32 data = vring_notification_data(vq);
+
+ writel(data, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
+
+ return true;
+}
+
/* Notify all virtqueues on an interrupt. */
static irqreturn_t vm_interrupt(int irq, void *opaque)
{
@@ -368,6 +378,12 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned int in
unsigned long flags;
unsigned int num;
int err;
+ bool (*notify)(struct virtqueue *vq);
+
+ if (__virtio_test_bit(vdev, VIRTIO_F_NOTIFICATION_DATA))
+ notify = vm_notify_with_data;
+ else
+ notify = vm_notify;
if (!name)
return NULL;
@@ -397,7 +413,7 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned int in
/* Create the vring */
vq = vring_create_virtqueue(index, num, VIRTIO_MMIO_VRING_ALIGN, vdev,
- true, true, ctx, vm_notify, callback, name);
+ true, true, ctx, notify, callback, name);
if (!vq) {
err = -ENOMEM;
goto error_new_virtqueue;
diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
index 9e496e288cfa..3bfc368b279e 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -288,6 +288,15 @@ static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
return vp_modern_config_vector(&vp_dev->mdev, vector);
}
+static bool vp_notify_with_data(struct virtqueue *vq)
+{
+ u32 data = vring_notification_data(vq);
+
+ iowrite32(data, (void __iomem *)vq->priv);
+
+ return true;
+}
+
static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
struct virtio_pci_vq_info *info,
unsigned int index,
@@ -301,6 +310,12 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
struct virtqueue *vq;
u16 num;
int err;
+ bool (*notify)(struct virtqueue *vq);
+
+ if (__virtio_test_bit(&vp_dev->vdev, VIRTIO_F_NOTIFICATION_DATA))
+ notify = vp_notify_with_data;
+ else
+ notify = vp_notify;
if (index >= vp_modern_get_num_queues(mdev))
return ERR_PTR(-EINVAL);
@@ -321,7 +336,7 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
vq = vring_create_virtqueue(index, num,
SMP_CACHE_BYTES, &vp_dev->vdev,
true, true, ctx,
- vp_notify, callback, name);
+ notify, callback, name);
if (!vq)
return ERR_PTR(-ENOMEM);
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 4c3bb0ddeb9b..837875cc3190 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -2752,6 +2752,21 @@ void vring_del_virtqueue(struct virtqueue *_vq)
}
EXPORT_SYMBOL_GPL(vring_del_virtqueue);
+u32 vring_notification_data(struct virtqueue *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+ u16 next;
+
+ if (vq->packed_ring)
+ next = (vq->packed.next_avail_idx & ~(1 << 15)) |
+ vq->packed.avail_wrap_counter << 15;
+ else
+ next = vq->split.avail_idx_shadow;
+
+ return next << 16 | _vq->index;
+}
+EXPORT_SYMBOL_GPL(vring_notification_data);
+
/* Manipulates transport-specific feature bits. */
void vring_transport_features(struct virtio_device *vdev)
{
@@ -2771,6 +2786,8 @@ void vring_transport_features(struct virtio_device *vdev)
break;
case VIRTIO_F_ORDER_PLATFORM:
break;
+ case VIRTIO_F_NOTIFICATION_DATA:
+ break;
default:
/* We don't understand this bit. */
__virtio_clear_bit(vdev, i);
diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h
index 8b95b69ef694..2550c9170f4f 100644
--- a/include/linux/virtio_ring.h
+++ b/include/linux/virtio_ring.h
@@ -117,4 +117,6 @@ void vring_del_virtqueue(struct virtqueue *vq);
void vring_transport_features(struct virtio_device *vdev);
irqreturn_t vring_interrupt(int irq, void *_vq);
+
+u32 vring_notification_data(struct virtqueue *_vq);
#endif /* _LINUX_VIRTIO_RING_H */
diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h
index 3c05162bc988..2c712c654165 100644
--- a/include/uapi/linux/virtio_config.h
+++ b/include/uapi/linux/virtio_config.h
@@ -99,6 +99,12 @@
*/
#define VIRTIO_F_SR_IOV 37
+/*
+ * This feature indicates that the driver passes extra data (besides
+ * identifying the virtqueue) in its device notifications.
+ */
+#define VIRTIO_F_NOTIFICATION_DATA 38
+
/*
* This feature indicates that the driver can reset a queue individually.
*/
--
2.35.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v5] virtio: add VIRTIO_F_NOTIFICATION_DATA feature support
2023-03-23 8:55 [PATCH v5] virtio: add VIRTIO_F_NOTIFICATION_DATA feature support Viktor Prutyanov
@ 2023-03-23 9:00 ` Xuan Zhuo
2023-03-24 3:09 ` Jason Wang
1 sibling, 0 replies; 6+ messages in thread
From: Xuan Zhuo @ 2023-03-23 9:00 UTC (permalink / raw)
To: Viktor Prutyanov
Cc: cohuck, pasic, farman, linux-s390, kvm, virtualization,
linux-kernel, yan, viktor, mst, jasowang
On Thu, 23 Mar 2023 11:55:51 +0300, Viktor Prutyanov <viktor@daynix.com> wrote:
> According to VirtIO spec v1.2, VIRTIO_F_NOTIFICATION_DATA feature
> indicates that the driver passes extra data along with the queue
> notifications.
>
> In a split queue case, the extra data is 16-bit available index. In a
> packed queue case, the extra data is 1-bit wrap counter and 15-bit
> available index.
>
> Add support for this feature for MMIO, channel I/O and modern PCI
> transports.
>
> Signed-off-by: Viktor Prutyanov <viktor@daynix.com>
> ---
> v5: replace ternary operator with if-else
> v4: remove VP_NOTIFY macro and legacy PCI support, add
> virtio_ccw_kvm_notify_with_data to virtio_ccw
> v3: support feature in virtio_ccw, remove VM_NOTIFY, use avail_idx_shadow,
> remove byte swap, rename to vring_notification_data
> v2: reject the feature in virtio_ccw, replace __le32 with u32
>
> Tested with disabled VIRTIO_F_NOTIFICATION_DATA on qemu-system-s390x
> (virtio-blk-ccw), qemu-system-riscv64 (virtio-blk-device,
> virtio-rng-device), qemu-system-x86_64 (virtio-blk-pci, virtio-net-pci)
> to make sure nothing is broken.
> Tested with enabled VIRTIO_F_NOTIFICATION_DATA on 64-bit RISC-V Linux
> and my hardware implementation of virtio-rng with MMIO.
>
> drivers/s390/virtio/virtio_ccw.c | 22 +++++++++++++++++++---
> drivers/virtio/virtio_mmio.c | 18 +++++++++++++++++-
> drivers/virtio/virtio_pci_modern.c | 17 ++++++++++++++++-
> drivers/virtio/virtio_ring.c | 17 +++++++++++++++++
> include/linux/virtio_ring.h | 2 ++
> include/uapi/linux/virtio_config.h | 6 ++++++
> 6 files changed, 77 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
> index 954fc31b4bc7..9a9c5d34454c 100644
> --- a/drivers/s390/virtio/virtio_ccw.c
> +++ b/drivers/s390/virtio/virtio_ccw.c
> @@ -391,7 +391,7 @@ static void virtio_ccw_drop_indicator(struct virtio_ccw_device *vcdev,
> ccw_device_dma_free(vcdev->cdev, thinint_area, sizeof(*thinint_area));
> }
>
> -static bool virtio_ccw_kvm_notify(struct virtqueue *vq)
> +static inline bool virtio_ccw_do_kvm_notify(struct virtqueue *vq, u32 data)
> {
> struct virtio_ccw_vq_info *info = vq->priv;
> struct virtio_ccw_device *vcdev;
> @@ -402,12 +402,22 @@ static bool virtio_ccw_kvm_notify(struct virtqueue *vq)
> BUILD_BUG_ON(sizeof(struct subchannel_id) != sizeof(unsigned int));
> info->cookie = kvm_hypercall3(KVM_S390_VIRTIO_CCW_NOTIFY,
> *((unsigned int *)&schid),
> - vq->index, info->cookie);
> + data, info->cookie);
> if (info->cookie < 0)
> return false;
> return true;
> }
>
> +static bool virtio_ccw_kvm_notify(struct virtqueue *vq)
> +{
> + return virtio_ccw_do_kvm_notify(vq, vq->index);
> +}
> +
> +static bool virtio_ccw_kvm_notify_with_data(struct virtqueue *vq)
> +{
> + return virtio_ccw_do_kvm_notify(vq, vring_notification_data(vq));
> +}
> +
> static int virtio_ccw_read_vq_conf(struct virtio_ccw_device *vcdev,
> struct ccw1 *ccw, int index)
> {
> @@ -501,6 +511,12 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
> u64 queue;
> unsigned long flags;
> bool may_reduce;
> + bool (*notify)(struct virtqueue *vq);
Generally speaking, the longest statement should be placed at the top.
Other LGTM.
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> +
> + if (__virtio_test_bit(vdev, VIRTIO_F_NOTIFICATION_DATA))
> + notify = virtio_ccw_kvm_notify_with_data;
> + else
> + notify = virtio_ccw_kvm_notify;
>
> /* Allocate queue. */
> info = kzalloc(sizeof(struct virtio_ccw_vq_info), GFP_KERNEL);
> @@ -524,7 +540,7 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
> may_reduce = vcdev->revision > 0;
> vq = vring_create_virtqueue(i, info->num, KVM_VIRTIO_CCW_RING_ALIGN,
> vdev, true, may_reduce, ctx,
> - virtio_ccw_kvm_notify, callback, name);
> + notify, callback, name);
>
> if (!vq) {
> /* For now, we fail if we can't get the requested size. */
> diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
> index 3ff746e3f24a..7e87f745f68d 100644
> --- a/drivers/virtio/virtio_mmio.c
> +++ b/drivers/virtio/virtio_mmio.c
> @@ -285,6 +285,16 @@ static bool vm_notify(struct virtqueue *vq)
> return true;
> }
>
> +static bool vm_notify_with_data(struct virtqueue *vq)
> +{
> + struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
> + u32 data = vring_notification_data(vq);
> +
> + writel(data, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
> +
> + return true;
> +}
> +
> /* Notify all virtqueues on an interrupt. */
> static irqreturn_t vm_interrupt(int irq, void *opaque)
> {
> @@ -368,6 +378,12 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned int in
> unsigned long flags;
> unsigned int num;
> int err;
> + bool (*notify)(struct virtqueue *vq);
> +
> + if (__virtio_test_bit(vdev, VIRTIO_F_NOTIFICATION_DATA))
> + notify = vm_notify_with_data;
> + else
> + notify = vm_notify;
>
> if (!name)
> return NULL;
> @@ -397,7 +413,7 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned int in
>
> /* Create the vring */
> vq = vring_create_virtqueue(index, num, VIRTIO_MMIO_VRING_ALIGN, vdev,
> - true, true, ctx, vm_notify, callback, name);
> + true, true, ctx, notify, callback, name);
> if (!vq) {
> err = -ENOMEM;
> goto error_new_virtqueue;
> diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> index 9e496e288cfa..3bfc368b279e 100644
> --- a/drivers/virtio/virtio_pci_modern.c
> +++ b/drivers/virtio/virtio_pci_modern.c
> @@ -288,6 +288,15 @@ static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
> return vp_modern_config_vector(&vp_dev->mdev, vector);
> }
>
> +static bool vp_notify_with_data(struct virtqueue *vq)
> +{
> + u32 data = vring_notification_data(vq);
> +
> + iowrite32(data, (void __iomem *)vq->priv);
> +
> + return true;
> +}
> +
> static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> struct virtio_pci_vq_info *info,
> unsigned int index,
> @@ -301,6 +310,12 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> struct virtqueue *vq;
> u16 num;
> int err;
> + bool (*notify)(struct virtqueue *vq);
> +
> + if (__virtio_test_bit(&vp_dev->vdev, VIRTIO_F_NOTIFICATION_DATA))
> + notify = vp_notify_with_data;
> + else
> + notify = vp_notify;
>
> if (index >= vp_modern_get_num_queues(mdev))
> return ERR_PTR(-EINVAL);
> @@ -321,7 +336,7 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> vq = vring_create_virtqueue(index, num,
> SMP_CACHE_BYTES, &vp_dev->vdev,
> true, true, ctx,
> - vp_notify, callback, name);
> + notify, callback, name);
> if (!vq)
> return ERR_PTR(-ENOMEM);
>
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index 4c3bb0ddeb9b..837875cc3190 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -2752,6 +2752,21 @@ void vring_del_virtqueue(struct virtqueue *_vq)
> }
> EXPORT_SYMBOL_GPL(vring_del_virtqueue);
>
> +u32 vring_notification_data(struct virtqueue *_vq)
> +{
> + struct vring_virtqueue *vq = to_vvq(_vq);
> + u16 next;
> +
> + if (vq->packed_ring)
> + next = (vq->packed.next_avail_idx & ~(1 << 15)) |
> + vq->packed.avail_wrap_counter << 15;
> + else
> + next = vq->split.avail_idx_shadow;
> +
> + return next << 16 | _vq->index;
> +}
> +EXPORT_SYMBOL_GPL(vring_notification_data);
> +
> /* Manipulates transport-specific feature bits. */
> void vring_transport_features(struct virtio_device *vdev)
> {
> @@ -2771,6 +2786,8 @@ void vring_transport_features(struct virtio_device *vdev)
> break;
> case VIRTIO_F_ORDER_PLATFORM:
> break;
> + case VIRTIO_F_NOTIFICATION_DATA:
> + break;
> default:
> /* We don't understand this bit. */
> __virtio_clear_bit(vdev, i);
> diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h
> index 8b95b69ef694..2550c9170f4f 100644
> --- a/include/linux/virtio_ring.h
> +++ b/include/linux/virtio_ring.h
> @@ -117,4 +117,6 @@ void vring_del_virtqueue(struct virtqueue *vq);
> void vring_transport_features(struct virtio_device *vdev);
>
> irqreturn_t vring_interrupt(int irq, void *_vq);
> +
> +u32 vring_notification_data(struct virtqueue *_vq);
> #endif /* _LINUX_VIRTIO_RING_H */
> diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h
> index 3c05162bc988..2c712c654165 100644
> --- a/include/uapi/linux/virtio_config.h
> +++ b/include/uapi/linux/virtio_config.h
> @@ -99,6 +99,12 @@
> */
> #define VIRTIO_F_SR_IOV 37
>
> +/*
> + * This feature indicates that the driver passes extra data (besides
> + * identifying the virtqueue) in its device notifications.
> + */
> +#define VIRTIO_F_NOTIFICATION_DATA 38
> +
> /*
> * This feature indicates that the driver can reset a queue individually.
> */
> --
> 2.35.1
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v5] virtio: add VIRTIO_F_NOTIFICATION_DATA feature support
2023-03-23 8:55 [PATCH v5] virtio: add VIRTIO_F_NOTIFICATION_DATA feature support Viktor Prutyanov
2023-03-23 9:00 ` Xuan Zhuo
@ 2023-03-24 3:09 ` Jason Wang
2023-03-24 5:31 ` Michael S. Tsirkin
1 sibling, 1 reply; 6+ messages in thread
From: Jason Wang @ 2023-03-24 3:09 UTC (permalink / raw)
To: Viktor Prutyanov
Cc: mst, cohuck, pasic, farman, linux-s390, kvm, virtualization,
linux-kernel, yan
On Thu, Mar 23, 2023 at 4:56 PM Viktor Prutyanov <viktor@daynix.com> wrote:
>
> According to VirtIO spec v1.2, VIRTIO_F_NOTIFICATION_DATA feature
> indicates that the driver passes extra data along with the queue
> notifications.
>
> In a split queue case, the extra data is 16-bit available index. In a
> packed queue case, the extra data is 1-bit wrap counter and 15-bit
> available index.
>
> Add support for this feature for MMIO, channel I/O and modern PCI
> transports.
>
> Signed-off-by: Viktor Prutyanov <viktor@daynix.com>
> ---
> v5: replace ternary operator with if-else
> v4: remove VP_NOTIFY macro and legacy PCI support, add
> virtio_ccw_kvm_notify_with_data to virtio_ccw
> v3: support feature in virtio_ccw, remove VM_NOTIFY, use avail_idx_shadow,
> remove byte swap, rename to vring_notification_data
> v2: reject the feature in virtio_ccw, replace __le32 with u32
>
> Tested with disabled VIRTIO_F_NOTIFICATION_DATA on qemu-system-s390x
> (virtio-blk-ccw), qemu-system-riscv64 (virtio-blk-device,
> virtio-rng-device), qemu-system-x86_64 (virtio-blk-pci, virtio-net-pci)
> to make sure nothing is broken.
> Tested with enabled VIRTIO_F_NOTIFICATION_DATA on 64-bit RISC-V Linux
> and my hardware implementation of virtio-rng with MMIO.
>
> drivers/s390/virtio/virtio_ccw.c | 22 +++++++++++++++++++---
> drivers/virtio/virtio_mmio.c | 18 +++++++++++++++++-
> drivers/virtio/virtio_pci_modern.c | 17 ++++++++++++++++-
> drivers/virtio/virtio_ring.c | 17 +++++++++++++++++
> include/linux/virtio_ring.h | 2 ++
> include/uapi/linux/virtio_config.h | 6 ++++++
> 6 files changed, 77 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
> index 954fc31b4bc7..9a9c5d34454c 100644
> --- a/drivers/s390/virtio/virtio_ccw.c
> +++ b/drivers/s390/virtio/virtio_ccw.c
> @@ -391,7 +391,7 @@ static void virtio_ccw_drop_indicator(struct virtio_ccw_device *vcdev,
> ccw_device_dma_free(vcdev->cdev, thinint_area, sizeof(*thinint_area));
> }
>
> -static bool virtio_ccw_kvm_notify(struct virtqueue *vq)
> +static inline bool virtio_ccw_do_kvm_notify(struct virtqueue *vq, u32 data)
> {
> struct virtio_ccw_vq_info *info = vq->priv;
> struct virtio_ccw_device *vcdev;
> @@ -402,12 +402,22 @@ static bool virtio_ccw_kvm_notify(struct virtqueue *vq)
> BUILD_BUG_ON(sizeof(struct subchannel_id) != sizeof(unsigned int));
> info->cookie = kvm_hypercall3(KVM_S390_VIRTIO_CCW_NOTIFY,
> *((unsigned int *)&schid),
> - vq->index, info->cookie);
> + data, info->cookie);
> if (info->cookie < 0)
> return false;
> return true;
> }
>
> +static bool virtio_ccw_kvm_notify(struct virtqueue *vq)
> +{
> + return virtio_ccw_do_kvm_notify(vq, vq->index);
> +}
> +
> +static bool virtio_ccw_kvm_notify_with_data(struct virtqueue *vq)
> +{
> + return virtio_ccw_do_kvm_notify(vq, vring_notification_data(vq));
> +}
> +
> static int virtio_ccw_read_vq_conf(struct virtio_ccw_device *vcdev,
> struct ccw1 *ccw, int index)
> {
> @@ -501,6 +511,12 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
> u64 queue;
> unsigned long flags;
> bool may_reduce;
> + bool (*notify)(struct virtqueue *vq);
> +
> + if (__virtio_test_bit(vdev, VIRTIO_F_NOTIFICATION_DATA))
> + notify = virtio_ccw_kvm_notify_with_data;
> + else
> + notify = virtio_ccw_kvm_notify;
>
> /* Allocate queue. */
> info = kzalloc(sizeof(struct virtio_ccw_vq_info), GFP_KERNEL);
> @@ -524,7 +540,7 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
> may_reduce = vcdev->revision > 0;
> vq = vring_create_virtqueue(i, info->num, KVM_VIRTIO_CCW_RING_ALIGN,
> vdev, true, may_reduce, ctx,
> - virtio_ccw_kvm_notify, callback, name);
> + notify, callback, name);
>
> if (!vq) {
> /* For now, we fail if we can't get the requested size. */
> diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
> index 3ff746e3f24a..7e87f745f68d 100644
> --- a/drivers/virtio/virtio_mmio.c
> +++ b/drivers/virtio/virtio_mmio.c
> @@ -285,6 +285,16 @@ static bool vm_notify(struct virtqueue *vq)
> return true;
> }
>
> +static bool vm_notify_with_data(struct virtqueue *vq)
> +{
> + struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
> + u32 data = vring_notification_data(vq);
> +
> + writel(data, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
> +
> + return true;
> +}
> +
> /* Notify all virtqueues on an interrupt. */
> static irqreturn_t vm_interrupt(int irq, void *opaque)
> {
> @@ -368,6 +378,12 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned int in
> unsigned long flags;
> unsigned int num;
> int err;
> + bool (*notify)(struct virtqueue *vq);
> +
> + if (__virtio_test_bit(vdev, VIRTIO_F_NOTIFICATION_DATA))
> + notify = vm_notify_with_data;
> + else
> + notify = vm_notify;
>
> if (!name)
> return NULL;
> @@ -397,7 +413,7 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned int in
>
> /* Create the vring */
> vq = vring_create_virtqueue(index, num, VIRTIO_MMIO_VRING_ALIGN, vdev,
> - true, true, ctx, vm_notify, callback, name);
> + true, true, ctx, notify, callback, name);
> if (!vq) {
> err = -ENOMEM;
> goto error_new_virtqueue;
> diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> index 9e496e288cfa..3bfc368b279e 100644
> --- a/drivers/virtio/virtio_pci_modern.c
> +++ b/drivers/virtio/virtio_pci_modern.c
> @@ -288,6 +288,15 @@ static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
> return vp_modern_config_vector(&vp_dev->mdev, vector);
> }
>
> +static bool vp_notify_with_data(struct virtqueue *vq)
> +{
> + u32 data = vring_notification_data(vq);
> +
> + iowrite32(data, (void __iomem *)vq->priv);
> +
> + return true;
> +}
> +
> static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> struct virtio_pci_vq_info *info,
> unsigned int index,
> @@ -301,6 +310,12 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> struct virtqueue *vq;
> u16 num;
> int err;
> + bool (*notify)(struct virtqueue *vq);
> +
> + if (__virtio_test_bit(&vp_dev->vdev, VIRTIO_F_NOTIFICATION_DATA))
> + notify = vp_notify_with_data;
> + else
> + notify = vp_notify;
>
> if (index >= vp_modern_get_num_queues(mdev))
> return ERR_PTR(-EINVAL);
> @@ -321,7 +336,7 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> vq = vring_create_virtqueue(index, num,
> SMP_CACHE_BYTES, &vp_dev->vdev,
> true, true, ctx,
> - vp_notify, callback, name);
> + notify, callback, name);
> if (!vq)
> return ERR_PTR(-ENOMEM);
>
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index 4c3bb0ddeb9b..837875cc3190 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -2752,6 +2752,21 @@ void vring_del_virtqueue(struct virtqueue *_vq)
> }
> EXPORT_SYMBOL_GPL(vring_del_virtqueue);
>
> +u32 vring_notification_data(struct virtqueue *_vq)
> +{
> + struct vring_virtqueue *vq = to_vvq(_vq);
> + u16 next;
> +
> + if (vq->packed_ring)
> + next = (vq->packed.next_avail_idx & ~(1 << 15)) |
> + vq->packed.avail_wrap_counter << 15;
Nit: We have VRING_PACKED_EVENT_F_WRAP_CTR which could be used for
replacing 15 here.
And we have many places for packing them into u16, it might be better
to introduce a helper.
Acked-by: Jason Wang <jasowang@redhat.com>
Thanks
> + else
> + next = vq->split.avail_idx_shadow;
> +
> + return next << 16 | _vq->index;
> +}
> +EXPORT_SYMBOL_GPL(vring_notification_data);
> +
> /* Manipulates transport-specific feature bits. */
> void vring_transport_features(struct virtio_device *vdev)
> {
> @@ -2771,6 +2786,8 @@ void vring_transport_features(struct virtio_device *vdev)
> break;
> case VIRTIO_F_ORDER_PLATFORM:
> break;
> + case VIRTIO_F_NOTIFICATION_DATA:
> + break;
> default:
> /* We don't understand this bit. */
> __virtio_clear_bit(vdev, i);
> diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h
> index 8b95b69ef694..2550c9170f4f 100644
> --- a/include/linux/virtio_ring.h
> +++ b/include/linux/virtio_ring.h
> @@ -117,4 +117,6 @@ void vring_del_virtqueue(struct virtqueue *vq);
> void vring_transport_features(struct virtio_device *vdev);
>
> irqreturn_t vring_interrupt(int irq, void *_vq);
> +
> +u32 vring_notification_data(struct virtqueue *_vq);
> #endif /* _LINUX_VIRTIO_RING_H */
> diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h
> index 3c05162bc988..2c712c654165 100644
> --- a/include/uapi/linux/virtio_config.h
> +++ b/include/uapi/linux/virtio_config.h
> @@ -99,6 +99,12 @@
> */
> #define VIRTIO_F_SR_IOV 37
>
> +/*
> + * This feature indicates that the driver passes extra data (besides
> + * identifying the virtqueue) in its device notifications.
> + */
> +#define VIRTIO_F_NOTIFICATION_DATA 38
> +
> /*
> * This feature indicates that the driver can reset a queue individually.
> */
> --
> 2.35.1
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v5] virtio: add VIRTIO_F_NOTIFICATION_DATA feature support
2023-03-24 3:09 ` Jason Wang
@ 2023-03-24 5:31 ` Michael S. Tsirkin
2023-03-24 7:44 ` Viktor Prutyanov
0 siblings, 1 reply; 6+ messages in thread
From: Michael S. Tsirkin @ 2023-03-24 5:31 UTC (permalink / raw)
To: Jason Wang
Cc: Viktor Prutyanov, cohuck, pasic, farman, linux-s390, kvm,
virtualization, linux-kernel, yan
On Fri, Mar 24, 2023 at 11:09:19AM +0800, Jason Wang wrote:
> On Thu, Mar 23, 2023 at 4:56 PM Viktor Prutyanov <viktor@daynix.com> wrote:
> >
> > According to VirtIO spec v1.2, VIRTIO_F_NOTIFICATION_DATA feature
> > indicates that the driver passes extra data along with the queue
> > notifications.
> >
> > In a split queue case, the extra data is 16-bit available index. In a
> > packed queue case, the extra data is 1-bit wrap counter and 15-bit
> > available index.
> >
> > Add support for this feature for MMIO, channel I/O and modern PCI
> > transports.
> >
> > Signed-off-by: Viktor Prutyanov <viktor@daynix.com>
> > ---
> > v5: replace ternary operator with if-else
> > v4: remove VP_NOTIFY macro and legacy PCI support, add
> > virtio_ccw_kvm_notify_with_data to virtio_ccw
> > v3: support feature in virtio_ccw, remove VM_NOTIFY, use avail_idx_shadow,
> > remove byte swap, rename to vring_notification_data
> > v2: reject the feature in virtio_ccw, replace __le32 with u32
> >
> > Tested with disabled VIRTIO_F_NOTIFICATION_DATA on qemu-system-s390x
> > (virtio-blk-ccw), qemu-system-riscv64 (virtio-blk-device,
> > virtio-rng-device), qemu-system-x86_64 (virtio-blk-pci, virtio-net-pci)
> > to make sure nothing is broken.
> > Tested with enabled VIRTIO_F_NOTIFICATION_DATA on 64-bit RISC-V Linux
> > and my hardware implementation of virtio-rng with MMIO.
> >
> > drivers/s390/virtio/virtio_ccw.c | 22 +++++++++++++++++++---
> > drivers/virtio/virtio_mmio.c | 18 +++++++++++++++++-
> > drivers/virtio/virtio_pci_modern.c | 17 ++++++++++++++++-
> > drivers/virtio/virtio_ring.c | 17 +++++++++++++++++
> > include/linux/virtio_ring.h | 2 ++
> > include/uapi/linux/virtio_config.h | 6 ++++++
> > 6 files changed, 77 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
> > index 954fc31b4bc7..9a9c5d34454c 100644
> > --- a/drivers/s390/virtio/virtio_ccw.c
> > +++ b/drivers/s390/virtio/virtio_ccw.c
> > @@ -391,7 +391,7 @@ static void virtio_ccw_drop_indicator(struct virtio_ccw_device *vcdev,
> > ccw_device_dma_free(vcdev->cdev, thinint_area, sizeof(*thinint_area));
> > }
> >
> > -static bool virtio_ccw_kvm_notify(struct virtqueue *vq)
> > +static inline bool virtio_ccw_do_kvm_notify(struct virtqueue *vq, u32 data)
> > {
> > struct virtio_ccw_vq_info *info = vq->priv;
> > struct virtio_ccw_device *vcdev;
> > @@ -402,12 +402,22 @@ static bool virtio_ccw_kvm_notify(struct virtqueue *vq)
> > BUILD_BUG_ON(sizeof(struct subchannel_id) != sizeof(unsigned int));
> > info->cookie = kvm_hypercall3(KVM_S390_VIRTIO_CCW_NOTIFY,
> > *((unsigned int *)&schid),
> > - vq->index, info->cookie);
> > + data, info->cookie);
> > if (info->cookie < 0)
> > return false;
> > return true;
> > }
> >
> > +static bool virtio_ccw_kvm_notify(struct virtqueue *vq)
> > +{
> > + return virtio_ccw_do_kvm_notify(vq, vq->index);
> > +}
> > +
> > +static bool virtio_ccw_kvm_notify_with_data(struct virtqueue *vq)
> > +{
> > + return virtio_ccw_do_kvm_notify(vq, vring_notification_data(vq));
> > +}
> > +
> > static int virtio_ccw_read_vq_conf(struct virtio_ccw_device *vcdev,
> > struct ccw1 *ccw, int index)
> > {
> > @@ -501,6 +511,12 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
> > u64 queue;
> > unsigned long flags;
> > bool may_reduce;
> > + bool (*notify)(struct virtqueue *vq);
> > +
> > + if (__virtio_test_bit(vdev, VIRTIO_F_NOTIFICATION_DATA))
> > + notify = virtio_ccw_kvm_notify_with_data;
> > + else
> > + notify = virtio_ccw_kvm_notify;
> >
> > /* Allocate queue. */
> > info = kzalloc(sizeof(struct virtio_ccw_vq_info), GFP_KERNEL);
> > @@ -524,7 +540,7 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
> > may_reduce = vcdev->revision > 0;
> > vq = vring_create_virtqueue(i, info->num, KVM_VIRTIO_CCW_RING_ALIGN,
> > vdev, true, may_reduce, ctx,
> > - virtio_ccw_kvm_notify, callback, name);
> > + notify, callback, name);
> >
> > if (!vq) {
> > /* For now, we fail if we can't get the requested size. */
> > diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
> > index 3ff746e3f24a..7e87f745f68d 100644
> > --- a/drivers/virtio/virtio_mmio.c
> > +++ b/drivers/virtio/virtio_mmio.c
> > @@ -285,6 +285,16 @@ static bool vm_notify(struct virtqueue *vq)
> > return true;
> > }
> >
> > +static bool vm_notify_with_data(struct virtqueue *vq)
> > +{
> > + struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
> > + u32 data = vring_notification_data(vq);
> > +
> > + writel(data, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
> > +
> > + return true;
> > +}
> > +
> > /* Notify all virtqueues on an interrupt. */
> > static irqreturn_t vm_interrupt(int irq, void *opaque)
> > {
> > @@ -368,6 +378,12 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned int in
> > unsigned long flags;
> > unsigned int num;
> > int err;
> > + bool (*notify)(struct virtqueue *vq);
> > +
> > + if (__virtio_test_bit(vdev, VIRTIO_F_NOTIFICATION_DATA))
> > + notify = vm_notify_with_data;
> > + else
> > + notify = vm_notify;
> >
> > if (!name)
> > return NULL;
> > @@ -397,7 +413,7 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned int in
> >
> > /* Create the vring */
> > vq = vring_create_virtqueue(index, num, VIRTIO_MMIO_VRING_ALIGN, vdev,
> > - true, true, ctx, vm_notify, callback, name);
> > + true, true, ctx, notify, callback, name);
> > if (!vq) {
> > err = -ENOMEM;
> > goto error_new_virtqueue;
> > diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> > index 9e496e288cfa..3bfc368b279e 100644
> > --- a/drivers/virtio/virtio_pci_modern.c
> > +++ b/drivers/virtio/virtio_pci_modern.c
> > @@ -288,6 +288,15 @@ static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
> > return vp_modern_config_vector(&vp_dev->mdev, vector);
> > }
> >
> > +static bool vp_notify_with_data(struct virtqueue *vq)
> > +{
> > + u32 data = vring_notification_data(vq);
> > +
> > + iowrite32(data, (void __iomem *)vq->priv);
> > +
> > + return true;
> > +}
> > +
> > static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> > struct virtio_pci_vq_info *info,
> > unsigned int index,
> > @@ -301,6 +310,12 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> > struct virtqueue *vq;
> > u16 num;
> > int err;
> > + bool (*notify)(struct virtqueue *vq);
> > +
> > + if (__virtio_test_bit(&vp_dev->vdev, VIRTIO_F_NOTIFICATION_DATA))
> > + notify = vp_notify_with_data;
> > + else
> > + notify = vp_notify;
> >
> > if (index >= vp_modern_get_num_queues(mdev))
> > return ERR_PTR(-EINVAL);
> > @@ -321,7 +336,7 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> > vq = vring_create_virtqueue(index, num,
> > SMP_CACHE_BYTES, &vp_dev->vdev,
> > true, true, ctx,
> > - vp_notify, callback, name);
> > + notify, callback, name);
> > if (!vq)
> > return ERR_PTR(-ENOMEM);
> >
> > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> > index 4c3bb0ddeb9b..837875cc3190 100644
> > --- a/drivers/virtio/virtio_ring.c
> > +++ b/drivers/virtio/virtio_ring.c
> > @@ -2752,6 +2752,21 @@ void vring_del_virtqueue(struct virtqueue *_vq)
> > }
> > EXPORT_SYMBOL_GPL(vring_del_virtqueue);
> >
> > +u32 vring_notification_data(struct virtqueue *_vq)
> > +{
> > + struct vring_virtqueue *vq = to_vvq(_vq);
> > + u16 next;
> > +
> > + if (vq->packed_ring)
> > + next = (vq->packed.next_avail_idx & ~(1 << 15)) |
> > + vq->packed.avail_wrap_counter << 15;
>
> Nit: We have VRING_PACKED_EVENT_F_WRAP_CTR which could be used for
> replacing 15 here.
>
> And we have many places for packing them into u16, it might be better
> to introduce a helper.
Not sure about a helper, I'd leave that for a future cleanup.
However I would use
& (-(1 << VRING_PACKED_EVENT_F_WRAP_CTR))
that's more robust - works for any value of VRING_PACKED_EVENT_F_WRAP_CTR
giving low bits 0 to VRING_PACKED_EVENT_F_WRAP_CTR,
and will keep working if someone copypasted it and changed
counter to a value different from 15.
> Acked-by: Jason Wang <jasowang@redhat.com>
>
> Thanks
>
> > + else
> > + next = vq->split.avail_idx_shadow;
> > +
> > + return next << 16 | _vq->index;
> > +}
> > +EXPORT_SYMBOL_GPL(vring_notification_data);
> > +
> > /* Manipulates transport-specific feature bits. */
> > void vring_transport_features(struct virtio_device *vdev)
> > {
> > @@ -2771,6 +2786,8 @@ void vring_transport_features(struct virtio_device *vdev)
> > break;
> > case VIRTIO_F_ORDER_PLATFORM:
> > break;
> > + case VIRTIO_F_NOTIFICATION_DATA:
> > + break;
> > default:
> > /* We don't understand this bit. */
> > __virtio_clear_bit(vdev, i);
> > diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h
> > index 8b95b69ef694..2550c9170f4f 100644
> > --- a/include/linux/virtio_ring.h
> > +++ b/include/linux/virtio_ring.h
> > @@ -117,4 +117,6 @@ void vring_del_virtqueue(struct virtqueue *vq);
> > void vring_transport_features(struct virtio_device *vdev);
> >
> > irqreturn_t vring_interrupt(int irq, void *_vq);
> > +
> > +u32 vring_notification_data(struct virtqueue *_vq);
> > #endif /* _LINUX_VIRTIO_RING_H */
> > diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h
> > index 3c05162bc988..2c712c654165 100644
> > --- a/include/uapi/linux/virtio_config.h
> > +++ b/include/uapi/linux/virtio_config.h
> > @@ -99,6 +99,12 @@
> > */
> > #define VIRTIO_F_SR_IOV 37
> >
> > +/*
> > + * This feature indicates that the driver passes extra data (besides
> > + * identifying the virtqueue) in its device notifications.
> > + */
> > +#define VIRTIO_F_NOTIFICATION_DATA 38
> > +
> > /*
> > * This feature indicates that the driver can reset a queue individually.
> > */
> > --
> > 2.35.1
> >
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v5] virtio: add VIRTIO_F_NOTIFICATION_DATA feature support
2023-03-24 5:31 ` Michael S. Tsirkin
@ 2023-03-24 7:44 ` Viktor Prutyanov
2023-03-24 9:07 ` Michael S. Tsirkin
0 siblings, 1 reply; 6+ messages in thread
From: Viktor Prutyanov @ 2023-03-24 7:44 UTC (permalink / raw)
To: Michael S. Tsirkin
Cc: Jason Wang, cohuck, pasic, farman, linux-s390, kvm,
virtualization, linux-kernel, yan
On Fri, Mar 24, 2023 at 8:31 AM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Fri, Mar 24, 2023 at 11:09:19AM +0800, Jason Wang wrote:
> > On Thu, Mar 23, 2023 at 4:56 PM Viktor Prutyanov <viktor@daynix.com> wrote:
> > >
> > > According to VirtIO spec v1.2, VIRTIO_F_NOTIFICATION_DATA feature
> > > indicates that the driver passes extra data along with the queue
> > > notifications.
> > >
> > > In a split queue case, the extra data is 16-bit available index. In a
> > > packed queue case, the extra data is 1-bit wrap counter and 15-bit
> > > available index.
> > >
> > > Add support for this feature for MMIO, channel I/O and modern PCI
> > > transports.
> > >
> > > Signed-off-by: Viktor Prutyanov <viktor@daynix.com>
> > > ---
> > > v5: replace ternary operator with if-else
> > > v4: remove VP_NOTIFY macro and legacy PCI support, add
> > > virtio_ccw_kvm_notify_with_data to virtio_ccw
> > > v3: support feature in virtio_ccw, remove VM_NOTIFY, use avail_idx_shadow,
> > > remove byte swap, rename to vring_notification_data
> > > v2: reject the feature in virtio_ccw, replace __le32 with u32
> > >
> > > Tested with disabled VIRTIO_F_NOTIFICATION_DATA on qemu-system-s390x
> > > (virtio-blk-ccw), qemu-system-riscv64 (virtio-blk-device,
> > > virtio-rng-device), qemu-system-x86_64 (virtio-blk-pci, virtio-net-pci)
> > > to make sure nothing is broken.
> > > Tested with enabled VIRTIO_F_NOTIFICATION_DATA on 64-bit RISC-V Linux
> > > and my hardware implementation of virtio-rng with MMIO.
> > >
> > > drivers/s390/virtio/virtio_ccw.c | 22 +++++++++++++++++++---
> > > drivers/virtio/virtio_mmio.c | 18 +++++++++++++++++-
> > > drivers/virtio/virtio_pci_modern.c | 17 ++++++++++++++++-
> > > drivers/virtio/virtio_ring.c | 17 +++++++++++++++++
> > > include/linux/virtio_ring.h | 2 ++
> > > include/uapi/linux/virtio_config.h | 6 ++++++
> > > 6 files changed, 77 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
> > > index 954fc31b4bc7..9a9c5d34454c 100644
> > > --- a/drivers/s390/virtio/virtio_ccw.c
> > > +++ b/drivers/s390/virtio/virtio_ccw.c
> > > @@ -391,7 +391,7 @@ static void virtio_ccw_drop_indicator(struct virtio_ccw_device *vcdev,
> > > ccw_device_dma_free(vcdev->cdev, thinint_area, sizeof(*thinint_area));
> > > }
> > >
> > > -static bool virtio_ccw_kvm_notify(struct virtqueue *vq)
> > > +static inline bool virtio_ccw_do_kvm_notify(struct virtqueue *vq, u32 data)
> > > {
> > > struct virtio_ccw_vq_info *info = vq->priv;
> > > struct virtio_ccw_device *vcdev;
> > > @@ -402,12 +402,22 @@ static bool virtio_ccw_kvm_notify(struct virtqueue *vq)
> > > BUILD_BUG_ON(sizeof(struct subchannel_id) != sizeof(unsigned int));
> > > info->cookie = kvm_hypercall3(KVM_S390_VIRTIO_CCW_NOTIFY,
> > > *((unsigned int *)&schid),
> > > - vq->index, info->cookie);
> > > + data, info->cookie);
> > > if (info->cookie < 0)
> > > return false;
> > > return true;
> > > }
> > >
> > > +static bool virtio_ccw_kvm_notify(struct virtqueue *vq)
> > > +{
> > > + return virtio_ccw_do_kvm_notify(vq, vq->index);
> > > +}
> > > +
> > > +static bool virtio_ccw_kvm_notify_with_data(struct virtqueue *vq)
> > > +{
> > > + return virtio_ccw_do_kvm_notify(vq, vring_notification_data(vq));
> > > +}
> > > +
> > > static int virtio_ccw_read_vq_conf(struct virtio_ccw_device *vcdev,
> > > struct ccw1 *ccw, int index)
> > > {
> > > @@ -501,6 +511,12 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
> > > u64 queue;
> > > unsigned long flags;
> > > bool may_reduce;
> > > + bool (*notify)(struct virtqueue *vq);
> > > +
> > > + if (__virtio_test_bit(vdev, VIRTIO_F_NOTIFICATION_DATA))
> > > + notify = virtio_ccw_kvm_notify_with_data;
> > > + else
> > > + notify = virtio_ccw_kvm_notify;
> > >
> > > /* Allocate queue. */
> > > info = kzalloc(sizeof(struct virtio_ccw_vq_info), GFP_KERNEL);
> > > @@ -524,7 +540,7 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
> > > may_reduce = vcdev->revision > 0;
> > > vq = vring_create_virtqueue(i, info->num, KVM_VIRTIO_CCW_RING_ALIGN,
> > > vdev, true, may_reduce, ctx,
> > > - virtio_ccw_kvm_notify, callback, name);
> > > + notify, callback, name);
> > >
> > > if (!vq) {
> > > /* For now, we fail if we can't get the requested size. */
> > > diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
> > > index 3ff746e3f24a..7e87f745f68d 100644
> > > --- a/drivers/virtio/virtio_mmio.c
> > > +++ b/drivers/virtio/virtio_mmio.c
> > > @@ -285,6 +285,16 @@ static bool vm_notify(struct virtqueue *vq)
> > > return true;
> > > }
> > >
> > > +static bool vm_notify_with_data(struct virtqueue *vq)
> > > +{
> > > + struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
> > > + u32 data = vring_notification_data(vq);
> > > +
> > > + writel(data, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
> > > +
> > > + return true;
> > > +}
> > > +
> > > /* Notify all virtqueues on an interrupt. */
> > > static irqreturn_t vm_interrupt(int irq, void *opaque)
> > > {
> > > @@ -368,6 +378,12 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned int in
> > > unsigned long flags;
> > > unsigned int num;
> > > int err;
> > > + bool (*notify)(struct virtqueue *vq);
> > > +
> > > + if (__virtio_test_bit(vdev, VIRTIO_F_NOTIFICATION_DATA))
> > > + notify = vm_notify_with_data;
> > > + else
> > > + notify = vm_notify;
> > >
> > > if (!name)
> > > return NULL;
> > > @@ -397,7 +413,7 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned int in
> > >
> > > /* Create the vring */
> > > vq = vring_create_virtqueue(index, num, VIRTIO_MMIO_VRING_ALIGN, vdev,
> > > - true, true, ctx, vm_notify, callback, name);
> > > + true, true, ctx, notify, callback, name);
> > > if (!vq) {
> > > err = -ENOMEM;
> > > goto error_new_virtqueue;
> > > diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> > > index 9e496e288cfa..3bfc368b279e 100644
> > > --- a/drivers/virtio/virtio_pci_modern.c
> > > +++ b/drivers/virtio/virtio_pci_modern.c
> > > @@ -288,6 +288,15 @@ static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
> > > return vp_modern_config_vector(&vp_dev->mdev, vector);
> > > }
> > >
> > > +static bool vp_notify_with_data(struct virtqueue *vq)
> > > +{
> > > + u32 data = vring_notification_data(vq);
> > > +
> > > + iowrite32(data, (void __iomem *)vq->priv);
> > > +
> > > + return true;
> > > +}
> > > +
> > > static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> > > struct virtio_pci_vq_info *info,
> > > unsigned int index,
> > > @@ -301,6 +310,12 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> > > struct virtqueue *vq;
> > > u16 num;
> > > int err;
> > > + bool (*notify)(struct virtqueue *vq);
> > > +
> > > + if (__virtio_test_bit(&vp_dev->vdev, VIRTIO_F_NOTIFICATION_DATA))
> > > + notify = vp_notify_with_data;
> > > + else
> > > + notify = vp_notify;
> > >
> > > if (index >= vp_modern_get_num_queues(mdev))
> > > return ERR_PTR(-EINVAL);
> > > @@ -321,7 +336,7 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> > > vq = vring_create_virtqueue(index, num,
> > > SMP_CACHE_BYTES, &vp_dev->vdev,
> > > true, true, ctx,
> > > - vp_notify, callback, name);
> > > + notify, callback, name);
> > > if (!vq)
> > > return ERR_PTR(-ENOMEM);
> > >
> > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> > > index 4c3bb0ddeb9b..837875cc3190 100644
> > > --- a/drivers/virtio/virtio_ring.c
> > > +++ b/drivers/virtio/virtio_ring.c
> > > @@ -2752,6 +2752,21 @@ void vring_del_virtqueue(struct virtqueue *_vq)
> > > }
> > > EXPORT_SYMBOL_GPL(vring_del_virtqueue);
> > >
> > > +u32 vring_notification_data(struct virtqueue *_vq)
> > > +{
> > > + struct vring_virtqueue *vq = to_vvq(_vq);
> > > + u16 next;
> > > +
> > > + if (vq->packed_ring)
> > > + next = (vq->packed.next_avail_idx & ~(1 << 15)) |
> > > + vq->packed.avail_wrap_counter << 15;
> >
> > Nit: We have VRING_PACKED_EVENT_F_WRAP_CTR which could be used for
> > replacing 15 here.
> >
> > And we have many places for packing them into u16, it might be better
> > to introduce a helper.
>
> Not sure about a helper, I'd leave that for a future cleanup.
>
> However I would use
>
> & (-(1 << VRING_PACKED_EVENT_F_WRAP_CTR))
Do you mean
& (~(1 << VRING_PACKED_EVENT_F_WRAP_CTR))
or maybe I missed something?
>
> that's more robust - works for any value of VRING_PACKED_EVENT_F_WRAP_CTR
> giving low bits 0 to VRING_PACKED_EVENT_F_WRAP_CTR,
> and will keep working if someone copypasted it and changed
> counter to a value different from 15.
>
>
> > Acked-by: Jason Wang <jasowang@redhat.com>
> >
> > Thanks
> >
> > > + else
> > > + next = vq->split.avail_idx_shadow;
> > > +
> > > + return next << 16 | _vq->index;
> > > +}
> > > +EXPORT_SYMBOL_GPL(vring_notification_data);
> > > +
> > > /* Manipulates transport-specific feature bits. */
> > > void vring_transport_features(struct virtio_device *vdev)
> > > {
> > > @@ -2771,6 +2786,8 @@ void vring_transport_features(struct virtio_device *vdev)
> > > break;
> > > case VIRTIO_F_ORDER_PLATFORM:
> > > break;
> > > + case VIRTIO_F_NOTIFICATION_DATA:
> > > + break;
> > > default:
> > > /* We don't understand this bit. */
> > > __virtio_clear_bit(vdev, i);
> > > diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h
> > > index 8b95b69ef694..2550c9170f4f 100644
> > > --- a/include/linux/virtio_ring.h
> > > +++ b/include/linux/virtio_ring.h
> > > @@ -117,4 +117,6 @@ void vring_del_virtqueue(struct virtqueue *vq);
> > > void vring_transport_features(struct virtio_device *vdev);
> > >
> > > irqreturn_t vring_interrupt(int irq, void *_vq);
> > > +
> > > +u32 vring_notification_data(struct virtqueue *_vq);
> > > #endif /* _LINUX_VIRTIO_RING_H */
> > > diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h
> > > index 3c05162bc988..2c712c654165 100644
> > > --- a/include/uapi/linux/virtio_config.h
> > > +++ b/include/uapi/linux/virtio_config.h
> > > @@ -99,6 +99,12 @@
> > > */
> > > #define VIRTIO_F_SR_IOV 37
> > >
> > > +/*
> > > + * This feature indicates that the driver passes extra data (besides
> > > + * identifying the virtqueue) in its device notifications.
> > > + */
> > > +#define VIRTIO_F_NOTIFICATION_DATA 38
> > > +
> > > /*
> > > * This feature indicates that the driver can reset a queue individually.
> > > */
> > > --
> > > 2.35.1
> > >
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v5] virtio: add VIRTIO_F_NOTIFICATION_DATA feature support
2023-03-24 7:44 ` Viktor Prutyanov
@ 2023-03-24 9:07 ` Michael S. Tsirkin
0 siblings, 0 replies; 6+ messages in thread
From: Michael S. Tsirkin @ 2023-03-24 9:07 UTC (permalink / raw)
To: Viktor Prutyanov
Cc: Jason Wang, cohuck, pasic, farman, linux-s390, kvm,
virtualization, linux-kernel, yan
On Fri, Mar 24, 2023 at 10:44:23AM +0300, Viktor Prutyanov wrote:
> On Fri, Mar 24, 2023 at 8:31 AM Michael S. Tsirkin <mst@redhat.com> wrote:
> >
> > On Fri, Mar 24, 2023 at 11:09:19AM +0800, Jason Wang wrote:
> > > On Thu, Mar 23, 2023 at 4:56 PM Viktor Prutyanov <viktor@daynix.com> wrote:
> > > >
> > > > According to VirtIO spec v1.2, VIRTIO_F_NOTIFICATION_DATA feature
> > > > indicates that the driver passes extra data along with the queue
> > > > notifications.
> > > >
> > > > In a split queue case, the extra data is 16-bit available index. In a
> > > > packed queue case, the extra data is 1-bit wrap counter and 15-bit
> > > > available index.
> > > >
> > > > Add support for this feature for MMIO, channel I/O and modern PCI
> > > > transports.
> > > >
> > > > Signed-off-by: Viktor Prutyanov <viktor@daynix.com>
> > > > ---
> > > > v5: replace ternary operator with if-else
> > > > v4: remove VP_NOTIFY macro and legacy PCI support, add
> > > > virtio_ccw_kvm_notify_with_data to virtio_ccw
> > > > v3: support feature in virtio_ccw, remove VM_NOTIFY, use avail_idx_shadow,
> > > > remove byte swap, rename to vring_notification_data
> > > > v2: reject the feature in virtio_ccw, replace __le32 with u32
> > > >
> > > > Tested with disabled VIRTIO_F_NOTIFICATION_DATA on qemu-system-s390x
> > > > (virtio-blk-ccw), qemu-system-riscv64 (virtio-blk-device,
> > > > virtio-rng-device), qemu-system-x86_64 (virtio-blk-pci, virtio-net-pci)
> > > > to make sure nothing is broken.
> > > > Tested with enabled VIRTIO_F_NOTIFICATION_DATA on 64-bit RISC-V Linux
> > > > and my hardware implementation of virtio-rng with MMIO.
> > > >
> > > > drivers/s390/virtio/virtio_ccw.c | 22 +++++++++++++++++++---
> > > > drivers/virtio/virtio_mmio.c | 18 +++++++++++++++++-
> > > > drivers/virtio/virtio_pci_modern.c | 17 ++++++++++++++++-
> > > > drivers/virtio/virtio_ring.c | 17 +++++++++++++++++
> > > > include/linux/virtio_ring.h | 2 ++
> > > > include/uapi/linux/virtio_config.h | 6 ++++++
> > > > 6 files changed, 77 insertions(+), 5 deletions(-)
> > > >
> > > > diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
> > > > index 954fc31b4bc7..9a9c5d34454c 100644
> > > > --- a/drivers/s390/virtio/virtio_ccw.c
> > > > +++ b/drivers/s390/virtio/virtio_ccw.c
> > > > @@ -391,7 +391,7 @@ static void virtio_ccw_drop_indicator(struct virtio_ccw_device *vcdev,
> > > > ccw_device_dma_free(vcdev->cdev, thinint_area, sizeof(*thinint_area));
> > > > }
> > > >
> > > > -static bool virtio_ccw_kvm_notify(struct virtqueue *vq)
> > > > +static inline bool virtio_ccw_do_kvm_notify(struct virtqueue *vq, u32 data)
> > > > {
> > > > struct virtio_ccw_vq_info *info = vq->priv;
> > > > struct virtio_ccw_device *vcdev;
> > > > @@ -402,12 +402,22 @@ static bool virtio_ccw_kvm_notify(struct virtqueue *vq)
> > > > BUILD_BUG_ON(sizeof(struct subchannel_id) != sizeof(unsigned int));
> > > > info->cookie = kvm_hypercall3(KVM_S390_VIRTIO_CCW_NOTIFY,
> > > > *((unsigned int *)&schid),
> > > > - vq->index, info->cookie);
> > > > + data, info->cookie);
> > > > if (info->cookie < 0)
> > > > return false;
> > > > return true;
> > > > }
> > > >
> > > > +static bool virtio_ccw_kvm_notify(struct virtqueue *vq)
> > > > +{
> > > > + return virtio_ccw_do_kvm_notify(vq, vq->index);
> > > > +}
> > > > +
> > > > +static bool virtio_ccw_kvm_notify_with_data(struct virtqueue *vq)
> > > > +{
> > > > + return virtio_ccw_do_kvm_notify(vq, vring_notification_data(vq));
> > > > +}
> > > > +
> > > > static int virtio_ccw_read_vq_conf(struct virtio_ccw_device *vcdev,
> > > > struct ccw1 *ccw, int index)
> > > > {
> > > > @@ -501,6 +511,12 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
> > > > u64 queue;
> > > > unsigned long flags;
> > > > bool may_reduce;
> > > > + bool (*notify)(struct virtqueue *vq);
> > > > +
> > > > + if (__virtio_test_bit(vdev, VIRTIO_F_NOTIFICATION_DATA))
> > > > + notify = virtio_ccw_kvm_notify_with_data;
> > > > + else
> > > > + notify = virtio_ccw_kvm_notify;
> > > >
> > > > /* Allocate queue. */
> > > > info = kzalloc(sizeof(struct virtio_ccw_vq_info), GFP_KERNEL);
> > > > @@ -524,7 +540,7 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
> > > > may_reduce = vcdev->revision > 0;
> > > > vq = vring_create_virtqueue(i, info->num, KVM_VIRTIO_CCW_RING_ALIGN,
> > > > vdev, true, may_reduce, ctx,
> > > > - virtio_ccw_kvm_notify, callback, name);
> > > > + notify, callback, name);
> > > >
> > > > if (!vq) {
> > > > /* For now, we fail if we can't get the requested size. */
> > > > diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
> > > > index 3ff746e3f24a..7e87f745f68d 100644
> > > > --- a/drivers/virtio/virtio_mmio.c
> > > > +++ b/drivers/virtio/virtio_mmio.c
> > > > @@ -285,6 +285,16 @@ static bool vm_notify(struct virtqueue *vq)
> > > > return true;
> > > > }
> > > >
> > > > +static bool vm_notify_with_data(struct virtqueue *vq)
> > > > +{
> > > > + struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
> > > > + u32 data = vring_notification_data(vq);
> > > > +
> > > > + writel(data, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
> > > > +
> > > > + return true;
> > > > +}
> > > > +
> > > > /* Notify all virtqueues on an interrupt. */
> > > > static irqreturn_t vm_interrupt(int irq, void *opaque)
> > > > {
> > > > @@ -368,6 +378,12 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned int in
> > > > unsigned long flags;
> > > > unsigned int num;
> > > > int err;
> > > > + bool (*notify)(struct virtqueue *vq);
> > > > +
> > > > + if (__virtio_test_bit(vdev, VIRTIO_F_NOTIFICATION_DATA))
> > > > + notify = vm_notify_with_data;
> > > > + else
> > > > + notify = vm_notify;
> > > >
> > > > if (!name)
> > > > return NULL;
> > > > @@ -397,7 +413,7 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned int in
> > > >
> > > > /* Create the vring */
> > > > vq = vring_create_virtqueue(index, num, VIRTIO_MMIO_VRING_ALIGN, vdev,
> > > > - true, true, ctx, vm_notify, callback, name);
> > > > + true, true, ctx, notify, callback, name);
> > > > if (!vq) {
> > > > err = -ENOMEM;
> > > > goto error_new_virtqueue;
> > > > diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> > > > index 9e496e288cfa..3bfc368b279e 100644
> > > > --- a/drivers/virtio/virtio_pci_modern.c
> > > > +++ b/drivers/virtio/virtio_pci_modern.c
> > > > @@ -288,6 +288,15 @@ static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
> > > > return vp_modern_config_vector(&vp_dev->mdev, vector);
> > > > }
> > > >
> > > > +static bool vp_notify_with_data(struct virtqueue *vq)
> > > > +{
> > > > + u32 data = vring_notification_data(vq);
> > > > +
> > > > + iowrite32(data, (void __iomem *)vq->priv);
> > > > +
> > > > + return true;
> > > > +}
> > > > +
> > > > static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> > > > struct virtio_pci_vq_info *info,
> > > > unsigned int index,
> > > > @@ -301,6 +310,12 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> > > > struct virtqueue *vq;
> > > > u16 num;
> > > > int err;
> > > > + bool (*notify)(struct virtqueue *vq);
> > > > +
> > > > + if (__virtio_test_bit(&vp_dev->vdev, VIRTIO_F_NOTIFICATION_DATA))
> > > > + notify = vp_notify_with_data;
> > > > + else
> > > > + notify = vp_notify;
> > > >
> > > > if (index >= vp_modern_get_num_queues(mdev))
> > > > return ERR_PTR(-EINVAL);
> > > > @@ -321,7 +336,7 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
> > > > vq = vring_create_virtqueue(index, num,
> > > > SMP_CACHE_BYTES, &vp_dev->vdev,
> > > > true, true, ctx,
> > > > - vp_notify, callback, name);
> > > > + notify, callback, name);
> > > > if (!vq)
> > > > return ERR_PTR(-ENOMEM);
> > > >
> > > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> > > > index 4c3bb0ddeb9b..837875cc3190 100644
> > > > --- a/drivers/virtio/virtio_ring.c
> > > > +++ b/drivers/virtio/virtio_ring.c
> > > > @@ -2752,6 +2752,21 @@ void vring_del_virtqueue(struct virtqueue *_vq)
> > > > }
> > > > EXPORT_SYMBOL_GPL(vring_del_virtqueue);
> > > >
> > > > +u32 vring_notification_data(struct virtqueue *_vq)
> > > > +{
> > > > + struct vring_virtqueue *vq = to_vvq(_vq);
> > > > + u16 next;
> > > > +
> > > > + if (vq->packed_ring)
> > > > + next = (vq->packed.next_avail_idx & ~(1 << 15)) |
> > > > + vq->packed.avail_wrap_counter << 15;
> > >
> > > Nit: We have VRING_PACKED_EVENT_F_WRAP_CTR which could be used for
> > > replacing 15 here.
> > >
> > > And we have many places for packing them into u16, it might be better
> > > to introduce a helper.
> >
> > Not sure about a helper, I'd leave that for a future cleanup.
> >
> > However I would use
> >
> > & (-(1 << VRING_PACKED_EVENT_F_WRAP_CTR))
>
> Do you mean
> & (~(1 << VRING_PACKED_EVENT_F_WRAP_CTR))
> or maybe I missed something?
Sorry.
I meant:
~(-(1 << VRING_PACKED_EVENT_F_WRAP_CTR))
which means "all bits above VRING_PACKED_EVENT_F_WRAP_CTR".
> >
> > that's more robust - works for any value of VRING_PACKED_EVENT_F_WRAP_CTR
> > giving low bits 0 to VRING_PACKED_EVENT_F_WRAP_CTR,
> > and will keep working if someone copypasted it and changed
> > counter to a value different from 15.
> >
> >
> > > Acked-by: Jason Wang <jasowang@redhat.com>
> > >
> > > Thanks
> > >
> > > > + else
> > > > + next = vq->split.avail_idx_shadow;
> > > > +
> > > > + return next << 16 | _vq->index;
> > > > +}
> > > > +EXPORT_SYMBOL_GPL(vring_notification_data);
> > > > +
> > > > /* Manipulates transport-specific feature bits. */
> > > > void vring_transport_features(struct virtio_device *vdev)
> > > > {
> > > > @@ -2771,6 +2786,8 @@ void vring_transport_features(struct virtio_device *vdev)
> > > > break;
> > > > case VIRTIO_F_ORDER_PLATFORM:
> > > > break;
> > > > + case VIRTIO_F_NOTIFICATION_DATA:
> > > > + break;
> > > > default:
> > > > /* We don't understand this bit. */
> > > > __virtio_clear_bit(vdev, i);
> > > > diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h
> > > > index 8b95b69ef694..2550c9170f4f 100644
> > > > --- a/include/linux/virtio_ring.h
> > > > +++ b/include/linux/virtio_ring.h
> > > > @@ -117,4 +117,6 @@ void vring_del_virtqueue(struct virtqueue *vq);
> > > > void vring_transport_features(struct virtio_device *vdev);
> > > >
> > > > irqreturn_t vring_interrupt(int irq, void *_vq);
> > > > +
> > > > +u32 vring_notification_data(struct virtqueue *_vq);
> > > > #endif /* _LINUX_VIRTIO_RING_H */
> > > > diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h
> > > > index 3c05162bc988..2c712c654165 100644
> > > > --- a/include/uapi/linux/virtio_config.h
> > > > +++ b/include/uapi/linux/virtio_config.h
> > > > @@ -99,6 +99,12 @@
> > > > */
> > > > #define VIRTIO_F_SR_IOV 37
> > > >
> > > > +/*
> > > > + * This feature indicates that the driver passes extra data (besides
> > > > + * identifying the virtqueue) in its device notifications.
> > > > + */
> > > > +#define VIRTIO_F_NOTIFICATION_DATA 38
> > > > +
> > > > /*
> > > > * This feature indicates that the driver can reset a queue individually.
> > > > */
> > > > --
> > > > 2.35.1
> > > >
> >
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2023-03-24 9:08 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-03-23 8:55 [PATCH v5] virtio: add VIRTIO_F_NOTIFICATION_DATA feature support Viktor Prutyanov
2023-03-23 9:00 ` Xuan Zhuo
2023-03-24 3:09 ` Jason Wang
2023-03-24 5:31 ` Michael S. Tsirkin
2023-03-24 7:44 ` Viktor Prutyanov
2023-03-24 9:07 ` Michael S. Tsirkin
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