* [PATCH v3 1/6] virtio: Add bool to VirtQueueElement
2024-06-20 17:56 [PATCH v3 0/6] virtio,vhost: Add VIRTIO_F_IN_ORDER support Jonah Palmer
@ 2024-06-20 17:56 ` Jonah Palmer
2024-06-20 17:56 ` [PATCH v3 2/6] virtio: virtqueue_pop - VIRTIO_F_IN_ORDER support Jonah Palmer
` (5 subsequent siblings)
6 siblings, 0 replies; 9+ messages in thread
From: Jonah Palmer @ 2024-06-20 17:56 UTC (permalink / raw)
To: qemu-devel
Cc: mst, raphael, kwolf, hreitz, jasowang, pbonzini, fam, eperezma,
stefanha, qemu-block, schalla, leiyang, virtio-fs, si-wei.liu,
boris.ostrovsky, jonah.palmer
Add the boolean 'in_order_filled' member to the VirtQueueElement structure.
The use of this boolean will signify whether the element has been processed
and is ready to be flushed (so long as the element is in-order). This
boolean is used to support the VIRTIO_F_IN_ORDER feature.
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Jonah Palmer <jonah.palmer@oracle.com>
---
include/hw/virtio/virtio.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 7d5ffdc145..88e70c1ae1 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -69,6 +69,8 @@ typedef struct VirtQueueElement
unsigned int ndescs;
unsigned int out_num;
unsigned int in_num;
+ /* Element has been processed (VIRTIO_F_IN_ORDER) */
+ bool in_order_filled;
hwaddr *in_addr;
hwaddr *out_addr;
struct iovec *in_sg;
--
2.43.0
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH v3 2/6] virtio: virtqueue_pop - VIRTIO_F_IN_ORDER support
2024-06-20 17:56 [PATCH v3 0/6] virtio,vhost: Add VIRTIO_F_IN_ORDER support Jonah Palmer
2024-06-20 17:56 ` [PATCH v3 1/6] virtio: Add bool to VirtQueueElement Jonah Palmer
@ 2024-06-20 17:56 ` Jonah Palmer
2024-06-20 17:56 ` [PATCH v3 3/6] virtio: virtqueue_ordered_fill " Jonah Palmer
` (4 subsequent siblings)
6 siblings, 0 replies; 9+ messages in thread
From: Jonah Palmer @ 2024-06-20 17:56 UTC (permalink / raw)
To: qemu-devel
Cc: mst, raphael, kwolf, hreitz, jasowang, pbonzini, fam, eperezma,
stefanha, qemu-block, schalla, leiyang, virtio-fs, si-wei.liu,
boris.ostrovsky, jonah.palmer
Add VIRTIO_F_IN_ORDER feature support in virtqueue_split_pop and
virtqueue_packed_pop.
VirtQueueElements popped from the available/descritpor ring are added to
the VirtQueue's used_elems array in-order and in the same fashion as
they would be added the used and descriptor rings, respectively.
This will allow us to keep track of the current order, what elements
have been written, as well as an element's essential data after being
processed.
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Jonah Palmer <jonah.palmer@oracle.com>
---
hw/virtio/virtio.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 893a072c9d..9cbf75f021 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -1630,6 +1630,12 @@ static void *virtqueue_split_pop(VirtQueue *vq, size_t sz)
elem->in_sg[i] = iov[out_num + i];
}
+ if (virtio_vdev_has_feature(vdev, VIRTIO_F_IN_ORDER)) {
+ vq->used_elems[vq->last_avail_idx - 1].index = elem->index;
+ vq->used_elems[vq->last_avail_idx - 1].len = elem->len;
+ vq->used_elems[vq->last_avail_idx - 1].ndescs = elem->ndescs;
+ }
+
vq->inuse++;
trace_virtqueue_pop(vq, elem, elem->in_num, elem->out_num);
@@ -1758,6 +1764,13 @@ static void *virtqueue_packed_pop(VirtQueue *vq, size_t sz)
elem->index = id;
elem->ndescs = (desc_cache == &indirect_desc_cache) ? 1 : elem_entries;
+
+ if (virtio_vdev_has_feature(vdev, VIRTIO_F_IN_ORDER)) {
+ vq->used_elems[vq->last_avail_idx].index = elem->index;
+ vq->used_elems[vq->last_avail_idx].len = elem->len;
+ vq->used_elems[vq->last_avail_idx].ndescs = elem->ndescs;
+ }
+
vq->last_avail_idx += elem->ndescs;
vq->inuse += elem->ndescs;
--
2.43.0
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH v3 3/6] virtio: virtqueue_ordered_fill - VIRTIO_F_IN_ORDER support
2024-06-20 17:56 [PATCH v3 0/6] virtio,vhost: Add VIRTIO_F_IN_ORDER support Jonah Palmer
2024-06-20 17:56 ` [PATCH v3 1/6] virtio: Add bool to VirtQueueElement Jonah Palmer
2024-06-20 17:56 ` [PATCH v3 2/6] virtio: virtqueue_pop - VIRTIO_F_IN_ORDER support Jonah Palmer
@ 2024-06-20 17:56 ` Jonah Palmer
2024-06-20 17:56 ` [PATCH v3 4/6] virtio: virtqueue_ordered_flush " Jonah Palmer
` (3 subsequent siblings)
6 siblings, 0 replies; 9+ messages in thread
From: Jonah Palmer @ 2024-06-20 17:56 UTC (permalink / raw)
To: qemu-devel
Cc: mst, raphael, kwolf, hreitz, jasowang, pbonzini, fam, eperezma,
stefanha, qemu-block, schalla, leiyang, virtio-fs, si-wei.liu,
boris.ostrovsky, jonah.palmer
Add VIRTIO_F_IN_ORDER feature support for the virtqueue_fill operation.
The goal of the virtqueue_ordered_fill operation when the
VIRTIO_F_IN_ORDER feature has been negotiated is to search for this
now-used element, set its length, and mark the element as filled in
the VirtQueue's used_elems array.
By marking the element as filled, it will indicate that this element has
been processed and is ready to be flushed, so long as the element is
in-order.
Reviewed-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Jonah Palmer <jonah.palmer@oracle.com>
---
hw/virtio/virtio.c | 44 +++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 43 insertions(+), 1 deletion(-)
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 9cbf75f021..e1dfec4655 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -873,6 +873,46 @@ static void virtqueue_packed_fill(VirtQueue *vq, const VirtQueueElement *elem,
vq->used_elems[idx].ndescs = elem->ndescs;
}
+static void virtqueue_ordered_fill(VirtQueue *vq, const VirtQueueElement *elem,
+ unsigned int len)
+{
+ unsigned int i, steps, max_steps;
+
+ i = vq->used_idx;
+ steps = 0;
+ /*
+ * We shouldn't need to increase 'i' by more than the distance
+ * between used_idx and last_avail_idx.
+ */
+ max_steps = (vq->last_avail_idx - vq->used_idx) % vq->vring.num;
+
+ /* Search for element in vq->used_elems */
+ while (steps <= max_steps) {
+ /* Found element, set length and mark as filled */
+ if (vq->used_elems[i].index == elem->index) {
+ vq->used_elems[i].len = len;
+ vq->used_elems[i].in_order_filled = true;
+ break;
+ }
+
+ i += vq->used_elems[i].ndescs;
+ steps += vq->used_elems[i].ndescs;
+
+ if (i >= vq->vring.num) {
+ i -= vq->vring.num;
+ }
+ }
+
+ /*
+ * We should be able to find a matching VirtQueueElement in
+ * used_elems. If we don't, this is an error.
+ */
+ if (steps >= max_steps) {
+ qemu_log_mask(LOG_GUEST_ERROR, "%s: %s cannot fill buffer id %u\n",
+ __func__, vdev->name, elem->index);
+ }
+}
+
static void virtqueue_packed_fill_desc(VirtQueue *vq,
const VirtQueueElement *elem,
unsigned int idx,
@@ -923,7 +963,9 @@ void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem,
return;
}
- if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
+ if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_IN_ORDER)) {
+ virtqueue_ordered_fill(vq, elem, len);
+ } else if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
virtqueue_packed_fill(vq, elem, len, idx);
} else {
virtqueue_split_fill(vq, elem, len, idx);
--
2.43.0
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH v3 4/6] virtio: virtqueue_ordered_flush - VIRTIO_F_IN_ORDER support
2024-06-20 17:56 [PATCH v3 0/6] virtio,vhost: Add VIRTIO_F_IN_ORDER support Jonah Palmer
` (2 preceding siblings ...)
2024-06-20 17:56 ` [PATCH v3 3/6] virtio: virtqueue_ordered_fill " Jonah Palmer
@ 2024-06-20 17:56 ` Jonah Palmer
2024-06-20 17:56 ` [PATCH v3 5/6] vhost, vhost-user: Add VIRTIO_F_IN_ORDER to vhost feature bits Jonah Palmer via
` (2 subsequent siblings)
6 siblings, 0 replies; 9+ messages in thread
From: Jonah Palmer @ 2024-06-20 17:56 UTC (permalink / raw)
To: qemu-devel
Cc: mst, raphael, kwolf, hreitz, jasowang, pbonzini, fam, eperezma,
stefanha, qemu-block, schalla, leiyang, virtio-fs, si-wei.liu,
boris.ostrovsky, jonah.palmer
Add VIRTIO_F_IN_ORDER feature support for the virtqueue_flush operation.
The goal of the virtqueue_ordered_flush operation when the
VIRTIO_F_IN_ORDER feature has been negotiated is to write elements to
the used/descriptor ring in-order and then update used_idx.
The function iterates through the VirtQueueElement used_elems array
in-order starting at vq->used_idx. If the element is valid (filled), the
element is written to the used/descriptor ring. This process continues
until we find an invalid (not filled) element.
For packed VQs, the first entry (at vq->used_idx) is written to the
descriptor ring last so the guest doesn't see any invalid descriptors.
If any elements were written, the used_idx is updated.
Signed-off-by: Jonah Palmer <jonah.palmer@oracle.com>
---
hw/virtio/virtio.c | 66 +++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 65 insertions(+), 1 deletion(-)
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index e1dfec4655..b0b1b556a2 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -1024,6 +1024,68 @@ static void virtqueue_packed_flush(VirtQueue *vq, unsigned int count)
}
}
+static void virtqueue_ordered_flush(VirtQueue *vq)
+{
+ unsigned int i = vq->used_idx;
+ unsigned int ndescs = 0;
+ uint16_t old = vq->used_idx;
+ bool packed;
+ VRingUsedElem uelem;
+
+ packed = virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED);
+
+ if (packed) {
+ if (unlikely(!vq->vring.desc)) {
+ return;
+ }
+ } else if (unlikely(!vq->vring.used)) {
+ return;
+ }
+
+ /* First expected in-order element isn't ready, nothing to do */
+ if (!vq->used_elems[i].in_order_filled) {
+ return;
+ }
+
+ /* Search for filled elements in-order */
+ while (vq->used_elems[i].in_order_filled) {
+ /*
+ * First entry for packed VQs is written last so the guest
+ * doesn't see invalid descriptors.
+ */
+ if (packed && i != vq->used_idx) {
+ virtqueue_packed_fill_desc(vq, &vq->used_elems[i], ndescs, false);
+ } else if (!packed) {
+ uelem.id = vq->used_elems[i].index;
+ uelem.len = vq->used_elems[i].len;
+ vring_used_write(vq, &uelem, i);
+ }
+
+ vq->used_elems[i].in_order_filled = false;
+ ndescs += vq->used_elems[i].ndescs;
+ i += ndescs;
+ if (i >= vq->vring.num) {
+ i -= vq->vring.num;
+ }
+ }
+
+ if (packed) {
+ virtqueue_packed_fill_desc(vq, &vq->used_elems[vq->used_idx], 0, true);
+ vq->used_idx += ndescs;
+ if (vq->used_idx >= vq->vring.num) {
+ vq->used_idx -= vq->vring.num;
+ vq->used_wrap_counter ^= 1;
+ vq->signalled_used_valid = false;
+ }
+ } else {
+ vring_used_idx_set(vq, i);
+ if (unlikely((int16_t)(i - vq->signalled_used) < (uint16_t)(i - old))) {
+ vq->signalled_used_valid = false;
+ }
+ }
+ vq->inuse -= ndescs;
+}
+
void virtqueue_flush(VirtQueue *vq, unsigned int count)
{
if (virtio_device_disabled(vq->vdev)) {
@@ -1031,7 +1093,9 @@ void virtqueue_flush(VirtQueue *vq, unsigned int count)
return;
}
- if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
+ if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_IN_ORDER)) {
+ virtqueue_ordered_flush(vq);
+ } else if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
virtqueue_packed_flush(vq, count);
} else {
virtqueue_split_flush(vq, count);
--
2.43.0
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH v3 5/6] vhost, vhost-user: Add VIRTIO_F_IN_ORDER to vhost feature bits
2024-06-20 17:56 [PATCH v3 0/6] virtio,vhost: Add VIRTIO_F_IN_ORDER support Jonah Palmer
` (3 preceding siblings ...)
2024-06-20 17:56 ` [PATCH v3 4/6] virtio: virtqueue_ordered_flush " Jonah Palmer
@ 2024-06-20 17:56 ` Jonah Palmer via
2024-06-20 17:56 ` [PATCH v3 6/6] virtio: Add VIRTIO_F_IN_ORDER property definition Jonah Palmer
2024-06-20 18:40 ` [PATCH v3 0/6] virtio,vhost: Add VIRTIO_F_IN_ORDER support Eugenio Perez Martin
6 siblings, 0 replies; 9+ messages in thread
From: Jonah Palmer via @ 2024-06-20 17:56 UTC (permalink / raw)
To: qemu-devel
Cc: mst, raphael, kwolf, hreitz, jasowang, pbonzini, fam, eperezma,
stefanha, qemu-block, schalla, leiyang, virtio-fs, si-wei.liu,
boris.ostrovsky, jonah.palmer
Add support for the VIRTIO_F_IN_ORDER feature across a variety of vhost
devices.
The inclusion of VIRTIO_F_IN_ORDER in the feature bits arrays for these
devices ensures that the backend is capable of offering and providing
support for this feature, and that it can be disabled if the backend
does not support it.
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Jonah Palmer <jonah.palmer@oracle.com>
---
hw/block/vhost-user-blk.c | 1 +
hw/net/vhost_net.c | 2 ++
hw/scsi/vhost-scsi.c | 1 +
hw/scsi/vhost-user-scsi.c | 1 +
hw/virtio/vhost-user-fs.c | 1 +
hw/virtio/vhost-user-vsock.c | 1 +
net/vhost-vdpa.c | 1 +
7 files changed, 8 insertions(+)
diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
index 9e6bbc6950..1dd0a8ef63 100644
--- a/hw/block/vhost-user-blk.c
+++ b/hw/block/vhost-user-blk.c
@@ -51,6 +51,7 @@ static const int user_feature_bits[] = {
VIRTIO_F_RING_PACKED,
VIRTIO_F_IOMMU_PLATFORM,
VIRTIO_F_RING_RESET,
+ VIRTIO_F_IN_ORDER,
VHOST_INVALID_FEATURE_BIT
};
diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index fd1a93701a..eb0b1c06e5 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -48,6 +48,7 @@ static const int kernel_feature_bits[] = {
VIRTIO_F_IOMMU_PLATFORM,
VIRTIO_F_RING_PACKED,
VIRTIO_F_RING_RESET,
+ VIRTIO_F_IN_ORDER,
VIRTIO_NET_F_HASH_REPORT,
VHOST_INVALID_FEATURE_BIT
};
@@ -76,6 +77,7 @@ static const int user_feature_bits[] = {
VIRTIO_F_IOMMU_PLATFORM,
VIRTIO_F_RING_PACKED,
VIRTIO_F_RING_RESET,
+ VIRTIO_F_IN_ORDER,
VIRTIO_NET_F_RSS,
VIRTIO_NET_F_HASH_REPORT,
VIRTIO_NET_F_GUEST_USO4,
diff --git a/hw/scsi/vhost-scsi.c b/hw/scsi/vhost-scsi.c
index ae26bc19a4..40e7630191 100644
--- a/hw/scsi/vhost-scsi.c
+++ b/hw/scsi/vhost-scsi.c
@@ -38,6 +38,7 @@ static const int kernel_feature_bits[] = {
VIRTIO_RING_F_EVENT_IDX,
VIRTIO_SCSI_F_HOTPLUG,
VIRTIO_F_RING_RESET,
+ VIRTIO_F_IN_ORDER,
VHOST_INVALID_FEATURE_BIT
};
diff --git a/hw/scsi/vhost-user-scsi.c b/hw/scsi/vhost-user-scsi.c
index a63b1f4948..1d59951ab7 100644
--- a/hw/scsi/vhost-user-scsi.c
+++ b/hw/scsi/vhost-user-scsi.c
@@ -36,6 +36,7 @@ static const int user_feature_bits[] = {
VIRTIO_RING_F_EVENT_IDX,
VIRTIO_SCSI_F_HOTPLUG,
VIRTIO_F_RING_RESET,
+ VIRTIO_F_IN_ORDER,
VHOST_INVALID_FEATURE_BIT
};
diff --git a/hw/virtio/vhost-user-fs.c b/hw/virtio/vhost-user-fs.c
index cca2cd41be..9243dbb128 100644
--- a/hw/virtio/vhost-user-fs.c
+++ b/hw/virtio/vhost-user-fs.c
@@ -33,6 +33,7 @@ static const int user_feature_bits[] = {
VIRTIO_F_RING_PACKED,
VIRTIO_F_IOMMU_PLATFORM,
VIRTIO_F_RING_RESET,
+ VIRTIO_F_IN_ORDER,
VHOST_INVALID_FEATURE_BIT
};
diff --git a/hw/virtio/vhost-user-vsock.c b/hw/virtio/vhost-user-vsock.c
index 9431b9792c..cc7e4e47b4 100644
--- a/hw/virtio/vhost-user-vsock.c
+++ b/hw/virtio/vhost-user-vsock.c
@@ -21,6 +21,7 @@ static const int user_feature_bits[] = {
VIRTIO_RING_F_INDIRECT_DESC,
VIRTIO_RING_F_EVENT_IDX,
VIRTIO_F_NOTIFY_ON_EMPTY,
+ VIRTIO_F_IN_ORDER,
VHOST_INVALID_FEATURE_BIT
};
diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 85e73dd6a7..ed3185acfa 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -62,6 +62,7 @@ const int vdpa_feature_bits[] = {
VIRTIO_F_RING_PACKED,
VIRTIO_F_RING_RESET,
VIRTIO_F_VERSION_1,
+ VIRTIO_F_IN_ORDER,
VIRTIO_NET_F_CSUM,
VIRTIO_NET_F_CTRL_GUEST_OFFLOADS,
VIRTIO_NET_F_CTRL_MAC_ADDR,
--
2.43.0
^ permalink raw reply related [flat|nested] 9+ messages in thread* [PATCH v3 6/6] virtio: Add VIRTIO_F_IN_ORDER property definition
2024-06-20 17:56 [PATCH v3 0/6] virtio,vhost: Add VIRTIO_F_IN_ORDER support Jonah Palmer
` (4 preceding siblings ...)
2024-06-20 17:56 ` [PATCH v3 5/6] vhost, vhost-user: Add VIRTIO_F_IN_ORDER to vhost feature bits Jonah Palmer via
@ 2024-06-20 17:56 ` Jonah Palmer
2024-06-20 18:40 ` [PATCH v3 0/6] virtio,vhost: Add VIRTIO_F_IN_ORDER support Eugenio Perez Martin
6 siblings, 0 replies; 9+ messages in thread
From: Jonah Palmer @ 2024-06-20 17:56 UTC (permalink / raw)
To: qemu-devel
Cc: mst, raphael, kwolf, hreitz, jasowang, pbonzini, fam, eperezma,
stefanha, qemu-block, schalla, leiyang, virtio-fs, si-wei.liu,
boris.ostrovsky, jonah.palmer
Extend the virtio device property definitions to include the
VIRTIO_F_IN_ORDER feature.
The default state of this feature is disabled, allowing it to be
explicitly enabled where it's supported.
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Jonah Palmer <jonah.palmer@oracle.com>
---
include/hw/virtio/virtio.h | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 88e70c1ae1..d33345ecc5 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -371,7 +371,9 @@ typedef struct VirtIORNGConf VirtIORNGConf;
DEFINE_PROP_BIT64("packed", _state, _field, \
VIRTIO_F_RING_PACKED, false), \
DEFINE_PROP_BIT64("queue_reset", _state, _field, \
- VIRTIO_F_RING_RESET, true)
+ VIRTIO_F_RING_RESET, true), \
+ DEFINE_PROP_BIT64("in_order", _state, _field, \
+ VIRTIO_F_IN_ORDER, false)
hwaddr virtio_queue_get_desc_addr(VirtIODevice *vdev, int n);
bool virtio_queue_enabled_legacy(VirtIODevice *vdev, int n);
--
2.43.0
^ permalink raw reply related [flat|nested] 9+ messages in thread* Re: [PATCH v3 0/6] virtio,vhost: Add VIRTIO_F_IN_ORDER support
2024-06-20 17:56 [PATCH v3 0/6] virtio,vhost: Add VIRTIO_F_IN_ORDER support Jonah Palmer
` (5 preceding siblings ...)
2024-06-20 17:56 ` [PATCH v3 6/6] virtio: Add VIRTIO_F_IN_ORDER property definition Jonah Palmer
@ 2024-06-20 18:40 ` Eugenio Perez Martin
2024-06-24 14:57 ` Jonah Palmer
6 siblings, 1 reply; 9+ messages in thread
From: Eugenio Perez Martin @ 2024-06-20 18:40 UTC (permalink / raw)
To: Jonah Palmer
Cc: qemu-devel, mst, raphael, kwolf, hreitz, jasowang, pbonzini, fam,
stefanha, qemu-block, schalla, leiyang, virtio-fs, si-wei.liu,
boris.ostrovsky
On Thu, Jun 20, 2024 at 7:56 PM Jonah Palmer <jonah.palmer@oracle.com> wrote:
>
> The goal of these patches is to add support to a variety of virtio and
> vhost devices for the VIRTIO_F_IN_ORDER transport feature. This feature
> indicates that all buffers are used by the device in the same order in
> which they were made available by the driver.
>
> These patches attempt to implement a generalized, non-device-specific
> solution to support this feature.
>
> The core feature behind this solution is a buffer mechanism in the form
> of a VirtQueue's used_elems VirtQueueElement array. This allows devices
> who always use buffers in-order by default to have a minimal overhead
> impact. Devices that may not always use buffers in-order likely will
> experience a performance hit. How large that performance hit is will
> depend on how frequently elements are completed out-of-order.
>
> A VirtQueue whose device uses this feature will use its used_elems
> VirtQueueElement array to hold used VirtQueueElements. The index that
> used elements are placed in used_elems is the same index on the
> used/descriptor ring that would satisfy the in-order requirement. In
> other words, used elements are placed in their in-order locations on
> used_elems and are only written to the used/descriptor ring once the
> elements on used_elems are able to continue their expected order.
>
> To differentiate between a "used" and "unused" element on the used_elems
> array (a "used" element being an element that has returned from
> processing and an "unused" element being an element that has not yet
> been processed), we added a boolean 'in_order_filled' member to the
> VirtQueueElement struct. This flag is set to true when the element comes
> back from processing (virtqueue_ordered_fill) and then set back to false
> once it's been written to the used/descriptor ring
> (virtqueue_ordered_flush).
>
> Testing:
> ========
> Testing was done using the dpdk-testpmd application on both the host and
> guest using the following configurations. Traffic was generated between
> the host and guest after running 'start tx_first' on both the host and
> guest dpdk-testpmd applications. Results are below after traffic was
> generated for several seconds.
>
> Relevant Qemu args:
> -------------------
> -chardev socket,id=char1,path=/tmp/vhost-user1,server=off
> -chardev socket,id=char2,path=/tmp/vhost-user2,server=off
> -netdev type=vhost-user,id=net1,chardev=char1,vhostforce=on,queues=1
> -netdev type=vhost-user,id=net2,chardev=char2,vhostforce=on,queues=1
> -device virtio-net-pci,in_order=true,packed=true,netdev=net1,
> mac=56:48:4f:53:54:00,mq=on,vectors=4,rx_queue_size=256
> -device virtio-net-pci,in_order=true,packed=true,netdev=net2,
> mac=56:48:4f:53:54:01,mq=on,vectors=4,rx_queue_size=256
>
Hi Jonah,
These tests are great, but others should also be performed. In
particular, QEMU should run ok with "tap" netdev with vhost=off
instead of vhost-user:
-netdev type=tap,id=net1,vhost=off
-netdev type=tap,id=net2,vhost=off
This way, packets are going through the modified code. With this
configuration, QEMU is the one forwarding the packets so testpmd is
not needed in the host. It's still needed in the guest as linux guest
driver does not support in_order. The guest kernel cmdline and testpmd
cmdline should require no changes from the configuration you describe
here.
And then try with in_order=true,packed=false and
in_order=true,packed=off in corresponding virtio-net-pci.
Performance comparison between in_order=true and in_order=false is
also interesting but we're not batching so I don't think we will get
an extreme improvement.
Does the plan work for you?
Thanks!
> Host dpdk-testpmd command:
> --------------------------
> dpdk-testpmd -l 0,2,3,4,5 --socket-mem=1024 -n 4
> --vdev 'net_vhost0,iface=/tmp/vhost-user1'
> --vdev 'net_vhost1,iface=/tmp/vhost-user2' --
> --portmask=f -i --rxq=1 --txq=1 --nb-cores=4 --forward-mode=io
>
> Guest dpdk-testpmd command:
> ---------------------------
> dpdk-testpmd -l 0,1 -a 0000:00:02.0 -a 0000:00:03.0 -- --portmask=3
> --rxq=1 --txq=1 --nb-cores=1 --forward-mode=io -i
>
> Results:
> --------
> +++++++++++++++ Accumulated forward statistics for all ports+++++++++++++++
> RX-packets: 79067488 RX-dropped: 0 RX-total: 79067488
> TX-packets: 79067552 TX-dropped: 0 TX-total: 79067552
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>
> ---
> v3: Drop Tested-by tags until patches are re-tested.
> Replace 'prev_avail_idx' with 'vq->last_avail_idx - 1' in
> virtqueue_split_pop.
> Remove redundant '+vq->vring.num' in 'max_steps' calculation in
> virtqueue_ordered_fill.
> Add test results to CV.
>
> v2: Make 'in_order_filled' more descriptive.
> Change 'j' to more descriptive var name in virtqueue_split_pop.
> Use more definitive search conditional in virtqueue_ordered_fill.
> Avoid code duplication in virtqueue_ordered_flush.
>
> v1: Move series from RFC to PATCH for submission.
>
> Jonah Palmer (6):
> virtio: Add bool to VirtQueueElement
> virtio: virtqueue_pop - VIRTIO_F_IN_ORDER support
> virtio: virtqueue_ordered_fill - VIRTIO_F_IN_ORDER support
> virtio: virtqueue_ordered_flush - VIRTIO_F_IN_ORDER support
> vhost,vhost-user: Add VIRTIO_F_IN_ORDER to vhost feature bits
> virtio: Add VIRTIO_F_IN_ORDER property definition
>
> hw/block/vhost-user-blk.c | 1 +
> hw/net/vhost_net.c | 2 +
> hw/scsi/vhost-scsi.c | 1 +
> hw/scsi/vhost-user-scsi.c | 1 +
> hw/virtio/vhost-user-fs.c | 1 +
> hw/virtio/vhost-user-vsock.c | 1 +
> hw/virtio/virtio.c | 123 ++++++++++++++++++++++++++++++++++-
> include/hw/virtio/virtio.h | 6 +-
> net/vhost-vdpa.c | 1 +
> 9 files changed, 134 insertions(+), 3 deletions(-)
>
> --
> 2.43.0
>
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCH v3 0/6] virtio,vhost: Add VIRTIO_F_IN_ORDER support
2024-06-20 18:40 ` [PATCH v3 0/6] virtio,vhost: Add VIRTIO_F_IN_ORDER support Eugenio Perez Martin
@ 2024-06-24 14:57 ` Jonah Palmer
0 siblings, 0 replies; 9+ messages in thread
From: Jonah Palmer @ 2024-06-24 14:57 UTC (permalink / raw)
To: Eugenio Perez Martin
Cc: qemu-devel, mst, raphael, kwolf, hreitz, jasowang, pbonzini, fam,
stefanha, qemu-block, schalla, leiyang, virtio-fs, si-wei.liu,
boris.ostrovsky
On 6/20/24 2:40 PM, Eugenio Perez Martin wrote:
> On Thu, Jun 20, 2024 at 7:56 PM Jonah Palmer <jonah.palmer@oracle.com> wrote:
>>
>> The goal of these patches is to add support to a variety of virtio and
>> vhost devices for the VIRTIO_F_IN_ORDER transport feature. This feature
>> indicates that all buffers are used by the device in the same order in
>> which they were made available by the driver.
>>
>> These patches attempt to implement a generalized, non-device-specific
>> solution to support this feature.
>>
>> The core feature behind this solution is a buffer mechanism in the form
>> of a VirtQueue's used_elems VirtQueueElement array. This allows devices
>> who always use buffers in-order by default to have a minimal overhead
>> impact. Devices that may not always use buffers in-order likely will
>> experience a performance hit. How large that performance hit is will
>> depend on how frequently elements are completed out-of-order.
>>
>> A VirtQueue whose device uses this feature will use its used_elems
>> VirtQueueElement array to hold used VirtQueueElements. The index that
>> used elements are placed in used_elems is the same index on the
>> used/descriptor ring that would satisfy the in-order requirement. In
>> other words, used elements are placed in their in-order locations on
>> used_elems and are only written to the used/descriptor ring once the
>> elements on used_elems are able to continue their expected order.
>>
>> To differentiate between a "used" and "unused" element on the used_elems
>> array (a "used" element being an element that has returned from
>> processing and an "unused" element being an element that has not yet
>> been processed), we added a boolean 'in_order_filled' member to the
>> VirtQueueElement struct. This flag is set to true when the element comes
>> back from processing (virtqueue_ordered_fill) and then set back to false
>> once it's been written to the used/descriptor ring
>> (virtqueue_ordered_flush).
>>
>> Testing:
>> ========
>> Testing was done using the dpdk-testpmd application on both the host and
>> guest using the following configurations. Traffic was generated between
>> the host and guest after running 'start tx_first' on both the host and
>> guest dpdk-testpmd applications. Results are below after traffic was
>> generated for several seconds.
>>
>> Relevant Qemu args:
>> -------------------
>> -chardev socket,id=char1,path=/tmp/vhost-user1,server=off
>> -chardev socket,id=char2,path=/tmp/vhost-user2,server=off
>> -netdev type=vhost-user,id=net1,chardev=char1,vhostforce=on,queues=1
>> -netdev type=vhost-user,id=net2,chardev=char2,vhostforce=on,queues=1
>> -device virtio-net-pci,in_order=true,packed=true,netdev=net1,
>> mac=56:48:4f:53:54:00,mq=on,vectors=4,rx_queue_size=256
>> -device virtio-net-pci,in_order=true,packed=true,netdev=net2,
>> mac=56:48:4f:53:54:01,mq=on,vectors=4,rx_queue_size=256
>>
>
> Hi Jonah,
>
> These tests are great, but others should also be performed. In
> particular, QEMU should run ok with "tap" netdev with vhost=off
> instead of vhost-user:
>
> -netdev type=tap,id=net1,vhost=off
> -netdev type=tap,id=net2,vhost=off
>
> This way, packets are going through the modified code. With this
> configuration, QEMU is the one forwarding the packets so testpmd is
> not needed in the host. It's still needed in the guest as linux guest
> driver does not support in_order. The guest kernel cmdline and testpmd
> cmdline should require no changes from the configuration you describe
> here.
>
Oof... I didn't even realize that my tests weren't actually testing all
of the modified code. I was so focused on getting DPDK to work that I
didn't think to check that. My apologies.
I am running into some trouble though trying to get packets flowing in
the guest. My Qemu args look like this:
# Regular virtio-net device
-device virtio-net-pci,netdev=net0,disable-legacy=off,disable-modern=off
-netdev tap,id=net0,vhost=off,ifname=tap0,script=${QEMU_IFUP},
downscript=no
# Virtio-net devices for testing
-netdev type=tap,id=net1,vhost=off,ifname=tap1,script=no,downscript=no
-netdev type=tap,id=net2,vhost=off,ifname=tap2,script=no,downscript=no
-device virtio-net-pci,in_order=true,packed=true,netdev=net1,
mac=56:48:4f:53:54:00,mq=on,vectors=4,rx_queue_size=256
-device virtio-net-pci,in_order=true,packed=true,netdev=net2,
mac=56:48:4f:53:54:01,mq=on,vectors=4,rx_queue_size=256
In the guest I have the virtio-net devices I'm using for testing bound
to the uio_pci_generic driver:
dpdk-devbind.py --status net
Network devices using DPDK-compatible driver
============================================
0000:00:02.0 'Virtio network device 1000' drv=uio_pci_generic
unused=virtio_pci,vfio-pci
0000:00:03.0 'Virtio network device 1000' drv=uio_pci_generic
unused=virtio_pci,vfio-pci
Network devices using kernel driver
===================================
0000:00:04.0 'Virtio network device 1000' if=enp0s4
drv=virtio-pci unused=virtio_pci,vfio-pci,uio_pci_generic *Active*
But then after running the dpdk-testpmd command in the guest:
dpdk-testpmd -l 0,1 -a 0000:00:02.0 -a 0000:00:03.0 --
--portmask=3 --rxq=1 --txq=1 --nb-cores=1 --forward-mode=io -i
EAL: Detected CPU lcores: 6
EAL: Detected NUMA nodes: 1
EAL: Detected static linkage of DPDK
EAL: Multi-process socket /var/run/dpdk/rte/mp_socket
EAL: Selected IOVA mode 'PA'
EAL: VFIO support initialized
EAL: Probe PCI driver: net_virtio (1af4:1000) device: 0000:00:02.0
(socket -1)
EAL: Probe PCI driver: net_virtio (1af4:1000) device: 0000:00:03.0
(socket -1)
TELEMETRY: No legacy callbacks, legacy socket not created
Set io packet forwarding mode
Interactive-mode selected
Warning: NUMA should be configured manually by using --port-numa-config
and --ring-numa-config parameters along with --numa.
testpmd: create a new mbuf pool <mb_pool_0>: n=155456, size=2176, socket=0
testpmd: preferred mempool ops selected: ring_mp_mc
Configuring Port 0 (socket 0)
Port 0: 56:48:4F:53:54:00
Configuring Port 1 (socket 0)
Port 1: 56:48:4F:53:54:01
Checking link statuses...
Done
I'm not able to see any packets flowing after starting packet forwarding
and running 'show port stats all':
testpmd> start
io packet forwarding - ports=2 - cores=1 - streams=2 - NUMA support
enabled, MP allocation mode: native
Logical Core 1 (socket 0) forwards packets on 2 streams:
RX P=0/Q=0 (socket 0) -> TX P=1/Q=0 (socket 0) peer=02:00:00:00:00:01
RX P=1/Q=0 (socket 0) -> TX P=0/Q=0 (socket 0) peer=02:00:00:00:00:00
io packet forwarding packets/burst=32
nb forwarding cores=1 - nb forwarding ports=2
port 0: RX queue number: 1 Tx queue number: 1
Rx offloads=0x0 Tx offloads=0x0
RX queue: 0
RX desc=0 - RX free threshold=0
RX threshold registers: pthresh=0 hthresh=0 wthresh=0
RX Offloads=0x0
TX queue: 0
TX desc=0 - TX free threshold=0
TX threshold registers: pthresh=0 hthresh=0 wthresh=0
TX offloads=0x0 - TX RS bit threshold=0
port 1: RX queue number: 1 Tx queue number: 1
Rx offloads=0x0 Tx offloads=0x0
RX queue: 0
RX desc=0 - RX free threshold=0
RX threshold registers: pthresh=0 hthresh=0 wthresh=0
RX Offloads=0x0
TX queue: 0
TX desc=0 - TX free threshold=0
TX threshold registers: pthresh=0 hthresh=0 wthresh=0
TX offloads=0x0 - TX RS bit threshold=0
testpmd>
testpmd> show port stats all
###### NIC statistics for port 0 ######
RX-packets: 0 RX-missed: 0 RX-bytes: 0
RX-errors: 0
RX-nombuf: 0
TX-packets: 0 TX-errors: 0 TX-bytes: 0
Throughput (since last show)
Rx-pps: 0 Rx-bps: 0
Tx-pps: 0 Tx-bps: 0
#########################################################
###### NIC statistics for port 1 ######
RX-packets: 0 RX-missed: 0 RX-bytes: 0
RX-errors: 0
RX-nombuf: 0
TX-packets: 0 TX-errors: 0 TX-bytes: 0
Throughput (since last show)
Rx-pps: 0 Rx-bps: 0
Tx-pps: 0 Tx-bps: 0
#########################################################
I'm still working on improving my networking skills so I'm going to try
and figure out what's going on here. Will let you know if I figure it
out and check in with you to see if the test results are satisfactory
before sending out a v4.
> And then try with in_order=true,packed=false and
> in_order=true,packed=off in corresponding virtio-net-pci.
>
> Performance comparison between in_order=true and in_order=false is
> also interesting but we're not batching so I don't think we will get
> an extreme improvement.
>
> Does the plan work for you?
>
> Thanks!
>
>> Host dpdk-testpmd command:
>> --------------------------
>> dpdk-testpmd -l 0,2,3,4,5 --socket-mem=1024 -n 4
>> --vdev 'net_vhost0,iface=/tmp/vhost-user1'
>> --vdev 'net_vhost1,iface=/tmp/vhost-user2' --
>> --portmask=f -i --rxq=1 --txq=1 --nb-cores=4 --forward-mode=io
>>
>> Guest dpdk-testpmd command:
>> ---------------------------
>> dpdk-testpmd -l 0,1 -a 0000:00:02.0 -a 0000:00:03.0 -- --portmask=3
>> --rxq=1 --txq=1 --nb-cores=1 --forward-mode=io -i
>>
>> Results:
>> --------
>> +++++++++++++++ Accumulated forward statistics for all ports+++++++++++++++
>> RX-packets: 79067488 RX-dropped: 0 RX-total: 79067488
>> TX-packets: 79067552 TX-dropped: 0 TX-total: 79067552
>> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>
>> ---
>> v3: Drop Tested-by tags until patches are re-tested.
>> Replace 'prev_avail_idx' with 'vq->last_avail_idx - 1' in
>> virtqueue_split_pop.
>> Remove redundant '+vq->vring.num' in 'max_steps' calculation in
>> virtqueue_ordered_fill.
>> Add test results to CV.
>>
>> v2: Make 'in_order_filled' more descriptive.
>> Change 'j' to more descriptive var name in virtqueue_split_pop.
>> Use more definitive search conditional in virtqueue_ordered_fill.
>> Avoid code duplication in virtqueue_ordered_flush.
>>
>> v1: Move series from RFC to PATCH for submission.
>>
>> Jonah Palmer (6):
>> virtio: Add bool to VirtQueueElement
>> virtio: virtqueue_pop - VIRTIO_F_IN_ORDER support
>> virtio: virtqueue_ordered_fill - VIRTIO_F_IN_ORDER support
>> virtio: virtqueue_ordered_flush - VIRTIO_F_IN_ORDER support
>> vhost,vhost-user: Add VIRTIO_F_IN_ORDER to vhost feature bits
>> virtio: Add VIRTIO_F_IN_ORDER property definition
>>
>> hw/block/vhost-user-blk.c | 1 +
>> hw/net/vhost_net.c | 2 +
>> hw/scsi/vhost-scsi.c | 1 +
>> hw/scsi/vhost-user-scsi.c | 1 +
>> hw/virtio/vhost-user-fs.c | 1 +
>> hw/virtio/vhost-user-vsock.c | 1 +
>> hw/virtio/virtio.c | 123 ++++++++++++++++++++++++++++++++++-
>> include/hw/virtio/virtio.h | 6 +-
>> net/vhost-vdpa.c | 1 +
>> 9 files changed, 134 insertions(+), 3 deletions(-)
>>
>> --
>> 2.43.0
>>
>
^ permalink raw reply [flat|nested] 9+ messages in thread