[PATCH v5 0/3] Vhost-vdpa Shadow Virtqueue RSS Support

[PATCH v5 0/3] Vhost-vdpa Shadow Virtqueue RSS Support

[Hawkins Jiawei]

This series enables shadowed CVQ to intercept RSS command
through shadowed CVQ, update the virtio NIC device model
so qemu send it in a migration, and the restore of that
RSS state in the destination.

Note that this patch should be based on
patch "Vhost-vdpa Shadow Virtqueue Hash calculation Support" at [1].

[1]. https://lore.kernel.org/all/cover.1698194366.git.yin31149@gmail.com/

ChangeLog
=========
v5: 
  - resolve conflict with the updated patch 
"Vhost-vdpa Shadow Virtqueue Hash calculation Support" at [1]

v4: https://lore.kernel.org/all/cover.1697904740.git.yin31149@gmail.com/
  - add do_rss argument and relative code in vhost_vdpa_net_load_rss()

v3: https://lore.kernel.org/all/cover.1693299194.git.yin31149@gmail.com/
  - resolve conflict with updated patch
"Vhost-vdpa Shadow Virtqueue Hash calculation Support" in patch
"vdpa: Restore receive-side scaling state"

RFC v2: https://lore.kernel.org/all/cover.1691926415.git.yin31149@gmail.com/
  - Correct the feature usage to VIRTIO_NET_F_HASH_REPORT when
loading the hash calculation state in
patch "vdpa: Restore receive-side scaling state"

RFC v1: https://lore.kernel.org/all/cover.1691766252.git.yin31149@gmail.com/

TestStep
========
1. regression testing using vp-vdpa device
  - For L0 guest, boot QEMU with two virtio-net-pci net device with
`ctrl_vq`, `mq`, `hash` features on, command line like:
	-netdev tap,...
	-device virtio-net-pci,disable-legacy=on,disable-modern=off,
iommu_platform=on,mq=on,ctrl_vq=on,hash=on,guest_announce=off,
indirect_desc=off,queue_reset=off,guest_uso4=off,guest_uso6=off,
host_uso=off,...

  - For L1 guest, apply the relative patch series and compile the
source code, start QEMU with two vdpa device with svq mode on,
enable the `ctrl_vq`, `mq`, `hash` features on, command line like:
      -netdev type=vhost-vdpa,x-svq=true,...
      -device virtio-net-pci,mq=on,guest_announce=off,ctrl_vq=on,
hash=on,...

  - For L2 source guest, run the following bash command:
```bash
#!/bin/sh

ethtool -K eth0 rxhash on
```
  - Gdb attach the destination VM and break at the
vhost_vdpa_net_load_rss()

  - Execute the live migration in L2 source monitor

  - Result
    * with this series, gdb can hit the breakpoint and continue
the executing without triggering any error or warning.




2. test the migration using vp-vdpa device
  - For L0 guest, boot QEMU with two virtio-net-pci net device with
`in-qemu` RSS, command line like:
	-netdev tap,vhost=off...
	-device virtio-net-pci,disable-legacy=on,disable-modern=off,
iommu_platform=on,mq=on,ctrl_vq=on,hash=on,rss=on,guest_announce=off,
indirect_desc=off,queue_reset=off,guest_uso4=off,guest_uso6=off,
host_uso=off,...

  - For L1 guest, apply the relative patch series and compile the
source code, start QEMU with two vdpa device with svq mode on,
enable the `ctrl_vq`, `mq`, `rss` features on, command line like:
      -netdev type=vhost-vdpa,x-svq=true,...
      -device virtio-net-pci,mq=on,guest_announce=off,ctrl_vq=on,
rss=on,...

  - For L2 source guest, run the following bash command:
```bash
#!/bin/sh

ethtool -K eth0 rxhash on
```

  - Execute the live migration in L2 source monitor

  - Result
    * with this series, L2 QEMU can execute without
triggering any error or warning. L0 QEMU echo
"Can't load eBPF RSS - fallback to software RSS".

Hawkins Jiawei (3):
  vdpa: Add SetSteeringEBPF method for NetClientState
  vdpa: Restore receive-side scaling state
  vdpa: Allow VIRTIO_NET_F_RSS in SVQ

 net/vhost-vdpa.c | 76 +++++++++++++++++++++++++++++++++---------------
 1 file changed, 53 insertions(+), 23 deletions(-)

-- 
2.25.1

[PATCH v5 1/3] vdpa: Add SetSteeringEBPF method for NetClientState

[Hawkins Jiawei]

At present, to enable the VIRTIO_NET_F_RSS feature, eBPF must
be loaded for the vhost backend.

Given that vhost-vdpa is one of the vhost backend, we need to
implement the SetSteeringEBPF method to support RSS for vhost-vdpa,
even if vhost-vdpa calculates the rss hash in the hardware device
instead of in the kernel by eBPF.

Although this requires QEMU to be compiled with `--enable-bpf`
configuration even if the vdpa device does not use eBPF to
calculate the rss hash, this can avoid adding the specific
conditional statements for vDPA case to enable the VIRTIO_NET_F_RSS
feature, which reduces code maintainbility.

Suggested-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
---
v5:
  - no changes

v4: https://lore.kernel.org/all/1c6faf4c5c3304c0bf14929143ccedb2e90dbcb2.1697904740.git.yin31149@gmail.com/
  - no code changes

v3: https://lore.kernel.org/all/30509e3c3b07bcadd95d5932aeb16820cb022902.1693299194.git.yin31149@gmail.com/

 net/vhost-vdpa.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 54f748d49d..3466936b87 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -241,6 +241,12 @@ static void vhost_vdpa_cleanup(NetClientState *nc)
     }
 }
 
+/** Dummy SetSteeringEBPF to support RSS for vhost-vdpa backend  */
+static bool vhost_vdpa_set_steering_ebpf(NetClientState *nc, int prog_fd)
+{
+    return true;
+}
+
 static bool vhost_vdpa_has_vnet_hdr(NetClientState *nc)
 {
     assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_VDPA);
@@ -423,6 +429,7 @@ static NetClientInfo net_vhost_vdpa_info = {
         .has_vnet_hdr = vhost_vdpa_has_vnet_hdr,
         .has_ufo = vhost_vdpa_has_ufo,
         .check_peer_type = vhost_vdpa_check_peer_type,
+        .set_steering_ebpf = vhost_vdpa_set_steering_ebpf,
 };
 
 static int64_t vhost_vdpa_get_vring_group(int device_fd, unsigned vq_index,
@@ -1258,6 +1265,7 @@ static NetClientInfo net_vhost_vdpa_cvq_info = {
     .has_vnet_hdr = vhost_vdpa_has_vnet_hdr,
     .has_ufo = vhost_vdpa_has_ufo,
     .check_peer_type = vhost_vdpa_check_peer_type,
+    .set_steering_ebpf = vhost_vdpa_set_steering_ebpf,
 };
 
 /*
-- 
2.25.1

[PATCH v5 2/3] vdpa: Restore receive-side scaling state

[Hawkins Jiawei]

This patch reuses vhost_vdpa_net_load_rss() with some
refactorings to restore the receive-side scaling state
at device's startup.

Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
---
v5:
  - resolve conflict with the updated patch 
"Vhost-vdpa Shadow Virtqueue Hash calculation Support"

v4: https://lore.kernel.org/all/79caf9bf05778ed5279e11bdd1f26b49baf373ce.1697904740.git.yin31149@gmail.com/
  - add do_rss argument and relative code in vhost_vdpa_net_load_rss()

v3: https://lore.kernel.org/all/47b17e160ba4e55b24790b7d73b22d2b437ebe3c.1693299194.git.yin31149@gmail.com/
  - resolve conflict with updated patch
"Vhost-vdpa Shadow Virtqueue Hash calculation Support"

RFC v2: https://lore.kernel.org/all/af33aa80bc4ef0b2cec6c21b9448866c517fde80.1691926415.git.yin31149@gmail.com/
  - Correct the feature usage to VIRTIO_NET_F_HASH_REPORT when
loading the hash calculation state

RFC v1: https://lore.kernel.org/all/93d5d82f0a5df71df326830033e50358c8b6be7a.1691766252.git.yin31149@gmail.com/

 net/vhost-vdpa.c | 67 +++++++++++++++++++++++++++++++-----------------
 1 file changed, 44 insertions(+), 23 deletions(-)

diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 3466936b87..a4cc1381fc 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -828,7 +828,7 @@ static int vhost_vdpa_net_load_mac(VhostVDPAState *s, const VirtIONet *n,
 
 static int vhost_vdpa_net_load_rss(VhostVDPAState *s, const VirtIONet *n,
                                    struct iovec *out_cursor,
-                                   struct iovec *in_cursor)
+                                   struct iovec *in_cursor, bool do_rss)
 {
     struct virtio_net_rss_config cfg = {};
     ssize_t r;
@@ -854,21 +854,35 @@ static int vhost_vdpa_net_load_rss(VhostVDPAState *s, const VirtIONet *n,
                        sizeof(n->rss_data.indirections_table[0]));
     cfg.hash_types = cpu_to_le32(n->rss_data.hash_types);
 
-    /*
-     * According to VirtIO standard, "Field reserved MUST contain zeroes.
-     * It is defined to make the structure to match the layout of
-     * virtio_net_rss_config structure, defined in 5.1.6.5.7.".
-     *
-     * Therefore, we need to zero the fields in
-     * struct virtio_net_rss_config, which corresponds to the
-     * `reserved` field in struct virtio_net_hash_config.
-     *
-     * Note that all other fields are zeroed at their definitions,
-     * except for the `indirection_table` field, where the actual data
-     * is stored in the `table` variable to ensure compatibility
-     * with RSS case. Therefore, we need to zero the `table` variable here.
-     */
-    table[0] = 0;
+    if (do_rss) {
+        /*
+         * According to VirtIO standard, "Number of entries in indirection_table
+         * is (indirection_table_mask + 1)".
+         */
+        cfg.indirection_table_mask = cpu_to_le16(n->rss_data.indirections_len -
+                                                 1);
+        cfg.unclassified_queue = cpu_to_le16(n->rss_data.default_queue);
+        for (int i = 0; i < n->rss_data.indirections_len; ++i) {
+            table[i] = cpu_to_le16(n->rss_data.indirections_table[i]);
+        }
+        cfg.max_tx_vq = cpu_to_le16(n->curr_queue_pairs);
+    } else {
+        /*
+         * According to VirtIO standard, "Field reserved MUST contain zeroes.
+         * It is defined to make the structure to match the layout of
+         * virtio_net_rss_config structure, defined in 5.1.6.5.7.".
+         *
+         * Therefore, we need to zero the fields in
+         * struct virtio_net_rss_config, which corresponds to the
+         * `reserved` field in struct virtio_net_hash_config.
+         *
+         * Note that all other fields are zeroed at their definitions,
+         * except for the `indirection_table` field, where the actual data
+         * is stored in the `table` variable to ensure compatibility
+         * with RSS case. Therefore, we need to zero the `table` variable here.
+         */
+        table[0] = 0;
+    }
 
     /*
      * Considering that virtio_net_handle_rss() currently does not restore
@@ -899,6 +913,7 @@ static int vhost_vdpa_net_load_rss(VhostVDPAState *s, const VirtIONet *n,
 
     r = vhost_vdpa_net_load_cmd(s, out_cursor, in_cursor,
                                 VIRTIO_NET_CTRL_MQ,
+                                do_rss ? VIRTIO_NET_CTRL_MQ_RSS_CONFIG :
                                 VIRTIO_NET_CTRL_MQ_HASH_CONFIG,
                                 data, ARRAY_SIZE(data));
     if (unlikely(r < 0)) {
@@ -933,13 +948,19 @@ static int vhost_vdpa_net_load_mq(VhostVDPAState *s,
         return r;
     }
 
-    if (!virtio_vdev_has_feature(&n->parent_obj, VIRTIO_NET_F_HASH_REPORT)) {
-        return 0;
-    }
-
-    r = vhost_vdpa_net_load_rss(s, n, out_cursor, in_cursor);
-    if (unlikely(r < 0)) {
-        return r;
+    if (virtio_vdev_has_feature(&n->parent_obj, VIRTIO_NET_F_RSS)) {
+        /* load the receive-side scaling state */
+        r = vhost_vdpa_net_load_rss(s, n, out_cursor, in_cursor, true);
+        if (unlikely(r < 0)) {
+            return r;
+        }
+    } else if (virtio_vdev_has_feature(&n->parent_obj,
+                                       VIRTIO_NET_F_HASH_REPORT)) {
+        /* load the hash calculation state */
+        r = vhost_vdpa_net_load_rss(s, n, out_cursor, in_cursor, false);
+        if (unlikely(r < 0)) {
+            return r;
+        }
     }
 
     return 0;
-- 
2.25.1

[PATCH v5 3/3] vdpa: Allow VIRTIO_NET_F_RSS in SVQ

[Hawkins Jiawei]

Enable SVQ with VIRTIO_NET_F_RSS feature.

Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
---
v5:
  - no changes

v4: https://lore.kernel.org/all/4ee7f3f339469f41626ca2c3ac7b1c574ebce901.1697904740.git.yin31149@gmail.com/
  - no code changes

v3: https://lore.kernel.org/all/2d2a378291bfac4144a0c0c473cf80415bb580b3.1693299194.git.yin31149@gmail.com/

 net/vhost-vdpa.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index a4cc1381fc..d0614d7954 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -122,6 +122,7 @@ static const uint64_t vdpa_svq_device_features =
     /* VHOST_F_LOG_ALL is exposed by SVQ */
     BIT_ULL(VHOST_F_LOG_ALL) |
     BIT_ULL(VIRTIO_NET_F_HASH_REPORT) |
+    BIT_ULL(VIRTIO_NET_F_RSS) |
     BIT_ULL(VIRTIO_NET_F_RSC_EXT) |
     BIT_ULL(VIRTIO_NET_F_STANDBY) |
     BIT_ULL(VIRTIO_NET_F_SPEED_DUPLEX);
-- 
2.25.1

Re: [PATCH v5 2/3] vdpa: Restore receive-side scaling state

[Eugenio Perez Martin]

On Wed, Oct 25, 2023 at 3:08 AM Hawkins Jiawei <yin31149@gmail.com> wrote:
>
> This patch reuses vhost_vdpa_net_load_rss() with some
> refactorings to restore the receive-side scaling state
> at device's startup.
>

Acked-by: Eugenio Pérez <eperezma@redhat.com>

> Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
> ---
> v5:
>   - resolve conflict with the updated patch
> "Vhost-vdpa Shadow Virtqueue Hash calculation Support"
>
> v4: https://lore.kernel.org/all/79caf9bf05778ed5279e11bdd1f26b49baf373ce.1697904740.git.yin31149@gmail.com/
>   - add do_rss argument and relative code in vhost_vdpa_net_load_rss()
>
> v3: https://lore.kernel.org/all/47b17e160ba4e55b24790b7d73b22d2b437ebe3c.1693299194.git.yin31149@gmail.com/
>   - resolve conflict with updated patch
> "Vhost-vdpa Shadow Virtqueue Hash calculation Support"
>
> RFC v2: https://lore.kernel.org/all/af33aa80bc4ef0b2cec6c21b9448866c517fde80.1691926415.git.yin31149@gmail.com/
>   - Correct the feature usage to VIRTIO_NET_F_HASH_REPORT when
> loading the hash calculation state
>
> RFC v1: https://lore.kernel.org/all/93d5d82f0a5df71df326830033e50358c8b6be7a.1691766252.git.yin31149@gmail.com/
>
>  net/vhost-vdpa.c | 67 +++++++++++++++++++++++++++++++-----------------
>  1 file changed, 44 insertions(+), 23 deletions(-)
>
> diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
> index 3466936b87..a4cc1381fc 100644
> --- a/net/vhost-vdpa.c
> +++ b/net/vhost-vdpa.c
> @@ -828,7 +828,7 @@ static int vhost_vdpa_net_load_mac(VhostVDPAState *s, const VirtIONet *n,
>
>  static int vhost_vdpa_net_load_rss(VhostVDPAState *s, const VirtIONet *n,
>                                     struct iovec *out_cursor,
> -                                   struct iovec *in_cursor)
> +                                   struct iovec *in_cursor, bool do_rss)
>  {
>      struct virtio_net_rss_config cfg = {};
>      ssize_t r;
> @@ -854,21 +854,35 @@ static int vhost_vdpa_net_load_rss(VhostVDPAState *s, const VirtIONet *n,
>                         sizeof(n->rss_data.indirections_table[0]));
>      cfg.hash_types = cpu_to_le32(n->rss_data.hash_types);
>
> -    /*
> -     * According to VirtIO standard, "Field reserved MUST contain zeroes.
> -     * It is defined to make the structure to match the layout of
> -     * virtio_net_rss_config structure, defined in 5.1.6.5.7.".
> -     *
> -     * Therefore, we need to zero the fields in
> -     * struct virtio_net_rss_config, which corresponds to the
> -     * `reserved` field in struct virtio_net_hash_config.
> -     *
> -     * Note that all other fields are zeroed at their definitions,
> -     * except for the `indirection_table` field, where the actual data
> -     * is stored in the `table` variable to ensure compatibility
> -     * with RSS case. Therefore, we need to zero the `table` variable here.
> -     */
> -    table[0] = 0;
> +    if (do_rss) {
> +        /*
> +         * According to VirtIO standard, "Number of entries in indirection_table
> +         * is (indirection_table_mask + 1)".
> +         */
> +        cfg.indirection_table_mask = cpu_to_le16(n->rss_data.indirections_len -
> +                                                 1);
> +        cfg.unclassified_queue = cpu_to_le16(n->rss_data.default_queue);
> +        for (int i = 0; i < n->rss_data.indirections_len; ++i) {
> +            table[i] = cpu_to_le16(n->rss_data.indirections_table[i]);
> +        }
> +        cfg.max_tx_vq = cpu_to_le16(n->curr_queue_pairs);
> +    } else {
> +        /*
> +         * According to VirtIO standard, "Field reserved MUST contain zeroes.
> +         * It is defined to make the structure to match the layout of
> +         * virtio_net_rss_config structure, defined in 5.1.6.5.7.".
> +         *
> +         * Therefore, we need to zero the fields in
> +         * struct virtio_net_rss_config, which corresponds to the
> +         * `reserved` field in struct virtio_net_hash_config.
> +         *
> +         * Note that all other fields are zeroed at their definitions,
> +         * except for the `indirection_table` field, where the actual data
> +         * is stored in the `table` variable to ensure compatibility
> +         * with RSS case. Therefore, we need to zero the `table` variable here.
> +         */
> +        table[0] = 0;
> +    }
>
>      /*
>       * Considering that virtio_net_handle_rss() currently does not restore
> @@ -899,6 +913,7 @@ static int vhost_vdpa_net_load_rss(VhostVDPAState *s, const VirtIONet *n,
>
>      r = vhost_vdpa_net_load_cmd(s, out_cursor, in_cursor,
>                                  VIRTIO_NET_CTRL_MQ,
> +                                do_rss ? VIRTIO_NET_CTRL_MQ_RSS_CONFIG :
>                                  VIRTIO_NET_CTRL_MQ_HASH_CONFIG,
>                                  data, ARRAY_SIZE(data));
>      if (unlikely(r < 0)) {
> @@ -933,13 +948,19 @@ static int vhost_vdpa_net_load_mq(VhostVDPAState *s,
>          return r;
>      }
>
> -    if (!virtio_vdev_has_feature(&n->parent_obj, VIRTIO_NET_F_HASH_REPORT)) {
> -        return 0;
> -    }
> -
> -    r = vhost_vdpa_net_load_rss(s, n, out_cursor, in_cursor);
> -    if (unlikely(r < 0)) {
> -        return r;
> +    if (virtio_vdev_has_feature(&n->parent_obj, VIRTIO_NET_F_RSS)) {
> +        /* load the receive-side scaling state */
> +        r = vhost_vdpa_net_load_rss(s, n, out_cursor, in_cursor, true);
> +        if (unlikely(r < 0)) {
> +            return r;
> +        }
> +    } else if (virtio_vdev_has_feature(&n->parent_obj,
> +                                       VIRTIO_NET_F_HASH_REPORT)) {
> +        /* load the hash calculation state */
> +        r = vhost_vdpa_net_load_rss(s, n, out_cursor, in_cursor, false);
> +        if (unlikely(r < 0)) {
> +            return r;
> +        }
>      }
>
>      return 0;
> --
> 2.25.1
>

Re: [PATCH v5 3/3] vdpa: Allow VIRTIO_NET_F_RSS in SVQ

[Eugenio Perez Martin]

On Wed, Oct 25, 2023 at 3:08 AM Hawkins Jiawei <yin31149@gmail.com> wrote:
>
> Enable SVQ with VIRTIO_NET_F_RSS feature.
>

Acked-by: Eugenio Pérez <eperezma@redhat.com>

> Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
> ---
> v5:
>   - no changes
>
> v4: https://lore.kernel.org/all/4ee7f3f339469f41626ca2c3ac7b1c574ebce901.1697904740.git.yin31149@gmail.com/
>   - no code changes
>
> v3: https://lore.kernel.org/all/2d2a378291bfac4144a0c0c473cf80415bb580b3.1693299194.git.yin31149@gmail.com/
>
>  net/vhost-vdpa.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
> index a4cc1381fc..d0614d7954 100644
> --- a/net/vhost-vdpa.c
> +++ b/net/vhost-vdpa.c
> @@ -122,6 +122,7 @@ static const uint64_t vdpa_svq_device_features =
>      /* VHOST_F_LOG_ALL is exposed by SVQ */
>      BIT_ULL(VHOST_F_LOG_ALL) |
>      BIT_ULL(VIRTIO_NET_F_HASH_REPORT) |
> +    BIT_ULL(VIRTIO_NET_F_RSS) |
>      BIT_ULL(VIRTIO_NET_F_RSC_EXT) |
>      BIT_ULL(VIRTIO_NET_F_STANDBY) |
>      BIT_ULL(VIRTIO_NET_F_SPEED_DUPLEX);
> --
> 2.25.1
>