* [PATCH v2 1/2] vdpa: Restore hash calculation state
2023-08-29 8:47 [PATCH v2 0/2] Vhost-vdpa Shadow Virtqueue Hash calculation Support Hawkins Jiawei
@ 2023-08-29 8:48 ` Hawkins Jiawei
2023-08-29 8:48 ` [PATCH v2 2/2] vdpa: Allow VIRTIO_NET_F_HASH_REPORT in SVQ Hawkins Jiawei
2023-10-19 18:11 ` [PATCH v2 0/2] Vhost-vdpa Shadow Virtqueue Hash calculation Support Michael S. Tsirkin
2 siblings, 0 replies; 4+ messages in thread
From: Hawkins Jiawei @ 2023-08-29 8:48 UTC (permalink / raw)
To: jasowang, mst, eperezma; +Cc: qemu-devel, yin31149, 18801353760
This patch introduces vhost_vdpa_net_load_rss() to restore
the hash calculation state at device's startup.
Note that vhost_vdpa_net_load_rss() has `do_rss` argument,
which allows future code to reuse this function to restore
the receive-side scaling state when the VIRTIO_NET_F_RSS
feature is enabled in SVQ. Currently, vhost_vdpa_net_load_rss()
could only be invoked when `do_rss` is set to false.
Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
---
Question:
It seems that virtio_net_handle_rss() currently does not restore the
hash key length parsed from the CVQ command sent from the guest into
n->rss_data and uses the maximum key length in other code.
So for `hash_key_length` field in VIRTIO_NET_CTRL_MQ_HASH_CONFIG command
sent to device, is it okay to also use the maximum key length as its value?
Or should we introduce the `hash_key_length` field in n->rss_data
structure to record the key length from guest and use this value?
ChangeLog:
v2:
- resolve conflict with updated patch
"vdpa: Send all CVQ state load commands in parallel"
- move the `table` declaration at the beginning of the
vhost_vdpa_net_load_rss()
RFC: https://lore.kernel.org/all/a54ca70b12ebe2f3c391864e41241697ab1aba30.1691762906.git.yin31149@gmail.com/
net/vhost-vdpa.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 91 insertions(+)
diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 818464b702..139bb79468 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -805,6 +805,88 @@ static int vhost_vdpa_net_load_mac(VhostVDPAState *s, const VirtIONet *n,
return 0;
}
+static int vhost_vdpa_net_load_rss(VhostVDPAState *s, const VirtIONet *n,
+ struct iovec *out_cursor,
+ struct iovec *in_cursor, bool do_rss)
+{
+ struct virtio_net_rss_config cfg;
+ ssize_t r;
+ g_autofree uint16_t *table = NULL;
+
+ /*
+ * According to VirtIO standard, "Initially the device has all hash
+ * types disabled and reports only VIRTIO_NET_HASH_REPORT_NONE.".
+ *
+ * Therefore, there is no need to send this CVQ command if the
+ * driver disable the all hash types, which aligns with
+ * the device's defaults.
+ *
+ * Note that the device's defaults can mismatch the driver's
+ * configuration only at live migration.
+ */
+ if (!n->rss_data.enabled ||
+ n->rss_data.hash_types == VIRTIO_NET_HASH_REPORT_NONE) {
+ return 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 the `reserved` field in
+ * struct virtio_net_hash_config.
+ */
+ memset(&cfg.indirection_table_mask, 0,
+ sizeof_field(struct virtio_net_hash_config, reserved));
+
+ table = g_malloc_n(n->rss_data.indirections_len,
+ sizeof(n->rss_data.indirections_table[0]));
+ for (int i = 0; i < n->rss_data.indirections_len; ++i) {
+ table[i] = cpu_to_le16(n->rss_data.indirections_table[i]);
+ }
+
+ /*
+ * Consider that virtio_net_handle_rss() currently does not restore the
+ * hash key length parsed from the CVQ command sent from the guest into
+ * n->rss_data and uses the maximum key length in other code, so we also
+ * employthe the maxium key length here.
+ */
+ cfg.hash_key_length = sizeof(n->rss_data.key);
+
+ const struct iovec data[] = {
+ {
+ .iov_base = &cfg,
+ .iov_len = offsetof(struct virtio_net_rss_config,
+ indirection_table),
+ }, {
+ .iov_base = table,
+ .iov_len = n->rss_data.indirections_len *
+ sizeof(n->rss_data.indirections_table[0]),
+ }, {
+ .iov_base = &cfg.max_tx_vq,
+ .iov_len = offsetof(struct virtio_net_rss_config, hash_key_data) -
+ offsetof(struct virtio_net_rss_config, max_tx_vq),
+ }, {
+ .iov_base = (void *)n->rss_data.key,
+ .iov_len = sizeof(n->rss_data.key),
+ }
+ };
+
+ r = vhost_vdpa_net_load_cmd(s, out_cursor, in_cursor,
+ VIRTIO_NET_CTRL_MQ,
+ VIRTIO_NET_CTRL_MQ_HASH_CONFIG,
+ data, ARRAY_SIZE(data));
+ if (unlikely(r < 0)) {
+ return r;
+ }
+
+ return 0;
+}
+
static int vhost_vdpa_net_load_mq(VhostVDPAState *s,
const VirtIONet *n,
struct iovec *out_cursor,
@@ -830,6 +912,15 @@ 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, false);
+ if (unlikely(r < 0)) {
+ return r;
+ }
+
return 0;
}
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH v2 0/2] Vhost-vdpa Shadow Virtqueue Hash calculation Support
2023-08-29 8:47 [PATCH v2 0/2] Vhost-vdpa Shadow Virtqueue Hash calculation Support Hawkins Jiawei
2023-08-29 8:48 ` [PATCH v2 1/2] vdpa: Restore hash calculation state Hawkins Jiawei
2023-08-29 8:48 ` [PATCH v2 2/2] vdpa: Allow VIRTIO_NET_F_HASH_REPORT in SVQ Hawkins Jiawei
@ 2023-10-19 18:11 ` Michael S. Tsirkin
2 siblings, 0 replies; 4+ messages in thread
From: Michael S. Tsirkin @ 2023-10-19 18:11 UTC (permalink / raw)
To: Hawkins Jiawei; +Cc: jasowang, eperezma, qemu-devel, 18801353760
On Tue, Aug 29, 2023 at 04:47:33PM +0800, Hawkins Jiawei wrote:
> This series enables shadowed CVQ to intercept
> VIRTIO_NET_CTRL_MQ_HASH_CONFIG command through shadowed CVQ,
> update the virtio NIC device model so qemu send it in a
> migration, and the restore of that Hash calculation state
> in the destination.
>
> Note that this patch should be based on
> patch "vdpa: Send all CVQ state load commands in parallel" at [1].
>
> [1]. https://lore.kernel.org/all/cover.1693287885.git.yin31149@gmail.com/
Dropped due to CI failures:
https://gitlab.com/qemu-project/qemu/-/jobs/5329820077
> TestStep
> ========
> 1. test the migration 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,...
>
> - 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.
>
>
> ChangeLog
> =========
> v2:
> - resolve conflict with updated patch
> "vdpa: Send all CVQ state load commands in parallel", move the
> `table` declaration at the beginning of the vhost_vdpa_net_load_rss()
> in patch
> "vdpa: Restore hash calculation state"
>
> RFC: https://lore.kernel.org/all/cover.1691762906.git.yin31149@gmail.com/#t
>
> Hawkins Jiawei (2):
> vdpa: Restore hash calculation state
> vdpa: Allow VIRTIO_NET_F_HASH_REPORT in SVQ
>
> net/vhost-vdpa.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 92 insertions(+)
>
> --
> 2.25.1
^ permalink raw reply [flat|nested] 4+ messages in thread