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qemu-kvm/SOURCES/kvm-vdpa-always-start-CVQ-i...

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From 84c203faa570b85eec006215768c83371c9f0399 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= <eperezma@redhat.com>
Date: Thu, 15 Dec 2022 12:31:44 +0100
Subject: [PATCH 12/14] vdpa: always start CVQ in SVQ mode if possible
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
RH-Author: Eugenio Pérez <eperezma@redhat.com>
RH-MergeRequest: 136: vDPA ASID support in Qemu
RH-Bugzilla: 2104412
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
RH-Acked-by: Cindy Lu <lulu@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
RH-Commit: [12/13] 83f94b3e163ca38d08dbf7c111a4cfa7a44e3dc2 (eperezmartin/qemu-kvm)
Isolate control virtqueue in its own group, allowing to intercept control
commands but letting dataplane run totally passthrough to the guest.
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <20221215113144.322011-13-eperezma@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
(cherry picked from commit c1a1008685af0327d9d03f03d43bdb77e7af5bea)
---
hw/virtio/vhost-vdpa.c | 3 +-
net/vhost-vdpa.c | 110 ++++++++++++++++++++++++++++++++++++++++-
2 files changed, 111 insertions(+), 2 deletions(-)
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index dc3498e995..72ff06673c 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -638,7 +638,8 @@ static int vhost_vdpa_set_backend_cap(struct vhost_dev *dev)
{
uint64_t features;
uint64_t f = 0x1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2 |
- 0x1ULL << VHOST_BACKEND_F_IOTLB_BATCH;
+ 0x1ULL << VHOST_BACKEND_F_IOTLB_BATCH |
+ 0x1ULL << VHOST_BACKEND_F_IOTLB_ASID;
int r;
if (vhost_vdpa_call(dev, VHOST_GET_BACKEND_FEATURES, &features)) {
diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index eea7a0df12..07d33dae26 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -101,6 +101,8 @@ static const uint64_t vdpa_svq_device_features =
BIT_ULL(VIRTIO_NET_F_RSC_EXT) |
BIT_ULL(VIRTIO_NET_F_STANDBY);
+#define VHOST_VDPA_NET_CVQ_ASID 1
+
VHostNetState *vhost_vdpa_get_vhost_net(NetClientState *nc)
{
VhostVDPAState *s = DO_UPCAST(VhostVDPAState, nc, nc);
@@ -242,6 +244,40 @@ static NetClientInfo net_vhost_vdpa_info = {
.check_peer_type = vhost_vdpa_check_peer_type,
};
+static int64_t vhost_vdpa_get_vring_group(int device_fd, unsigned vq_index)
+{
+ struct vhost_vring_state state = {
+ .index = vq_index,
+ };
+ int r = ioctl(device_fd, VHOST_VDPA_GET_VRING_GROUP, &state);
+
+ if (unlikely(r < 0)) {
+ error_report("Cannot get VQ %u group: %s", vq_index,
+ g_strerror(errno));
+ return r;
+ }
+
+ return state.num;
+}
+
+static int vhost_vdpa_set_address_space_id(struct vhost_vdpa *v,
+ unsigned vq_group,
+ unsigned asid_num)
+{
+ struct vhost_vring_state asid = {
+ .index = vq_group,
+ .num = asid_num,
+ };
+ int r;
+
+ r = ioctl(v->device_fd, VHOST_VDPA_SET_GROUP_ASID, &asid);
+ if (unlikely(r < 0)) {
+ error_report("Can't set vq group %u asid %u, errno=%d (%s)",
+ asid.index, asid.num, errno, g_strerror(errno));
+ }
+ return r;
+}
+
static void vhost_vdpa_cvq_unmap_buf(struct vhost_vdpa *v, void *addr)
{
VhostIOVATree *tree = v->iova_tree;
@@ -316,11 +352,75 @@ dma_map_err:
static int vhost_vdpa_net_cvq_start(NetClientState *nc)
{
VhostVDPAState *s;
- int r;
+ struct vhost_vdpa *v;
+ uint64_t backend_features;
+ int64_t cvq_group;
+ int cvq_index, r;
assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_VDPA);
s = DO_UPCAST(VhostVDPAState, nc, nc);
+ v = &s->vhost_vdpa;
+
+ v->shadow_data = s->always_svq;
+ v->shadow_vqs_enabled = s->always_svq;
+ s->vhost_vdpa.address_space_id = VHOST_VDPA_GUEST_PA_ASID;
+
+ if (s->always_svq) {
+ /* SVQ is already configured for all virtqueues */
+ goto out;
+ }
+
+ /*
+ * If we early return in these cases SVQ will not be enabled. The migration
+ * will be blocked as long as vhost-vdpa backends will not offer _F_LOG.
+ *
+ * Calling VHOST_GET_BACKEND_FEATURES as they are not available in v->dev
+ * yet.
+ */
+ r = ioctl(v->device_fd, VHOST_GET_BACKEND_FEATURES, &backend_features);
+ if (unlikely(r < 0)) {
+ error_report("Cannot get vdpa backend_features: %s(%d)",
+ g_strerror(errno), errno);
+ return -1;
+ }
+ if (!(backend_features & VHOST_BACKEND_F_IOTLB_ASID) ||
+ !vhost_vdpa_net_valid_svq_features(v->dev->features, NULL)) {
+ return 0;
+ }
+
+ /*
+ * Check if all the virtqueues of the virtio device are in a different vq
+ * than the last vq. VQ group of last group passed in cvq_group.
+ */
+ cvq_index = v->dev->vq_index_end - 1;
+ cvq_group = vhost_vdpa_get_vring_group(v->device_fd, cvq_index);
+ if (unlikely(cvq_group < 0)) {
+ return cvq_group;
+ }
+ for (int i = 0; i < cvq_index; ++i) {
+ int64_t group = vhost_vdpa_get_vring_group(v->device_fd, i);
+
+ if (unlikely(group < 0)) {
+ return group;
+ }
+
+ if (group == cvq_group) {
+ return 0;
+ }
+ }
+
+ r = vhost_vdpa_set_address_space_id(v, cvq_group, VHOST_VDPA_NET_CVQ_ASID);
+ if (unlikely(r < 0)) {
+ return r;
+ }
+
+ v->iova_tree = vhost_iova_tree_new(v->iova_range.first,
+ v->iova_range.last);
+ v->shadow_vqs_enabled = true;
+ s->vhost_vdpa.address_space_id = VHOST_VDPA_NET_CVQ_ASID;
+
+out:
if (!s->vhost_vdpa.shadow_vqs_enabled) {
return 0;
}
@@ -349,6 +449,14 @@ static void vhost_vdpa_net_cvq_stop(NetClientState *nc)
if (s->vhost_vdpa.shadow_vqs_enabled) {
vhost_vdpa_cvq_unmap_buf(&s->vhost_vdpa, s->cvq_cmd_out_buffer);
vhost_vdpa_cvq_unmap_buf(&s->vhost_vdpa, s->status);
+ if (!s->always_svq) {
+ /*
+ * If only the CVQ is shadowed we can delete this safely.
+ * If all the VQs are shadows this will be needed by the time the
+ * device is started again to register SVQ vrings and similar.
+ */
+ g_clear_pointer(&s->vhost_vdpa.iova_tree, vhost_iova_tree_delete);
+ }
}
}
--
2.31.1
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