From 70c72316c26e95cd18b4d46b83e78ba3a148212c Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= <eperezma@redhat.com>

Date: Tue, 23 Aug 2022 20:30:33 +0200

Subject: [PATCH 18/23] vdpa: Move command buffers map to start of net device

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RH-Author: Eugenio Pérez <eperezma@redhat.com>

RH-MergeRequest: 116: vdpa: Restore device state on destination

RH-Bugzilla: 2114060

RH-Acked-by: Cindy Lu <lulu@redhat.com>

RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

RH-Commit: [17/21] 7a9824fa618f5c2904648b50e3078474cd3987aa (eperezmartin/qemu-kvm)

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2114060

Upstream status: git@github.com:jasowang/qemu.git net-next

As this series will reuse them to restore the device state at the end of

a migration (or a device start), let's allocate only once at the device

start so we don't duplicate their map and unmap.

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

Acked-by: Jason Wang <jasowang@redhat.com>

Signed-off-by: Jason Wang <jasowang@redhat.com>

(cherry picked from commit d7d73dec14cebcebd8de774424795aeb821236c1)

---

 net/vhost-vdpa.c | 123 ++++++++++++++++++++++-------------------------

 1 file changed, 58 insertions(+), 65 deletions(-)

diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c

index 03e4cf1abc..17626feb8d 100644

--- a/net/vhost-vdpa.c

+++ b/net/vhost-vdpa.c

@@ -263,29 +263,20 @@ static size_t vhost_vdpa_net_cvq_cmd_page_len(void)

     return ROUND_UP(vhost_vdpa_net_cvq_cmd_len(), qemu_real_host_page_size);

 }

-/** Copy and map a guest buffer. */

-static bool vhost_vdpa_cvq_map_buf(struct vhost_vdpa *v,

-                                   const struct iovec *out_data,

-                                   size_t out_num, size_t data_len, void *buf,

-                                   size_t *written, bool write)

+/** Map CVQ buffer. */

+static int vhost_vdpa_cvq_map_buf(struct vhost_vdpa *v, void *buf, size_t size,

+                                  bool write)

 {

     DMAMap map = {};

     int r;

-    if (unlikely(!data_len)) {

-        qemu_log_mask(LOG_GUEST_ERROR, "%s: invalid legnth of %s buffer\n",

-                      __func__, write ? "in" : "out");

-        return false;

-    }

-

-    *written = iov_to_buf(out_data, out_num, 0, buf, data_len);

     map.translated_addr = (hwaddr)(uintptr_t)buf;

-    map.size = vhost_vdpa_net_cvq_cmd_page_len() - 1;

+    map.size = size - 1;

     map.perm = write ? IOMMU_RW : IOMMU_RO,

     r = vhost_iova_tree_map_alloc(v->iova_tree, &map);

     if (unlikely(r != IOVA_OK)) {

         error_report("Cannot map injected element");

-        return false;

+        return r;

     }

     r = vhost_vdpa_dma_map(v, map.iova, vhost_vdpa_net_cvq_cmd_page_len(), buf,

@@ -294,50 +285,58 @@ static bool vhost_vdpa_cvq_map_buf(struct vhost_vdpa *v,

         goto dma_map_err;

     }

-    return true;

+    return 0;

 dma_map_err:

     vhost_iova_tree_remove(v->iova_tree, map);

-    return false;

+    return r;

 }

-/**

- * Copy the guest element into a dedicated buffer suitable to be sent to NIC

- *

- * @iov: [0] is the out buffer, [1] is the in one

- */

-static bool vhost_vdpa_net_cvq_map_elem(VhostVDPAState *s,

-                                        VirtQueueElement *elem,

-                                        struct iovec *iov)

+static int vhost_vdpa_net_cvq_start(NetClientState *nc)

 {

-    size_t in_copied;

-    bool ok;

+    VhostVDPAState *s;

+    int r;

-    iov[0].iov_base = s->cvq_cmd_out_buffer;

-    ok = vhost_vdpa_cvq_map_buf(&s->vhost_vdpa, elem->out_sg, elem->out_num,

-                                vhost_vdpa_net_cvq_cmd_len(), iov[0].iov_base,

-                                &iov[0].iov_len, false);

-    if (unlikely(!ok)) {

-        return false;

+    assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_VDPA);

+

+    s = DO_UPCAST(VhostVDPAState, nc, nc);

+    if (!s->vhost_vdpa.shadow_vqs_enabled) {

+        return 0;

     }

-    iov[1].iov_base = s->cvq_cmd_in_buffer;

-    ok = vhost_vdpa_cvq_map_buf(&s->vhost_vdpa, NULL, 0,

-                                sizeof(virtio_net_ctrl_ack), iov[1].iov_base,

-                                &in_copied, true);

-    if (unlikely(!ok)) {

+    r = vhost_vdpa_cvq_map_buf(&s->vhost_vdpa, s->cvq_cmd_out_buffer,

+                               vhost_vdpa_net_cvq_cmd_page_len(), false);

+    if (unlikely(r < 0)) {

+        return r;

+    }

+

+    r = vhost_vdpa_cvq_map_buf(&s->vhost_vdpa, s->cvq_cmd_in_buffer,

+                               vhost_vdpa_net_cvq_cmd_page_len(), true);

+    if (unlikely(r < 0)) {

         vhost_vdpa_cvq_unmap_buf(&s->vhost_vdpa, s->cvq_cmd_out_buffer);

-        return false;

     }

-    iov[1].iov_len = sizeof(virtio_net_ctrl_ack);

-    return true;

+    return r;

+}

+

+static void vhost_vdpa_net_cvq_stop(NetClientState *nc)

+{

+    VhostVDPAState *s = DO_UPCAST(VhostVDPAState, nc, nc);

+

+    assert(nc->info->type == NET_CLIENT_DRIVER_VHOST_VDPA);

+

+    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->cvq_cmd_in_buffer);

+    }

 }

 static NetClientInfo net_vhost_vdpa_cvq_info = {

     .type = NET_CLIENT_DRIVER_VHOST_VDPA,

     .size = sizeof(VhostVDPAState),

     .receive = vhost_vdpa_receive,

+    .start = vhost_vdpa_net_cvq_start,

+    .stop = vhost_vdpa_net_cvq_stop,

     .cleanup = vhost_vdpa_cleanup,

     .has_vnet_hdr = vhost_vdpa_has_vnet_hdr,

     .has_ufo = vhost_vdpa_has_ufo,

@@ -348,19 +347,17 @@ static NetClientInfo net_vhost_vdpa_cvq_info = {

  * Do not forward commands not supported by SVQ. Otherwise, the device could

  * accept it and qemu would not know how to update the device model.

  */

-static bool vhost_vdpa_net_cvq_validate_cmd(const struct iovec *out,

-                                            size_t out_num)

+static bool vhost_vdpa_net_cvq_validate_cmd(const void *out_buf, size_t len)

 {

     struct virtio_net_ctrl_hdr ctrl;

-    size_t n;

-    n = iov_to_buf(out, out_num, 0, &ctrl, sizeof(ctrl));

-    if (unlikely(n < sizeof(ctrl))) {

+    if (unlikely(len < sizeof(ctrl))) {

         qemu_log_mask(LOG_GUEST_ERROR,

-                      "%s: invalid legnth of out buffer %zu\n", __func__, n);

+                      "%s: invalid legnth of out buffer %zu\n", __func__, len);

         return false;

     }

+    memcpy(&ctrl, out_buf, sizeof(ctrl));

     switch (ctrl.class) {

     case VIRTIO_NET_CTRL_MAC:

         switch (ctrl.cmd) {

@@ -392,10 +389,14 @@ static int vhost_vdpa_net_handle_ctrl_avail(VhostShadowVirtqueue *svq,

     VhostVDPAState *s = opaque;

     size_t in_len, dev_written;

     virtio_net_ctrl_ack status = VIRTIO_NET_ERR;

-    /* out and in buffers sent to the device */

-    struct iovec dev_buffers[2] = {

-        { .iov_base = s->cvq_cmd_out_buffer },

-        { .iov_base = s->cvq_cmd_in_buffer },

+    /* Out buffer sent to both the vdpa device and the device model */

+    struct iovec out = {

+        .iov_base = s->cvq_cmd_out_buffer,

+    };

+    /* In buffer sent to the device */

+    const struct iovec dev_in = {

+        .iov_base = s->cvq_cmd_in_buffer,

+        .iov_len = sizeof(virtio_net_ctrl_ack),

     };

     /* in buffer used for device model */

     const struct iovec in = {

@@ -405,17 +406,15 @@ static int vhost_vdpa_net_handle_ctrl_avail(VhostShadowVirtqueue *svq,

     int r = -EINVAL;

     bool ok;

-    ok = vhost_vdpa_net_cvq_map_elem(s, elem, dev_buffers);

-    if (unlikely(!ok)) {

-        goto out;

-    }

-

-    ok = vhost_vdpa_net_cvq_validate_cmd(&dev_buffers[0], 1);

+    out.iov_len = iov_to_buf(elem->out_sg, elem->out_num, 0,

+                             s->cvq_cmd_out_buffer,

+                             vhost_vdpa_net_cvq_cmd_len());

+    ok = vhost_vdpa_net_cvq_validate_cmd(s->cvq_cmd_out_buffer, out.iov_len);

     if (unlikely(!ok)) {

         goto out;

     }

-    r = vhost_svq_add(svq, &dev_buffers[0], 1, &dev_buffers[1], 1, elem);

+    r = vhost_svq_add(svq, &out, 1, &dev_in, 1, elem);

     if (unlikely(r != 0)) {

         if (unlikely(r == -ENOSPC)) {

             qemu_log_mask(LOG_GUEST_ERROR, "%s: No space on device queue\n",

@@ -435,13 +434,13 @@ static int vhost_vdpa_net_handle_ctrl_avail(VhostShadowVirtqueue *svq,

         goto out;

     }

-    memcpy(&status, dev_buffers[1].iov_base, sizeof(status));

+    memcpy(&status, s->cvq_cmd_in_buffer, sizeof(status));

     if (status != VIRTIO_NET_OK) {

         goto out;

     }

     status = VIRTIO_NET_ERR;

-    virtio_net_handle_ctrl_iov(svq->vdev, &in, 1, dev_buffers, 1);

+    virtio_net_handle_ctrl_iov(svq->vdev, &in, 1, &out, 1);

     if (status != VIRTIO_NET_OK) {

         error_report("Bad CVQ processing in model");

     }

@@ -454,12 +453,6 @@ out:

     }

     vhost_svq_push_elem(svq, elem, MIN(in_len, sizeof(status)));

     g_free(elem);

-    if (dev_buffers[0].iov_base) {

-        vhost_vdpa_cvq_unmap_buf(&s->vhost_vdpa, dev_buffers[0].iov_base);

-    }

-    if (dev_buffers[1].iov_base) {

-        vhost_vdpa_cvq_unmap_buf(&s->vhost_vdpa, dev_buffers[1].iov_base);

-    }

     return r;

 }

-- 

2.31.1