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88 lines
3.4 KiB
88 lines
3.4 KiB
From 3f2ba7cce6b272a8b5c8953e8923e799e4aa7b88 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= <eperezma@redhat.com>
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Date: Mon, 18 Jul 2022 14:05:45 +0200
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Subject: [PATCH 02/23] vhost: Get vring base from vq, not svq
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Eugenio Pérez <eperezma@redhat.com>
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RH-MergeRequest: 116: vdpa: Restore device state on destination
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RH-Bugzilla: 2114060
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RH-Acked-by: Cindy Lu <lulu@redhat.com>
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RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
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RH-Commit: [1/21] e7e0294bbc98f69ccdbc4af4715857e77b017f80 (eperezmartin/qemu-kvm)
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Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2114060
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Upstream status: Merged
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The SVQ vring used idx usually match with the guest visible one, as long
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as all the guest buffers (GPA) maps to exactly one buffer within qemu's
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VA. However, as we can see in virtqueue_map_desc, a single guest buffer
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could map to many buffers in SVQ vring.
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Also, its also a mistake to rewind them at the source of migration.
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Since VirtQueue is able to migrate the inflight descriptors, its
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responsability of the destination to perform the rewind just in case it
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cannot report the inflight descriptors to the device.
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This makes easier to migrate between backends or to recover them in
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vhost devices that support set in flight descriptors.
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Fixes: 6d0b22266633 ("vdpa: Adapt vhost_vdpa_get_vring_base to SVQ")
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Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
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Signed-off-by: Jason Wang <jasowang@redhat.com>
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(cherry picked from commit 2fdac348fd3d243bb964937236af3cc27ae7af2b)
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---
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hw/virtio/vhost-vdpa.c | 24 ++++++++++++------------
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1 file changed, 12 insertions(+), 12 deletions(-)
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diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
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index 03dc6014b0..96334ab5b6 100644
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--- a/hw/virtio/vhost-vdpa.c
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+++ b/hw/virtio/vhost-vdpa.c
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@@ -1177,7 +1177,18 @@ static int vhost_vdpa_set_vring_base(struct vhost_dev *dev,
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struct vhost_vring_state *ring)
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{
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struct vhost_vdpa *v = dev->opaque;
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+ VirtQueue *vq = virtio_get_queue(dev->vdev, ring->index);
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+ /*
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+ * vhost-vdpa devices does not support in-flight requests. Set all of them
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+ * as available.
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+ *
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+ * TODO: This is ok for networking, but other kinds of devices might
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+ * have problems with these retransmissions.
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+ */
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+ while (virtqueue_rewind(vq, 1)) {
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+ continue;
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+ }
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if (v->shadow_vqs_enabled) {
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/*
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* Device vring base was set at device start. SVQ base is handled by
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@@ -1193,21 +1204,10 @@ static int vhost_vdpa_get_vring_base(struct vhost_dev *dev,
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struct vhost_vring_state *ring)
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{
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struct vhost_vdpa *v = dev->opaque;
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- int vdpa_idx = ring->index - dev->vq_index;
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int ret;
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if (v->shadow_vqs_enabled) {
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- VhostShadowVirtqueue *svq = g_ptr_array_index(v->shadow_vqs, vdpa_idx);
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-
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- /*
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- * Setting base as last used idx, so destination will see as available
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- * all the entries that the device did not use, including the in-flight
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- * processing ones.
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- *
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- * TODO: This is ok for networking, but other kinds of devices might
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- * have problems with these retransmissions.
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- */
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- ring->num = svq->last_used_idx;
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+ ring->num = virtio_queue_get_last_avail_idx(dev->vdev, ring->index);
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return 0;
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}
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--
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2.31.1
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