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From:   =?UTF-8?q?Eugenio=20P=C3=A9rez?= <eperezma@redhat.com>
To:     mst@redhat.com
Cc:     leiyang@redhat.com, Laurent Vivier <lvivier@redhat.com>,
        sgarzare@redhat.com, jasowang@redhat.com,
        Zhu Lingshan <lingshan.zhu@intel.com>,
        virtualization@lists.linux-foundation.org, si-wei.liu@oracle.com,
        linux-kernel@vger.kernel.org, lulu@redhat.com,
        Gautam Dawar <gdawar@xilinx.com>, alvaro.karsz@solid-run.com
Subject: [PATCH 1/2] vdpa_sim: not reset state in vdpasim_queue_ready
Date:   Wed, 18 Jan 2023 17:43:58 +0100
Message-Id: <20230118164359.1523760-2-eperezma@redhat.com>
In-Reply-To: <20230118164359.1523760-1-eperezma@redhat.com>
References: <20230118164359.1523760-1-eperezma@redhat.com>
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vdpasim_queue_ready calls vringh_init_iotlb, which resets split indexes.
But it can be called after setting a ring base with
vdpasim_set_vq_state.

Fix it by stashing them. They're still resetted in vdpasim_vq_reset.

This was discovered and tested live migrating the vdpa_sim_net device.

Fixes: 2c53d0f64c06 ("vdpasim: vDPA device simulator")
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 drivers/vdpa/vdpa_sim/vdpa_sim.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index cb88891b44a8..8839232a3fcb 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -66,6 +66,7 @@ static void vdpasim_vq_notify(struct vringh *vring)
 static void vdpasim_queue_ready(struct vdpasim *vdpasim, unsigned int idx)
 {
 	struct vdpasim_virtqueue *vq = &vdpasim->vqs[idx];
+	uint16_t last_avail_idx = vq->vring.last_avail_idx;
 
 	vringh_init_iotlb(&vq->vring, vdpasim->features, vq->num, false,
 			  (struct vring_desc *)(uintptr_t)vq->desc_addr,
@@ -74,6 +75,7 @@ static void vdpasim_queue_ready(struct vdpasim *vdpasim, unsigned int idx)
 			  (struct vring_used *)
 			  (uintptr_t)vq->device_addr);
 
+	vq->vring.last_avail_idx = last_avail_idx;
 	vq->vring.notify = vdpasim_vq_notify;
 }
 
-- 
2.31.1