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vhost_vdpa: assign irq bypass producer token correctly

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[ Upstream commit 02e9e9366fefe461719da5d173385b6685f70319 ]

We used to call irq_bypass_unregister_producer() in
vhost_vdpa_setup_vq_irq() which is problematic as we don't know if the
token pointer is still valid or not.

Actually, we use the eventfd_ctx as the token so the life cycle of the
token should be bound to the VHOST_SET_VRING_CALL instead of
vhost_vdpa_setup_vq_irq() which could be called by set_status().

Fixing this by setting up irq bypass producer's token when handling
VHOST_SET_VRING_CALL and un-registering the producer before calling
vhost_vring_ioctl() to prevent a possible use after free as eventfd
could have been released in vhost_vring_ioctl(). And such registering
and unregistering will only be done if DRIVER_OK is set.

Reported-by: Dragos Tatulea <dtatulea@nvidia.com>
Tested-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com>
Fixes: 2cf1ba9a4d15 ("vhost_vdpa: implement IRQ offloading in vhost_vdpa")
Signed-off-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20240816031900.18013-1-jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Jason Wang 2024-08-16 11:19:00 +08:00 • committed by Ksawlii
parent aebec28879
commit 092748cc8b
1 changed files with 13 additions and 3 deletions
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16
drivers/vhost/vdpa.c
View file

@ -100,11 +100,9 @@ static void vhost_vdpa_setup_vq_irq(struct vhost_vdpa *v, u16 qid)
if (irq < 0)
return;
irq_bypass_unregister_producer(&vq->call_ctx.producer);
if (!vq->call_ctx.ctx)
return;
vq->call_ctx.producer.token = vq->call_ctx.ctx;
vq->call_ctx.producer.irq = irq;
ret = irq_bypass_register_producer(&vq->call_ctx.producer);
if (unlikely(ret))
@ -397,6 +395,14 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
vq->last_avail_idx = vq_state.avail_index;
break;
case VHOST_SET_VRING_CALL:
if (vq->call_ctx.ctx) {
if (ops->get_status(vdpa) &
VIRTIO_CONFIG_S_DRIVER_OK)
vhost_vdpa_unsetup_vq_irq(v, idx);
vq->call_ctx.producer.token = NULL;
}
break;
}
r = vhost_vring_ioctl(&v->vdev, cmd, argp);
@ -423,13 +429,16 @@ static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
cb.callback = vhost_vdpa_virtqueue_cb;
cb.private = vq;
cb.trigger = vq->call_ctx.ctx;
vq->call_ctx.producer.token = vq->call_ctx.ctx;
if (ops->get_status(vdpa) &
VIRTIO_CONFIG_S_DRIVER_OK)
vhost_vdpa_setup_vq_irq(v, idx);
} else {
cb.callback = NULL;
cb.private = NULL;
cb.trigger = NULL;
}
ops->set_vq_cb(vdpa, idx, &cb);
vhost_vdpa_setup_vq_irq(v, idx);
break;
case VHOST_SET_VRING_NUM:
@ -890,6 +899,7 @@ static int vhost_vdpa_open(struct inode *inode, struct file *filep)
for (i = 0; i < nvqs; i++) {
vqs[i] = &v->vqs[i];
vqs[i]->handle_kick = handle_vq_kick;
vqs[i]->call_ctx.ctx = NULL;
}
vhost_dev_init(dev, vqs, nvqs, 0, 0, 0, false,
vhost_vdpa_process_iotlb_msg);