[PATCH 6.12 09/24] crypto: virtio - Add spinlock protection with virtqueue notification

Greg Kroah-Hartman
2026-02-13T13:56:22Z

From: Bibo Mao <maobibo@loongson.cn>

commit b505047ffc8057555900d2d3a005d033e6967382 upstream.

When VM boots with one virtio-crypto PCI device and builtin backend,
run openssl benchmark command with multiple processes, such as
openssl speed -evp aes-128-cbc -engine afalg -seconds 10 -multi 32

openssl processes will hangup and there is error reported like this:
virtio_crypto virtio0: dataq.0:id 3 is not a head!

It seems that the data virtqueue need protection when it is handled
for virtio done notification. If the spinlock protection is added
in virtcrypto_done_task(), openssl benchmark with multiple processes
works well.

Fixes: fed93fb62e05 ("crypto: virtio - Handle dataq logic with tasklet")
Cc: stable@vger.kernel.org
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Acked-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/crypto/virtio/virtio_crypto_core.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/drivers/crypto/virtio/virtio_crypto_core.c
+++ b/drivers/crypto/virtio/virtio_crypto_core.c
@@ -75,15 +75,20 @@ static void virtcrypto_done_task(unsigne
struct data_queue *data_vq = (struct data_queue *)data;
struct virtqueue *vq = data_vq->vq;
struct virtio_crypto_request *vc_req;
+ unsigned long flags;
unsigned int len;

+ spin_lock_irqsave(&data_vq->lock, flags);
do {
virtqueue_disable_cb(vq);
while ((vc_req = virtqueue_get_buf(vq, &len)) != NULL) {
+ spin_unlock_irqrestore(&data_vq->lock, flags);
if (vc_req->alg_cb)
vc_req->alg_cb(vc_req, len);
+ spin_lock_irqsave(&data_vq->lock, flags);
}
} while (!virtqueue_enable_cb(vq));
+ spin_unlock_irqrestore(&data_vq->lock, flags);
}

static void virtcrypto_dataq_callback(struct virtqueue *vq)