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From: Maxime Coquelin <maxime.coquelin@redhat.com>
To: mst@redhat.com,
	jasowang@redhat.com,
	xuanzhuo@linux.alibaba.com,
	xieyongji@bytedance.com,
	virtualization@lists.linux-foundation.org,
	linux-kernel@vger.kernel.org,
	david.marchand@redhat.com,
	lulu@redhat.com
Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
Subject: [PATCH v6 2/3] vduse: Temporarily fail if control queue features requested
Date: Thu,  4 Jan 2024 16:37:52 +0100
Message-ID: <20240104153753.2931026-3-maxime.coquelin@redhat.com>
In-Reply-To: <20240104153753.2931026-1-maxime.coquelin@redhat.com>
References: <20240104153753.2931026-1-maxime.coquelin@redhat.com>
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Virtio-net driver control queue implementation is not safe
when used with VDUSE. If the VDUSE application does not
reply to control queue messages, it currently ends up
hanging the kernel thread sending this command.

Some work is on-going to make the control queue
implementation robust with VDUSE. Until it is completed,
let's fail features check if any control-queue related
feature is requested.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 drivers/vdpa/vdpa_user/vduse_dev.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 0486ff672408..94f54ea2eb06 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -28,6 +28,7 @@
 #include <uapi/linux/virtio_config.h>
 #include <uapi/linux/virtio_ids.h>
 #include <uapi/linux/virtio_blk.h>
+#include <uapi/linux/virtio_ring.h>
 #include <linux/mod_devicetable.h>
 
 #include "iova_domain.h"
@@ -46,6 +47,15 @@
 
 #define IRQ_UNBOUND -1
 
+#define VDUSE_NET_INVALID_FEATURES_MASK         \
+	(BIT_ULL(VIRTIO_NET_F_CTRL_VQ) |        \
+	 BIT_ULL(VIRTIO_NET_F_CTRL_RX)   |      \
+	 BIT_ULL(VIRTIO_NET_F_CTRL_VLAN) |      \
+	 BIT_ULL(VIRTIO_NET_F_GUEST_ANNOUNCE) | \
+	 BIT_ULL(VIRTIO_NET_F_MQ) |             \
+	 BIT_ULL(VIRTIO_NET_F_CTRL_MAC_ADDR) |  \
+	 BIT_ULL(VIRTIO_NET_F_RSS))
+
 struct vduse_virtqueue {
 	u16 index;
 	u16 num_max;
@@ -1680,6 +1690,9 @@ static bool features_is_valid(struct vduse_dev_config *config)
 	if ((config->device_id == VIRTIO_ID_BLOCK) &&
 			(config->features & (1ULL << VIRTIO_BLK_F_CONFIG_WCE)))
 		return false;
+	else if ((config->device_id == VIRTIO_ID_NET) &&
+			(config->features & VDUSE_NET_INVALID_FEATURES_MASK))
+		return false;
 
 	return true;
 }
-- 
2.43.0