virtio/vhost: Factor vring operation

The VHOST_VRING* ioctls are common to all device types, move them to
virtio/vhost.c

Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Link: https://lore.kernel.org/r/20230606130426.978945-3-jean-philippe@linaro.org
Signed-off-by: Will Deacon <will@kernel.org>

5 files changed, 38 insertions, 76 deletions

diff --git a/include/kvm/virtio.h b/include/kvm/virtio.h
index 4cc2e3d2..daea8554 100644
--- a/include/kvm/virtio.h
+++ b/include/kvm/virtio.h
@@ -259,6 +259,8 @@ void virtio_set_guest_features(struct kvm *kvm, struct virtio_device *vdev,
 void virtio_notify_status(struct kvm *kvm, struct virtio_device *vdev,
 			  void *dev, u8 status);
 void virtio_vhost_init(struct kvm *kvm, int vhost_fd);
+void virtio_vhost_set_vring(struct kvm *kvm, int vhost_fd, u32 index,
+			    struct virt_queue *queue);
 
 int virtio_transport_parser(const struct option *opt, const char *arg, int unset);
 
diff --git a/virtio/net.c b/virtio/net.c
index 65fdbd17..b7c64a08 100644
--- a/virtio/net.c
+++ b/virtio/net.c
@@ -600,10 +600,8 @@ static bool is_ctrl_vq(struct net_dev *ndev, u32 vq)
 
 static int init_vq(struct kvm *kvm, void *dev, u32 vq)
 {
-	struct vhost_vring_state state = { .index = vq };
 	struct vhost_vring_file file = { .index = vq };
 	struct net_dev_queue *net_queue;
-	struct vhost_vring_addr addr;
 	struct net_dev *ndev = dev;
 	struct virt_queue *queue;
 	int r;
@@ -634,28 +632,7 @@ static int init_vq(struct kvm *kvm, void *dev, u32 vq)
 		return 0;
 	}
 
-	if (queue->endian != VIRTIO_ENDIAN_HOST)
-		die_perror("VHOST requires the same endianness in guest and host");
-
-	state.num = queue->vring.num;
-	r = ioctl(ndev->vhost_fd, VHOST_SET_VRING_NUM, &state);
-	if (r < 0)
-		die_perror("VHOST_SET_VRING_NUM failed");
-	state.num = 0;
-	r = ioctl(ndev->vhost_fd, VHOST_SET_VRING_BASE, &state);
-	if (r < 0)
-		die_perror("VHOST_SET_VRING_BASE failed");
-
-	addr = (struct vhost_vring_addr) {
-		.index = vq,
-		.desc_user_addr = (u64)(unsigned long)queue->vring.desc,
-		.avail_user_addr = (u64)(unsigned long)queue->vring.avail,
-		.used_user_addr = (u64)(unsigned long)queue->vring.used,
-	};
-
-	r = ioctl(ndev->vhost_fd, VHOST_SET_VRING_ADDR, &addr);
-	if (r < 0)
-		die_perror("VHOST_SET_VRING_ADDR failed");
+	virtio_vhost_set_vring(kvm, ndev->vhost_fd, vq, queue);
 
 	file.fd = ndev->tap_fd;
 	r = ioctl(ndev->vhost_fd, VHOST_NET_SET_BACKEND, &file);
diff --git a/virtio/scsi.c b/virtio/scsi.c
index 621a8334..6aa0909f 100644
--- a/virtio/scsi.c
+++ b/virtio/scsi.c
@@ -72,11 +72,8 @@ static void notify_status(struct kvm *kvm, void *dev, u32 status)
 
 static int init_vq(struct kvm *kvm, void *dev, u32 vq)
 {
-	struct vhost_vring_state state = { .index = vq };
-	struct vhost_vring_addr addr;
 	struct scsi_dev *sdev = dev;
 	struct virt_queue *queue;
-	int r;
 
 	compat__remove_message(compat_id);
 
@@ -87,26 +84,7 @@ static int init_vq(struct kvm *kvm, void *dev, u32 vq)
 	if (sdev->vhost_fd == 0)
 		return 0;
 
-	state.num = queue->vring.num;
-	r = ioctl(sdev->vhost_fd, VHOST_SET_VRING_NUM, &state);
-	if (r < 0)
-		die_perror("VHOST_SET_VRING_NUM failed");
-	state.num = 0;
-	r = ioctl(sdev->vhost_fd, VHOST_SET_VRING_BASE, &state);
-	if (r < 0)
-		die_perror("VHOST_SET_VRING_BASE failed");
-
-	addr = (struct vhost_vring_addr) {
-		.index = vq,
-		.desc_user_addr = (u64)(unsigned long)queue->vring.desc,
-		.avail_user_addr = (u64)(unsigned long)queue->vring.avail,
-		.used_user_addr = (u64)(unsigned long)queue->vring.used,
-	};
-
-	r = ioctl(sdev->vhost_fd, VHOST_SET_VRING_ADDR, &addr);
-	if (r < 0)
-		die_perror("VHOST_SET_VRING_ADDR failed");
-
+	virtio_vhost_set_vring(kvm, sdev->vhost_fd, vq, queue);
 	return 0;
 }
 
diff --git a/virtio/vhost.c b/virtio/vhost.c
index f9f72f51..afe37465 100644
--- a/virtio/vhost.c
+++ b/virtio/vhost.c
@@ -1,7 +1,8 @@
+#include "kvm/virtio.h"
+
 #include <linux/kvm.h>
 #include <linux/vhost.h>
 #include <linux/list.h>
-#include "kvm/virtio.h"
 
 void virtio_vhost_init(struct kvm *kvm, int vhost_fd)
 {
@@ -34,3 +35,33 @@ void virtio_vhost_init(struct kvm *kvm, int vhost_fd)
 
 	free(mem);
 }
+
+void virtio_vhost_set_vring(struct kvm *kvm, int vhost_fd, u32 index,
+			    struct virt_queue *queue)
+{
+	int r;
+	struct vhost_vring_addr addr = {
+		.index = index,
+		.desc_user_addr = (u64)(unsigned long)queue->vring.desc,
+		.avail_user_addr = (u64)(unsigned long)queue->vring.avail,
+		.used_user_addr = (u64)(unsigned long)queue->vring.used,
+	};
+	struct vhost_vring_state state = { .index = index };
+
+	if (queue->endian != VIRTIO_ENDIAN_HOST)
+		die("VHOST requires the same endianness in guest and host");
+
+	state.num = queue->vring.num;
+	r = ioctl(vhost_fd, VHOST_SET_VRING_NUM, &state);
+	if (r < 0)
+		die_perror("VHOST_SET_VRING_NUM failed");
+
+	state.num = 0;
+	r = ioctl(vhost_fd, VHOST_SET_VRING_BASE, &state);
+	if (r < 0)
+		die_perror("VHOST_SET_VRING_BASE failed");
+
+	r = ioctl(vhost_fd, VHOST_SET_VRING_ADDR, &addr);
+	if (r < 0)
+		die_perror("VHOST_SET_VRING_ADDR failed");
+}
diff --git a/virtio/vsock.c b/virtio/vsock.c
index 4b8be8d7..2f7906f2 100644
--- a/virtio/vsock.c
+++ b/virtio/vsock.c
@@ -62,44 +62,18 @@ static bool is_event_vq(u32 vq)
 
 static int init_vq(struct kvm *kvm, void *dev, u32 vq)
 {
-	struct vhost_vring_state state = { .index = vq };
-	struct vhost_vring_addr addr;
 	struct vsock_dev *vdev = dev;
 	struct virt_queue *queue;
-	int r;
 
 	compat__remove_message(compat_id);
 
 	queue		= &vdev->vqs[vq];
 	virtio_init_device_vq(kvm, &vdev->vdev, queue, VIRTIO_VSOCK_QUEUE_SIZE);
 
-	if (vdev->vhost_fd == -1)
+	if (vdev->vhost_fd == -1 || is_event_vq(vq))
 		return 0;
 
-	if (is_event_vq(vq))
-		return 0;
-
-	state.num = queue->vring.num;
-	r = ioctl(vdev->vhost_fd, VHOST_SET_VRING_NUM, &state);
-	if (r < 0)
-		die_perror("VHOST_SET_VRING_NUM failed");
-
-	state.num = 0;
-	r = ioctl(vdev->vhost_fd, VHOST_SET_VRING_BASE, &state);
-	if (r < 0)
-		die_perror("VHOST_SET_VRING_BASE failed");
-
-	addr = (struct vhost_vring_addr) {
-		.index = vq,
-		.desc_user_addr = (u64)(unsigned long)queue->vring.desc,
-		.avail_user_addr = (u64)(unsigned long)queue->vring.avail,
-		.used_user_addr = (u64)(unsigned long)queue->vring.used,
-	};
-
-	r = ioctl(vdev->vhost_fd, VHOST_SET_VRING_ADDR, &addr);
-	if (r < 0)
-		die_perror("VHOST_SET_VRING_ADDR failed");
-
+	virtio_vhost_set_vring(kvm, vdev->vhost_fd, vq, queue);
 	return 0;
 }