[PATCH v2 14/30] virtio: Add get_shm_region method

Vivek Goyal
2019-05-15T19:31:19Z

From: Sebastien Boeuf <sebastien.boeuf@intel.com>

Virtio defines 'shared memory regions' that provide a continuously
shared region between the host and guest.

Provide a method to find a particular region on a device.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
include/linux/virtio_config.h | 17 +++++++++++++++++
1 file changed, 17 insertions(+)

diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index bb4cc4910750..c859f000a751 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -10,6 +10,11 @@

struct irq_affinity;

+struct virtio_shm_region {
+ u64 addr;
+ u64 len;
+};
+
/**
* virtio_config_ops - operations for configuring a virtio device
* Note: Do not assume that a transport implements all of the operations
@@ -65,6 +70,7 @@ struct irq_affinity;
* the caller can then copy.
* @set_vq_affinity: set the affinity for a virtqueue (optional).
* @get_vq_affinity: get the affinity for a virtqueue (optional).
+ * @get_shm_region: get a shared memory region based on the index.
*/
typedef void vq_callback_t(struct virtqueue *);
struct virtio_config_ops {
@@ -88,6 +94,8 @@ struct virtio_config_ops {
const struct cpumask *cpu_mask);
const struct cpumask *(*get_vq_affinity)(struct virtio_device *vdev,
int index);
+ bool (*get_shm_region)(struct virtio_device *vdev,
+ struct virtio_shm_region *region, u8 id);
};

/* If driver didn't advertise the feature, it will never appear. */
@@ -250,6 +258,15 @@ int virtqueue_set_affinity(struct virtqueue *vq, const struct cpumask *cpu_mask)
return 0;
}

+static inline
+bool virtio_get_shm_region(struct virtio_device *vdev,
+ struct virtio_shm_region *region, u8 id)
+{
+ if (!vdev->config->get_shm_region)
+ return false;
+ return vdev->config->get_shm_region(vdev, region, id);
+}
+
static inline bool virtio_is_little_endian(struct virtio_device *vdev)
{
return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) ||
--
2.20.1