[PATCH 1/7] virtio_pci_modern: introduce helper to map vq notify area

Jason Wang
2021-04-15T07:32:14Z

This patch factors out the logic of vq notify area mapping. Following
patches will switch to use this common helpers for both virtio_pci
library and virtio-pci vDPA driver.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/virtio/virtio_pci_modern_dev.c | 35 ++++++++++++++++++++++++++
include/linux/virtio_pci_modern.h | 2 ++
2 files changed, 37 insertions(+)

diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c
index cbd667496bb1..28cb5847fafa 100644
--- a/drivers/virtio/virtio_pci_modern_dev.c
+++ b/drivers/virtio/virtio_pci_modern_dev.c
@@ -593,6 +593,41 @@ u16 vp_modern_get_queue_notify_off(struct virtio_pci_modern_device *mdev,
}
EXPORT_SYMBOL_GPL(vp_modern_get_queue_notify_off);

+/*
+ * vp_modern_map_vq_notify - map notification area for a
+ * specific virtqueue
+ * @mdev: the modern virtio-pci device
+ * @index: the queue index
+ *
+ * Returns the address of the notification area
+ */
+void *vp_modern_map_vq_notify(struct virtio_pci_modern_device *mdev,
+ u16 index)
+{
+ u16 off = vp_modern_get_queue_notify_off(mdev, index);
+
+ if (mdev->notify_base) {
+ /* offset should not wrap */
+ if ((u64)off * mdev->notify_offset_multiplier + 2
+ > mdev->notify_len) {
+ dev_warn(&mdev->pci_dev->dev,
+ "bad notification offset %u (x %u) "
+ "for queue %u > %zd",
+ off, mdev->notify_offset_multiplier,
+ index, mdev->notify_len);
+ return NULL;
+ }
+ return (void __force *)mdev->notify_base +
+ off * mdev->notify_offset_multiplier;
+ } else {
+ return (void __force *)vp_modern_map_capability(mdev,
+ mdev->notify_map_cap, 2, 2,
+ off * mdev->notify_offset_multiplier, 2,
+ NULL);
+ }
+}
+EXPORT_SYMBOL_GPL(vp_modern_map_vq_notify);
+
MODULE_VERSION("0.1");
MODULE_DESCRIPTION("Modern Virtio PCI Device");
MODULE_AUTHOR("Jason Wang <jasowang@redhat.com>");
diff --git a/include/linux/virtio_pci_modern.h b/include/linux/virtio_pci_modern.h
index f26acbeec965..1b95d39b00fc 100644
--- a/include/linux/virtio_pci_modern.h
+++ b/include/linux/virtio_pci_modern.h
@@ -106,6 +106,8 @@ void __iomem *vp_modern_map_capability(struct virtio_pci_modern_device *mdev, in
u32 align,
u32 start, u32 size,
size_t *len);
+void *vp_modern_map_vq_notify(struct virtio_pci_modern_device *mdev,
+ u16 index);
int vp_modern_probe(struct virtio_pci_modern_device *mdev);
void vp_modern_remove(struct virtio_pci_modern_device *mdev);
#endif
--
2.18.1