[PATCH v3] vringh: IOMEM support
From: Shunsuke Mie
Date: Tue Apr 25 2023 - 06:23:07 EST
Introduce a new memory accessor for vringh. It is able to use vringh to
virtio rings located on io-memory region.
Signed-off-by: Shunsuke Mie <mie@xxxxxxxxxx>
---
Changes from v2: https://lore.kernel.org/virtualization/20230202090934.549556-1-mie@xxxxxxxxxx/
- Focus on an adding io memory APIs
Remove vringh API unification and some fixes.
- Rebase on next-20230414
drivers/vhost/Kconfig | 6 ++
drivers/vhost/vringh.c | 129 +++++++++++++++++++++++++++++++++++++++++
include/linux/vringh.h | 33 +++++++++++
3 files changed, 168 insertions(+)
diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig
index b455d9ab6f3d..4b0dbb4a8ab3 100644
--- a/drivers/vhost/Kconfig
+++ b/drivers/vhost/Kconfig
@@ -6,6 +6,12 @@ config VHOST_IOTLB
This option is selected by any driver which needs to support
an IOMMU in software.
+config VHOST_RING_IOMEM
+ tristate
+ select VHOST_IOMEM
+ help
+ This option enables vringh APIs to supports io memory space.
+
config VHOST_RING
tristate
select VHOST_IOTLB
diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
index 955d938eb663..ce5a88eecc05 100644
--- a/drivers/vhost/vringh.c
+++ b/drivers/vhost/vringh.c
@@ -1604,4 +1604,133 @@ EXPORT_SYMBOL(vringh_need_notify_iotlb);
#endif
+#if IS_REACHABLE(CONFIG_VHOST_RING_IOMEM)
+
+static inline int getu16_iomem(const struct vringh *vrh, u16 *val,
+ const __virtio16 *p)
+{
+ *val = vringh16_to_cpu(vrh, ioread16(p));
+ return 0;
+}
+
+static inline int putu16_iomem(const struct vringh *vrh, __virtio16 *p, u16 val)
+{
+ iowrite16(cpu_to_vringh16(vrh, val), p);
+ return 0;
+}
+
+static inline int copydesc_iomem(const struct vringh *vrh, void *dst,
+ const void *src, size_t len)
+{
+ memcpy_fromio(dst, src, len);
+ return 0;
+}
+
+static int putused_iomem(const struct vringh *vrh, struct vring_used_elem *dst,
+ const struct vring_used_elem *src, unsigned int num)
+{
+ memcpy_toio(dst, src, num * sizeof(*dst));
+ return 0;
+}
+
+static inline int xfer_from_iomem(const struct vringh *vrh, void *src,
+ void *dst, size_t len)
+{
+ memcpy_fromio(dst, src, len);
+ return 0;
+}
+
+static inline int xfer_to_iomem(const struct vringh *vrh, void *dst, void *src,
+ size_t len)
+{
+ memcpy_toio(dst, src, len);
+ return 0;
+}
+
+int vringh_init_iomem(struct vringh *vrh, u64 features, unsigned int num,
+ bool weak_barriers, struct vring_desc *desc,
+ struct vring_avail *avail, struct vring_used *used)
+{
+ return vringh_init_kern(vrh, features, num, weak_barriers, desc, avail,
+ used);
+}
+EXPORT_SYMBOL(vringh_init_iomem);
+
+int vringh_getdesc_iomem(struct vringh *vrh, struct vringh_kiov *riov,
+ struct vringh_kiov *wiov, u16 *head, gfp_t gfp)
+{
+ int err;
+
+ err = __vringh_get_head(vrh, getu16_iomem, &vrh->last_avail_idx);
+ if (err < 0)
+ return err;
+
+ /* Empty... */
+ if (err == vrh->vring.num)
+ return 0;
+
+ *head = err;
+ err = __vringh_iov(vrh, *head, riov, wiov, no_range_check, NULL, gfp,
+ copydesc_iomem);
+ if (err)
+ return err;
+
+ return 1;
+}
+EXPORT_SYMBOL(vringh_getdesc_iomem);
+
+ssize_t vringh_iov_pull_iomem(struct vringh *vrh, struct vringh_kiov *riov,
+ void *dst, size_t len)
+{
+ return vringh_iov_xfer(vrh, riov, dst, len, xfer_from_iomem);
+}
+EXPORT_SYMBOL(vringh_iov_pull_iomem);
+
+ssize_t vringh_iov_push_iomem(struct vringh *vrh, struct vringh_kiov *wiov,
+ const void *src, size_t len)
+{
+ return vringh_iov_xfer(vrh, wiov, (void *)src, len, xfer_to_iomem);
+}
+EXPORT_SYMBOL(vringh_iov_push_iomem);
+
+void vringh_abandon_iomem(struct vringh *vrh, unsigned int num)
+{
+ /* We only update vring_avail_event(vr) when we want to be notified,
+ * so we haven't changed that yet.
+ */
+ vrh->last_avail_idx -= num;
+}
+EXPORT_SYMBOL(vringh_abandon_iomem);
+
+int vringh_complete_iomem(struct vringh *vrh, u16 head, u32 len)
+{
+ struct vring_used_elem used;
+
+ used.id = cpu_to_vringh32(vrh, head);
+ used.len = cpu_to_vringh32(vrh, len);
+
+ return __vringh_complete(vrh, &used, 1, putu16_iomem, putused_iomem);
+}
+EXPORT_SYMBOL(vringh_complete_iomem);
+
+bool vringh_notify_enable_iomem(struct vringh *vrh)
+{
+ return __vringh_notify_enable(vrh, getu16_iomem, putu16_iomem);
+}
+EXPORT_SYMBOL(vringh_notify_enable_iomem);
+
+void vringh_notify_disable_iomem(struct vringh *vrh)
+{
+ __vringh_notify_disable(vrh, putu16_iomem);
+}
+EXPORT_SYMBOL(vringh_notify_disable_iomem);
+
+int vringh_need_notify_iomem(struct vringh *vrh)
+{
+ return __vringh_need_notify(vrh, getu16_iomem);
+}
+EXPORT_SYMBOL(vringh_need_notify_iomem);
+
+#endif /* CONFIG_VHOST_RING_IOMEM */
+
MODULE_LICENSE("GPL");
diff --git a/include/linux/vringh.h b/include/linux/vringh.h
index c3a8117dabe8..c03d045f7f3f 100644
--- a/include/linux/vringh.h
+++ b/include/linux/vringh.h
@@ -330,4 +330,37 @@ int vringh_need_notify_iotlb(struct vringh *vrh);
#endif /* CONFIG_VHOST_IOTLB */
+#if IS_REACHABLE(CONFIG_VHOST_RING_IOMEM)
+
+int vringh_init_iomem(struct vringh *vrh, u64 features,
+ unsigned int num, bool weak_barriers,
+ struct vring_desc *desc,
+ struct vring_avail *avail,
+ struct vring_used *used);
+
+
+int vringh_getdesc_iomem(struct vringh *vrh,
+ struct vringh_kiov *riov,
+ struct vringh_kiov *wiov,
+ u16 *head,
+ gfp_t gfp);
+
+ssize_t vringh_iov_pull_iomem(struct vringh *vrh,
+ struct vringh_kiov *riov,
+ void *dst, size_t len);
+ssize_t vringh_iov_push_iomem(struct vringh *vrh,
+ struct vringh_kiov *wiov,
+ const void *src, size_t len);
+
+void vringh_abandon_iomem(struct vringh *vrh, unsigned int num);
+
+int vringh_complete_iomem(struct vringh *vrh, u16 head, u32 len);
+
+bool vringh_notify_enable_iomem(struct vringh *vrh);
+void vringh_notify_disable_iomem(struct vringh *vrh);
+
+int vringh_need_notify_iomem(struct vringh *vrh);
+
+#endif /* CONFIG_VHOST_RING_IOMEM */
+
#endif /* _LINUX_VRINGH_H */
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2.25.1