This patch introduces the new memory accessor for vringh. It is able to
use vringh to virtio rings located on iomemory region.
Signed-off-by: Shunsuke Mie <mie@xxxxxxxxxx>
---
drivers/vhost/Kconfig | 6 ++++
drivers/vhost/vringh.c | 76 ++++++++++++++++++++++++++++++++++++++++++
include/linux/vringh.h | 8 +++++
3 files changed, 90 insertions(+)
diff --git a/drivers/vhost/Kconfig b/drivers/vhost/Kconfig
index 587fbae06182..a79a4efbc817 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_IOMEM
+ tristate
+ select VHOST_RING
+ help
+ Generic IOMEM implementation for vhost and vringh.
+
config VHOST_RING
tristate
select VHOST_IOTLB
diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c
index 46fb315483ed..e3d9c7281ad0 100644
--- a/drivers/vhost/vringh.c
+++ b/drivers/vhost/vringh.c
@@ -18,6 +18,9 @@
#include <linux/highmem.h>
#include <linux/vhost_iotlb.h>
#endif
+#if IS_REACHABLE(CONFIG_VHOST_IOMEM)
+#include <linux/io.h>
+#endif
#include <uapi/linux/virtio_config.h>
static __printf(1,2) __cold void vringh_bad(const char *fmt, ...)
@@ -1165,4 +1168,77 @@ EXPORT_SYMBOL(vringh_set_iotlb);
#endif
+#if IS_REACHABLE(CONFIG_VHOST_IOMEM)
+
+/* io-memory space access helpers. */
+static int getu16_iomem(const struct vringh *vrh, u16 *val, const __virtio16 *p)
+{
+ *val = vringh16_to_cpu(vrh, ioread16(p));
+ return 0;
+}
+
+static int putu16_iomem(const struct vringh *vrh, __virtio16 *p, u16 val)
+{
+ iowrite16(cpu_to_vringh16(vrh, val), p);
+ return 0;
+}
+
+static 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 int xfer_from_iomem(const struct vringh *vrh, void *src, void *dst,
+ size_t len)
+{
+ memcpy_fromio(dst, src, len);
+ return 0;
+}
+
+static int xfer_to_iomem(const struct vringh *vrh, void *dst, void *src,
+ size_t len)
+{
+ memcpy_toio(dst, src, len);
+ return 0;
+}
+
+static struct vringh_ops iomem_vringh_ops = {
+ .getu16 = getu16_iomem,
+ .putu16 = putu16_iomem,
+ .xfer_from = xfer_from_iomem,
+ .xfer_to = xfer_to_iomem,
+ .putused = putused_iomem,
+ .copydesc = copydesc_iomem,
+ .range_check = no_range_check,
+ .getrange = NULL,
+};
+
+int vringh_init_iomem(struct vringh *vrh, u64 features, unsigned int num,
+ bool weak_barriers, gfp_t gfp, struct vring_desc *desc,
+ struct vring_avail *avail, struct vring_used *used)
+{
+ int err;
+
+ err = __vringh_init(vrh, features, num, weak_barriers, gfp, desc, avail,
+ used);
+ if (err)
+ return err;
+
+ memcpy(&vrh->ops, &iomem_vringh_ops, sizeof(iomem_vringh_ops));
+
+ return 0;
+}
+EXPORT_SYMBOL(vringh_init_iomem);
+
+#endif
+
MODULE_LICENSE("GPL");
diff --git a/include/linux/vringh.h b/include/linux/vringh.h
index 89c73605c85f..420c2d0ed398 100644
--- a/include/linux/vringh.h
+++ b/include/linux/vringh.h
@@ -265,4 +265,12 @@ int vringh_init_iotlb(struct vringh *vrh, u64 features,
#endif /* CONFIG_VHOST_IOTLB */
+#if IS_REACHABLE(CONFIG_VHOST_IOMEM)
+
+int vringh_init_iomem(struct vringh *vrh, u64 features, unsigned int num,
+ bool weak_barriers, gfp_t gfp, struct vring_desc *desc,
+ struct vring_avail *avail, struct vring_used *used);
+
+#endif /* CONFIG_VHOST_IOMEM */
+
#endif /* _LINUX_VRINGH_H */
--
2.25.1
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