[PATCH v3 26/38] virtio_config: LE config space accessors

Michael S. Tsirkin
2020-08-05T19:28:34Z

To be used by modern code, as well as to handle LE only fields such as
balloon.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
include/linux/virtio_config.h | 65 +++++++++++++++++++++++++++++++++++
1 file changed, 65 insertions(+)

diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index 441fd6dd42ab..5b5196fec899 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -375,6 +375,71 @@ static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val)
sizeof(virtio_cwrite_v)); \
} while(0)

+/*
+ * Nothing virtio-specific about these, but let's worry about generalizing
+ * these later.
+ */
+#define virtio_le_to_cpu(x) \
+ _Generic((x), \
+ __u8: (x), \
+ __le16: le16_to_cpu(x), \
+ __le32: le32_to_cpu(x), \
+ __le64: le64_to_cpu(x) \
+ )
+
+#define virtio_cpu_to_le(x, m) \
+ _Generic((m), \
+ __u8: (x), \
+ __le16: cpu_to_le16(x), \
+ __le32: cpu_to_le32(x), \
+ __le64: cpu_to_le64(x) \
+ )
+
+/* LE (e.g. modern) Config space accessors. */
+#define virtio_cread_le(vdev, structname, member, ptr) \
+ do { \
+ typeof(((structname*)0)->member) virtio_cread_v; \
+ \
+ might_sleep(); \
+ /* Sanity check: must match the member's type */ \
+ typecheck(typeof(virtio_le_to_cpu(virtio_cread_v)), *(ptr)); \
+ \
+ switch (sizeof(virtio_cread_v)) { \
+ case 1: \
+ case 2: \
+ case 4: \
+ vdev->config->get((vdev), \
+ offsetof(structname, member), \
+ &virtio_cread_v, \
+ sizeof(virtio_cread_v)); \
+ break; \
+ default: \
+ __virtio_cread_many((vdev), \
+ offsetof(structname, member), \
+ &virtio_cread_v, \
+ 1, \
+ sizeof(virtio_cread_v)); \
+ break; \
+ } \
+ *(ptr) = virtio_le_to_cpu(virtio_cread_v); \
+ } while(0)
+
+/* Config space accessors. */
+#define virtio_cwrite_le(vdev, structname, member, ptr) \
+ do { \
+ typeof(((structname*)0)->member) virtio_cwrite_v = \
+ virtio_cpu_to_le(*(ptr), ((structname*)0)->member); \
+ \
+ might_sleep(); \
+ /* Sanity check: must match the member's type */ \
+ typecheck(typeof(virtio_le_to_cpu(virtio_cwrite_v)), *(ptr)); \
+ \
+ vdev->config->set((vdev), offsetof(structname, member), \
+ &virtio_cwrite_v, \
+ sizeof(virtio_cwrite_v)); \
+ } while(0)
+
+
/* Read @count fields, @bytes each. */
static inline void __virtio_cread_many(struct virtio_device *vdev,
unsigned int offset,
--
MST