v4.19.13 snapshot.
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
new file mode 100644
index 0000000..32baf8e
--- /dev/null
+++ b/include/linux/virtio_config.h
@@ -0,0 +1,444 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_VIRTIO_CONFIG_H
+#define _LINUX_VIRTIO_CONFIG_H
+
+#include <linux/err.h>
+#include <linux/bug.h>
+#include <linux/virtio.h>
+#include <linux/virtio_byteorder.h>
+#include <uapi/linux/virtio_config.h>
+
+struct irq_affinity;
+
+/**
+ * virtio_config_ops - operations for configuring a virtio device
+ * @get: read the value of a configuration field
+ * vdev: the virtio_device
+ * offset: the offset of the configuration field
+ * buf: the buffer to write the field value into.
+ * len: the length of the buffer
+ * @set: write the value of a configuration field
+ * vdev: the virtio_device
+ * offset: the offset of the configuration field
+ * buf: the buffer to read the field value from.
+ * len: the length of the buffer
+ * @generation: config generation counter
+ * vdev: the virtio_device
+ * Returns the config generation counter
+ * @get_status: read the status byte
+ * vdev: the virtio_device
+ * Returns the status byte
+ * @set_status: write the status byte
+ * vdev: the virtio_device
+ * status: the new status byte
+ * @reset: reset the device
+ * vdev: the virtio device
+ * After this, status and feature negotiation must be done again
+ * Device must not be reset from its vq/config callbacks, or in
+ * parallel with being added/removed.
+ * @find_vqs: find virtqueues and instantiate them.
+ * vdev: the virtio_device
+ * nvqs: the number of virtqueues to find
+ * vqs: on success, includes new virtqueues
+ * callbacks: array of callbacks, for each virtqueue
+ * include a NULL entry for vqs that do not need a callback
+ * names: array of virtqueue names (mainly for debugging)
+ * include a NULL entry for vqs unused by driver
+ * Returns 0 on success or error status
+ * @del_vqs: free virtqueues found by find_vqs().
+ * @get_features: get the array of feature bits for this device.
+ * vdev: the virtio_device
+ * Returns the first 32 feature bits (all we currently need).
+ * @finalize_features: confirm what device features we'll be using.
+ * vdev: the virtio_device
+ * This gives the final feature bits for the device: it can change
+ * the dev->feature bits if it wants.
+ * Returns 0 on success or error status
+ * @bus_name: return the bus name associated with the device
+ * vdev: the virtio_device
+ * This returns a pointer to the bus name a la pci_name from which
+ * the caller can then copy.
+ * @set_vq_affinity: set the affinity for a virtqueue.
+ * @get_vq_affinity: get the affinity for a virtqueue (optional).
+ */
+typedef void vq_callback_t(struct virtqueue *);
+struct virtio_config_ops {
+ void (*get)(struct virtio_device *vdev, unsigned offset,
+ void *buf, unsigned len);
+ void (*set)(struct virtio_device *vdev, unsigned offset,
+ const void *buf, unsigned len);
+ u32 (*generation)(struct virtio_device *vdev);
+ u8 (*get_status)(struct virtio_device *vdev);
+ void (*set_status)(struct virtio_device *vdev, u8 status);
+ void (*reset)(struct virtio_device *vdev);
+ int (*find_vqs)(struct virtio_device *, unsigned nvqs,
+ struct virtqueue *vqs[], vq_callback_t *callbacks[],
+ const char * const names[], const bool *ctx,
+ struct irq_affinity *desc);
+ void (*del_vqs)(struct virtio_device *);
+ u64 (*get_features)(struct virtio_device *vdev);
+ int (*finalize_features)(struct virtio_device *vdev);
+ const char *(*bus_name)(struct virtio_device *vdev);
+ int (*set_vq_affinity)(struct virtqueue *vq,
+ const struct cpumask *cpu_mask);
+ const struct cpumask *(*get_vq_affinity)(struct virtio_device *vdev,
+ int index);
+};
+
+/* If driver didn't advertise the feature, it will never appear. */
+void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
+ unsigned int fbit);
+
+/**
+ * __virtio_test_bit - helper to test feature bits. For use by transports.
+ * Devices should normally use virtio_has_feature,
+ * which includes more checks.
+ * @vdev: the device
+ * @fbit: the feature bit
+ */
+static inline bool __virtio_test_bit(const struct virtio_device *vdev,
+ unsigned int fbit)
+{
+ /* Did you forget to fix assumptions on max features? */
+ if (__builtin_constant_p(fbit))
+ BUILD_BUG_ON(fbit >= 64);
+ else
+ BUG_ON(fbit >= 64);
+
+ return vdev->features & BIT_ULL(fbit);
+}
+
+/**
+ * __virtio_set_bit - helper to set feature bits. For use by transports.
+ * @vdev: the device
+ * @fbit: the feature bit
+ */
+static inline void __virtio_set_bit(struct virtio_device *vdev,
+ unsigned int fbit)
+{
+ /* Did you forget to fix assumptions on max features? */
+ if (__builtin_constant_p(fbit))
+ BUILD_BUG_ON(fbit >= 64);
+ else
+ BUG_ON(fbit >= 64);
+
+ vdev->features |= BIT_ULL(fbit);
+}
+
+/**
+ * __virtio_clear_bit - helper to clear feature bits. For use by transports.
+ * @vdev: the device
+ * @fbit: the feature bit
+ */
+static inline void __virtio_clear_bit(struct virtio_device *vdev,
+ unsigned int fbit)
+{
+ /* Did you forget to fix assumptions on max features? */
+ if (__builtin_constant_p(fbit))
+ BUILD_BUG_ON(fbit >= 64);
+ else
+ BUG_ON(fbit >= 64);
+
+ vdev->features &= ~BIT_ULL(fbit);
+}
+
+/**
+ * virtio_has_feature - helper to determine if this device has this feature.
+ * @vdev: the device
+ * @fbit: the feature bit
+ */
+static inline bool virtio_has_feature(const struct virtio_device *vdev,
+ unsigned int fbit)
+{
+ if (fbit < VIRTIO_TRANSPORT_F_START)
+ virtio_check_driver_offered_feature(vdev, fbit);
+
+ return __virtio_test_bit(vdev, fbit);
+}
+
+/**
+ * virtio_has_iommu_quirk - determine whether this device has the iommu quirk
+ * @vdev: the device
+ */
+static inline bool virtio_has_iommu_quirk(const struct virtio_device *vdev)
+{
+ /*
+ * Note the reverse polarity of the quirk feature (compared to most
+ * other features), this is for compatibility with legacy systems.
+ */
+ return !virtio_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM);
+}
+
+static inline
+struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
+ vq_callback_t *c, const char *n)
+{
+ vq_callback_t *callbacks[] = { c };
+ const char *names[] = { n };
+ struct virtqueue *vq;
+ int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names, NULL,
+ NULL);
+ if (err < 0)
+ return ERR_PTR(err);
+ return vq;
+}
+
+static inline
+int virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs,
+ struct virtqueue *vqs[], vq_callback_t *callbacks[],
+ const char * const names[],
+ struct irq_affinity *desc)
+{
+ return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, NULL, desc);
+}
+
+static inline
+int virtio_find_vqs_ctx(struct virtio_device *vdev, unsigned nvqs,
+ struct virtqueue *vqs[], vq_callback_t *callbacks[],
+ const char * const names[], const bool *ctx,
+ struct irq_affinity *desc)
+{
+ return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, ctx,
+ desc);
+}
+
+/**
+ * virtio_device_ready - enable vq use in probe function
+ * @vdev: the device
+ *
+ * Driver must call this to use vqs in the probe function.
+ *
+ * Note: vqs are enabled automatically after probe returns.
+ */
+static inline
+void virtio_device_ready(struct virtio_device *dev)
+{
+ unsigned status = dev->config->get_status(dev);
+
+ BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK);
+ dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK);
+}
+
+static inline
+const char *virtio_bus_name(struct virtio_device *vdev)
+{
+ if (!vdev->config->bus_name)
+ return "virtio";
+ return vdev->config->bus_name(vdev);
+}
+
+/**
+ * virtqueue_set_affinity - setting affinity for a virtqueue
+ * @vq: the virtqueue
+ * @cpu: the cpu no.
+ *
+ * Pay attention the function are best-effort: the affinity hint may not be set
+ * due to config support, irq type and sharing.
+ *
+ */
+static inline
+int virtqueue_set_affinity(struct virtqueue *vq, const struct cpumask *cpu_mask)
+{
+ struct virtio_device *vdev = vq->vdev;
+ if (vdev->config->set_vq_affinity)
+ return vdev->config->set_vq_affinity(vq, cpu_mask);
+ return 0;
+}
+
+static inline bool virtio_is_little_endian(struct virtio_device *vdev)
+{
+ return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) ||
+ virtio_legacy_is_little_endian();
+}
+
+/* Memory accessors */
+static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val)
+{
+ return __virtio16_to_cpu(virtio_is_little_endian(vdev), val);
+}
+
+static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val)
+{
+ return __cpu_to_virtio16(virtio_is_little_endian(vdev), val);
+}
+
+static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val)
+{
+ return __virtio32_to_cpu(virtio_is_little_endian(vdev), val);
+}
+
+static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val)
+{
+ return __cpu_to_virtio32(virtio_is_little_endian(vdev), val);
+}
+
+static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val)
+{
+ return __virtio64_to_cpu(virtio_is_little_endian(vdev), val);
+}
+
+static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val)
+{
+ return __cpu_to_virtio64(virtio_is_little_endian(vdev), val);
+}
+
+/* Config space accessors. */
+#define virtio_cread(vdev, structname, member, ptr) \
+ do { \
+ /* Must match the member's type, and be integer */ \
+ if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
+ (*ptr) = 1; \
+ \
+ switch (sizeof(*ptr)) { \
+ case 1: \
+ *(ptr) = virtio_cread8(vdev, \
+ offsetof(structname, member)); \
+ break; \
+ case 2: \
+ *(ptr) = virtio_cread16(vdev, \
+ offsetof(structname, member)); \
+ break; \
+ case 4: \
+ *(ptr) = virtio_cread32(vdev, \
+ offsetof(structname, member)); \
+ break; \
+ case 8: \
+ *(ptr) = virtio_cread64(vdev, \
+ offsetof(structname, member)); \
+ break; \
+ default: \
+ BUG(); \
+ } \
+ } while(0)
+
+/* Config space accessors. */
+#define virtio_cwrite(vdev, structname, member, ptr) \
+ do { \
+ /* Must match the member's type, and be integer */ \
+ if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
+ BUG_ON((*ptr) == 1); \
+ \
+ switch (sizeof(*ptr)) { \
+ case 1: \
+ virtio_cwrite8(vdev, \
+ offsetof(structname, member), \
+ *(ptr)); \
+ break; \
+ case 2: \
+ virtio_cwrite16(vdev, \
+ offsetof(structname, member), \
+ *(ptr)); \
+ break; \
+ case 4: \
+ virtio_cwrite32(vdev, \
+ offsetof(structname, member), \
+ *(ptr)); \
+ break; \
+ case 8: \
+ virtio_cwrite64(vdev, \
+ offsetof(structname, member), \
+ *(ptr)); \
+ break; \
+ default: \
+ BUG(); \
+ } \
+ } while(0)
+
+/* Read @count fields, @bytes each. */
+static inline void __virtio_cread_many(struct virtio_device *vdev,
+ unsigned int offset,
+ void *buf, size_t count, size_t bytes)
+{
+ u32 old, gen = vdev->config->generation ?
+ vdev->config->generation(vdev) : 0;
+ int i;
+
+ do {
+ old = gen;
+
+ for (i = 0; i < count; i++)
+ vdev->config->get(vdev, offset + bytes * i,
+ buf + i * bytes, bytes);
+
+ gen = vdev->config->generation ?
+ vdev->config->generation(vdev) : 0;
+ } while (gen != old);
+}
+
+static inline void virtio_cread_bytes(struct virtio_device *vdev,
+ unsigned int offset,
+ void *buf, size_t len)
+{
+ __virtio_cread_many(vdev, offset, buf, len, 1);
+}
+
+static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset)
+{
+ u8 ret;
+ vdev->config->get(vdev, offset, &ret, sizeof(ret));
+ return ret;
+}
+
+static inline void virtio_cwrite8(struct virtio_device *vdev,
+ unsigned int offset, u8 val)
+{
+ vdev->config->set(vdev, offset, &val, sizeof(val));
+}
+
+static inline u16 virtio_cread16(struct virtio_device *vdev,
+ unsigned int offset)
+{
+ u16 ret;
+ vdev->config->get(vdev, offset, &ret, sizeof(ret));
+ return virtio16_to_cpu(vdev, (__force __virtio16)ret);
+}
+
+static inline void virtio_cwrite16(struct virtio_device *vdev,
+ unsigned int offset, u16 val)
+{
+ val = (__force u16)cpu_to_virtio16(vdev, val);
+ vdev->config->set(vdev, offset, &val, sizeof(val));
+}
+
+static inline u32 virtio_cread32(struct virtio_device *vdev,
+ unsigned int offset)
+{
+ u32 ret;
+ vdev->config->get(vdev, offset, &ret, sizeof(ret));
+ return virtio32_to_cpu(vdev, (__force __virtio32)ret);
+}
+
+static inline void virtio_cwrite32(struct virtio_device *vdev,
+ unsigned int offset, u32 val)
+{
+ val = (__force u32)cpu_to_virtio32(vdev, val);
+ vdev->config->set(vdev, offset, &val, sizeof(val));
+}
+
+static inline u64 virtio_cread64(struct virtio_device *vdev,
+ unsigned int offset)
+{
+ u64 ret;
+ __virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret));
+ return virtio64_to_cpu(vdev, (__force __virtio64)ret);
+}
+
+static inline void virtio_cwrite64(struct virtio_device *vdev,
+ unsigned int offset, u64 val)
+{
+ val = (__force u64)cpu_to_virtio64(vdev, val);
+ vdev->config->set(vdev, offset, &val, sizeof(val));
+}
+
+/* Conditional config space accessors. */
+#define virtio_cread_feature(vdev, fbit, structname, member, ptr) \
+ ({ \
+ int _r = 0; \
+ if (!virtio_has_feature(vdev, fbit)) \
+ _r = -ENOENT; \
+ else \
+ virtio_cread((vdev), structname, member, ptr); \
+ _r; \
+ })
+
+#endif /* _LINUX_VIRTIO_CONFIG_H */