/* 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 <linux/compiler_types.h>
#include <uapi/linux/virtio_config.h>
struct irq_affinity;
struct virtio_shm_region {
u64 addr;
u64 len;
};
typedef void vq_callback_t(struct virtqueue *);
/**
* struct virtqueue_info - Info for a virtqueue passed to find_vqs().
* @name: virtqueue description. Used mainly for debugging, NULL for
* a virtqueue unused by the driver.
* @callback: A callback to invoke on a used buffer notification.
* NULL for a virtqueue that does not need a callback.
* @ctx: A flag to indicate to maintain an extra context per virtqueue.
*/
struct virtqueue_info {
const char *name;
vq_callback_t *callback;
bool ctx;
};
/**
* struct virtio_config_ops - operations for configuring a virtio device
* Note: Do not assume that a transport implements all of the operations
* getting/setting a value as a simple read/write! Generally speaking,
* any of @get/@set, @get_status/@set_status, or @get_features/
* @finalize_features are NOT safe to be called from an atomic
* context.
* @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 (optional)
* 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
* vqs_info: array of virtqueue info structures
* Returns 0 on success or error status
* @del_vqs: free virtqueues found by find_vqs().
* @synchronize_cbs: synchronize with the virtqueue callbacks (optional)
* The function guarantees that all memory operations on the
* queue before it are visible to the vring_interrupt() that is
* called after it.
* vdev: the virtio_device
* @get_features: get the array of feature bits for this device.
* vdev: the virtio_device
* Returns the first 64 feature bits (all we currently need).
* @finalize_features: confirm what device features we'll be using.
* vdev: the virtio_device
* This sends the driver feature bits to the device: it can change
* the dev->feature bits if it wants.
* Note that despite the name this can be called any number of
* times.
* Returns 0 on success or error status
* @bus_name: return the bus name associated with the device (optional)
* 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 (optional).
* @get_vq_affinity: get the affinity for a virtqueue (optional).
* @get_shm_region: get a shared memory region based on the index.
* @disable_vq_and_reset: reset a queue individually (optional).
* vq: the virtqueue
* Returns 0 on success or error status
* disable_vq_and_reset will guarantee that the callbacks are disabled and
* synchronized.
* Except for the callback, the caller should guarantee that the vring is
* not accessed by any functions of virtqueue.
* @enable_vq_after_reset: enable a reset queue
* vq: the virtqueue
* Returns 0 on success or error status
* If disable_vq_and_reset is set, then enable_vq_after_reset must also be
* set.
*/
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 *vdev, unsigned int nvqs,
struct virtqueue *vqs[],
struct virtqueue_info vqs_info[],
struct irq_affinity *desc);
void (*del_vqs)(struct virtio_device *);
void (*synchronize_cbs)(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);
bool (*get_shm_region)(struct virtio_device *vdev,
struct virtio_shm_region *region, u8 id);
int (*disable_vq_and_reset)(struct virtqueue *vq);
int (*enable_vq_after_reset)(struct virtqueue *vq);
};
/* 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_dma_quirk - determine whether this device has the DMA quirk
* @vdev: the device
*/
static inline bool virtio_has_dma_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_ACCESS_PLATFORM);
}
static inline
int virtio_find_vqs(struct virtio_device *vdev, unsigned int nvqs,
struct virtqueue *vqs[],
struct virtqueue_info vqs_info[],
struct irq_affinity *desc)
{
return vdev->config->find_vqs(vdev, nvqs, vqs, vqs_info, desc);
}
static inline
struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
vq_callback_t *c, const char *n)
{
struct virtqueue_info vqs_info[] = {
{ n, c },
};
struct virtqueue *vq;
int err = virtio_find_vqs(vdev, 1, &vq, vqs_info, NULL);
if (err < 0)
return ERR_PTR(err);
return vq;
}
/**
* virtio_synchronize_cbs - synchronize with virtqueue callbacks
* @dev: the virtio device
*/
static inline
void virtio_synchronize_cbs(struct virtio_device *dev)
{
if (dev->config->synchronize_cbs) {
dev->config->synchronize_cbs(dev);
} else {
/*
* A best effort fallback to synchronize with
* interrupts, preemption and softirq disabled
* regions. See comment above synchronize_rcu().
*/
synchronize_rcu();
}
}
/**
* virtio_device_ready - enable vq use in probe function
* @dev: the virtio 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);
WARN_ON(status & VIRTIO_CONFIG_S_DRIVER_OK);
#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION
/*
* The virtio_synchronize_cbs() makes sure vring_interrupt()
* will see the driver specific setup if it sees vq->broken
* as false (even if the notifications come before DRIVER_OK).
*/
virtio_synchronize_cbs(dev);
__virtio_unbreak_device(dev);
#endif
/*
* The transport should ensure the visibility of vq->broken
* before setting DRIVER_OK. See the comments for the transport
* specific set_status() method.
*
* A well behaved device will only notify a virtqueue after
* DRIVER_OK, this means the device should "see" the coherenct
* memory write that set vq->broken as false which is done by
* the driver when it sees DRIVER_OK, then the following
* driver's vring_interrupt() will see vq->broken as false so
* we won't lose any notification.
*/
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_mask: the cpu mask
*
* 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_get_shm_region(struct virtio_device *vdev,
struct virtio_shm_region *region, u8 id)
{
if (!vdev->config->get_shm_region)
return false;
return vdev->config->get_shm_region(vdev, region, id);
}
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);
}
#define virtio_to_cpu(vdev, x) \
_Generic((x), \
__u8: (x), \
__virtio16: virtio16_to_cpu((vdev), (x)), \
__virtio32: virtio32_to_cpu((vdev), (x)), \
__virtio64: virtio64_to_cpu((vdev), (x)) \
)
#define cpu_to_virtio(vdev, x, m) \
_Generic((m), \
__u8: (x), \
__virtio16: cpu_to_virtio16((vdev), (x)), \
__virtio32: cpu_to_virtio32((vdev), (x)), \
__virtio64: cpu_to_virtio64((vdev), (x)) \
)
#define __virtio_native_type(structname, member) \
typeof(virtio_to_cpu(NULL, ((structname*)0)->member))
/* Config space accessors. */
#define virtio_cread(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_to_cpu((vdev), 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_to_cpu(vdev, virtio_cread_v); \
} while(0)
/* Config space accessors. */
#define virtio_cwrite(vdev, structname, member, ptr) \
do { \
typeof(((structname*)0)->member) virtio_cwrite_v = \
cpu_to_virtio(vdev, *(ptr), ((structname*)0)->member); \
\
might_sleep(); \
/* Sanity check: must match the member's type */ \
typecheck(typeof(virtio_to_cpu((vdev), virtio_cwrite_v)), *(ptr)); \
\
vdev->config->set((vdev), offsetof(structname, member), \
&virtio_cwrite_v, \
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: (u8)(x), \
__le16: (u16)le16_to_cpu(x), \
__le32: (u32)le32_to_cpu(x), \
__le64: (u64)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)
#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,
void *buf, size_t count, size_t bytes)
{
u32 old, gen = vdev->config->generation ?
vdev->config->generation(vdev) : 0;
int i;
might_sleep();
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;
might_sleep();
vdev->config->get(vdev, offset, &ret, sizeof(ret));
return ret;
}
static inline void virtio_cwrite8(struct virtio_device *vdev,
unsigned int offset, u8 val)
{
might_sleep();
vdev->config->set(vdev, offset, &val, sizeof(val));
}
static inline u16 virtio_cread16(struct virtio_device *vdev,
unsigned int offset)
{
__virtio16 ret;
might_sleep();
vdev->config->get(vdev, offset, &ret, sizeof(ret));
return virtio16_to_cpu(vdev, ret);
}
static inline void virtio_cwrite16(struct virtio_device *vdev,
unsigned int offset, u16 val)
{
__virtio16 v;
might_sleep();
v = cpu_to_virtio16(vdev, val);
vdev->config->set(vdev, offset, &v, sizeof(v));
}
static inline u32 virtio_cread32(struct virtio_device *vdev,
unsigned int offset)
{
__virtio32 ret;
might_sleep();
vdev->config->get(vdev, offset, &ret, sizeof(ret));
return virtio32_to_cpu(vdev, ret);
}
static inline void virtio_cwrite32(struct virtio_device *vdev,
unsigned int offset, u32 val)
{
__virtio32 v;
might_sleep();
v = cpu_to_virtio32(vdev, val);
vdev->config->set(vdev, offset, &v, sizeof(v));
}
static inline u64 virtio_cread64(struct virtio_device *vdev,
unsigned int offset)
{
__virtio64 ret;
__virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret));
return virtio64_to_cpu(vdev, ret);
}
static inline void virtio_cwrite64(struct virtio_device *vdev,
unsigned int offset, u64 val)
{
__virtio64 v;
might_sleep();
v = cpu_to_virtio64(vdev, val);
vdev->config->set(vdev, offset, &v, sizeof(v));
}
/* 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; \
})
/* Conditional config space accessors. */
#define virtio_cread_le_feature(vdev, fbit, structname, member, ptr) \
({ \
int _r = 0; \
if (!virtio_has_feature(vdev, fbit)) \
_r = -ENOENT; \
else \
virtio_cread_le((vdev), structname, member, ptr); \
_r; \
})
#endif /* _LINUX_VIRTIO_CONFIG_H */
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