d71de9ec6b
virtio 1.0 spec says:
Drivers MUST NOT assume reads from fields greater than 32 bits wide are
atomic, nor are reads from multiple fields: drivers SHOULD read device
configuration space fields like so:
u32 before, after;
do {
before = get_config_generation(device);
// read config entry/entries.
after = get_config_generation(device);
} while (after != before);
Do exactly this, for transports that support it.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
400 lines
12 KiB
C
400 lines
12 KiB
C
#ifndef _LINUX_VIRTIO_CONFIG_H
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#define _LINUX_VIRTIO_CONFIG_H
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#include <linux/err.h>
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#include <linux/bug.h>
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#include <linux/virtio.h>
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#include <linux/virtio_byteorder.h>
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#include <uapi/linux/virtio_config.h>
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/**
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* virtio_config_ops - operations for configuring a virtio device
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* @get: read the value of a configuration field
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* vdev: the virtio_device
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* offset: the offset of the configuration field
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* buf: the buffer to write the field value into.
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* len: the length of the buffer
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* @set: write the value of a configuration field
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* vdev: the virtio_device
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* offset: the offset of the configuration field
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* buf: the buffer to read the field value from.
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* len: the length of the buffer
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* @generation: config generation counter
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* vdev: the virtio_device
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* Returns the config generation counter
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* @get_status: read the status byte
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* vdev: the virtio_device
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* Returns the status byte
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* @set_status: write the status byte
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* vdev: the virtio_device
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* status: the new status byte
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* @reset: reset the device
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* vdev: the virtio device
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* After this, status and feature negotiation must be done again
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* Device must not be reset from its vq/config callbacks, or in
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* parallel with being added/removed.
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* @find_vqs: find virtqueues and instantiate them.
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* vdev: the virtio_device
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* nvqs: the number of virtqueues to find
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* vqs: on success, includes new virtqueues
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* callbacks: array of callbacks, for each virtqueue
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* include a NULL entry for vqs that do not need a callback
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* names: array of virtqueue names (mainly for debugging)
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* include a NULL entry for vqs unused by driver
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* Returns 0 on success or error status
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* @del_vqs: free virtqueues found by find_vqs().
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* @get_features: get the array of feature bits for this device.
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* vdev: the virtio_device
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* Returns the first 32 feature bits (all we currently need).
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* @finalize_features: confirm what device features we'll be using.
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* vdev: the virtio_device
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* This gives the final feature bits for the device: it can change
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* the dev->feature bits if it wants.
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* Returns 0 on success or error status
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* @bus_name: return the bus name associated with the device
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* vdev: the virtio_device
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* This returns a pointer to the bus name a la pci_name from which
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* the caller can then copy.
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* @set_vq_affinity: set the affinity for a virtqueue.
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*/
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typedef void vq_callback_t(struct virtqueue *);
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struct virtio_config_ops {
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void (*get)(struct virtio_device *vdev, unsigned offset,
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void *buf, unsigned len);
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void (*set)(struct virtio_device *vdev, unsigned offset,
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const void *buf, unsigned len);
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u32 (*generation)(struct virtio_device *vdev);
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u8 (*get_status)(struct virtio_device *vdev);
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void (*set_status)(struct virtio_device *vdev, u8 status);
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void (*reset)(struct virtio_device *vdev);
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int (*find_vqs)(struct virtio_device *, unsigned nvqs,
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struct virtqueue *vqs[],
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vq_callback_t *callbacks[],
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const char *names[]);
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void (*del_vqs)(struct virtio_device *);
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u64 (*get_features)(struct virtio_device *vdev);
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int (*finalize_features)(struct virtio_device *vdev);
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const char *(*bus_name)(struct virtio_device *vdev);
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int (*set_vq_affinity)(struct virtqueue *vq, int cpu);
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};
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/* If driver didn't advertise the feature, it will never appear. */
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void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
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unsigned int fbit);
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/**
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* __virtio_test_bit - helper to test feature bits. For use by transports.
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* Devices should normally use virtio_has_feature,
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* which includes more checks.
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* @vdev: the device
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* @fbit: the feature bit
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*/
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static inline bool __virtio_test_bit(const struct virtio_device *vdev,
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unsigned int fbit)
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{
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/* Did you forget to fix assumptions on max features? */
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if (__builtin_constant_p(fbit))
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BUILD_BUG_ON(fbit >= 64);
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else
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BUG_ON(fbit >= 64);
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return vdev->features & BIT_ULL(fbit);
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}
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/**
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* __virtio_set_bit - helper to set feature bits. For use by transports.
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* @vdev: the device
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* @fbit: the feature bit
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*/
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static inline void __virtio_set_bit(struct virtio_device *vdev,
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unsigned int fbit)
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{
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/* Did you forget to fix assumptions on max features? */
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if (__builtin_constant_p(fbit))
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BUILD_BUG_ON(fbit >= 64);
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else
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BUG_ON(fbit >= 64);
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vdev->features |= BIT_ULL(fbit);
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}
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/**
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* __virtio_clear_bit - helper to clear feature bits. For use by transports.
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* @vdev: the device
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* @fbit: the feature bit
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*/
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static inline void __virtio_clear_bit(struct virtio_device *vdev,
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unsigned int fbit)
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{
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/* Did you forget to fix assumptions on max features? */
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if (__builtin_constant_p(fbit))
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BUILD_BUG_ON(fbit >= 64);
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else
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BUG_ON(fbit >= 64);
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vdev->features &= ~BIT_ULL(fbit);
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}
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/**
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* virtio_has_feature - helper to determine if this device has this feature.
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* @vdev: the device
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* @fbit: the feature bit
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*/
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static inline bool virtio_has_feature(const struct virtio_device *vdev,
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unsigned int fbit)
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{
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if (fbit < VIRTIO_TRANSPORT_F_START)
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virtio_check_driver_offered_feature(vdev, fbit);
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return __virtio_test_bit(vdev, fbit);
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}
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static inline
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struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
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vq_callback_t *c, const char *n)
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{
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vq_callback_t *callbacks[] = { c };
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const char *names[] = { n };
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struct virtqueue *vq;
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int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names);
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if (err < 0)
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return ERR_PTR(err);
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return vq;
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}
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/**
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* virtio_device_ready - enable vq use in probe function
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* @vdev: the device
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*
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* Driver must call this to use vqs in the probe function.
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*
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* Note: vqs are enabled automatically after probe returns.
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*/
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static inline
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void virtio_device_ready(struct virtio_device *dev)
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{
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unsigned status = dev->config->get_status(dev);
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BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK);
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dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK);
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}
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static inline
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const char *virtio_bus_name(struct virtio_device *vdev)
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{
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if (!vdev->config->bus_name)
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return "virtio";
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return vdev->config->bus_name(vdev);
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}
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/**
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* virtqueue_set_affinity - setting affinity for a virtqueue
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* @vq: the virtqueue
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* @cpu: the cpu no.
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*
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* Pay attention the function are best-effort: the affinity hint may not be set
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* due to config support, irq type and sharing.
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*
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*/
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static inline
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int virtqueue_set_affinity(struct virtqueue *vq, int cpu)
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{
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struct virtio_device *vdev = vq->vdev;
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if (vdev->config->set_vq_affinity)
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return vdev->config->set_vq_affinity(vq, cpu);
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return 0;
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}
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/* Memory accessors */
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static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val)
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{
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return __virtio16_to_cpu(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
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}
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static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val)
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{
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return __cpu_to_virtio16(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
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}
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static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val)
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{
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return __virtio32_to_cpu(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
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}
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static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val)
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{
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return __cpu_to_virtio32(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
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}
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static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val)
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{
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return __virtio64_to_cpu(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
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}
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static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val)
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{
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return __cpu_to_virtio64(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
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}
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/* Config space accessors. */
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#define virtio_cread(vdev, structname, member, ptr) \
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do { \
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/* Must match the member's type, and be integer */ \
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if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
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(*ptr) = 1; \
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\
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switch (sizeof(*ptr)) { \
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case 1: \
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*(ptr) = virtio_cread8(vdev, \
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offsetof(structname, member)); \
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break; \
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case 2: \
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*(ptr) = virtio_cread16(vdev, \
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offsetof(structname, member)); \
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break; \
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case 4: \
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*(ptr) = virtio_cread32(vdev, \
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offsetof(structname, member)); \
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break; \
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case 8: \
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*(ptr) = virtio_cread64(vdev, \
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offsetof(structname, member)); \
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break; \
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default: \
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BUG(); \
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} \
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} while(0)
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/* Config space accessors. */
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#define virtio_cwrite(vdev, structname, member, ptr) \
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do { \
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/* Must match the member's type, and be integer */ \
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if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
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BUG_ON((*ptr) == 1); \
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\
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switch (sizeof(*ptr)) { \
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case 1: \
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virtio_cwrite8(vdev, \
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offsetof(structname, member), \
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*(ptr)); \
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break; \
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case 2: \
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virtio_cwrite16(vdev, \
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offsetof(structname, member), \
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*(ptr)); \
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break; \
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case 4: \
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virtio_cwrite32(vdev, \
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offsetof(structname, member), \
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*(ptr)); \
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break; \
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case 8: \
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virtio_cwrite64(vdev, \
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offsetof(structname, member), \
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*(ptr)); \
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break; \
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default: \
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BUG(); \
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} \
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} while(0)
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static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset)
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{
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u8 ret;
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vdev->config->get(vdev, offset, &ret, sizeof(ret));
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return ret;
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}
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/* Read @count fields, @bytes each. */
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static inline void __virtio_cread_many(struct virtio_device *vdev,
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unsigned int offset,
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void *buf, size_t count, size_t bytes)
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{
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u32 old, gen = vdev->config->generation ?
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vdev->config->generation(vdev) : 0;
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int i;
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do {
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old = gen;
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for (i = 0; i < count; i++)
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vdev->config->get(vdev, offset + bytes * i,
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buf + i * bytes, bytes);
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gen = vdev->config->generation ?
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vdev->config->generation(vdev) : 0;
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} while (gen != old);
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}
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static inline void virtio_cread_bytes(struct virtio_device *vdev,
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unsigned int offset,
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void *buf, size_t len)
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{
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__virtio_cread_many(vdev, offset, buf, len, 1);
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}
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static inline void virtio_cwrite8(struct virtio_device *vdev,
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unsigned int offset, u8 val)
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{
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vdev->config->set(vdev, offset, &val, sizeof(val));
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}
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static inline u16 virtio_cread16(struct virtio_device *vdev,
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unsigned int offset)
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{
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u16 ret;
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vdev->config->get(vdev, offset, &ret, sizeof(ret));
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return virtio16_to_cpu(vdev, (__force __virtio16)ret);
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}
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static inline void virtio_cwrite16(struct virtio_device *vdev,
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unsigned int offset, u16 val)
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{
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val = (__force u16)cpu_to_virtio16(vdev, val);
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vdev->config->set(vdev, offset, &val, sizeof(val));
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}
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static inline u32 virtio_cread32(struct virtio_device *vdev,
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unsigned int offset)
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{
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u32 ret;
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vdev->config->get(vdev, offset, &ret, sizeof(ret));
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return virtio32_to_cpu(vdev, (__force __virtio32)ret);
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}
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static inline void virtio_cwrite32(struct virtio_device *vdev,
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unsigned int offset, u32 val)
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{
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val = (__force u32)cpu_to_virtio32(vdev, val);
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vdev->config->set(vdev, offset, &val, sizeof(val));
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}
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static inline u64 virtio_cread64(struct virtio_device *vdev,
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unsigned int offset)
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{
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u64 ret;
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vdev->config->get(vdev, offset, &ret, sizeof(ret));
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__virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret));
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return virtio64_to_cpu(vdev, (__force __virtio64)ret);
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}
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static inline void virtio_cwrite64(struct virtio_device *vdev,
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unsigned int offset, u64 val)
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{
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val = (__force u64)cpu_to_virtio64(vdev, val);
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vdev->config->set(vdev, offset, &val, sizeof(val));
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}
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/* Conditional config space accessors. */
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#define virtio_cread_feature(vdev, fbit, structname, member, ptr) \
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({ \
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int _r = 0; \
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if (!virtio_has_feature(vdev, fbit)) \
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_r = -ENOENT; \
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else \
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virtio_cread((vdev), structname, member, ptr); \
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_r; \
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})
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#endif /* _LINUX_VIRTIO_CONFIG_H */
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