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012665391d
"virtio: core support for config generation" fixed reading up 64 bit values, adding generation checks for such reads. By mistake, it left an explicit get call in place as well. the result is that the value is read twice, the first result is discarded. Not a big deal since this only happens with virtio blk and only on boot ATM, so performance isn't affected, but let's clean it up. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
398 lines
11 KiB
C
398 lines
11 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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/* 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 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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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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__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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