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1a93769399
The interaction between virtio and IOMMUs is messy. On most systems with virtio, physical addresses match bus addresses, and it doesn't particularly matter which one we use to program the device. On some systems, including Xen and any system with a physical device that speaks virtio behind a physical IOMMU, we must program the IOMMU for virtio DMA to work at all. On other systems, including SPARC and PPC64, virtio-pci devices are enumerated as though they are behind an IOMMU, but the virtio host ignores the IOMMU, so we must either pretend that the IOMMU isn't there or somehow map everything as the identity. Add a feature bit to detect that quirk: VIRTIO_F_IOMMU_PLATFORM. Any device with this feature bit set to 0 needs a quirk and has to be passed physical addresses (as opposed to bus addresses) even though the device is behind an IOMMU. Note: it has to be a per-device quirk because for example, there could be a mix of passed-through and virtual virtio devices. As another example, some devices could be implemented by an out of process hypervisor backend (in case of qemu vhost, or vhost-user) and so support for an IOMMU needs to be coded up separately. It would be cleanest to handle this in IOMMU core code, but that needs per-device DMA ops. While we are waiting for that to be implemented, use a work-around in virtio core. Note: a "noiommu" feature is a quirk - add a wrapper to make that clear. Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
417 lines
12 KiB
C
417 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 * const 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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/**
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* virtio_has_iommu_quirk - determine whether this device has the iommu quirk
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* @vdev: the device
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*/
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static inline bool virtio_has_iommu_quirk(const struct virtio_device *vdev)
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{
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/*
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* Note the reverse polarity of the quirk feature (compared to most
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* other features), this is for compatibility with legacy systems.
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*/
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return !virtio_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM);
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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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static inline bool virtio_is_little_endian(struct virtio_device *vdev)
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{
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return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) ||
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virtio_legacy_is_little_endian();
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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_is_little_endian(vdev), 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_is_little_endian(vdev), 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_is_little_endian(vdev), 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_is_little_endian(vdev), 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_is_little_endian(vdev), 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_is_little_endian(vdev), 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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