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virtio_config.h
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/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _LINUX_VIRTIO_CONFIG_H #define _LINUX_VIRTIO_CONFIG_H #include <linux/err.h> #include <linux/bug.h> #include <linux/virtio.h> #include <linux/virtio_byteorder.h> #include <linux/compiler_types.h> #include <uapi/linux/virtio_config.h> struct irq_affinity; struct virtio_shm_region { u64 addr; u64 len; }; typedef void vq_callback_t(struct virtqueue *); /** * struct virtio_config_ops - operations for configuring a virtio device * Note: Do not assume that a transport implements all of the operations * getting/setting a value as a simple read/write! Generally speaking, * any of @get/@set, @get_status/@set_status, or @get_features/ * @finalize_features are NOT safe to be called from an atomic * context. * @get: read the value of a configuration field * vdev: the virtio_device * offset: the offset of the configuration field * buf: the buffer to write the field value into. * len: the length of the buffer * @set: write the value of a configuration field * vdev: the virtio_device * offset: the offset of the configuration field * buf: the buffer to read the field value from. * len: the length of the buffer * @generation: config generation counter (optional) * vdev: the virtio_device * Returns the config generation counter * @get_status: read the status byte * vdev: the virtio_device * Returns the status byte * @set_status: write the status byte * vdev: the virtio_device * status: the new status byte * @reset: reset the device * vdev: the virtio device * After this, status and feature negotiation must be done again * Device must not be reset from its vq/config callbacks, or in * parallel with being added/removed. * @find_vqs: find virtqueues and instantiate them. * vdev: the virtio_device * nvqs: the number of virtqueues to find * vqs: on success, includes new virtqueues * callbacks: array of callbacks, for each virtqueue * include a NULL entry for vqs that do not need a callback * names: array of virtqueue names (mainly for debugging) * include a NULL entry for vqs unused by driver * Returns 0 on success or error status * @del_vqs: free virtqueues found by find_vqs(). * @synchronize_cbs: synchronize with the virtqueue callbacks (optional) * The function guarantees that all memory operations on the * queue before it are visible to the vring_interrupt() that is * called after it. * vdev: the virtio_device * @get_features: get the array of feature bits for this device. * vdev: the virtio_device * Returns the first 64 feature bits (all we currently need). * @finalize_features: confirm what device features we'll be using. * vdev: the virtio_device * This sends the driver feature bits to the device: it can change * the dev->feature bits if it wants. * Note that despite the name this can be called any number of * times. * Returns 0 on success or error status * @bus_name: return the bus name associated with the device (optional) * vdev: the virtio_device * This returns a pointer to the bus name a la pci_name from which * the caller can then copy. * @set_vq_affinity: set the affinity for a virtqueue (optional). * @get_vq_affinity: get the affinity for a virtqueue (optional). * @get_shm_region: get a shared memory region based on the index. * @disable_vq_and_reset: reset a queue individually (optional). * vq: the virtqueue * Returns 0 on success or error status * disable_vq_and_reset will guarantee that the callbacks are disabled and * synchronized. * Except for the callback, the caller should guarantee that the vring is * not accessed by any functions of virtqueue. * @enable_vq_after_reset: enable a reset queue * vq: the virtqueue * Returns 0 on success or error status * If disable_vq_and_reset is set, then enable_vq_after_reset must also be * set. * @create_avq: create admin virtqueue resource. * @destroy_avq: destroy admin virtqueue resource. */ struct virtio_config_ops { void (*get)(struct virtio_device *vdev, unsigned offset, void *buf, unsigned len); void (*set)(struct virtio_device *vdev, unsigned offset, const void *buf, unsigned len); u32 (*generation)(struct virtio_device *vdev); u8 (*get_status)(struct virtio_device *vdev); void (*set_status)(struct virtio_device *vdev, u8 status); void (*reset)(struct virtio_device *vdev); int (*find_vqs)(struct virtio_device *, unsigned nvqs, struct virtqueue *vqs[], vq_callback_t *callbacks[], const char * const names[], const bool *ctx, struct irq_affinity *desc); void (*del_vqs)(struct virtio_device *); void (*synchronize_cbs)(struct virtio_device *); u64 (*get_features)(struct virtio_device *vdev); int (*finalize_features)(struct virtio_device *vdev); const char *(*bus_name)(struct virtio_device *vdev); int (*set_vq_affinity)(struct virtqueue *vq, const struct cpumask *cpu_mask); const struct cpumask *(*get_vq_affinity)(struct virtio_device *vdev, int index); bool (*get_shm_region)(struct virtio_device *vdev, struct virtio_shm_region *region, u8 id); int (*disable_vq_and_reset)(struct virtqueue *vq); int (*enable_vq_after_reset)(struct virtqueue *vq); int (*create_avq)(struct virtio_device *vdev); void (*destroy_avq)(struct virtio_device *vdev); }; /* If driver didn't advertise the feature, it will never appear. */ void virtio_check_driver_offered_feature(const struct virtio_device *vdev, unsigned int fbit); /** * __virtio_test_bit - helper to test feature bits. For use by transports. * Devices should normally use virtio_has_feature, * which includes more checks. * @vdev: the device * @fbit: the feature bit */ static inline bool __virtio_test_bit(const struct virtio_device *vdev, unsigned int fbit) { /* Did you forget to fix assumptions on max features? */ if (__builtin_constant_p(fbit)) BUILD_BUG_ON(fbit >= 64); else BUG_ON(fbit >= 64); return vdev->features & BIT_ULL(fbit); } /** * __virtio_set_bit - helper to set feature bits. For use by transports. * @vdev: the device * @fbit: the feature bit */ static inline void __virtio_set_bit(struct virtio_device *vdev, unsigned int fbit) { /* Did you forget to fix assumptions on max features? */ if (__builtin_constant_p(fbit)) BUILD_BUG_ON(fbit >= 64); else BUG_ON(fbit >= 64); vdev->features |= BIT_ULL(fbit); } /** * __virtio_clear_bit - helper to clear feature bits. For use by transports. * @vdev: the device * @fbit: the feature bit */ static inline void __virtio_clear_bit(struct virtio_device *vdev, unsigned int fbit) { /* Did you forget to fix assumptions on max features? */ if (__builtin_constant_p(fbit)) BUILD_BUG_ON(fbit >= 64); else BUG_ON(fbit >= 64); vdev->features &= ~BIT_ULL(fbit); } /** * virtio_has_feature - helper to determine if this device has this feature. * @vdev: the device * @fbit: the feature bit */ static inline bool virtio_has_feature(const struct virtio_device *vdev, unsigned int fbit) { if (fbit < VIRTIO_TRANSPORT_F_START) virtio_check_driver_offered_feature(vdev, fbit); return __virtio_test_bit(vdev, fbit); } /** * virtio_has_dma_quirk - determine whether this device has the DMA quirk * @vdev: the device */ static inline bool virtio_has_dma_quirk(const struct virtio_device *vdev) { /* * Note the reverse polarity of the quirk feature (compared to most * other features), this is for compatibility with legacy systems. */ return !virtio_has_feature(vdev, VIRTIO_F_ACCESS_PLATFORM); } static inline struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev, vq_callback_t *c, const char *n) { vq_callback_t *callbacks[] = { c }; const char *names[] = { n }; struct virtqueue *vq; int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names, NULL, NULL); if (err < 0) return ERR_PTR(err); return vq; } static inline int virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs, struct virtqueue *vqs[], vq_callback_t *callbacks[], const char * const names[], struct irq_affinity *desc) { return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, NULL, desc); } static inline int virtio_find_vqs_ctx(struct virtio_device *vdev, unsigned nvqs, struct virtqueue *vqs[], vq_callback_t *callbacks[], const char * const names[], const bool *ctx, struct irq_affinity *desc) { return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, ctx, desc); } /** * virtio_synchronize_cbs - synchronize with virtqueue callbacks * @dev: the virtio device */ static inline void virtio_synchronize_cbs(struct virtio_device *dev) { if (dev->config->synchronize_cbs) { dev->config->synchronize_cbs(dev); } else { /* * A best effort fallback to synchronize with * interrupts, preemption and softirq disabled * regions. See comment above synchronize_rcu(). */ synchronize_rcu(); } } /** * virtio_device_ready - enable vq use in probe function * @dev: the virtio device * * Driver must call this to use vqs in the probe function. * * Note: vqs are enabled automatically after probe returns. */ static inline void virtio_device_ready(struct virtio_device *dev) { unsigned status = dev->config->get_status(dev); WARN_ON(status & VIRTIO_CONFIG_S_DRIVER_OK); #ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION /* * The virtio_synchronize_cbs() makes sure vring_interrupt() * will see the driver specific setup if it sees vq->broken * as false (even if the notifications come before DRIVER_OK). */ virtio_synchronize_cbs(dev); __virtio_unbreak_device(dev); #endif /* * The transport should ensure the visibility of vq->broken * before setting DRIVER_OK. See the comments for the transport * specific set_status() method. * * A well behaved device will only notify a virtqueue after * DRIVER_OK, this means the device should "see" the coherenct * memory write that set vq->broken as false which is done by * the driver when it sees DRIVER_OK, then the following * driver's vring_interrupt() will see vq->broken as false so * we won't lose any notification. */ dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK); } static inline const char *virtio_bus_name(struct virtio_device *vdev) { if (!vdev->config->bus_name) return "virtio"; return vdev->config->bus_name(vdev); } /** * virtqueue_set_affinity - setting affinity for a virtqueue * @vq: the virtqueue * @cpu_mask: the cpu mask * * Pay attention the function are best-effort: the affinity hint may not be set * due to config support, irq type and sharing. * */ static inline int virtqueue_set_affinity(struct virtqueue *vq, const struct cpumask *cpu_mask) { struct virtio_device *vdev = vq->vdev; if (vdev->config->set_vq_affinity) return vdev->config->set_vq_affinity(vq, cpu_mask); return 0; } static inline bool virtio_get_shm_region(struct virtio_device *vdev, struct virtio_shm_region *region, u8 id) { if (!vdev->config->get_shm_region) return false; return vdev->config->get_shm_region(vdev, region, id); } static inline bool virtio_is_little_endian(struct virtio_device *vdev) { return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) || virtio_legacy_is_little_endian(); } /* Memory accessors */ static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val) { return __virtio16_to_cpu(virtio_is_little_endian(vdev), val); } static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val) { return __cpu_to_virtio16(virtio_is_little_endian(vdev), val); } static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val) { return __virtio32_to_cpu(virtio_is_little_endian(vdev), val); } static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val) { return __cpu_to_virtio32(virtio_is_little_endian(vdev), val); } static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val) { return __virtio64_to_cpu(virtio_is_little_endian(vdev), val); } static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val) { return __cpu_to_virtio64(virtio_is_little_endian(vdev), val); } #define virtio_to_cpu(vdev, x) \ _Generic((x), \ __u8: (x), \ __virtio16: virtio16_to_cpu((vdev), (x)), \ __virtio32: virtio32_to_cpu((vdev), (x)), \ __virtio64: virtio64_to_cpu((vdev), (x)) \ ) #define cpu_to_virtio(vdev, x, m) \ _Generic((m), \ __u8: (x), \ __virtio16: cpu_to_virtio16((vdev), (x)), \ __virtio32: cpu_to_virtio32((vdev), (x)), \ __virtio64: cpu_to_virtio64((vdev), (x)) \ ) #define __virtio_native_type(structname, member) \ typeof(virtio_to_cpu(NULL, ((structname*)0)->member)) /* Config space accessors. */ #define virtio_cread(vdev, structname, member, ptr) \ do { \ typeof(((structname*)0)->member) virtio_cread_v; \ \ might_sleep(); \ /* Sanity check: must match the member's type */ \ typecheck(typeof(virtio_to_cpu((vdev), virtio_cread_v)), *(ptr)); \ \ switch (sizeof(virtio_cread_v)) { \ case 1: \ case 2: \ case 4: \ vdev->config->get((vdev), \ offsetof(structname, member), \ &virtio_cread_v, \ sizeof(virtio_cread_v)); \ break; \ default: \ __virtio_cread_many((vdev), \ offsetof(structname, member), \ &virtio_cread_v, \ 1, \ sizeof(virtio_cread_v)); \ break; \ } \ *(ptr) = virtio_to_cpu(vdev, virtio_cread_v); \ } while(0) /* Config space accessors. */ #define virtio_cwrite(vdev, structname, member, ptr) \ do { \ typeof(((structname*)0)->member) virtio_cwrite_v = \ cpu_to_virtio(vdev, *(ptr), ((structname*)0)->member); \ \ might_sleep(); \ /* Sanity check: must match the member's type */ \ typecheck(typeof(virtio_to_cpu((vdev), virtio_cwrite_v)), *(ptr)); \ \ vdev->config->set((vdev), offsetof(structname, member), \ &virtio_cwrite_v, \ sizeof(virtio_cwrite_v)); \ } while(0) /* * Nothing virtio-specific about these, but let's worry about generalizing * these later. */ #define virtio_le_to_cpu(x) \ _Generic((x), \ __u8: (u8)(x), \ __le16: (u16)le16_to_cpu(x), \ __le32: (u32)le32_to_cpu(x), \ __le64: (u64)le64_to_cpu(x) \ ) #define virtio_cpu_to_le(x, m) \ _Generic((m), \ __u8: (x), \ __le16: cpu_to_le16(x), \ __le32: cpu_to_le32(x), \ __le64: cpu_to_le64(x) \ ) /* LE (e.g. modern) Config space accessors. */ #define virtio_cread_le(vdev, structname, member, ptr) \ do { \ typeof(((structname*)0)->member) virtio_cread_v; \ \ might_sleep(); \ /* Sanity check: must match the member's type */ \ typecheck(typeof(virtio_le_to_cpu(virtio_cread_v)), *(ptr)); \ \ switch (sizeof(virtio_cread_v)) { \ case 1: \ case 2: \ case 4: \ vdev->config->get((vdev), \ offsetof(structname, member), \ &virtio_cread_v, \ sizeof(virtio_cread_v)); \ break; \ default: \ __virtio_cread_many((vdev), \ offsetof(structname, member), \ &virtio_cread_v, \ 1, \ sizeof(virtio_cread_v)); \ break; \ } \ *(ptr) = virtio_le_to_cpu(virtio_cread_v); \ } while(0) #define virtio_cwrite_le(vdev, structname, member, ptr) \ do { \ typeof(((structname*)0)->member) virtio_cwrite_v = \ virtio_cpu_to_le(*(ptr), ((structname*)0)->member); \ \ might_sleep(); \ /* Sanity check: must match the member's type */ \ typecheck(typeof(virtio_le_to_cpu(virtio_cwrite_v)), *(ptr)); \ \ vdev->config->set((vdev), offsetof(structname, member), \ &virtio_cwrite_v, \ sizeof(virtio_cwrite_v)); \ } while(0) /* Read @count fields, @bytes each. */ static inline void __virtio_cread_many(struct virtio_device *vdev, unsigned int offset, void *buf, size_t count, size_t bytes) { u32 old, gen = vdev->config->generation ? vdev->config->generation(vdev) : 0; int i; might_sleep(); do { old = gen; for (i = 0; i < count; i++) vdev->config->get(vdev, offset + bytes * i, buf + i * bytes, bytes); gen = vdev->config->generation ? vdev->config->generation(vdev) : 0; } while (gen != old); } static inline void virtio_cread_bytes(struct virtio_device *vdev, unsigned int offset, void *buf, size_t len) { __virtio_cread_many(vdev, offset, buf, len, 1); } static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset) { u8 ret; might_sleep(); vdev->config->get(vdev, offset, &ret, sizeof(ret)); return ret; } static inline void virtio_cwrite8(struct virtio_device *vdev, unsigned int offset, u8 val) { might_sleep(); vdev->config->set(vdev, offset, &val, sizeof(val)); } static inline u16 virtio_cread16(struct virtio_device *vdev, unsigned int offset) { __virtio16 ret; might_sleep(); vdev->config->get(vdev, offset, &ret, sizeof(ret)); return virtio16_to_cpu(vdev, ret); } static inline void virtio_cwrite16(struct virtio_device *vdev, unsigned int offset, u16 val) { __virtio16 v; might_sleep(); v = cpu_to_virtio16(vdev, val); vdev->config->set(vdev, offset, &v, sizeof(v)); } static inline u32 virtio_cread32(struct virtio_device *vdev, unsigned int offset) { __virtio32 ret; might_sleep(); vdev->config->get(vdev, offset, &ret, sizeof(ret)); return virtio32_to_cpu(vdev, ret); } static inline void virtio_cwrite32(struct virtio_device *vdev, unsigned int offset, u32 val) { __virtio32 v; might_sleep(); v = cpu_to_virtio32(vdev, val); vdev->config->set(vdev, offset, &v, sizeof(v)); } static inline u64 virtio_cread64(struct virtio_device *vdev, unsigned int offset) { __virtio64 ret; __virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret)); return virtio64_to_cpu(vdev, ret); } static inline void virtio_cwrite64(struct virtio_device *vdev, unsigned int offset, u64 val) { __virtio64 v; might_sleep(); v = cpu_to_virtio64(vdev, val); vdev->config->set(vdev, offset, &v, sizeof(v)); } /* Conditional config space accessors. */ #define virtio_cread_feature(vdev, fbit, structname, member, ptr) \ ({ \ int _r = 0; \ if (!virtio_has_feature(vdev, fbit)) \ _r = -ENOENT; \ else \ virtio_cread((vdev), structname, member, ptr); \ _r; \ }) /* Conditional config space accessors. */ #define virtio_cread_le_feature(vdev, fbit, structname, member, ptr) \ ({ \ int _r = 0; \ if (!virtio_has_feature(vdev, fbit)) \ _r = -ENOENT; \ else \ virtio_cread_le((vdev), structname, member, ptr); \ _r; \ }) #endif /* _LINUX_VIRTIO_CONFIG_H */