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Diffstat (limited to 'include/linux/virtio_config.h')
| -rw-r--r-- | include/linux/virtio_config.h | 623 |
1 files changed, 623 insertions, 0 deletions
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h new file mode 100644 index 000000000..4b517649c --- /dev/null +++ b/include/linux/virtio_config.h @@ -0,0 +1,623 @@ +/* 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; +}; + +/** + * 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: 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. + */ +typedef void vq_callback_t(struct virtqueue *); +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); +}; + +/* 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 */ |