This adds reserved_mem_device_init() helper to attach the specified reserved-memory region to the device.

This is required to attach a reserved-memory region with a non-DT device.

Signed-off-by: Viresh Kumar viresh.kumar@linaro.org --- drivers/of/of_reserved_mem.c | 64 ++++++++++++++++++++------------- include/linux/of_reserved_mem.h | 7 ++++ 2 files changed, 47 insertions(+), 24 deletions(-)

diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c index 77016c0cc296..e0a86c3fa656 100644 --- a/drivers/of/of_reserved_mem.c +++ b/drivers/of/of_reserved_mem.c @@ -606,6 +606,45 @@ struct rmem_assigned_device { static LIST_HEAD(of_rmem_assigned_device_list); static DEFINE_MUTEX(of_rmem_assigned_device_mutex);

+/** + * reserved_mem_device_init() - assign reserved memory region to given device + * @dev: Pointer to the device to configure + * @rmem: Pointer to the reserved memory region + * + * This function assigns the @rmem reserved memory region to the @dev device. + * + * Returns error code or zero on success. + */ +int reserved_mem_device_init(struct device *dev, struct reserved_mem *rmem) +{ + struct rmem_assigned_device *rd; + int ret; + + if (!dev || !rmem || !rmem->ops || !rmem->ops->device_init) + return -EINVAL; + + rd = kmalloc(sizeof(*rd), GFP_KERNEL); + if (!rd) + return -ENOMEM; + + ret = rmem->ops->device_init(rmem, dev); + if (ret == 0) { + rd->dev = dev; + rd->rmem = rmem; + + mutex_lock(&of_rmem_assigned_device_mutex); + list_add(&rd->list, &of_rmem_assigned_device_list); + mutex_unlock(&of_rmem_assigned_device_mutex); + + dev_info(dev, "assigned reserved memory node %s\n", rmem->name); + } else { + kfree(rd); + } + + return ret; +} +EXPORT_SYMBOL_GPL(reserved_mem_device_init); + /** * of_reserved_mem_device_init_by_idx() - assign reserved memory region to * given device @@ -624,10 +663,8 @@ static DEFINE_MUTEX(of_rmem_assigned_device_mutex); int of_reserved_mem_device_init_by_idx(struct device *dev, struct device_node *np, int idx) { - struct rmem_assigned_device *rd; struct device_node *target; struct reserved_mem *rmem; - int ret;

if (!np || !dev) return -EINVAL; @@ -644,28 +681,7 @@ int of_reserved_mem_device_init_by_idx(struct device *dev, rmem = of_reserved_mem_lookup(target); of_node_put(target);

- if (!rmem || !rmem->ops || !rmem->ops->device_init) - return -EINVAL; - - rd = kmalloc(sizeof(struct rmem_assigned_device), GFP_KERNEL); - if (!rd) - return -ENOMEM; - - ret = rmem->ops->device_init(rmem, dev); - if (ret == 0) { - rd->dev = dev; - rd->rmem = rmem; - - mutex_lock(&of_rmem_assigned_device_mutex); - list_add(&rd->list, &of_rmem_assigned_device_list); - mutex_unlock(&of_rmem_assigned_device_mutex); - - dev_info(dev, "assigned reserved memory node %s\n", rmem->name); - } else { - kfree(rd); - } - - return ret; + return reserved_mem_device_init(dev, rmem); } EXPORT_SYMBOL_GPL(of_reserved_mem_device_init_by_idx);

diff --git a/include/linux/of_reserved_mem.h b/include/linux/of_reserved_mem.h index f573423359f4..3933f1d39e9a 100644 --- a/include/linux/of_reserved_mem.h +++ b/include/linux/of_reserved_mem.h @@ -37,6 +37,7 @@ int of_reserved_mem_device_init_by_idx(struct device *dev, int of_reserved_mem_device_init_by_name(struct device *dev, struct device_node *np, const char *name); +int reserved_mem_device_init(struct device *dev, struct reserved_mem *rmem); void of_reserved_mem_device_release(struct device *dev);

struct reserved_mem *of_reserved_mem_lookup(struct device_node *np); @@ -64,6 +65,12 @@ static inline int of_reserved_mem_device_init_by_name(struct device *dev, return -ENOSYS; }

+static inline int reserved_mem_device_init(struct device *dev, + struct reserved_mem *rmem) +{ + return -ENOSYS; +} + static inline void of_reserved_mem_device_release(struct device *pdev) { }

static inline struct reserved_mem *of_reserved_mem_lookup(struct device_node *np)

This introduces support for a new Virtio transport type: "virtio-msg". Unlike existing transport types like virtio-mmio or virtio-pci which rely on memory-mapped registers, virtio-msg implements transport operations via structured message exchanges using standard virtqueues.

It separates bus-level functionality (e.g., device enumeration, hotplug events) from device-specific operations (e.g., feature negotiation, virtqueue setup), ensuring that a single, generic transport layer can be reused across multiple bus implementations (like ARM Firmware Framework (FF-A), IPC, etc.).

Signed-off-by: Viresh Kumar viresh.kumar@linaro.org --- MAINTAINERS | 7 + drivers/virtio/Kconfig | 7 + drivers/virtio/Makefile | 1 + drivers/virtio/virtio_msg.c | 655 +++++++++++++++++++++++++++ drivers/virtio/virtio_msg_internal.h | 56 +++ include/uapi/linux/virtio_msg.h | 213 +++++++++ 6 files changed, 939 insertions(+) create mode 100644 drivers/virtio/virtio_msg.c create mode 100644 drivers/virtio/virtio_msg_internal.h create mode 100644 include/uapi/linux/virtio_msg.h

diff --git a/MAINTAINERS b/MAINTAINERS index c0b444e5fd5a..7d9ecac4fdbd 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -26358,6 +26358,13 @@ W: https://virtio-mem.gitlab.io/ F: drivers/virtio/virtio_mem.c F: include/uapi/linux/virtio_mem.h

+VIRTIO MSG TRANSPORT +M: Viresh Kumar viresh.kumar@linaro.org +L: virtualization@lists.linux.dev +S: Maintained +F: drivers/virtio/virtio_msg* +F: include/uapi/linux/virtio_msg* + VIRTIO PMEM DRIVER M: Pankaj Gupta pankaj.gupta.linux@gmail.com L: virtualization@lists.linux.dev diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig index 6db5235a7693..690ac98850b6 100644 --- a/drivers/virtio/Kconfig +++ b/drivers/virtio/Kconfig @@ -171,6 +171,13 @@ config VIRTIO_MMIO_CMDLINE_DEVICES

If unsure, say 'N'.

+config VIRTIO_MSG + tristate + select VIRTIO + help + This enables support for Virtio message transport. This option is + selected by any driver which implements the virtio message bus. + config VIRTIO_DMA_SHARED_BUFFER tristate depends on DMA_SHARED_BUFFER diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile index eefcfe90d6b8..3eff8ca72446 100644 --- a/drivers/virtio/Makefile +++ b/drivers/virtio/Makefile @@ -4,6 +4,7 @@ obj-$(CONFIG_VIRTIO_ANCHOR) += virtio_anchor.o obj-$(CONFIG_VIRTIO_PCI_LIB) += virtio_pci_modern_dev.o obj-$(CONFIG_VIRTIO_PCI_LIB_LEGACY) += virtio_pci_legacy_dev.o obj-$(CONFIG_VIRTIO_MMIO) += virtio_mmio.o +obj-$(CONFIG_VIRTIO_MSG) += virtio_msg.o obj-$(CONFIG_VIRTIO_PCI) += virtio_pci.o virtio_pci-y := virtio_pci_modern.o virtio_pci_common.o virtio_pci-$(CONFIG_VIRTIO_PCI_LEGACY) += virtio_pci_legacy.o diff --git a/drivers/virtio/virtio_msg.c b/drivers/virtio/virtio_msg.c new file mode 100644 index 000000000000..7034818475ab --- /dev/null +++ b/drivers/virtio/virtio_msg.c @@ -0,0 +1,655 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Virtio message transport. + * + * Copyright (C) 2025 Google LLC and Linaro. + * Viresh Kumar viresh.kumar@linaro.org + * + * The virtio-msg transport encapsulates virtio operations as discrete message + * exchanges rather than relying on PCI or memory-mapped I/O regions. It + * separates bus-level functionality (e.g., device enumeration, hotplug events) + * from device-specific operations (e.g., feature negotiation, virtqueue setup), + * ensuring that a single, generic transport layer can be reused across multiple + * bus implementations (like ARM Firmware Framework (FF-A), IPC, etc.). + * + * This file implements the generic Virtio message transport layer. + */ + +#define pr_fmt(fmt) "virtio-msg: " fmt + +#include <linux/err.h> +#include <linux/list.h> +#include <linux/slab.h> +#include <linux/virtio.h> +#include <linux/virtio_config.h> +#include <linux/virtio_ring.h> +#include <uapi/linux/virtio_msg.h> + +#include "virtio_msg_internal.h" + +#define to_virtio_msg_device(_dev) \ + container_of(_dev, struct virtio_msg_device, vdev) + +static void msg_prepare(struct virtio_msg *vmsg, bool bus, u8 msg_id, + u16 dev_id, u16 payload_size) +{ + u16 size = sizeof(*vmsg) + payload_size; + + memset(vmsg, 0, size); + + if (bus) { + vmsg->type = VIRTIO_MSG_TYPE_BUS; + } else { + vmsg->type = VIRTIO_MSG_TYPE_TRANSPORT; + vmsg->dev_id = cpu_to_le16(dev_id); + } + + vmsg->msg_id = msg_id; + vmsg->msg_size = cpu_to_le16(size); +} + +static void transport_msg_prepare(struct virtio_msg_device *vmdev, u8 msg_id, + u16 payload_size) +{ + msg_prepare(vmdev->request, false, msg_id, vmdev->dev_id, payload_size); +} + +/** + * virtio_msg_prepare - Initialize a virtio message for bus transfer + * @vmsg: Pointer to the virtio message structure to initialize + * @msg_id: Message ID to set in the message header + * @payload_size: Size of the payload (in bytes) + * + * Prepares a virtio_msg structure for transmission over the bus transport + * (VIRTIO_MSG_TYPE_BUS). The payload buffer follows the header. + */ +void virtio_msg_prepare(struct virtio_msg *vmsg, u8 msg_id, u16 payload_size) +{ + msg_prepare(vmsg, true, msg_id, 0, payload_size); +} +EXPORT_SYMBOL_GPL(virtio_msg_prepare); + +static int virtio_msg_xfer(struct virtio_msg_device *vmdev) +{ + int ret; + + memset(vmdev->response, 0, vmdev->msg_size); + + ret = vmdev->ops->transfer(vmdev, vmdev->request, vmdev->response); + if (ret) + dev_err(&vmdev->vdev.dev, "Transfer request failed (%d)\n", ret); + + return ret; +} + +static inline int virtio_msg_send(struct virtio_msg_device *vmdev) +{ + int ret; + + ret = vmdev->ops->transfer(vmdev, vmdev->request, NULL); + if (ret) + dev_err(&vmdev->vdev.dev, "Send request failed (%d)\n", ret); + + return ret; +} + +static int virtio_msg_get_device_info(struct virtio_msg_device *vmdev) +{ + struct get_device_info_resp *payload = virtio_msg_payload(vmdev->response); + struct virtio_device *vdev = &vmdev->vdev; + u32 num_feature_bits; + int ret; + + static_assert(sizeof(*vmdev->response) + sizeof(*payload) < + VIRTIO_MSG_MIN_SIZE); + + transport_msg_prepare(vmdev, VIRTIO_MSG_DEVICE_INFO, 0); + + ret = virtio_msg_xfer(vmdev); + if (ret) + return ret; + + vdev->id.device = le32_to_cpu(payload->device_id); + if (vdev->id.device == 0) { + /* + * A virtio device with ID 0 is a placeholder and indicates no + * valid device function is present. + */ + return -ENODEV; + } + + vdev->id.vendor = le32_to_cpu(payload->vendor_id); + vmdev->config_size = le32_to_cpu(payload->config_size); + num_feature_bits = le32_to_cpu(payload->num_feature_bits); + + /* Linux supports 64 feature bits */ + if (num_feature_bits != 64) { + dev_err(&vdev->dev, "Incompatible num_feature_bits (%u)\n", + num_feature_bits); + return -EINVAL; + } + + return 0; +} + +static u64 virtio_msg_get_features(struct virtio_device *vdev) +{ + struct virtio_msg_device *vmdev = to_virtio_msg_device(vdev); + struct get_features *req_payload = virtio_msg_payload(vmdev->request); + struct get_features_resp *res_payload = virtio_msg_payload(vmdev->response); + __le32 *features; + int ret; + + static_assert(sizeof(*vmdev->request) + sizeof(*req_payload) < + VIRTIO_MSG_MIN_SIZE); + static_assert(sizeof(*vmdev->response) + sizeof(*res_payload) < + VIRTIO_MSG_MIN_SIZE); + + transport_msg_prepare(vmdev, VIRTIO_MSG_GET_DEV_FEATURES, + sizeof(*req_payload)); + + /* Linux supports 64 feature bits */ + req_payload->num = cpu_to_le32(2); + req_payload->index = 0; + + ret = virtio_msg_xfer(vmdev); + if (ret) + return 0; + + features = (__le32 *)res_payload->features; + return ((u64)(le32_to_cpu(features[1])) << 32) | le32_to_cpu(features[0]); +} + +static int virtio_msg_finalize_features(struct virtio_device *vdev) +{ + struct virtio_msg_device *vmdev = to_virtio_msg_device(vdev); + struct set_features *payload = virtio_msg_payload(vmdev->request); + __le32 *features = (__le32 *)payload->features; + + static_assert(sizeof(*vmdev->request) + sizeof(*payload) < + VIRTIO_MSG_MIN_SIZE); + + /* Give virtio_ring a chance to accept features */ + vring_transport_features(vdev); + + transport_msg_prepare(vmdev, VIRTIO_MSG_SET_DRV_FEATURES, sizeof(*payload)); + + /* Linux supports 64 feature bits */ + payload->num = cpu_to_le32(2); + payload->index = 0; + + features[0] = cpu_to_le32((u32)vmdev->vdev.features); + features[1] = cpu_to_le32(vmdev->vdev.features >> 32); + + return virtio_msg_xfer(vmdev); +} + +static void virtio_msg_get(struct virtio_device *vdev, unsigned int offset, + void *buf, unsigned int len) +{ + struct virtio_msg_device *vmdev = to_virtio_msg_device(vdev); + struct get_config *req_payload = virtio_msg_payload(vmdev->request); + struct get_config_resp *res_payload = virtio_msg_payload(vmdev->response); + u32 i = 0, max; + + static_assert(sizeof(*vmdev->request) + sizeof(*req_payload) < + VIRTIO_MSG_MIN_SIZE); + static_assert(sizeof(*vmdev->response) + sizeof(*res_payload) < + VIRTIO_MSG_MIN_SIZE); + + if (offset + len > vmdev->config_size) { + dev_err(&vmdev->vdev.dev, + "Invalid config read operation: %u: %u: %u\n", offset, + len, vmdev->config_size); + return; + } + + /* Maximum payload size available in the response message buffer */ + max = vmdev->msg_size - sizeof(*vmdev->response) - sizeof(*res_payload); + + transport_msg_prepare(vmdev, VIRTIO_MSG_GET_CONFIG, sizeof(*req_payload)); + + while (i != len) { + u32 size = min(max, len - i); + + req_payload->offset = cpu_to_le32(offset + i); + req_payload->size = cpu_to_le32(size); + + if (virtio_msg_xfer(vmdev)) + return; + + /* Buffer holds the data in little endian */ + memcpy(buf + i, res_payload->config, size); + i += size; + } + + vmdev->generation_count = le32_to_cpu(res_payload->generation); +} + +static void virtio_msg_set(struct virtio_device *vdev, unsigned int offset, + const void *buf, unsigned int len) +{ + struct virtio_msg_device *vmdev = to_virtio_msg_device(vdev); + struct set_config *payload = virtio_msg_payload(vmdev->request); + u32 i = 0, max; + + static_assert(sizeof(*vmdev->request) + sizeof(*payload) < + VIRTIO_MSG_MIN_SIZE); + + if (offset + len > vmdev->config_size) { + dev_err(&vmdev->vdev.dev, + "Invalid config write operation: %u: %u: %u\n", offset, + len, vmdev->config_size); + return; + } + + /* Maximum payload size available in the request message buffer */ + max = vmdev->msg_size - sizeof(*vmdev->request) - sizeof(*payload); + + transport_msg_prepare(vmdev, VIRTIO_MSG_SET_CONFIG, sizeof(*payload)); + payload->generation = cpu_to_le32(vmdev->generation_count); + + while (i != len) { + u32 size = min(max, len - i); + + payload->offset = cpu_to_le32(offset + i); + payload->size = cpu_to_le32(size); + + /* Buffer holds the data in little endian */ + memcpy(payload->config, buf + i, size); + i += size; + + if (virtio_msg_xfer(vmdev)) + return; + } +} + +static u32 virtio_msg_generation(struct virtio_device *vdev) +{ + struct virtio_msg_device *vmdev = to_virtio_msg_device(vdev); + struct get_config *req_payload = virtio_msg_payload(vmdev->request); + struct get_config_resp *res_payload = virtio_msg_payload(vmdev->response); + + transport_msg_prepare(vmdev, VIRTIO_MSG_GET_CONFIG, sizeof(*req_payload)); + req_payload->offset = cpu_to_le32(0); + req_payload->size = cpu_to_le32(0); + + if (virtio_msg_xfer(vmdev)) + return 0; + + vmdev->generation_count = le32_to_cpu(res_payload->generation); + return vmdev->generation_count; +} + +static u8 virtio_msg_get_status(struct virtio_device *vdev) +{ + struct virtio_msg_device *vmdev = to_virtio_msg_device(vdev); + struct get_device_status_resp *payload = virtio_msg_payload(vmdev->response); + + static_assert(sizeof(*vmdev->response) + sizeof(*payload) < + VIRTIO_MSG_MIN_SIZE); + + transport_msg_prepare(vmdev, VIRTIO_MSG_GET_DEVICE_STATUS, 0); + + if (virtio_msg_xfer(vmdev)) + return 0; + + return (u8)le32_to_cpu(payload->status); +} + +static void virtio_msg_set_status(struct virtio_device *vdev, u8 status) +{ + struct virtio_msg_device *vmdev = to_virtio_msg_device(vdev); + struct set_device_status *payload = virtio_msg_payload(vmdev->request); + + static_assert(sizeof(*vmdev->request) + sizeof(*payload) < + VIRTIO_MSG_MIN_SIZE); + + transport_msg_prepare(vmdev, VIRTIO_MSG_SET_DEVICE_STATUS, sizeof(*payload)); + payload->status = cpu_to_le32(status); + + if (virtio_msg_xfer(vmdev)) + dev_warn(&vmdev->vdev.dev, "Set status %u failed\n", status); +} + +static void virtio_msg_vq_reset(struct virtqueue *vq) +{ + struct virtio_msg_device *vmdev = to_virtio_msg_device(vq->vdev); + struct reset_vqueue *payload = virtio_msg_payload(vmdev->request); + + static_assert(sizeof(*vmdev->request) + sizeof(*payload) < + VIRTIO_MSG_MIN_SIZE); + + transport_msg_prepare(vmdev, VIRTIO_MSG_RESET_VQUEUE, sizeof(*payload)); + payload->index = cpu_to_le32(vq->index); + + if (virtio_msg_xfer(vmdev)) + dev_warn(&vmdev->vdev.dev, "Virtqueue reset failed\n"); +} + +static void virtio_msg_reset(struct virtio_device *vdev) +{ + /* Setting status to 0 initiates a device reset */ + virtio_msg_set_status(vdev, 0); +} + +static bool _vmsg_notify(struct virtqueue *vq, u32 index, u32 offset, u32 wrap) +{ + struct virtio_msg_device *vmdev = to_virtio_msg_device(vq->vdev); + struct event_avail *payload = virtio_msg_payload(vmdev->request); + u32 val; + + static_assert(sizeof(*vmdev->request) + sizeof(*payload) < + VIRTIO_MSG_MIN_SIZE); + + transport_msg_prepare(vmdev, VIRTIO_MSG_EVENT_AVAIL, sizeof(*payload)); + payload->index = cpu_to_le32(index); + + val = offset & ((1U << VIRTIO_MSG_EVENT_AVAIL_WRAP_SHIFT) - 1); + val |= wrap & (1U << VIRTIO_MSG_EVENT_AVAIL_WRAP_SHIFT); + payload->next_offset_wrap = cpu_to_le32(val); + + return !virtio_msg_send(vmdev); +} + +static bool virtio_msg_notify(struct virtqueue *vq) +{ + return _vmsg_notify(vq, vq->index, 0, 0); +} + +static bool virtio_msg_notify_with_data(struct virtqueue *vq) +{ + u32 index, offset, wrap, data = vring_notification_data(vq); + + index = data | 0xFFFF; + data >>= 16; + offset = data | 0x7FFF; + wrap = data >> 15; + + return _vmsg_notify(vq, index, offset, wrap); +} + +/** + * virtio_msg_event - Handle an incoming event message for a virtio message device. + * @vmdev: Pointer to the virtio message device. + * @vmsg: Pointer to the incoming virtio message containing the event. + * + * Processes an event message received from the bus layer for the given + * virtio message device. Depending on the message type, this function either: + * + * - Triggers the device configuration change handler if the message is of type + * VIRTIO_MSG_EVENT_CONFIG. + * + * - Delivers a used-buffer notification to the corresponding virtqueue if the + * message is of type VIRTIO_MSG_EVENT_USED. + * + * Return: 0 on success, -EIO if the interrupt handler fails, -EINVAL for + * unknown message types or invalid virtqueue indices. + */ +int virtio_msg_event(struct virtio_msg_device *vmdev, struct virtio_msg *vmsg) +{ + struct event_used *payload = virtio_msg_payload(vmsg); + struct device *dev = &vmdev->vdev.dev; + struct virtqueue *vq; + unsigned int index; + + if (vmsg->msg_id == VIRTIO_MSG_EVENT_CONFIG) { + virtio_config_changed(&vmdev->vdev); + return 0; + } + + if (vmsg->msg_id == VIRTIO_MSG_EVENT_USED) { + index = le32_to_cpu(payload->index); + + virtio_device_for_each_vq(&vmdev->vdev, vq) { + if (index == vq->index) { + if (vring_interrupt(0, vq) != IRQ_HANDLED) + return -EIO; + + return 0; + } + } + + dev_err(dev, "Failed to find virtqueue (%u)", index); + } else { + dev_err(dev, "Unexpected message id: (%u)\n", vmsg->msg_id); + } + + return -EINVAL; +} +EXPORT_SYMBOL_GPL(virtio_msg_event); + +static void virtio_msg_del_vqs(struct virtio_device *vdev) +{ + struct virtqueue *vq, *n; + + list_for_each_entry_safe(vq, n, &vdev->vqs, list) { + virtio_msg_vq_reset(vq); + vring_del_virtqueue(vq); + } +} + +static int virtio_msg_vq_get(struct virtio_msg_device *vmdev, unsigned int *num, + unsigned int index) +{ + struct get_vqueue *req_payload = virtio_msg_payload(vmdev->request); + struct get_vqueue_resp *res_payload = virtio_msg_payload(vmdev->response); + int ret; + + static_assert(sizeof(*vmdev->request) + sizeof(*req_payload) < + VIRTIO_MSG_MIN_SIZE); + static_assert(sizeof(*vmdev->response) + sizeof(*res_payload) < + VIRTIO_MSG_MIN_SIZE); + + transport_msg_prepare(vmdev, VIRTIO_MSG_GET_VQUEUE, sizeof(*req_payload)); + req_payload->index = cpu_to_le32(index); + + ret = virtio_msg_xfer(vmdev); + if (ret) + return ret; + + *num = le32_to_cpu(res_payload->max_size); + if (!*num) + return -ENOENT; + + return 0; +} + +static int virtio_msg_vq_set(struct virtio_msg_device *vmdev, + struct virtqueue *vq, unsigned int index) +{ + struct set_vqueue *payload = virtio_msg_payload(vmdev->request); + + static_assert(sizeof(*vmdev->request) + sizeof(*payload) < + VIRTIO_MSG_MIN_SIZE); + + transport_msg_prepare(vmdev, VIRTIO_MSG_SET_VQUEUE, sizeof(*payload)); + payload->index = cpu_to_le32(index); + payload->size = cpu_to_le32(virtqueue_get_vring_size(vq)); + payload->descriptor_addr = cpu_to_le64(virtqueue_get_desc_addr(vq)); + payload->driver_addr = cpu_to_le64(virtqueue_get_avail_addr(vq)); + payload->device_addr = cpu_to_le64(virtqueue_get_used_addr(vq)); + + return virtio_msg_xfer(vmdev); +} + +static struct virtqueue * +virtio_msg_setup_vq(struct virtio_msg_device *vmdev, unsigned int index, + void (*callback)(struct virtqueue *vq), const char *name, + bool ctx) +{ + bool (*notify)(struct virtqueue *vq); + struct virtqueue *vq; + unsigned int num; + int ret; + + if (__virtio_test_bit(&vmdev->vdev, VIRTIO_F_NOTIFICATION_DATA)) + notify = virtio_msg_notify_with_data; + else + notify = virtio_msg_notify; + + ret = virtio_msg_vq_get(vmdev, &num, index); + if (ret) + return ERR_PTR(ret); + + vq = vring_create_virtqueue(index, num, PAGE_SIZE, &vmdev->vdev, true, + true, ctx, notify, callback, name); + if (!vq) + return ERR_PTR(-ENOMEM); + + vq->num_max = num; + + ret = virtio_msg_vq_set(vmdev, vq, index); + if (ret) { + vring_del_virtqueue(vq); + return ERR_PTR(ret); + } + + return vq; +} + +static int virtio_msg_find_vqs(struct virtio_device *vdev, unsigned int nvqs, + struct virtqueue *vqs[], + struct virtqueue_info vqs_info[], + struct irq_affinity *desc) +{ + struct virtio_msg_device *vmdev = to_virtio_msg_device(vdev); + int i, queue_idx = 0; + + for (i = 0; i < nvqs; ++i) { + struct virtqueue_info *vqi = &vqs_info[i]; + + if (!vqi->name) { + vqs[i] = NULL; + continue; + } + + vqs[i] = virtio_msg_setup_vq(vmdev, queue_idx++, vqi->callback, + vqi->name, vqi->ctx); + if (IS_ERR(vqs[i])) { + virtio_msg_del_vqs(vdev); + return PTR_ERR(vqs[i]); + } + } + + return 0; +} + +static const char *virtio_msg_bus_name(struct virtio_device *vdev) +{ + struct virtio_msg_device *vmdev = to_virtio_msg_device(vdev); + + return vmdev->bus_name; +} + +static void virtio_msg_synchronize_cbs(struct virtio_device *vdev) +{ + struct virtio_msg_device *vmdev = to_virtio_msg_device(vdev); + + vmdev->ops->synchronize_cbs(vmdev); +} + +static void virtio_msg_release_dev(struct device *_d) +{ + struct virtio_device *vdev = + container_of(_d, struct virtio_device, dev); + struct virtio_msg_device *vmdev = to_virtio_msg_device(vdev); + + if (vmdev->ops->release) + vmdev->ops->release(vmdev); +} + +static struct virtio_config_ops virtio_msg_config_ops = { + .get = virtio_msg_get, + .set = virtio_msg_set, + .generation = virtio_msg_generation, + .get_status = virtio_msg_get_status, + .set_status = virtio_msg_set_status, + .reset = virtio_msg_reset, + .find_vqs = virtio_msg_find_vqs, + .del_vqs = virtio_msg_del_vqs, + .get_features = virtio_msg_get_features, + .finalize_features = virtio_msg_finalize_features, + .bus_name = virtio_msg_bus_name, +}; + +/** + * virtio_msg_register - Register a virtio message device with the virtio core + * @vmdev: Pointer to the virtio message device to register + * + * Initializes and registers a virtio message device. + * + * Return: 0 on success, or a negative error code on failure. + */ +int virtio_msg_register(struct virtio_msg_device *vmdev) +{ + u32 version; + int ret; + + if (!vmdev || !vmdev->ops || !vmdev->ops->bus_info || + !vmdev->ops->transfer) + return -EINVAL; + + vmdev->bus_name = vmdev->ops->bus_info(vmdev, &vmdev->msg_size, + &version); + if (version != VIRTIO_MSG_REVISION_1 || + vmdev->msg_size < VIRTIO_MSG_MIN_SIZE) + return -EINVAL; + + /* + * Allocate per-device request and response buffers, each of size + * `msg_size`. + * + * Since requests are serialized per device, one pair of buffers + * suffices. + */ + vmdev->request = kzalloc(2 * vmdev->msg_size, GFP_KERNEL); + if (!vmdev->request) + return -ENOMEM; + + vmdev->response = (void *)vmdev->request + vmdev->msg_size; + + vmdev->vdev.config = &virtio_msg_config_ops; + vmdev->vdev.dev.release = virtio_msg_release_dev; + + if (vmdev->ops->synchronize_cbs) + virtio_msg_config_ops.synchronize_cbs = virtio_msg_synchronize_cbs; + + ret = virtio_msg_get_device_info(vmdev); + if (ret) { + if (vmdev->ops->release) + vmdev->ops->release(vmdev); + goto free; + } + + ret = register_virtio_device(&vmdev->vdev); + if (ret) { + put_device(&vmdev->vdev.dev); + goto free; + } + + return 0; + +free: + kfree(vmdev->request); + return ret; +} +EXPORT_SYMBOL_GPL(virtio_msg_register); + +/** + * virtio_msg_unregister - Unregister a virtio message device + * @vmdev: Pointer to the virtio message device to unregister + * + * Unregisters a previously registered virtio message device from the virtio + * core and releases associated resources. + */ +void virtio_msg_unregister(struct virtio_msg_device *vmdev) +{ + unregister_virtio_device(&vmdev->vdev); + kfree(vmdev->request); +} +EXPORT_SYMBOL_GPL(virtio_msg_unregister); + +MODULE_AUTHOR("Viresh Kumar viresh.kumar@linaro.org"); +MODULE_DESCRIPTION("Virtio message transport"); +MODULE_LICENSE("GPL"); diff --git a/drivers/virtio/virtio_msg_internal.h b/drivers/virtio/virtio_msg_internal.h new file mode 100644 index 000000000000..b7c2cb44b67b --- /dev/null +++ b/drivers/virtio/virtio_msg_internal.h @@ -0,0 +1,56 @@ +/* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) */ +/* + * Virtio message transport header. + * + * Copyright (C) 2025 Google LLC and Linaro. + * Viresh Kumar viresh.kumar@linaro.org + */ + +#ifndef _DRIVERS_VIRTIO_MSG_INTERNAL_H +#define _DRIVERS_VIRTIO_MSG_INTERNAL_H + +#include <linux/virtio.h> +#include <uapi/linux/virtio_msg.h> + +struct virtio_msg_device; + +/* + * struct virtio_msg_ops - Virtio message bus operations. + * @bus_info: Return bus information. + * @transfer: Transfer a message. + * @synchronize_cbs: Synchronize with the virtqueue callbacks (optional). + * @release: Release the resources corresponding to the device (optional). + */ +struct virtio_msg_ops { + const char *(*bus_info)(struct virtio_msg_device *vmdev, u16 *msg_size, u32 *rev); + int (*transfer)(struct virtio_msg_device *vmdev, struct virtio_msg *request, + struct virtio_msg *response); + void (*synchronize_cbs)(struct virtio_msg_device *vmdev); + void (*release)(struct virtio_msg_device *vmdev); +}; + +/* + * Representation of a device using virtio message + * transport. + */ +struct virtio_msg_device { + struct virtio_device vdev; + struct virtio_msg_ops *ops; + const char *bus_name; + void *bus_data; + u32 generation_count; + u32 config_size; + u16 msg_size; + u16 dev_id; + + struct virtio_msg *request; + struct virtio_msg *response; +}; + +int virtio_msg_register(struct virtio_msg_device *vmdev); +void virtio_msg_unregister(struct virtio_msg_device *vmdev); + +void virtio_msg_prepare(struct virtio_msg *vmsg, u8 msg_id, u16 payload_size); +int virtio_msg_event(struct virtio_msg_device *vmdev, struct virtio_msg *vmsg); + +#endif /* _DRIVERS_VIRTIO_MSG_INTERNAL_H */ diff --git a/include/uapi/linux/virtio_msg.h b/include/uapi/linux/virtio_msg.h new file mode 100644 index 000000000000..4f619906015b --- /dev/null +++ b/include/uapi/linux/virtio_msg.h @@ -0,0 +1,213 @@ +/* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) */ +/* + * Virtio message transport header. + * + * Copyright (c) 2025 Advanced Micro Devices, Inc. + * Written by Edgar E. Iglesias edgar.iglesias@amd.com + * + * Copyright (C) 2025 Google LLC and Linaro. + * Viresh Kumar viresh.kumar@linaro.org + */ + +#ifndef _LINUX_VIRTIO_MSG_H +#define _LINUX_VIRTIO_MSG_H + +#include <linux/types.h> + +/* Virtio message transport definitions */ + +/* Message types */ +#define VIRTIO_MSG_DEVICE_INFO 0x02 +#define VIRTIO_MSG_GET_DEV_FEATURES 0x03 +#define VIRTIO_MSG_SET_DRV_FEATURES 0x04 +#define VIRTIO_MSG_GET_CONFIG 0x05 +#define VIRTIO_MSG_SET_CONFIG 0x06 +#define VIRTIO_MSG_GET_DEVICE_STATUS 0x07 +#define VIRTIO_MSG_SET_DEVICE_STATUS 0x08 +#define VIRTIO_MSG_GET_VQUEUE 0x09 +#define VIRTIO_MSG_SET_VQUEUE 0x0a +#define VIRTIO_MSG_RESET_VQUEUE 0x0b +#define VIRTIO_MSG_GET_SHM 0x0c +#define VIRTIO_MSG_EVENT_CONFIG 0x40 +#define VIRTIO_MSG_EVENT_AVAIL 0x41 +#define VIRTIO_MSG_EVENT_USED 0x42 +#define VIRTIO_MSG_MAX VIRTIO_MSG_EVENT_USED + +#define VIRTIO_MSG_MIN_SIZE 44 +#define VIRTIO_MSG_MAX_SIZE 65536 +#define VIRTIO_MSG_REVISION_1 0x1 + +/* Message payload format */ + +struct get_device_info_resp { + __le32 device_id; + __le32 vendor_id; + __le32 num_feature_bits; + __le32 config_size; + __le32 max_vq_count; + __le16 admin_vq_start_idx; + __le16 admin_vq_count; +} __attribute__((packed)); + +struct get_features { + __le32 index; + __le32 num; +} __attribute__((packed)); + +struct get_features_resp { + __le32 index; + __le32 num; + __u8 features[]; +} __attribute__((packed)); + +struct set_features { + __le32 index; + __le32 num; + __u8 features[]; +} __attribute__((packed)); + +struct get_config { + __le32 offset; + __le32 size; +} __attribute__((packed)); + +struct get_config_resp { + __le32 generation; + __le32 offset; + __le32 size; + __u8 config[]; +} __attribute__((packed)); + +struct set_config { + __le32 generation; + __le32 offset; + __le32 size; + __u8 config[]; +} __attribute__((packed)); + +struct set_config_resp { + __le32 generation; + __le32 offset; + __le32 size; + __u8 config[]; +} __attribute__((packed)); + +struct get_device_status_resp { + __le32 status; +} __attribute__((packed)); + +struct set_device_status { + __le32 status; +} __attribute__((packed)); + +struct set_device_status_resp { + __le32 status; +} __attribute__((packed)); + +struct get_vqueue { + __le32 index; +} __attribute__((packed)); + +struct get_vqueue_resp { + __le32 index; + __le32 max_size; + __le32 size; + __le64 descriptor_addr; + __le64 driver_addr; + __le64 device_addr; +} __attribute__((packed)); + +struct set_vqueue { + __le32 index; + __le32 unused; + __le32 size; + __le64 descriptor_addr; + __le64 driver_addr; + __le64 device_addr; +} __attribute__((packed)); + +struct reset_vqueue { + __le32 index; +} __attribute__((packed)); + +struct get_shm { + __le32 index; +} __attribute__((packed)); + +struct get_shm_resp { + __le32 index; + __le32 count; + __le32 addr; +} __attribute__((packed)); + +struct event_config { + __le32 status; + __le32 generation; + __le32 offset; + __le32 size; + __u8 config[]; +} __attribute__((packed)); + +struct event_avail { + __le32 index; + #define VIRTIO_MSG_EVENT_AVAIL_WRAP_SHIFT 31 + __le32 next_offset_wrap; +} __attribute__((packed)); + +struct event_used { + __le32 index; +} __attribute__((packed)); + +struct virtio_msg { + #define VIRTIO_MSG_TYPE_REQUEST (0 << 0) + #define VIRTIO_MSG_TYPE_RESPONSE (1 << 0) + #define VIRTIO_MSG_TYPE_TRANSPORT (0 << 1) + #define VIRTIO_MSG_TYPE_BUS (1 << 1) + __u8 type; + + __u8 msg_id; + __le16 dev_id; + __le16 msg_size; + __u8 payload[]; +} __attribute__((packed)); + +static inline void *virtio_msg_payload(struct virtio_msg *vmsg) +{ + return &vmsg->payload; +} + +/* Virtio message bus definitions */ + +/* Message types */ +#define VIRTIO_MSG_BUS_GET_DEVICES 0x02 +#define VIRTIO_MSG_BUS_PING 0x03 +#define VIRTIO_MSG_BUS_EVENT_DEVICE 0x40 + +struct bus_get_devices { + __le16 offset; + __le16 num; +} __attribute__((packed)); + +struct bus_get_devices_resp { + __le16 offset; + __le16 num; + __le16 next_offset; + __u8 devices[]; +} __attribute__((packed)); + +struct bus_event_device { + __le16 dev_num; + #define VIRTIO_MSG_BUS_EVENT_DEV_STATE_READY 0x1 + #define VIRTIO_MSG_BUS_EVENT_DEV_STATE_REMOVED 0x2 + __le16 dev_state; +} __attribute__((packed)); + +struct bus_ping { + __le32 data; +} __attribute__((packed)); + +struct bus_ping_resp { + __le32 data; +} __attribute__((packed)); + +#endif /* _LINUX_VIRTIO_MSG_H */

Introduce a virtio-msg bus implementation based on the Arm FF-A (Firmware Framework for Arm) communication interface.

This bus enables virtio-msg transport over secure channels typically used between the normal world OS and a secure OS or hypervisor. It leverages the standardized FF-A interface to exchange messages with a remote backend service.

The implementation integrates with the core virtio-msg transport and uses FF-A service calls to transmit and receive messages.

Optionally, this bus supports attaching a reserved-memory region to constrain DMA-coherent and streaming DMA allocations to a well-defined contiguous area. This memory can be pre-mapped on the remote side, reducing runtime overhead and preventing accidental sharing of unrelated pages due to page-granularity mapping.

To enable reserved memory, the following device tree node should be defined (the node must be named "vmsgffa"):

reserved-memory { #address-cells = <2>; #size-cells = <2>; ranges;

vmsgffa@100000000 { compatible = "restricted-dma-pool"; reg = <0x00000001 0x00000000 0x0 0x00400000>; /* 4 MiB */ }; };

Signed-off-by: Viresh Kumar viresh.kumar@linaro.org --- drivers/virtio/Kconfig | 12 +- drivers/virtio/Makefile | 1 + drivers/virtio/virtio_msg_ffa.c | 505 ++++++++++++++++++++++++++++ include/uapi/linux/virtio_msg_ffa.h | 94 ++++++ 4 files changed, 611 insertions(+), 1 deletion(-) create mode 100644 drivers/virtio/virtio_msg_ffa.c create mode 100644 include/uapi/linux/virtio_msg_ffa.h

diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig index a86025c9e008..683152477e3f 100644 --- a/drivers/virtio/Kconfig +++ b/drivers/virtio/Kconfig @@ -176,7 +176,8 @@ config VIRTIO_MSG select VIRTIO help This enables support for Virtio message transport. This option is - selected by any driver which implements the virtio message bus. + selected by any driver which implements the virtio message bus, such + as VIRTIO_MSG_FFA.

config VIRTIO_MSG_USER tristate "Userspace interface for virtio message transport" @@ -186,6 +187,15 @@ config VIRTIO_MSG_USER can be used to read / write messages over virtio-msg transport from userspace.

+config VIRTIO_MSG_FFA + tristate "FF-A bus driver for virtio message transport" + depends on ARM_FFA_TRANSPORT + select VIRTIO_MSG + help + This implements a Virtio message bus based on ARM FF-A protocol. + + If unsure, say N. + config VIRTIO_DMA_SHARED_BUFFER tristate depends on DMA_SHARED_BUFFER diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile index 5b664c5f5f25..96ec0a9c4a7a 100644 --- a/drivers/virtio/Makefile +++ b/drivers/virtio/Makefile @@ -7,6 +7,7 @@ obj-$(CONFIG_VIRTIO_MMIO) += virtio_mmio.o virtio_msg_transport-y := virtio_msg.o virtio_msg_transport-$(CONFIG_VIRTIO_MSG_USER) += virtio_msg_user.o obj-$(CONFIG_VIRTIO_MSG) += virtio_msg_transport.o +obj-$(CONFIG_VIRTIO_MSG_FFA) += virtio_msg_ffa.o obj-$(CONFIG_VIRTIO_PCI) += virtio_pci.o virtio_pci-y := virtio_pci_modern.o virtio_pci_common.o virtio_pci-$(CONFIG_VIRTIO_PCI_LEGACY) += virtio_pci_legacy.o diff --git a/drivers/virtio/virtio_msg_ffa.c b/drivers/virtio/virtio_msg_ffa.c new file mode 100644 index 000000000000..e7f2cbcd238b --- /dev/null +++ b/drivers/virtio/virtio_msg_ffa.c @@ -0,0 +1,505 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * FF-A bus implementation for Virtio message transport. + * + * Copyright (C) 2025 Google LLC and Linaro. + * Viresh Kumar viresh.kumar@linaro.org + * + * This implements the FF-A (Arm Firmware Framework) bus for Virtio msg + * transport. + */ + +#define pr_fmt(fmt) "virtio-msg-ffa: " fmt + +#include <linux/arm_ffa.h> +#include <linux/err.h> +#include <linux/module.h> +#include <linux/of_reserved_mem.h> +#include <linux/pm.h> +#include <linux/slab.h> +#include <linux/types.h> +#include <linux/virtio.h> +#include <uapi/linux/virtio_msg_ffa.h> + +#include "virtio_msg_internal.h" + +struct virtio_msg_indirect_data { + struct completion completion; + struct virtio_msg *response; +}; + +struct virtio_msg_device_data { + struct virtio_msg_device vmdev; + struct virtio_msg_indirect_data idata; +}; + +/* Represents FF-A corresponding to a partition */ +struct virtio_msg_ffa_device { + struct ffa_device *ffa_dev; + struct reserved_mem *rmem; + struct virtio_msg_indirect_data idata; + struct virtio_msg_device_data *vmdevs; + int (*send)(struct virtio_msg_ffa_device *vmfdev, + struct virtio_msg *request, + struct virtio_msg *response, + struct virtio_msg_indirect_data *idata); + int vmdev_count; + u16 msg_size; +}; + +#define to_vmdevdata(_vmdev) \ + container_of(_vmdev, struct virtio_msg_device_data, vmdev) +#define to_vmfdev(_vmdev) ((struct virtio_msg_ffa_device *)(_vmdev)->bus_data) + +static int vmsg_ffa_send_direct(struct virtio_msg_ffa_device *vmfdev, + struct virtio_msg *request, + struct virtio_msg *response, + struct virtio_msg_indirect_data *idata_unused) +{ + struct ffa_device *ffa_dev = vmfdev->ffa_dev; + struct ffa_send_direct_data2 ffa_data; + int ret; + + memcpy(&ffa_data, request, request->msg_size); + + ret = ffa_dev->ops->msg_ops->sync_send_receive2(ffa_dev, &ffa_data); + if (ret) { + dev_dbg(&ffa_dev->dev, + "Unable to send direct FF-A message: %d\n", ret); + return ret; + } + + if (response) + memcpy(response, &ffa_data, vmfdev->msg_size); + + return 0; +} + +static int vmsg_ffa_send_indirect(struct virtio_msg_ffa_device *vmfdev, + struct virtio_msg *request, + struct virtio_msg *response, + struct virtio_msg_indirect_data *idata) +{ + struct ffa_device *ffa_dev = vmfdev->ffa_dev; + struct device *dev = &ffa_dev->dev; + int ret, count = 10; + + /* + * Store the response pointer in idata structure. This will be updated + * by vmsg_ffa_notifier_cb() later. + */ + idata->response = response; + +try_again: + ret = ffa_dev->ops->msg_ops->indirect_send(ffa_dev, request, + request->msg_size); + if (ret == -EBUSY && --count) { + cpu_relax(); + goto try_again; + } + + if (ret) { + dev_err(dev, "Failed sending indirect FF-A message: %d\n", ret); + return ret; + } + + /* + * Always wait for the operation to finish, otherwise we may start + * another operation while the previous one is still ongoing. + */ + ret = wait_for_completion_interruptible_timeout(&idata->completion, 1000); + if (ret < 0) { + dev_err(dev, "Interrupted - waiting for a response: %d\n", ret); + } else if (!ret) { + dev_err(dev, "Timed out waiting for a response\n"); + ret = -ETIMEDOUT; + } else { + ret = 0; + } + + return ret; +} + +static struct virtio_msg_device * +find_vmdev(struct virtio_msg_ffa_device *vmfdev, u16 dev_id) +{ + int i; + + /* Find the device corresponding to a dev_id */ + for (i = 0; i < vmfdev->vmdev_count; i++) { + if (vmfdev->vmdevs[i].vmdev.dev_id == dev_id) + return &vmfdev->vmdevs[i].vmdev; + } + + dev_err(&vmfdev->ffa_dev->dev, "Couldn't find matching vmdev: %d\n", + dev_id); + return NULL; +} + +static void vmsg_ffa_notifier_cb(int notify_id, void *cb_data, void *buf) +{ + struct virtio_msg_ffa_device *vmfdev = cb_data; + struct ffa_device *ffa_dev = vmfdev->ffa_dev; + struct virtio_msg_indirect_data *idata; + struct virtio_msg_device *vmdev; + struct virtio_msg *vmsg = buf; + + /* + * We can either receive a response message (to a previously sent + * request), or an EVENT_USED request message. + */ + if (vmsg->type & VIRTIO_MSG_TYPE_RESPONSE) { + if (vmsg->type & VIRTIO_MSG_TYPE_BUS) { + idata = &vmfdev->idata; + } else { + vmdev = find_vmdev(vmfdev, le16_to_cpu(vmsg->dev_id)); + if (!vmdev) + return; + + idata = &to_vmdevdata(vmdev)->idata; + } + + if (idata->response) + memcpy(idata->response, vmsg, vmsg->msg_size); + + complete(&idata->completion); + + return; + } + + /* Only support EVENT_USED virtio request messages */ + if (vmsg->type & VIRTIO_MSG_TYPE_BUS || + vmsg->msg_id != VIRTIO_MSG_EVENT_USED) { + dev_err(&ffa_dev->dev, "Unsupported message received\n"); + return; + } + + vmdev = find_vmdev(vmfdev, le16_to_cpu(vmsg->dev_id)); + if (!vmdev) + return; + + virtio_msg_event(vmdev, vmsg); +} + +static int vmsg_ffa_notify_setup(struct virtio_msg_ffa_device *vmfdev) +{ + struct ffa_device *ffa_dev = vmfdev->ffa_dev; + int ret; + + ret = ffa_dev->ops->notifier_ops->fwk_notify_request(ffa_dev, + &vmsg_ffa_notifier_cb, vmfdev, 0); + if (ret) + dev_err(&ffa_dev->dev, "Unable to request notifier: %d\n", ret); + + return ret; +} + +static void vmsg_ffa_notify_cleanup(struct virtio_msg_ffa_device *vmfdev) +{ + struct ffa_device *ffa_dev = vmfdev->ffa_dev; + int ret; + + ret = ffa_dev->ops->notifier_ops->fwk_notify_relinquish(ffa_dev, 0); + if (ret) + dev_err(&ffa_dev->dev, "Unable to relinquish notifier: %d\n", ret); +} + +static int vmsg_ffa_bus_get_devices(struct virtio_msg_ffa_device *vmfdev, + u16 *map, u16 *count) +{ + u8 req_buf[VIRTIO_MSG_FFA_BUS_MSG_SIZE]; + u8 res_buf[VIRTIO_MSG_FFA_BUS_MSG_SIZE]; + struct virtio_msg *request = (struct virtio_msg *)&req_buf; + struct virtio_msg *response = (struct virtio_msg *)&res_buf; + struct bus_get_devices *req_payload = virtio_msg_payload(request); + struct bus_get_devices_resp *res_payload = virtio_msg_payload(response); + int ret; + + static_assert(sizeof(*request) + sizeof(*req_payload) < + VIRTIO_MSG_FFA_BUS_MSG_SIZE); + static_assert(sizeof(*response) + sizeof(*res_payload) < + VIRTIO_MSG_FFA_BUS_MSG_SIZE); + + virtio_msg_prepare(request, VIRTIO_MSG_BUS_GET_DEVICES, + sizeof(*req_payload)); + req_payload->offset = 0; + req_payload->num = cpu_to_le16(0xFF); + + ret = vmfdev->send(vmfdev, request, response, &vmfdev->idata); + if (ret < 0) + return ret; + + *count = le16_to_cpu(res_payload->num); + if (!*count) + return -ENODEV; + + if (res_payload->offset != req_payload->offset) + return -EINVAL; + + /* Support up to 16 devices for now */ + if (res_payload->next_offset) + return -EINVAL; + + map[0] = res_payload->devices[0]; + map[1] = res_payload->devices[1]; + + return 0; +} + +static int vmsg_ffa_bus_version(struct virtio_msg_ffa_device *vmfdev) +{ + u8 req_buf[VIRTIO_MSG_FFA_BUS_MSG_SIZE]; + u8 res_buf[VIRTIO_MSG_FFA_BUS_MSG_SIZE]; + struct virtio_msg *request = (struct virtio_msg *)&req_buf; + struct virtio_msg *response = (struct virtio_msg *)&res_buf; + struct bus_ffa_version *req_payload = virtio_msg_payload(request); + struct bus_ffa_version_resp *res_payload = virtio_msg_payload(response); + u32 features; + int ret; + + static_assert(sizeof(*request) + sizeof(*req_payload) < + VIRTIO_MSG_FFA_BUS_MSG_SIZE); + static_assert(sizeof(*response) + sizeof(*res_payload) < + VIRTIO_MSG_FFA_BUS_MSG_SIZE); + + virtio_msg_prepare(request, VIRTIO_MSG_FFA_BUS_VERSION, + sizeof(*req_payload)); + req_payload->driver_version = cpu_to_le32(VIRTIO_MSG_FFA_BUS_VERSION_1_0); + req_payload->vmsg_revision = cpu_to_le32(VIRTIO_MSG_REVISION_1); + req_payload->vmsg_features = cpu_to_le32(VIRTIO_MSG_FEATURES); + req_payload->features = cpu_to_le32(VIRTIO_MSG_FFA_FEATURE_BOTH_SUPP); + req_payload->area_num = cpu_to_le16(VIRTIO_MSG_FFA_AREA_ID_MAX); + + ret = vmfdev->send(vmfdev, request, response, &vmfdev->idata); + if (ret < 0) + return ret; + + if (le32_to_cpu(res_payload->device_version) != VIRTIO_MSG_FFA_BUS_VERSION_1_0) + return -EINVAL; + + if (le32_to_cpu(res_payload->vmsg_revision) != VIRTIO_MSG_REVISION_1) + return -EINVAL; + + if (le32_to_cpu(res_payload->vmsg_features) != VIRTIO_MSG_FEATURES) + return -EINVAL; + + features = le32_to_cpu(res_payload->features); + + /* + * - Direct message must be supported if it already worked. + * - Indirect message must be supported if it already worked + * - And direct message must not be supported since it didn't work. + */ + if ((ffa_partition_supports_direct_recv(vmfdev->ffa_dev) && + !(features & VIRTIO_MSG_FFA_FEATURE_DIRECT_MSG_RX_SUPP)) || + (ffa_partition_supports_indirect_msg(vmfdev->ffa_dev) && + !(features & VIRTIO_MSG_FFA_FEATURE_INDIRECT_MSG_SUPP))) { + dev_err(&vmfdev->ffa_dev->dev, "Invalid features\n"); + return -EINVAL; + } + + return 0; +} + +static int virtio_msg_ffa_transfer(struct virtio_msg_device *vmdev, + struct virtio_msg *request, + struct virtio_msg *response) +{ + struct virtio_msg_indirect_data *idata = &to_vmdevdata(vmdev)->idata; + struct virtio_msg_ffa_device *vmfdev = to_vmfdev(vmdev); + + return vmfdev->send(vmfdev, request, response, idata); +} + +static const char *virtio_msg_ffa_bus_info(struct virtio_msg_device *vmdev, + u16 *msg_size, u32 *rev) +{ + struct virtio_msg_ffa_device *vmfdev = to_vmfdev(vmdev); + + *msg_size = vmfdev->msg_size; + *rev = VIRTIO_MSG_REVISION_1; + + return dev_name(&vmfdev->ffa_dev->dev); +} + +static struct virtio_msg_ops vmf_ops = { + .transfer = virtio_msg_ffa_transfer, + .bus_info = virtio_msg_ffa_bus_info, +}; + +static void remove_vmdevs(struct virtio_msg_ffa_device *vmfdev, int count) +{ + while (count--) + virtio_msg_unregister(&vmfdev->vmdevs[count].vmdev); +} + +static int virtio_msg_ffa_probe(struct ffa_device *ffa_dev) +{ + struct virtio_msg_ffa_device *vmfdev; + struct device *dev = &ffa_dev->dev; + struct virtio_msg_device *vmdev; + unsigned long devices = 0; + int ret, i = 0, bit; + u16 count; + + vmfdev = devm_kzalloc(dev, sizeof(*vmfdev), GFP_KERNEL); + if (!vmfdev) + return -ENOMEM; + + if (ffa_partition_supports_direct_recv(ffa_dev)) { + vmfdev->send = vmsg_ffa_send_direct; + } else if (ffa_partition_supports_indirect_msg(ffa_dev)) { + vmfdev->send = vmsg_ffa_send_indirect; + } else { + dev_err(dev, "Direct or Indirect messages not supported\n"); + return -EINVAL; + } + + vmfdev->ffa_dev = ffa_dev; + vmfdev->msg_size = VIRTIO_MSG_FFA_BUS_MSG_SIZE; + ffa_dev_set_drvdata(ffa_dev, vmfdev); + init_completion(&vmfdev->idata.completion); + + ret = vmsg_ffa_notify_setup(vmfdev); + if (ret) + return ret; + + ret = vmsg_ffa_bus_version(vmfdev); + if (ret) + goto notify_cleanup; + + ret = vmsg_ffa_bus_get_devices(vmfdev, (u16 *)&devices, &count); + if (ret) + goto notify_cleanup; + + ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(64)); + if (ret) + dev_warn(dev, "Failed to enable 64-bit or 32-bit DMA\n"); + + vmfdev->rmem = of_reserved_mem_lookup_by_name("vmsgffa"); + if (!IS_ERR(vmfdev->rmem)) { + ret = reserved_mem_device_init(dev, vmfdev->rmem); + if (ret) + goto rmem_free; + } else { + dev_info(dev, "Continuing without reserved-memory block\n"); + } + + vmfdev->vmdevs = devm_kcalloc(dev, count, sizeof(*vmfdev->vmdevs), + GFP_KERNEL); + if (!vmfdev->vmdevs) { + ret = -ENOMEM; + goto rmem_free; + } + vmfdev->vmdev_count = count; + + for_each_set_bit(bit, &devices, sizeof(devices)) { + init_completion(&vmfdev->vmdevs[i].idata.completion); + vmdev = &vmfdev->vmdevs[i].vmdev; + vmdev->dev_id = bit; + vmdev->ops = &vmf_ops; + vmdev->vdev.dev.parent = dev; + vmdev->bus_data = vmfdev; + + ret = virtio_msg_register(vmdev); + if (ret) { + dev_err(dev, "Failed to register virtio-msg device (%d)\n", ret); + goto unregister; + } + + i++; + } + + return 0; + +unregister: + remove_vmdevs(vmfdev, i); +rmem_free: + if (!IS_ERR(vmfdev->rmem)) + of_reserved_mem_device_release(dev); +notify_cleanup: + vmsg_ffa_notify_cleanup(vmfdev); + return ret; +} + +static void virtio_msg_ffa_remove(struct ffa_device *ffa_dev) +{ + struct virtio_msg_ffa_device *vmfdev = ffa_dev->dev.driver_data; + + remove_vmdevs(vmfdev, vmfdev->vmdev_count); + + if (!IS_ERR(vmfdev->rmem)) + of_reserved_mem_device_release(&ffa_dev->dev); + + vmsg_ffa_notify_cleanup(vmfdev); +} + +static const struct ffa_device_id virtio_msg_ffa_device_ids[] = { + /* c66028b5-2498-4aa1-9de7-77da6122abf0 */ + { UUID_INIT(0xc66028b5, 0x2498, 0x4aa1, + 0x9d, 0xe7, 0x77, 0xda, 0x61, 0x22, 0xab, 0xf0) }, + {} +}; + +static int __maybe_unused virtio_msg_ffa_suspend(struct device *dev) +{ + struct virtio_msg_ffa_device *vmfdev = dev_get_drvdata(dev); + int ret, i, index; + + for (i = 0; i < vmfdev->vmdev_count; i++) { + index = vmfdev->vmdev_count - i - 1; + ret = virtio_device_freeze(&vmfdev->vmdevs[index].vmdev.vdev); + if (ret) + return ret; + } + + return 0; +} + +static int __maybe_unused virtio_msg_ffa_resume(struct device *dev) +{ + struct virtio_msg_ffa_device *vmfdev = dev_get_drvdata(dev); + int ret, i; + + for (i = 0; i < vmfdev->vmdev_count; i++) { + ret = virtio_device_restore(&vmfdev->vmdevs[i].vmdev.vdev); + if (ret) + return ret; + } + + return 0; +} + +static const struct dev_pm_ops virtio_msg_ffa_pm_ops = { + SET_SYSTEM_SLEEP_PM_OPS(virtio_msg_ffa_suspend, virtio_msg_ffa_resume) +}; + +static struct ffa_driver virtio_msg_ffa_driver = { + .name = "virtio-msg-ffa", + .probe = virtio_msg_ffa_probe, + .remove = virtio_msg_ffa_remove, + .id_table = virtio_msg_ffa_device_ids, + .driver = { + .pm = &virtio_msg_ffa_pm_ops, + }, +}; + +static int virtio_msg_ffa_init(void) +{ + if (IS_REACHABLE(CONFIG_ARM_FFA_TRANSPORT)) + return ffa_register(&virtio_msg_ffa_driver); + else + return -EOPNOTSUPP; +} +module_init(virtio_msg_ffa_init); + +static void virtio_msg_ffa_exit(void) +{ + if (IS_REACHABLE(CONFIG_ARM_FFA_TRANSPORT)) + ffa_unregister(&virtio_msg_ffa_driver); +} +module_exit(virtio_msg_ffa_exit); + +MODULE_AUTHOR("Viresh Kumar viresh.kumar@linaro.org"); +MODULE_DESCRIPTION("Virtio message FF-A bus driver"); +MODULE_LICENSE("GPL"); diff --git a/include/uapi/linux/virtio_msg_ffa.h b/include/uapi/linux/virtio_msg_ffa.h new file mode 100644 index 000000000000..adcc081b483a --- /dev/null +++ b/include/uapi/linux/virtio_msg_ffa.h @@ -0,0 +1,94 @@ +/* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) */ +/* + * Virtio message FF-A (Arm Firmware Framework) bus header. + * + * Copyright (C) 2025 Google LLC and Linaro. + * Viresh Kumar viresh.kumar@linaro.org + */ + +#ifndef _LINUX_VIRTIO_MSG_FFA_H +#define _LINUX_VIRTIO_MSG_FFA_H + +#include <linux/types.h> + +/* Message types */ +#define VIRTIO_MSG_FFA_BUS_VERSION 0x80 +#define VIRTIO_MSG_FFA_BUS_AREA_SHARE 0x81 +#define VIRTIO_MSG_FFA_BUS_AREA_UNSHARE 0x82 +#define VIRTIO_MSG_FFA_BUS_RESET 0x83 +#define VIRTIO_MSG_FFA_BUS_EVENT_POLL 0x84 +#define VIRTIO_MSG_FFA_BUS_AREA_RELEASE 0xC0 + +#define VIRTIO_MSG_FEATURES 0 +#define VIRTIO_MSG_FFA_BUS_VERSION_1_0 0x1 +#define VIRTIO_MSG_FFA_BUS_MSG_SIZE VIRTIO_MSG_MIN_SIZE + +#define VIRTIO_MSG_FFA_FEATURE_DIRECT_MSG_RX_SUPP (1 << 0) +#define VIRTIO_MSG_FFA_FEATURE_DIRECT_MSG_TX_SUPP (1 << 1) +#define VIRTIO_MSG_FFA_FEATURE_DIRECT_MSG_SUPP \ + (VIRTIO_MSG_FFA_FEATURE_DIRECT_MSG_RX_SUPP | \ + VIRTIO_MSG_FFA_FEATURE_DIRECT_MSG_TX_SUPP) + +#define VIRTIO_MSG_FFA_FEATURE_INDIRECT_MSG_RX_SUPP (1 << 2) +#define VIRTIO_MSG_FFA_FEATURE_INDIRECT_MSG_TX_SUPP (1 << 3) +#define VIRTIO_MSG_FFA_FEATURE_INDIRECT_MSG_SUPP \ + (VIRTIO_MSG_FFA_FEATURE_INDIRECT_MSG_RX_SUPP | \ + VIRTIO_MSG_FFA_FEATURE_INDIRECT_MSG_TX_SUPP) + +#define VIRTIO_MSG_FFA_FEATURE_BOTH_SUPP \ + (VIRTIO_MSG_FFA_FEATURE_DIRECT_MSG_SUPP | \ + VIRTIO_MSG_FFA_FEATURE_INDIRECT_MSG_SUPP) + +#define VIRTIO_MSG_FFA_AREA_ID_MAX 0xFF +#define VIRTIO_MSG_FFA_AREA_ID_OFFSET 56 +#define VIRTIO_MSG_FFA_OFFSET_MASK \ + ((ULL(1) << VIRTIO_MSG_FFA_AREA_ID_OFFSET) - 1) + +#define VIRTIO_MSG_FFA_RESULT_ERROR (1 << 0) +#define VIRTIO_MSG_FFA_RESULT_BUSY (1 << 1) + +/* Message payload format */ + +struct bus_ffa_version { + __le32 driver_version; + __le32 vmsg_revision; + __le32 vmsg_features; + __le32 features; + __le16 area_num; +} __attribute__((packed)); + +struct bus_ffa_version_resp { + __le32 device_version; + __le32 vmsg_revision; + __le32 vmsg_features; + __le32 features; + __le16 area_num; +} __attribute__((packed)); + +struct bus_area_share { + __le16 area_id; + __le64 mem_handle; + __le64 tag; + __le32 count; + __le32 attr; +} __attribute__((packed)); + +struct bus_area_share_resp { + __le16 area_id; + __le16 result; +} __attribute__((packed)); + +struct bus_area_unshare { + __le16 area_id; +} __attribute__((packed)); + +struct bus_area_unshare_resp { + __le16 area_id; + __le16 result; +} __attribute__((packed)); + +struct bus_area_release { + __le16 area_id; +} __attribute__((packed)); + +#endif /* _LINUX_VIRTIO_MSG_FFA_H */