Re: [PATCH v5 10/13] gunyah: rsc_mgr: Add resource manager RPC core

Dmitry Baryshkov
2022-10-12T22:52:25Z

On 11/10/2022 03:08, Elliot Berman wrote:
> The resource manager is a special virtual machine which is always
> running on a Gunyah system. It provides APIs for creating and destroying
> VMs, secure memory management, sharing/lending of memory between VMs,
> and setup of inter-VM communication. Calls to the resource manager are
> made via message queues.
>
> This patch implements the basic probing and RPC mechanism to make those
> API calls. Request/response calls can be made with gh_rm_call.
> Drivers can also register to notifications pushed by RM via
> gh_rm_register_notifier
>
> Specific API calls that resource manager supports will be implemented in
> subsequent patches.
>
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> ---
> MAINTAINERS | 2 +-
> drivers/virt/gunyah/Kconfig | 20 +-
> drivers/virt/gunyah/Makefile | 3 +
> drivers/virt/gunyah/rsc_mgr.c | 601 +++++++++++++++++++++++++++++++++
> drivers/virt/gunyah/rsc_mgr.h | 34 ++
> include/linux/gunyah_rsc_mgr.h | 26 ++
> 6 files changed, 682 insertions(+), 4 deletions(-)
> create mode 100644 drivers/virt/gunyah/rsc_mgr.c
> create mode 100644 drivers/virt/gunyah/rsc_mgr.h
> create mode 100644 include/linux/gunyah_rsc_mgr.h
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 599804836d05..8a3d79b56698 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -8891,7 +8891,7 @@ F: arch/arm64/gunyah/
> F: drivers/mailbox/gunyah-msgq.c
> F: drivers/virt/gunyah/
> F: include/asm-generic/gunyah.h
> -F: include/linux/gunyah.h
> +F: include/linux/gunyah*.h
>
> HABANALABS PCI DRIVER
> M: Oded Gabbay <ogabbay@kernel.org>
> diff --git a/drivers/virt/gunyah/Kconfig b/drivers/virt/gunyah/Kconfig
> index f4c822a82f1a..78deed3c4562 100644
> --- a/drivers/virt/gunyah/Kconfig
> +++ b/drivers/virt/gunyah/Kconfig
> @@ -3,9 +3,6 @@
> config GUNYAH
> tristate "Gunyah Virtualization drivers"
> depends on ARM64
> - select AUXILIARY_BUS
> - select MAILBOX
> - select GUNYAH_MESSAGE_QUEUES

This should be squashed into earlier patches

> help
> The Gunyah drivers are the helper interfaces that runs in a guest VM
> such as basic inter-VM IPC and signaling mechanisms, and higher level
> @@ -13,3 +10,20 @@ config GUNYAH
>
> Say Y/M here to enable the drivers needed to interact in a Gunyah
> virtual environment.
> +
> +if GUNYAH

Just `depends on GUNYAH'

> +
> +config GUNYAH_RESORUCE_MANAGER
> + tristate "Gunyah Resource Manager"
> + select MAILBOX
> + select GUNYAH_MESSAGE_QUEUES
> + default y
> + help
> + The resource manager (RM) is a privileged application VM supporting
> + the Gunyah Hypervisor. Enable this driver to support communicating
> + with Gunyah RM. This is typically required for a VM running under
> + Gunyah wanting to have Gunyah-awareness.
> +
> + Say Y/M here if unsure.
> +
> +endif
> diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
> index dc081e2dc02b..2cae8ea5bc7d 100644
> --- a/drivers/virt/gunyah/Makefile
> +++ b/drivers/virt/gunyah/Makefile
> @@ -1,2 +1,5 @@
> gunyah-y += gunyah.o
> obj-$(CONFIG_GUNYAH) += gunyah.o
> +
> +gunyah_rsc_mgr-y += rsc_mgr.o
> +obj-$(CONFIG_GUNYAH_RESORUCE_MANAGER) += gunyah_rsc_mgr.o

You know, you don't have to do this...

> diff --git a/drivers/virt/gunyah/rsc_mgr.c b/drivers/virt/gunyah/rsc_mgr.c
> new file mode 100644
> index 000000000000..0e2f04984ada
> --- /dev/null
> +++ b/drivers/virt/gunyah/rsc_mgr.c
> @@ -0,0 +1,601 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +#define pr_fmt(fmt) "gh_rsc_mgr: " fmt
> +
> +#include <linux/of.h>
> +#include <linux/slab.h>
> +#include <linux/mutex.h>
> +#include <linux/sched.h>
> +#include <linux/gunyah.h>
> +#include <linux/module.h>
> +#include <linux/of_irq.h>
> +#include <linux/kthread.h>
> +#include <linux/notifier.h>
> +#include <linux/workqueue.h>
> +#include <linux/completion.h>
> +#include <linux/gunyah_rsc_mgr.h>
> +#include <linux/platform_device.h>
> +
> +#include "rsc_mgr.h"
> +
> +/* Resource Manager Header */
> +struct gh_rm_rpc_hdr {
> + u8 version:4,
> + hdr_words:4;

Does the following work? It looks better:

u8 version: 4;
u8 hdr_words: 4;

etc.

> + u8 type:2,
> + fragments:6;
> + u16 seq;
> + u32 msg_id;
> +} __packed;
> +
> +/* Standard reply header */
> +struct gh_rm_rpc_reply_hdr {
> + struct gh_rm_rpc_hdr rpc_hdr;
> + u32 err_code;
> +} __packed;
> +
> +/* RPC Header versions */
> +#define GH_RM_RPC_HDR_VERSION_ONE 0x1
> +
> +/* RPC Header words */
> +#define GH_RM_RPC_HDR_WORDS 0x2
> +
> +/* RPC Message types */
> +#define GH_RM_RPC_TYPE_CONT 0x0
> +#define GH_RM_RPC_TYPE_REQ 0x1
> +#define GH_RM_RPC_TYPE_RPLY 0x2
> +#define GH_RM_RPC_TYPE_NOTIF 0x3
> +
> +#define GH_RM_MAX_NUM_FRAGMENTS 62
> +
> +#define GH_RM_MAX_MSG_SIZE (GH_MSGQ_MAX_MSG_SIZE - sizeof(struct gh_rm_rpc_hdr))
> +
> +/**
> + * struct gh_rm_connection - Represents a complete message from resource manager
> + * @payload: Combined payload of all the fragments (i.e. msg headers stripped off).
> + * @size: Size of the payload.
> + * @ret: Linux return code, set in case there was an error processing the connection.
> + * @msg_id: Message ID from the header.
> + * @type: GH_RM_RPC_TYPE_RPLY or GH_RM_RPC_TYPE_NOTIF.
> + * @num_fragments: total number of fragments expected to be received for this connection.
> + * @fragments_recieved: fragments received so far.
> + * @rm_error: For request/reply sequences with standard replies.
> + * @seq: Sequence ID for the main message.
> + */
> +struct gh_rm_connection {
> + void *payload;
> + size_t size;
> + int ret;
> + u32 msg_id;
> + u8 type;
> +
> + u8 num_fragments;
> + u8 fragments_received;
> +
> + /* only for req/reply sequence */
> + u32 rm_error;
> + u16 seq;
> + struct completion seq_done;
> +};
> +
> +struct gh_rm_notif_complete {
> + struct gh_rm_connection *conn;
> + struct work_struct work;
> +};
> +
> +struct gh_rsc_mgr {
> + struct gunyah_msgq msgq;
> + struct mbox_client msgq_client;
> + struct gh_rm_connection *active_rx_connection;
> + int last_tx_ret;
> +
> + struct idr call_idr;
> + struct mutex call_idr_lock;
> +
> + struct mutex send_lock;
> +
> + struct work_struct recv_work;
> +};
> +
> +static struct gh_rsc_mgr *__rsc_mgr;
> +SRCU_NOTIFIER_HEAD_STATIC(gh_rm_notifier);
> +
> +static struct gh_rm_connection *gh_rm_alloc_connection(u32 msg_id, u8 type)
> +{
> + struct gh_rm_connection *connection;
> +
> + connection = kzalloc(sizeof(*connection), GFP_KERNEL);
> + if (!connection)
> + return NULL;
> +
> + connection->type = type;
> + connection->msg_id = msg_id;
> +
> + return connection;
> +}
> +
> +/**
> + * gh_rm_init_connection_payload() - Fills the first message for a connection.
> + */
> +static int gh_rm_init_connection_payload(struct gh_rm_connection *connection, void *msg,
> + size_t hdr_size, size_t payload_size)

Both calling sites pass payload_size as msg_size - hdr_size. I'd suggest
moving this calculation here.

> +{
> + struct gh_rm_rpc_hdr *hdr = msg;
> + size_t max_buf_size;
> +
> + connection->num_fragments = hdr->fragments;
> + connection->fragments_received = 0;
> + connection->type = hdr->type;
> +
> + /* There's not going to be any payload, no need to allocate buffer. */
> + if (!payload_size && !connection->num_fragments)
> + return 0;
> +
> + /*
> + * maximum payload size is GH_MSGQ_MAX_MSG_SIZE - hdr_size
> + * and can received (hdr->fragments + 1) of those
> + */
> + max_buf_size = (GH_MSGQ_MAX_MSG_SIZE - hdr_size) * (hdr->fragments + 1);
> +
> + connection->payload = kzalloc(max_buf_size, GFP_KERNEL);
> + if (!connection->payload)
> + return -ENOMEM;
> +
> + memcpy(connection->payload, msg + hdr_size, payload_size);
> + connection->size = payload_size;
> + return 0;
> +}
> +
> +static void gh_rm_notif_work(struct work_struct *work)
> +{
> + struct gh_rm_notif_complete *notif = container_of(work, struct gh_rm_notif_complete, work);
> + struct gh_rm_connection *connection = notif->conn;
> + u32 notif_id = connection->msg_id;
> + struct gh_rm_notification notification = {
> + .buff = connection->payload,
> + .size = connection->size,
> + };
> +
> + srcu_notifier_call_chain(&gh_rm_notifier, notif_id, &notification);
> +
> + kfree(connection->payload);
> + kfree(connection);
> + kfree(notif);
> +}
> +
> +static struct gh_rm_connection *gh_rm_process_notif(struct gh_rsc_mgr *rsc_mgr,
> + void *msg, size_t msg_size)
> +{
> + struct gh_rm_rpc_hdr *hdr = msg;
> + struct gh_rm_connection *connection;
> +
> + connection = gh_rm_alloc_connection(hdr->msg_id, hdr->type);
> + if (!connection) {
> + pr_err("Failed to alloc connection for notification, dropping.\n");
> + return NULL;
> + }
> +
> + if (gh_rm_init_connection_payload(connection, msg, sizeof(*hdr), msg_size - sizeof(*hdr))) {
> + pr_err("Failed to alloc connection buffer for notification, dropping.\n");
> + kfree(connection);
> + return NULL;
> + }
> +
> + return connection;
> +}
> +
> +static struct gh_rm_connection *gh_rm_process_rply(struct gh_rsc_mgr *rsc_mgr,
> + void *msg, size_t msg_size)
> +{
> + struct gh_rm_rpc_reply_hdr *reply_hdr = msg;
> + struct gh_rm_rpc_hdr *hdr = msg;
> + struct gh_rm_connection *connection;
> +
> + if (mutex_lock_interruptible(&rsc_mgr->call_idr_lock))
> + return ERR_PTR(-ERESTARTSYS);
> +
> + connection = idr_find(&rsc_mgr->call_idr, hdr->seq);
> + mutex_unlock(&rsc_mgr->call_idr_lock);
> +
> + if (!connection) {
> + pr_err("Failed to find connection for sequence %u\n", hdr->seq);
> + return NULL;
> + }
> + if (connection->msg_id != hdr->msg_id) {
> + pr_err("Reply for sequence %u expected msg_id: %x but got %x\n", hdr->seq,
> + connection->msg_id, hdr->msg_id);
> + /*
> + * Don't complete connection and error the client, maybe resource manager will
> + * send us the expected reply sequence soon.
> + */
> + return NULL;
> + }
> +
> + if (gh_rm_init_connection_payload(connection, msg, sizeof(*reply_hdr),
> + msg_size - sizeof(*reply_hdr))) {
> + pr_err("Failed to alloc connection buffer for sequence %d\n", hdr->seq);
> + /* Send connection complete and error the client. */
> + connection->ret = -ENOMEM;
> + complete(&connection->seq_done);
> + return NULL;
> + }
> +
> + connection->rm_error = reply_hdr->err_code;
> + return connection;
> +}
> +
> +static void gh_rm_process_cont(struct gh_rm_connection *connection, void *msg, size_t msg_size)
> +{
> + struct gh_rm_rpc_hdr *hdr = msg;
> + size_t payload_size = msg_size - sizeof(*hdr);
> +
> + /*
> + * hdr->fragments and hdr->msg_id preserves the value from first reply or notif message.
> + * For sake of sanity, check if it's still intact.
> + */
> + if (connection->msg_id != hdr->msg_id)
> + pr_warn("Appending mismatched continuation with id %d to connection with id %d\n",
> + hdr->msg_id, connection->msg_id);
> + if (connection->num_fragments != hdr->fragments)
> + pr_warn("Number of fragments mismatch for seq: %d\n", hdr->seq);
> +
> + memcpy(connection->payload + connection->size, msg + sizeof(*hdr), payload_size);
> + connection->size += payload_size;
> + connection->fragments_received++;
> +}
> +
> +static bool gh_rm_complete_connection(struct gh_rm_connection *connection)
> +{
> + struct gh_rm_notif_complete *notif_work;
> +
> + if (!connection)
> + return false;
> +
> + if (connection->fragments_received != connection->num_fragments)
> + return false;
> +
> + switch (connection->type) {
> + case GH_RM_RPC_TYPE_RPLY:
> + complete(&connection->seq_done);
> + break;
> + case GH_RM_RPC_TYPE_NOTIF:
> + notif_work = kzalloc(sizeof(*notif_work), GFP_KERNEL);
> + if (notif_work == NULL)
> + break;
> +
> + notif_work->conn = connection;
> + INIT_WORK(&notif_work->work, gh_rm_notif_work);
> +
> + schedule_work(&notif_work->work);
> + break;
> + default:
> + pr_err("Invalid message type (%d) received\n", connection->type);
> + break;
> + }
> +
> + return true;
> +}
> +
> +static void gh_rm_abort_connection(struct gh_rm_connection *connection)
> +{
> + switch (connection->type) {
> + case GH_RM_RPC_TYPE_RPLY:
> + connection->ret = -EIO;
> + complete(&connection->seq_done);
> + break;
> + case GH_RM_RPC_TYPE_NOTIF:
> + fallthrough;
> + default:
> + kfree(connection->payload);
> + kfree(connection);
> + }
> +}
> +
> +static void gh_rm_msgq_rx_data(struct mbox_client *cl, void *mssg)
> +{
> + struct gh_rsc_mgr *rsc_mgr = container_of(cl, struct gh_rsc_mgr, msgq_client);
> + struct gunyah_msgq_rx_data *rx_data = mssg;
> + void *msg = rx_data->data;
> + size_t msg_size = rx_data->length;
> + struct gh_rm_rpc_hdr *hdr;
> +
> + if (msg_size <= sizeof(struct gh_rm_rpc_hdr)) {
> + pr_err("Invalid message size received: %ld is too small\n", msg_size);
> + return;
> + }
> +
> + hdr = msg;
> + switch (hdr->type) {
> + case GH_RM_RPC_TYPE_NOTIF:
> + if (rsc_mgr->active_rx_connection) {
> + /* Not possible per protocol. Do something better than BUG_ON */
> + pr_warn("Received start of new notification without finishing existing message series.\n");
> + gh_rm_abort_connection(rsc_mgr->active_rx_connection);
> + }
> + rsc_mgr->active_rx_connection = gh_rm_process_notif(rsc_mgr, msg, msg_size);
> + break;
> + case GH_RM_RPC_TYPE_RPLY:
> + if (rsc_mgr->active_rx_connection) {
> + /* Not possible per protocol. Do something better than BUG_ON */
> + pr_warn("Received start of new reply without finishing existing message series.\n");
> + gh_rm_abort_connection(rsc_mgr->active_rx_connection);
> + }
> + rsc_mgr->active_rx_connection = gh_rm_process_rply(rsc_mgr, msg, msg_size);
> + break;
> + case GH_RM_RPC_TYPE_CONT:
> + if (!rsc_mgr->active_rx_connection) {
> + pr_warn("Received a continuation message without receiving initial message\n");
> + break;
> + }
> + gh_rm_process_cont(rsc_mgr->active_rx_connection, msg, msg_size);
> + break;
> + default:
> + pr_err("Invalid message type (%d) received\n", hdr->type);
> + return;
> + }
> +
> + if (gh_rm_complete_connection(rsc_mgr->active_rx_connection))
> + rsc_mgr->active_rx_connection = NULL;
> +}
> +
> +static void gh_rm_msgq_tx_done(struct mbox_client *cl, void *mssg, int r)
> +{
> + struct gh_rsc_mgr *rsc_mgr = container_of(cl, struct gh_rsc_mgr, msgq_client);
> +
> + kfree(mssg);
> + rsc_mgr->last_tx_ret = r;
> +}
> +
> +static int gh_rm_send_request(struct gh_rsc_mgr *rsc_mgr, u32 message_id,
> + const void *req_buff, size_t req_buff_size,
> + struct gh_rm_connection *connection)
> +{
> + size_t buff_size_remaining = req_buff_size;
> + const void *req_buff_curr = req_buff;
> + struct gh_rm_rpc_hdr *hdr;
> + u32 cont_fragments = req_buff_size / GH_RM_MAX_MSG_SIZE;
> + size_t payload_size;
> + struct gunyah_msgq_tx_data *msg;
> + int i, ret;
> +
> + if (WARN(cont_fragments > GH_RM_MAX_NUM_FRAGMENTS,
> + "Limit exceeded for the number of fragments: %u\n", cont_fragments))
> + return -E2BIG;
> +
> + ret = mutex_lock_interruptible(&rsc_mgr->send_lock);
> + if (ret)
> + return ret;
> +
> + /* Consider also the 'request' packet for the loop count */
> + for (i = 0; i <= cont_fragments; i++) {
> + if (buff_size_remaining > GH_RM_MAX_MSG_SIZE) {
> + payload_size = GH_RM_MAX_MSG_SIZE;
> + buff_size_remaining -= payload_size;
> + } else {
> + payload_size = buff_size_remaining;
> + }
> +
> + msg = kzalloc(sizeof(*msg) + GH_MSGQ_MAX_MSG_SIZE, GFP_KERNEL);
> + if (!msg) {
> + ret = -ENOMEM;
> + goto out;
> + }
> +
> + /* Fill header */
> + hdr = (struct gh_rm_rpc_hdr *)msg->data;
> + hdr->version = GH_RM_RPC_HDR_VERSION_ONE;
> + hdr->hdr_words = GH_RM_RPC_HDR_WORDS;
> + hdr->type = i == 0 ? GH_RM_RPC_TYPE_REQ : GH_RM_RPC_TYPE_CONT;
> + hdr->fragments = cont_fragments;
> + hdr->seq = connection->seq;
> + hdr->msg_id = message_id;
> +
> + /* Copy payload */
> + memcpy(msg->data + sizeof(*hdr), req_buff_curr, payload_size);
> + req_buff_curr += payload_size;
> +
> + /* Force the last fragment to immediately alert the receiver */
> + msg->push = i == cont_fragments;
> + msg->length = sizeof(*hdr) + payload_size;
> +
> + ret = mbox_send_message(gunyah_msgq_chan(&rsc_mgr->msgq), msg);
> + if (ret < 0) {
> + kfree(msg);
> + break;
> + }
> +
> + if (rsc_mgr->last_tx_ret) {
> + ret = rsc_mgr->last_tx_ret;
> + break;
> + }
> + }
> +
> +out:
> + mutex_unlock(&rsc_mgr->send_lock);
> + return ret < 0 ? ret : 0;
> +}
> +
> +/**
> + * gh_rm_call: Achieve request-response type communication with RPC
> + * @message_id: The RM RPC message-id
> + * @req_buff: Request buffer that contains the payload
> + * @req_buff_size: Total size of the payload
> + * @resp_buf: Pointer to a response buffer
> + * @resp_buff_size: Size of the response buffer
> + * @reply_err_code: Returns Gunyah standard error code for the response
> + *
> + * Make a request to the RM-VM and wait for reply back. For a successful
> + * response, the function returns the payload. The size of the payload is set in resp_buff_size.
> + * The resp_buf should be freed by the caller.
> + *
> + * Context: Process context. Will sleep waiting for reply.
> + * Return: >0 is standard reply error from RM. <0 on internal error.
> + */
> +int gh_rm_call(u32 message_id, void *req_buff, size_t req_buff_size,
> + void **resp_buf, size_t *resp_buff_size)
> +{
> + struct gh_rm_connection *connection;
> + int ret;
> + struct gh_rsc_mgr *rsc_mgr = __rsc_mgr;
> +
> + /* messaged_id 0 is reserved */
> + if (!message_id)
> + return -EINVAL;
> +
> + if (!rsc_mgr)
> + return -EPROBE_DEFER;
> +
> + connection = gh_rm_alloc_connection(message_id, GH_RM_RPC_TYPE_RPLY);
> + if (!connection)
> + return -ENOMEM;
> +
> + init_completion(&connection->seq_done);
> +
> + /* Allocate a new seq number for this connection */
> + if (mutex_lock_interruptible(&rsc_mgr->call_idr_lock)) {
> + kfree(connection);
> + return -ERESTARTSYS;
> + }
> + connection->seq = idr_alloc_cyclic(&rsc_mgr->call_idr, connection, 0, U16_MAX, GFP_KERNEL);
> + mutex_unlock(&rsc_mgr->call_idr_lock);
> +
> + /* Send the request to the Resource Manager */
> + ret = gh_rm_send_request(rsc_mgr, message_id, req_buff, req_buff_size, connection);
> + if (ret < 0)
> + goto out;
> +
> + /* Wait for response */
> + ret = wait_for_completion_interruptible(&connection->seq_done);
> + if (ret)
> + goto out;
> +
> + if (connection->ret) {
> + ret = connection->ret;
> + kfree(connection->payload);
> + goto out;
> + }
> +
> + if (connection->rm_error) {
> + ret = connection->rm_error;
> + kfree(connection->payload);
> + goto out;
> + }
> +
> + *resp_buf = connection->payload;
> + *resp_buff_size = connection->size;
> +
> +out:
> + mutex_lock(&rsc_mgr->call_idr_lock);
> + idr_remove(&rsc_mgr->call_idr, connection->seq);
> + mutex_unlock(&rsc_mgr->call_idr_lock);
> +
> + kfree(connection);
> + return ret;
> +}
> +
> +int gh_rm_register_notifier(struct notifier_block *nb)
> +{
> + return srcu_notifier_chain_register(&gh_rm_notifier, nb);
> +}
> +EXPORT_SYMBOL_GPL(gh_rm_register_notifier);
> +
> +int gh_rm_unregister_notifier(struct notifier_block *nb)
> +{
> + return srcu_notifier_chain_unregister(&gh_rm_notifier, nb);
> +}
> +EXPORT_SYMBOL_GPL(gh_rm_unregister_notifier);
> +
> +static int gh_msgq_platform_probe_direction(struct platform_device *pdev,
> + u8 gh_type, int idx, struct gunyah_resource *ghrsc)
> +{
> + int ret;
> + struct device_node *node = pdev->dev.of_node;
> +
> + ghrsc->type = gh_type;
> +
> + ghrsc->irq = platform_get_irq(pdev, idx);
> + if (ghrsc->irq < 0) {
> + dev_err(&pdev->dev, "Failed to get irq%d: %d\n", idx, ghrsc->irq);
> + return ghrsc->irq;
> + }
> +
> + ret = of_property_read_u64_index(node, "reg", idx, &ghrsc->capid);

Is there any reason why can't you use platform_get_resource() here?

> + if (ret) {
> + dev_err(&pdev->dev, "Failed to get capid%d: %d\n", idx, ret);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static int gh_rm_drv_probe(struct platform_device *pdev)
> +{
> + struct gh_rsc_mgr *rsc_mgr;
> + struct gunyah_resource tx_ghrsc, rx_ghrsc;
> + int ret;
> +
> + rsc_mgr = devm_kzalloc(&pdev->dev, sizeof(*rsc_mgr), GFP_KERNEL);
> + if (!rsc_mgr)
> + return -ENOMEM;
> + platform_set_drvdata(pdev, rsc_mgr);
> +
> + mutex_init(&rsc_mgr->call_idr_lock);
> + idr_init(&rsc_mgr->call_idr);
> + mutex_init(&rsc_mgr->send_lock);
> +
> + ret = gh_msgq_platform_probe_direction(pdev, GUNYAH_RESOURCE_TYPE_MSGQ_TX, 0, &tx_ghrsc);
> + if (ret)
> + return ret;
> +
> + ret = gh_msgq_platform_probe_direction(pdev, GUNYAH_RESOURCE_TYPE_MSGQ_RX, 1, &rx_ghrsc);
> + if (ret)
> + return ret;
> +
> + rsc_mgr->msgq_client.dev = &pdev->dev;
> + rsc_mgr->msgq_client.tx_block = true;
> + rsc_mgr->msgq_client.rx_callback = gh_rm_msgq_rx_data;
> + rsc_mgr->msgq_client.tx_done = gh_rm_msgq_tx_done;
> +
> + ret = gunyah_msgq_init(&pdev->dev, &rsc_mgr->msgq, &rsc_mgr->msgq_client,
> + &tx_ghrsc, &rx_ghrsc);
> + if (ret)
> + return ret;
> +
> + __rsc_mgr = rsc_mgr;
> +
> + return 0;
> +}
> +
> +static int gh_rm_drv_remove(struct platform_device *pdev)
> +{
> + struct gh_rsc_mgr *rsc_mgr = platform_get_drvdata(pdev);
> +
> + __rsc_mgr = NULL;
> +
> + mbox_free_channel(gunyah_msgq_chan(&rsc_mgr->msgq));
> + gunyah_msgq_remove(&rsc_mgr->msgq);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id gh_rm_of_match[] = {
> + { .compatible = "gunyah-resource-manager" },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, gh_rm_of_match);
> +
> +static struct platform_driver gh_rm_driver = {
> + .probe = gh_rm_drv_probe,
> + .remove = gh_rm_drv_remove,
> + .driver = {
> + .name = "gh_rsc_mgr",
> + .of_match_table = gh_rm_of_match,
> + },
> +};
> +module_platform_driver(gh_rsc_mgr_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Gunyah Resource Manager Driver");
> diff --git a/drivers/virt/gunyah/rsc_mgr.h b/drivers/virt/gunyah/rsc_mgr.h
> new file mode 100644
> index 000000000000..e4f2499267bf
> --- /dev/null
> +++ b/drivers/virt/gunyah/rsc_mgr.h
> @@ -0,0 +1,34 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +#ifndef __GH_RSC_MGR_PRIV_H
> +#define __GH_RSC_MGR_PRIV_H
> +
> +#include <linux/gunyah.h>
> +
> +/* RM Error codes */
> +#define GH_RM_ERROR_OK 0x0
> +#define GH_RM_ERROR_UNIMPLEMENTED 0xFFFFFFFF
> +#define GH_RM_ERROR_NOMEM 0x1
> +#define GH_RM_ERROR_NORESOURCE 0x2
> +#define GH_RM_ERROR_DENIED 0x3
> +#define GH_RM_ERROR_INVALID 0x4
> +#define GH_RM_ERROR_BUSY 0x5
> +#define GH_RM_ERROR_ARGUMENT_INVALID 0x6
> +#define GH_RM_ERROR_HANDLE_INVALID 0x7
> +#define GH_RM_ERROR_VALIDATE_FAILED 0x8
> +#define GH_RM_ERROR_MAP_FAILED 0x9
> +#define GH_RM_ERROR_MEM_INVALID 0xA
> +#define GH_RM_ERROR_MEM_INUSE 0xB
> +#define GH_RM_ERROR_MEM_RELEASED 0xC
> +#define GH_RM_ERROR_VMID_INVALID 0xD
> +#define GH_RM_ERROR_LOOKUP_FAILED 0xE
> +#define GH_RM_ERROR_IRQ_INVALID 0xF
> +#define GH_RM_ERROR_IRQ_INUSE 0x10
> +#define GH_RM_ERROR_IRQ_RELEASED 0x11
> +
> +int gh_rm_call(u32 message_id, void *req_buff, size_t req_buff_size,
> + void **resp_buf, size_t *resp_buff_size);
> +
> +#endif
> diff --git a/include/linux/gunyah_rsc_mgr.h b/include/linux/gunyah_rsc_mgr.h
> new file mode 100644
> index 000000000000..b3b37225b7fb
> --- /dev/null
> +++ b/include/linux/gunyah_rsc_mgr.h
> @@ -0,0 +1,26 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +#ifndef _GUNYAH_RSC_MGR_H
> +#define _GUNYAH_RSC_MGR_H
> +
> +#include <linux/list.h>
> +#include <linux/notifier.h>
> +#include <linux/gunyah.h>
> +
> +#define GH_VMID_INVAL U16_MAX
> +
> +/* Gunyah recognizes VMID0 as an alias to the current VM's ID */
> +#define GH_VMID_SELF 0
> +
> +struct gh_rm_notification {
> + const void *buff;
> + const size_t size;
> +};
> +
> +int gh_rm_register_notifier(struct notifier_block *nb);
> +int gh_rm_unregister_notifier(struct notifier_block *nb);
> +
> +#endif

--
With best wishes
Dmitry