diff mbox series

[v11,08/26] gunyah: rsc_mgr: Add resource manager RPC core

Message ID 20230304010632.2127470-9-quic_eberman@quicinc.com
State New
Headers show
Series Drivers for gunyah hypervisor | expand

Commit Message

Elliot Berman March 4, 2023, 1:06 a.m. UTC 
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>
---
 drivers/virt/gunyah/Makefile   |   3 +
 drivers/virt/gunyah/rsc_mgr.c  | 688 +++++++++++++++++++++++++++++++++
 drivers/virt/gunyah/rsc_mgr.h  |  16 +
 include/linux/gunyah_rsc_mgr.h |  21 +
 4 files changed, 728 insertions(+)
 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

Comments

Alex Elder March 31, 2023, 2:25 p.m. UTC | #1 
On 3/3/23 7:06 PM, 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.

Mostly very simple issues noted here.	-Alex

> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> ---
>   drivers/virt/gunyah/Makefile   |   3 +
>   drivers/virt/gunyah/rsc_mgr.c  | 688 +++++++++++++++++++++++++++++++++
>   drivers/virt/gunyah/rsc_mgr.h  |  16 +
>   include/linux/gunyah_rsc_mgr.h |  21 +
>   4 files changed, 728 insertions(+)
>   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/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
> index 34f32110faf9..cc864ff5abbb 100644
> --- a/drivers/virt/gunyah/Makefile
> +++ b/drivers/virt/gunyah/Makefile
> @@ -1,3 +1,6 @@
>   # SPDX-License-Identifier: GPL-2.0
>   
>   obj-$(CONFIG_GUNYAH) += gunyah.o
> +
> +gunyah_rsc_mgr-y += rsc_mgr.o
> +obj-$(CONFIG_GUNYAH) += gunyah_rsc_mgr.o
> diff --git a/drivers/virt/gunyah/rsc_mgr.c b/drivers/virt/gunyah/rsc_mgr.c
> new file mode 100644
> index 000000000000..67813c9a52db
> --- /dev/null
> +++ b/drivers/virt/gunyah/rsc_mgr.c
> @@ -0,0 +1,688 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +

. . .

> +static void gh_rm_try_complete_connection(struct gh_rm *rm)
> +{
> +	struct gh_rm_connection *connection = rm->active_rx_connection;
> +
> +	if (!connection || connection->fragments_received != connection->num_fragments)
> +		return;
> +
> +	switch (connection->type) {
> +	case RM_RPC_TYPE_REPLY:
> +		complete(&connection->reply.seq_done);
> +		break;
> +	case RM_RPC_TYPE_NOTIF:
> +		schedule_work(&connection->notification.work);
> +		break;
> +	default:
> +		dev_err_ratelimited(rm->dev, "Invalid message type (%d) received\n",

s/%d/%u/

> +					connection->type);
> +		gh_rm_abort_connection(rm);
> +		break;
> +	}
> +
> +	rm->active_rx_connection = NULL;
> +}
> +
> +static void gh_rm_msgq_rx_data(struct mbox_client *cl, void *mssg)
> +{
> +	struct gh_rm *rm = container_of(cl, struct gh_rm, msgq_client);
> +	struct gh_msgq_rx_data *rx_data = mssg;
> +	size_t msg_size = rx_data->length;
> +	void *msg = rx_data->data;
> +	struct gh_rm_rpc_hdr *hdr;
> +
> +	if (msg_size < sizeof(*hdr) || msg_size > GH_MSGQ_MAX_MSG_SIZE)
> +		return;
> +
> +	hdr = msg;
> +	if (hdr->api != RM_RPC_API) {
> +		dev_err(rm->dev, "Unknown RM RPC API version: %x\n", hdr->api);
> +		return;
> +	}
> +
> +	switch (FIELD_GET(RM_RPC_TYPE_MASK, hdr->type)) {
> +	case RM_RPC_TYPE_NOTIF:
> +		gh_rm_process_notif(rm, msg, msg_size);
> +		break;
> +	case RM_RPC_TYPE_REPLY:
> +		gh_rm_process_rply(rm, msg, msg_size);
> +		break;
> +	case RM_RPC_TYPE_CONTINUATION:
> +		gh_rm_process_cont(rm, rm->active_rx_connection, msg, msg_size);
> +		break;
> +	default:
> +		dev_err(rm->dev, "Invalid message type (%lu) received\n",
> +			FIELD_GET(RM_RPC_TYPE_MASK, hdr->type));
> +		return;
> +	}
> +
> +	gh_rm_try_complete_connection(rm);
> +}
> +
> +static void gh_rm_msgq_tx_done(struct mbox_client *cl, void *mssg, int r)
> +{
> +	struct gh_rm *rm = container_of(cl, struct gh_rm, msgq_client);
> +
> +	kmem_cache_free(rm->cache, mssg);
> +	rm->last_tx_ret = r;
> +}
> +
> +static int gh_rm_send_request(struct gh_rm *rm, u32 message_id,
> +			      const void *req_buff, size_t req_buf_size,
> +			      struct gh_rm_connection *connection)
> +{
> +	size_t buf_size_remaining = req_buf_size;
> +	const void *req_buf_curr = req_buff;
> +	struct gh_msgq_tx_data *msg;
> +	struct gh_rm_rpc_hdr *hdr, hdr_template;
> +	u32 cont_fragments = 0;
> +	size_t payload_size;
> +	void *payload;
> +	int ret;
> +
> +	if (req_buf_size > GH_RM_MAX_NUM_FRAGMENTS * GH_RM_MAX_MSG_SIZE) {
> +		dev_warn(rm->dev, "Limit exceeded for the number of fragments: %u\n",
> +			cont_fragments);

You are printing the value of cont_fragments here when it's just zero.

> +		dump_stack();
> +		return -E2BIG;
> +	}
> +

Move the computation of cont_fragments prior to the block above.
You could use a ?: statement to assign it.

> +	if (req_buf_size)
> +		cont_fragments = (req_buf_size - 1) / GH_RM_MAX_MSG_SIZE;
> +
> +	hdr_template.api = RM_RPC_API;
> +	hdr_template.type = FIELD_PREP(RM_RPC_TYPE_MASK, RM_RPC_TYPE_REQUEST) |
> +			FIELD_PREP(RM_RPC_FRAGMENTS_MASK, cont_fragments);

The line above should be indented further.

> +	hdr_template.seq = cpu_to_le16(connection->reply.seq);
> +	hdr_template.msg_id = cpu_to_le32(message_id);
> +
> +	ret = mutex_lock_interruptible(&rm->send_lock);
> +	if (ret)
> +		return ret;
> +
> +	/* Consider also the 'request' packet for the loop count */

I don't think the comment above is helpful.

> +	do {
> +		msg = kmem_cache_zalloc(rm->cache, GFP_KERNEL);
> +		if (!msg) {
> +			ret = -ENOMEM;
> +			goto out;
> +		}
> +
> +		/* Fill header */
> +		hdr = (struct gh_rm_rpc_hdr *)msg->data;

I personally would prefer &msg->data[0] in this case.

> +		*hdr = hdr_template;
> +
> +		/* Copy payload */
> +		payload = hdr + 1;

I think I might have suggested using "hdr + 1" here.

Elsewhere you use something like:
	payload = (char *)hdr + sizeof(hdr);
or something similar.  I suggest you choose one approach and use
it consistently througout the driver.  Either is fine, but I
have a slight preference for the "hdr + 1" way.

> +		payload_size = min(buf_size_remaining, GH_RM_MAX_MSG_SIZE);
> +		memcpy(payload, req_buf_curr, payload_size);
> +		req_buf_curr += payload_size;
> +		buf_size_remaining -= payload_size;
> +
> +		/* Force the last fragment to immediately alert the receiver */
> +		msg->push = !buf_size_remaining;
> +		msg->length = sizeof(*hdr) + payload_size;
> +
> +		ret = mbox_send_message(gh_msgq_chan(&rm->msgq), msg);
> +		if (ret < 0) {
> +			kmem_cache_free(rm->cache, msg);
> +			break;
> +		}
> +
> +		if (rm->last_tx_ret) {
> +			ret = rm->last_tx_ret;
> +			break;
> +		}
> +
> +		hdr_template.type = FIELD_PREP(RM_RPC_TYPE_MASK, RM_RPC_TYPE_CONTINUATION) |
> +					FIELD_PREP(RM_RPC_FRAGMENTS_MASK, cont_fragments);
> +	} while (buf_size_remaining);
> +
> +out:
> +	mutex_unlock(&rm->send_lock);
> +	return ret < 0 ? ret : 0;
> +}
> +
> +/**
> + * gh_rm_call: Achieve request-response type communication with RPC
> + * @rm: Pointer to Gunyah resource manager internal data
> + * @message_id: The RM RPC message-id
> + * @req_buff: Request buffer that contains the payload
> + * @req_buf_size: Total size of the payload
> + * @resp_buf: Pointer to a response buffer
> + * @resp_buf_size: Size of the response buffer
> + *
> + * Make a request to the RM-VM and wait for reply back. For a successful

I think you could just say "to the RM and wait"...

Overall I suggest using "RM" or "RM VM" consistently when you talk
about the Resource Manager.  This is the only place I see "RM-VM".

> + * response, the function returns the payload. The size of the payload is set in
> + * resp_buf_size. The resp_buf should be freed by the caller when 0 is returned

s/should/must/

> + * and resp_buf_size != 0.
> + *
> + * req_buff should be not NULL for req_buf_size >0. If req_buf_size == 0,
> + * req_buff *can* be NULL and no additional payload is sent.

I'd say use "buf" or "buff" but not both in your naming
convention.

> + *
> + * Context: Process context. Will sleep waiting for reply.
> + * Return: 0 on success. <0 if error.
> + */
> +int gh_rm_call(struct gh_rm *rm, u32 message_id, void *req_buff, size_t req_buf_size,
> +		void **resp_buf, size_t *resp_buf_size)

I suspect you could define the request buffer as a pointer to const;
can you?

> +{
> +	struct gh_rm_connection *connection;
> +	u32 seq_id;
> +	int ret;
> +
> +	/* message_id 0 is reserved. req_buf_size implies req_buf is not NULL */
> +	if (!message_id || (!req_buff && req_buf_size) || !rm)

If you're going to check for a null RM pointer, I'd check it first.

> +		return -EINVAL;
> +
> +
> +	connection = kzalloc(sizeof(*connection), GFP_KERNEL);
> +	if (!connection)
> +		return -ENOMEM;
> +
> +	connection->type = RM_RPC_TYPE_REPLY;
> +	connection->msg_id = cpu_to_le32(message_id);
> +
> +	init_completion(&connection->reply.seq_done);

. . .

> diff --git a/include/linux/gunyah_rsc_mgr.h b/include/linux/gunyah_rsc_mgr.h
> new file mode 100644
> index 000000000000..deca9b3da541
> --- /dev/null
> +++ b/include/linux/gunyah_rsc_mgr.h
> @@ -0,0 +1,21 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (c) 2022-2023 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

Add a tab before U16_MAX; it will line up more nicely
when you define GH_MEM_HANDLE_INVAL later.

> +
> +struct gh_rm;
> +int gh_rm_notifier_register(struct gh_rm *rm, struct notifier_block *nb);
> +int gh_rm_notifier_unregister(struct gh_rm *rm, struct notifier_block *nb);
> +struct device *gh_rm_get(struct gh_rm *rm);
> +void gh_rm_put(struct gh_rm *rm);
> +
> +#endif
Elliot Berman April 3, 2023, 8:34 p.m. UTC | #2 
On 3/31/2023 7:25 AM, Alex Elder wrote:
> On 3/3/23 7:06 PM, 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.
> 
> Mostly very simple issues noted here.    -Alex
> 
>> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
>> ---
>>   drivers/virt/gunyah/Makefile   |   3 +
>>   drivers/virt/gunyah/rsc_mgr.c  | 688 +++++++++++++++++++++++++++++++++
>>   drivers/virt/gunyah/rsc_mgr.h  |  16 +
>>   include/linux/gunyah_rsc_mgr.h |  21 +
>>   4 files changed, 728 insertions(+)
>>   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/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
>> index 34f32110faf9..cc864ff5abbb 100644
>> --- a/drivers/virt/gunyah/Makefile
>> +++ b/drivers/virt/gunyah/Makefile
>> @@ -1,3 +1,6 @@
>>   # SPDX-License-Identifier: GPL-2.0
>>   obj-$(CONFIG_GUNYAH) += gunyah.o
>> +
>> +gunyah_rsc_mgr-y += rsc_mgr.o
>> +obj-$(CONFIG_GUNYAH) += gunyah_rsc_mgr.o
>> diff --git a/drivers/virt/gunyah/rsc_mgr.c 
>> b/drivers/virt/gunyah/rsc_mgr.c
>> new file mode 100644
>> index 000000000000..67813c9a52db
>> --- /dev/null
>> +++ b/drivers/virt/gunyah/rsc_mgr.c
>> @@ -0,0 +1,688 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All 
>> rights reserved.
>> + */
>> +
> 
> . . .
> 
>> +static void gh_rm_try_complete_connection(struct gh_rm *rm)
>> +{
>> +    struct gh_rm_connection *connection = rm->active_rx_connection;
>> +
>> +    if (!connection || connection->fragments_received != 
>> connection->num_fragments)
>> +        return;
>> +
>> +    switch (connection->type) {
>> +    case RM_RPC_TYPE_REPLY:
>> +        complete(&connection->reply.seq_done);
>> +        break;
>> +    case RM_RPC_TYPE_NOTIF:
>> +        schedule_work(&connection->notification.work);
>> +        break;
>> +    default:
>> +        dev_err_ratelimited(rm->dev, "Invalid message type (%d) 
>> received\n",
> 
> s/%d/%u/
> 
>> +                    connection->type);
>> +        gh_rm_abort_connection(rm);
>> +        break;
>> +    }
>> +
>> +    rm->active_rx_connection = NULL;
>> +}
>> +
>> +static void gh_rm_msgq_rx_data(struct mbox_client *cl, void *mssg)
>> +{
>> +    struct gh_rm *rm = container_of(cl, struct gh_rm, msgq_client);
>> +    struct gh_msgq_rx_data *rx_data = mssg;
>> +    size_t msg_size = rx_data->length;
>> +    void *msg = rx_data->data;
>> +    struct gh_rm_rpc_hdr *hdr;
>> +
>> +    if (msg_size < sizeof(*hdr) || msg_size > GH_MSGQ_MAX_MSG_SIZE)
>> +        return;
>> +
>> +    hdr = msg;
>> +    if (hdr->api != RM_RPC_API) {
>> +        dev_err(rm->dev, "Unknown RM RPC API version: %x\n", hdr->api);
>> +        return;
>> +    }
>> +
>> +    switch (FIELD_GET(RM_RPC_TYPE_MASK, hdr->type)) {
>> +    case RM_RPC_TYPE_NOTIF:
>> +        gh_rm_process_notif(rm, msg, msg_size);
>> +        break;
>> +    case RM_RPC_TYPE_REPLY:
>> +        gh_rm_process_rply(rm, msg, msg_size);
>> +        break;
>> +    case RM_RPC_TYPE_CONTINUATION:
>> +        gh_rm_process_cont(rm, rm->active_rx_connection, msg, msg_size);
>> +        break;
>> +    default:
>> +        dev_err(rm->dev, "Invalid message type (%lu) received\n",
>> +            FIELD_GET(RM_RPC_TYPE_MASK, hdr->type));
>> +        return;
>> +    }
>> +
>> +    gh_rm_try_complete_connection(rm);
>> +}
>> +
>> +static void gh_rm_msgq_tx_done(struct mbox_client *cl, void *mssg, 
>> int r)
>> +{
>> +    struct gh_rm *rm = container_of(cl, struct gh_rm, msgq_client);
>> +
>> +    kmem_cache_free(rm->cache, mssg);
>> +    rm->last_tx_ret = r;
>> +}
>> +
>> +static int gh_rm_send_request(struct gh_rm *rm, u32 message_id,
>> +                  const void *req_buff, size_t req_buf_size,
>> +                  struct gh_rm_connection *connection)
>> +{
>> +    size_t buf_size_remaining = req_buf_size;
>> +    const void *req_buf_curr = req_buff;
>> +    struct gh_msgq_tx_data *msg;
>> +    struct gh_rm_rpc_hdr *hdr, hdr_template;
>> +    u32 cont_fragments = 0;
>> +    size_t payload_size;
>> +    void *payload;
>> +    int ret;
>> +
>> +    if (req_buf_size > GH_RM_MAX_NUM_FRAGMENTS * GH_RM_MAX_MSG_SIZE) {
>> +        dev_warn(rm->dev, "Limit exceeded for the number of 
>> fragments: %u\n",
>> +            cont_fragments);
> 
> You are printing the value of cont_fragments here when it's just zero.
> 
>> +        dump_stack();
>> +        return -E2BIG;
>> +    }
>> +
> 
> Move the computation of cont_fragments prior to the block above.
> You could use a ?: statement to assign it.
> 
>> +    if (req_buf_size)
>> +        cont_fragments = (req_buf_size - 1) / GH_RM_MAX_MSG_SIZE;
>> +
>> +    hdr_template.api = RM_RPC_API;
>> +    hdr_template.type = FIELD_PREP(RM_RPC_TYPE_MASK, 
>> RM_RPC_TYPE_REQUEST) |
>> +            FIELD_PREP(RM_RPC_FRAGMENTS_MASK, cont_fragments);
> 
> The line above should be indented further.
> 
>> +    hdr_template.seq = cpu_to_le16(connection->reply.seq);
>> +    hdr_template.msg_id = cpu_to_le32(message_id);
>> +
>> +    ret = mutex_lock_interruptible(&rm->send_lock);
>> +    if (ret)
>> +        return ret;
>> +
>> +    /* Consider also the 'request' packet for the loop count */
> 
> I don't think the comment above is helpful.
> 
>> +    do {
>> +        msg = kmem_cache_zalloc(rm->cache, GFP_KERNEL);
>> +        if (!msg) {
>> +            ret = -ENOMEM;
>> +            goto out;
>> +        }
>> +
>> +        /* Fill header */
>> +        hdr = (struct gh_rm_rpc_hdr *)msg->data;
> 
> I personally would prefer &msg->data[0] in this case.
> 
>> +        *hdr = hdr_template;
>> +
>> +        /* Copy payload */
>> +        payload = hdr + 1;
> 
> I think I might have suggested using "hdr + 1" here.
> 
> Elsewhere you use something like:
>      payload = (char *)hdr + sizeof(hdr);
> or something similar.  I suggest you choose one approach and use
> it consistently througout the driver.  Either is fine, but I
> have a slight preference for the "hdr + 1" way.
> 

I think you might be referencing the memcpy in 
gh_rm_init_connection_payload. In the gh_rm_init_connection_payload, 
hdr_size is not fixed: for notifications, it's just the RPC header. For 
responses, there is the RPC header + the "RM error code". To be able to 
re-use same header processing, I'd have to do byte arithmetic rather 
than the "hdr + 1" way. I also prefer the "hdr + 1" way, but if I am 
going to be consistent, need to stick with byte arithmetic.

>> +        payload_size = min(buf_size_remaining, GH_RM_MAX_MSG_SIZE);
>> +        memcpy(payload, req_buf_curr, payload_size);
>> +        req_buf_curr += payload_size;
>> +        buf_size_remaining -= payload_size;
>> +
>> +        /* Force the last fragment to immediately alert the receiver */
>> +        msg->push = !buf_size_remaining;
>> +        msg->length = sizeof(*hdr) + payload_size;
>> +
>> +        ret = mbox_send_message(gh_msgq_chan(&rm->msgq), msg);
>> +        if (ret < 0) {
>> +            kmem_cache_free(rm->cache, msg);
>> +            break;
>> +        }
>> +
>> +        if (rm->last_tx_ret) {
>> +            ret = rm->last_tx_ret;
>> +            break;
>> +        }
>> +
>> +        hdr_template.type = FIELD_PREP(RM_RPC_TYPE_MASK, 
>> RM_RPC_TYPE_CONTINUATION) |
>> +                    FIELD_PREP(RM_RPC_FRAGMENTS_MASK, cont_fragments);
>> +    } while (buf_size_remaining);
>> +
>> +out:
>> +    mutex_unlock(&rm->send_lock);
>> +    return ret < 0 ? ret : 0;
>> +}
>> +
>> +/**
>> + * gh_rm_call: Achieve request-response type communication with RPC
>> + * @rm: Pointer to Gunyah resource manager internal data
>> + * @message_id: The RM RPC message-id
>> + * @req_buff: Request buffer that contains the payload
>> + * @req_buf_size: Total size of the payload
>> + * @resp_buf: Pointer to a response buffer
>> + * @resp_buf_size: Size of the response buffer
>> + *
>> + * Make a request to the RM-VM and wait for reply back. For a successful
> 
> I think you could just say "to the RM and wait"...
> 
> Overall I suggest using "RM" or "RM VM" consistently when you talk
> about the Resource Manager.  This is the only place I see "RM-VM".
> 
>> + * response, the function returns the payload. The size of the 
>> payload is set in
>> + * resp_buf_size. The resp_buf should be freed by the caller when 0 
>> is returned
> 
> s/should/must/
> 
>> + * and resp_buf_size != 0.
>> + *
>> + * req_buff should be not NULL for req_buf_size >0. If req_buf_size 
>> == 0,
>> + * req_buff *can* be NULL and no additional payload is sent.
> 
> I'd say use "buf" or "buff" but not both in your naming
> convention.
> 

Not intentional -- will make it consistent.

>> + *
>> + * Context: Process context. Will sleep waiting for reply.
>> + * Return: 0 on success. <0 if error.
>> + */
>> +int gh_rm_call(struct gh_rm *rm, u32 message_id, void *req_buff, 
>> size_t req_buf_size,
>> +        void **resp_buf, size_t *resp_buf_size)
> 
> I suspect you could define the request buffer as a pointer to const;
> can you?
> 

I can!

>> +{
>> +    struct gh_rm_connection *connection;
>> +    u32 seq_id;
>> +    int ret;
>> +
>> +    /* message_id 0 is reserved. req_buf_size implies req_buf is not 
>> NULL */
>> +    if (!message_id || (!req_buff && req_buf_size) || !rm)
> 
> If you're going to check for a null RM pointer, I'd check it first.
> 
>> +        return -EINVAL;
>> +
>> +
>> +    connection = kzalloc(sizeof(*connection), GFP_KERNEL);
>> +    if (!connection)
>> +        return -ENOMEM;
>> +
>> +    connection->type = RM_RPC_TYPE_REPLY;
>> +    connection->msg_id = cpu_to_le32(message_id);
>> +
>> +    init_completion(&connection->reply.seq_done);
> 
> . . .
> 
>> diff --git a/include/linux/gunyah_rsc_mgr.h 
>> b/include/linux/gunyah_rsc_mgr.h
>> new file mode 100644
>> index 000000000000..deca9b3da541
>> --- /dev/null
>> +++ b/include/linux/gunyah_rsc_mgr.h
>> @@ -0,0 +1,21 @@
>> +/* SPDX-License-Identifier: GPL-2.0-only */
>> +/*
>> + * Copyright (c) 2022-2023 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
> 
> Add a tab before U16_MAX; it will line up more nicely
> when you define GH_MEM_HANDLE_INVAL later.
> 
>> +
>> +struct gh_rm;
>> +int gh_rm_notifier_register(struct gh_rm *rm, struct notifier_block 
>> *nb);
>> +int gh_rm_notifier_unregister(struct gh_rm *rm, struct notifier_block 
>> *nb);
>> +struct device *gh_rm_get(struct gh_rm *rm);
>> +void gh_rm_put(struct gh_rm *rm);
>> +
>> +#endif
>
diff mbox series

Patch

diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
index 34f32110faf9..cc864ff5abbb 100644
--- a/drivers/virt/gunyah/Makefile
+++ b/drivers/virt/gunyah/Makefile
@@ -1,3 +1,6 @@ 
 # SPDX-License-Identifier: GPL-2.0
 
 obj-$(CONFIG_GUNYAH) += gunyah.o
+
+gunyah_rsc_mgr-y += rsc_mgr.o
+obj-$(CONFIG_GUNYAH) += gunyah_rsc_mgr.o
diff --git a/drivers/virt/gunyah/rsc_mgr.c b/drivers/virt/gunyah/rsc_mgr.c
new file mode 100644
index 000000000000..67813c9a52db
--- /dev/null
+++ b/drivers/virt/gunyah/rsc_mgr.c
@@ -0,0 +1,688 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#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/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"
+
+#define RM_RPC_API_VERSION_MASK		GENMASK(3, 0)
+#define RM_RPC_HEADER_WORDS_MASK	GENMASK(7, 4)
+#define RM_RPC_API_VERSION		FIELD_PREP(RM_RPC_API_VERSION_MASK, 1)
+#define RM_RPC_HEADER_WORDS		FIELD_PREP(RM_RPC_HEADER_WORDS_MASK, \
+						(sizeof(struct gh_rm_rpc_hdr) / sizeof(u32)))
+#define RM_RPC_API			(RM_RPC_API_VERSION | RM_RPC_HEADER_WORDS)
+
+#define RM_RPC_TYPE_CONTINUATION	0x0
+#define RM_RPC_TYPE_REQUEST		0x1
+#define RM_RPC_TYPE_REPLY		0x2
+#define RM_RPC_TYPE_NOTIF		0x3
+#define RM_RPC_TYPE_MASK		GENMASK(1, 0)
+
+#define GH_RM_MAX_NUM_FRAGMENTS		62
+#define RM_RPC_FRAGMENTS_MASK		GENMASK(7, 2)
+
+struct gh_rm_rpc_hdr {
+	u8 api;
+	u8 type;
+	__le16 seq;
+	__le32 msg_id;
+} __packed;
+
+struct gh_rm_rpc_reply_hdr {
+	struct gh_rm_rpc_hdr hdr;
+	__le32 err_code; /* GH_RM_ERROR_* */
+} __packed;
+
+#define GH_RM_MAX_MSG_SIZE	(GH_MSGQ_MAX_MSG_SIZE - sizeof(struct gh_rm_rpc_hdr))
+
+/* RM Error codes */
+enum gh_rm_error {
+	GH_RM_ERROR_OK			= 0x0,
+	GH_RM_ERROR_UNIMPLEMENTED	= 0xFFFFFFFF,
+	GH_RM_ERROR_NOMEM		= 0x1,
+	GH_RM_ERROR_NORESOURCE		= 0x2,
+	GH_RM_ERROR_DENIED		= 0x3,
+	GH_RM_ERROR_INVALID		= 0x4,
+	GH_RM_ERROR_BUSY		= 0x5,
+	GH_RM_ERROR_ARGUMENT_INVALID	= 0x6,
+	GH_RM_ERROR_HANDLE_INVALID	= 0x7,
+	GH_RM_ERROR_VALIDATE_FAILED	= 0x8,
+	GH_RM_ERROR_MAP_FAILED		= 0x9,
+	GH_RM_ERROR_MEM_INVALID		= 0xA,
+	GH_RM_ERROR_MEM_INUSE		= 0xB,
+	GH_RM_ERROR_MEM_RELEASED	= 0xC,
+	GH_RM_ERROR_VMID_INVALID	= 0xD,
+	GH_RM_ERROR_LOOKUP_FAILED	= 0xE,
+	GH_RM_ERROR_IRQ_INVALID		= 0xF,
+	GH_RM_ERROR_IRQ_INUSE		= 0x10,
+	GH_RM_ERROR_IRQ_RELEASED	= 0x11,
+};
+
+/**
+ * struct gh_rm_connection - Represents a complete message from resource manager
+ * @payload: Combined payload of all the fragments (msg headers stripped off).
+ * @size: Size of the payload received so far.
+ * @msg_id: Message ID from the header.
+ * @type: RM_RPC_TYPE_REPLY or RM_RPC_TYPE_NOTIF.
+ * @num_fragments: total number of fragments expected to be received.
+ * @fragments_received: fragments received so far.
+ * @reply: Fields used for request/reply sequences
+ * @notification: Fields used for notifiations
+ */
+struct gh_rm_connection {
+	void *payload;
+	size_t size;
+	__le32 msg_id;
+	u8 type;
+
+	u8 num_fragments;
+	u8 fragments_received;
+
+	union {
+		/**
+		 * @ret: Linux return code, there was an error processing connection
+		 * @seq: Sequence ID for the main message.
+		 * @rm_error: For request/reply sequences with standard replies
+		 * @seq_done: Signals caller that the RM reply has been received
+		 */
+		struct {
+			int ret;
+			u16 seq;
+			enum gh_rm_error rm_error;
+			struct completion seq_done;
+		} reply;
+
+		/**
+		 * @rm: Pointer to the RM that launched the connection
+		 * @work: Triggered when all fragments of a notification received
+		 */
+		struct {
+			struct gh_rm *rm;
+			struct work_struct work;
+		} notification;
+	};
+};
+
+/**
+ * struct gh_rm - private data for communicating w/Gunyah resource manager
+ * @dev: pointer to device
+ * @tx_ghrsc: message queue resource to TX to RM
+ * @rx_ghrsc: message queue resource to RX from RM
+ * @msgq: mailbox instance of above
+ * @active_rx_connection: ongoing gh_rm_connection for which we're receiving fragments
+ * @last_tx_ret: return value of last mailbox tx
+ * @call_xarray: xarray to allocate & lookup sequence IDs for Request/Response flows
+ * @next_seq: next ID to allocate (for xa_alloc_cyclic)
+ * @cache: cache for allocating Tx messages
+ * @send_lock: synchronization to allow only one request to be sent at a time
+ * @nh: notifier chain for clients interested in RM notification messages
+ */
+struct gh_rm {
+	struct device *dev;
+	struct gh_resource tx_ghrsc;
+	struct gh_resource rx_ghrsc;
+	struct gh_msgq msgq;
+	struct mbox_client msgq_client;
+	struct gh_rm_connection *active_rx_connection;
+	int last_tx_ret;
+
+	struct xarray call_xarray;
+	u32 next_seq;
+
+	struct kmem_cache *cache;
+	struct mutex send_lock;
+	struct blocking_notifier_head nh;
+};
+
+/**
+ * gh_rm_remap_error() - Remap Gunyah resource manager errors into a Linux error code
+ * @gh_error: "Standard" return value from Gunyah resource manager
+ */
+static inline int gh_rm_remap_error(enum gh_rm_error rm_error)
+{
+	switch (rm_error) {
+	case GH_RM_ERROR_OK:
+		return 0;
+	case GH_RM_ERROR_UNIMPLEMENTED:
+		return -EOPNOTSUPP;
+	case GH_RM_ERROR_NOMEM:
+		return -ENOMEM;
+	case GH_RM_ERROR_NORESOURCE:
+		return -ENODEV;
+	case GH_RM_ERROR_DENIED:
+		return -EPERM;
+	case GH_RM_ERROR_BUSY:
+		return -EBUSY;
+	case GH_RM_ERROR_INVALID:
+	case GH_RM_ERROR_ARGUMENT_INVALID:
+	case GH_RM_ERROR_HANDLE_INVALID:
+	case GH_RM_ERROR_VALIDATE_FAILED:
+	case GH_RM_ERROR_MAP_FAILED:
+	case GH_RM_ERROR_MEM_INVALID:
+	case GH_RM_ERROR_MEM_INUSE:
+	case GH_RM_ERROR_MEM_RELEASED:
+	case GH_RM_ERROR_VMID_INVALID:
+	case GH_RM_ERROR_LOOKUP_FAILED:
+	case GH_RM_ERROR_IRQ_INVALID:
+	case GH_RM_ERROR_IRQ_INUSE:
+	case GH_RM_ERROR_IRQ_RELEASED:
+		return -EINVAL;
+	default:
+		return -EBADMSG;
+	}
+}
+
+static int gh_rm_init_connection_payload(struct gh_rm_connection *connection, void *msg,
+					size_t hdr_size, size_t msg_size)
+{
+	size_t max_buf_size, payload_size;
+	struct gh_rm_rpc_hdr *hdr = msg;
+
+	if (msg_size < hdr_size)
+		return -EINVAL;
+
+	payload_size = msg_size - hdr_size;
+
+	connection->num_fragments = FIELD_GET(RM_RPC_FRAGMENTS_MASK, hdr->type);
+	connection->fragments_received = 0;
+
+	/* There's not going to be any payload, no need to allocate buffer. */
+	if (!payload_size && !connection->num_fragments)
+		return 0;
+
+	if (connection->num_fragments > GH_RM_MAX_NUM_FRAGMENTS)
+		return -EINVAL;
+
+	max_buf_size = payload_size + (connection->num_fragments * GH_RM_MAX_MSG_SIZE);
+
+	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_abort_connection(struct gh_rm *rm)
+{
+	switch (rm->active_rx_connection->type) {
+	case RM_RPC_TYPE_REPLY:
+		rm->active_rx_connection->reply.ret = -EIO;
+		complete(&rm->active_rx_connection->reply.seq_done);
+		break;
+	case RM_RPC_TYPE_NOTIF:
+		fallthrough;
+	default:
+		kfree(rm->active_rx_connection->payload);
+		kfree(rm->active_rx_connection);
+	}
+
+	rm->active_rx_connection = NULL;
+}
+
+static void gh_rm_notif_work(struct work_struct *work)
+{
+	struct gh_rm_connection *connection = container_of(work, struct gh_rm_connection,
+								notification.work);
+	struct gh_rm *rm = connection->notification.rm;
+
+	blocking_notifier_call_chain(&rm->nh, connection->msg_id, connection->payload);
+
+	gh_rm_put(rm);
+	kfree(connection->payload);
+	kfree(connection);
+}
+
+static void gh_rm_process_notif(struct gh_rm *rm, void *msg, size_t msg_size)
+{
+	struct gh_rm_connection *connection;
+	struct gh_rm_rpc_hdr *hdr = msg;
+	int ret;
+
+	if (rm->active_rx_connection)
+		gh_rm_abort_connection(rm);
+
+	connection = kzalloc(sizeof(*connection), GFP_KERNEL);
+	if (!connection)
+		return;
+
+	connection->type = RM_RPC_TYPE_NOTIF;
+	connection->msg_id = hdr->msg_id;
+
+	gh_rm_get(rm);
+	connection->notification.rm = rm;
+	INIT_WORK(&connection->notification.work, gh_rm_notif_work);
+
+	ret = gh_rm_init_connection_payload(connection, msg, sizeof(*hdr), msg_size);
+	if (ret) {
+		dev_err(rm->dev, "Failed to initialize connection for notification: %d\n", ret);
+		gh_rm_put(rm);
+		kfree(connection);
+		return;
+	}
+
+	rm->active_rx_connection = connection;
+}
+
+static void gh_rm_process_rply(struct gh_rm *rm, void *msg, size_t msg_size)
+{
+	struct gh_rm_rpc_reply_hdr *reply_hdr = msg;
+	struct gh_rm_connection *connection;
+	u16 seq_id;
+
+	seq_id = le16_to_cpu(reply_hdr->hdr.seq);
+	connection = xa_load(&rm->call_xarray, seq_id);
+
+	if (!connection || connection->msg_id != reply_hdr->hdr.msg_id)
+		return;
+
+	if (rm->active_rx_connection)
+		gh_rm_abort_connection(rm);
+
+	if (gh_rm_init_connection_payload(connection, msg, sizeof(*reply_hdr), msg_size)) {
+		dev_err(rm->dev, "Failed to alloc connection buffer for sequence %d\n", seq_id);
+		/* Send connection complete and error the client. */
+		connection->reply.ret = -ENOMEM;
+		complete(&connection->reply.seq_done);
+		return;
+	}
+
+	connection->reply.rm_error = le32_to_cpu(reply_hdr->err_code);
+	rm->active_rx_connection = connection;
+}
+
+static void gh_rm_process_cont(struct gh_rm *rm, 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);
+
+	if (!rm->active_rx_connection)
+		return;
+
+	/*
+	 * hdr->fragments and hdr->msg_id preserves the value from first reply
+	 * or notif message. To detect mishandling, check it's still intact.
+	 */
+	if (connection->msg_id != hdr->msg_id ||
+		connection->num_fragments != FIELD_GET(RM_RPC_FRAGMENTS_MASK, hdr->type)) {
+		gh_rm_abort_connection(rm);
+		return;
+	}
+
+	memcpy(connection->payload + connection->size, msg + sizeof(*hdr), payload_size);
+	connection->size += payload_size;
+	connection->fragments_received++;
+}
+
+static void gh_rm_try_complete_connection(struct gh_rm *rm)
+{
+	struct gh_rm_connection *connection = rm->active_rx_connection;
+
+	if (!connection || connection->fragments_received != connection->num_fragments)
+		return;
+
+	switch (connection->type) {
+	case RM_RPC_TYPE_REPLY:
+		complete(&connection->reply.seq_done);
+		break;
+	case RM_RPC_TYPE_NOTIF:
+		schedule_work(&connection->notification.work);
+		break;
+	default:
+		dev_err_ratelimited(rm->dev, "Invalid message type (%d) received\n",
+					connection->type);
+		gh_rm_abort_connection(rm);
+		break;
+	}
+
+	rm->active_rx_connection = NULL;
+}
+
+static void gh_rm_msgq_rx_data(struct mbox_client *cl, void *mssg)
+{
+	struct gh_rm *rm = container_of(cl, struct gh_rm, msgq_client);
+	struct gh_msgq_rx_data *rx_data = mssg;
+	size_t msg_size = rx_data->length;
+	void *msg = rx_data->data;
+	struct gh_rm_rpc_hdr *hdr;
+
+	if (msg_size < sizeof(*hdr) || msg_size > GH_MSGQ_MAX_MSG_SIZE)
+		return;
+
+	hdr = msg;
+	if (hdr->api != RM_RPC_API) {
+		dev_err(rm->dev, "Unknown RM RPC API version: %x\n", hdr->api);
+		return;
+	}
+
+	switch (FIELD_GET(RM_RPC_TYPE_MASK, hdr->type)) {
+	case RM_RPC_TYPE_NOTIF:
+		gh_rm_process_notif(rm, msg, msg_size);
+		break;
+	case RM_RPC_TYPE_REPLY:
+		gh_rm_process_rply(rm, msg, msg_size);
+		break;
+	case RM_RPC_TYPE_CONTINUATION:
+		gh_rm_process_cont(rm, rm->active_rx_connection, msg, msg_size);
+		break;
+	default:
+		dev_err(rm->dev, "Invalid message type (%lu) received\n",
+			FIELD_GET(RM_RPC_TYPE_MASK, hdr->type));
+		return;
+	}
+
+	gh_rm_try_complete_connection(rm);
+}
+
+static void gh_rm_msgq_tx_done(struct mbox_client *cl, void *mssg, int r)
+{
+	struct gh_rm *rm = container_of(cl, struct gh_rm, msgq_client);
+
+	kmem_cache_free(rm->cache, mssg);
+	rm->last_tx_ret = r;
+}
+
+static int gh_rm_send_request(struct gh_rm *rm, u32 message_id,
+			      const void *req_buff, size_t req_buf_size,
+			      struct gh_rm_connection *connection)
+{
+	size_t buf_size_remaining = req_buf_size;
+	const void *req_buf_curr = req_buff;
+	struct gh_msgq_tx_data *msg;
+	struct gh_rm_rpc_hdr *hdr, hdr_template;
+	u32 cont_fragments = 0;
+	size_t payload_size;
+	void *payload;
+	int ret;
+
+	if (req_buf_size > GH_RM_MAX_NUM_FRAGMENTS * GH_RM_MAX_MSG_SIZE) {
+		dev_warn(rm->dev, "Limit exceeded for the number of fragments: %u\n",
+			cont_fragments);
+		dump_stack();
+		return -E2BIG;
+	}
+
+	if (req_buf_size)
+		cont_fragments = (req_buf_size - 1) / GH_RM_MAX_MSG_SIZE;
+
+	hdr_template.api = RM_RPC_API;
+	hdr_template.type = FIELD_PREP(RM_RPC_TYPE_MASK, RM_RPC_TYPE_REQUEST) |
+			FIELD_PREP(RM_RPC_FRAGMENTS_MASK, cont_fragments);
+	hdr_template.seq = cpu_to_le16(connection->reply.seq);
+	hdr_template.msg_id = cpu_to_le32(message_id);
+
+	ret = mutex_lock_interruptible(&rm->send_lock);
+	if (ret)
+		return ret;
+
+	/* Consider also the 'request' packet for the loop count */
+	do {
+		msg = kmem_cache_zalloc(rm->cache, GFP_KERNEL);
+		if (!msg) {
+			ret = -ENOMEM;
+			goto out;
+		}
+
+		/* Fill header */
+		hdr = (struct gh_rm_rpc_hdr *)msg->data;
+		*hdr = hdr_template;
+
+		/* Copy payload */
+		payload = hdr + 1;
+		payload_size = min(buf_size_remaining, GH_RM_MAX_MSG_SIZE);
+		memcpy(payload, req_buf_curr, payload_size);
+		req_buf_curr += payload_size;
+		buf_size_remaining -= payload_size;
+
+		/* Force the last fragment to immediately alert the receiver */
+		msg->push = !buf_size_remaining;
+		msg->length = sizeof(*hdr) + payload_size;
+
+		ret = mbox_send_message(gh_msgq_chan(&rm->msgq), msg);
+		if (ret < 0) {
+			kmem_cache_free(rm->cache, msg);
+			break;
+		}
+
+		if (rm->last_tx_ret) {
+			ret = rm->last_tx_ret;
+			break;
+		}
+
+		hdr_template.type = FIELD_PREP(RM_RPC_TYPE_MASK, RM_RPC_TYPE_CONTINUATION) |
+					FIELD_PREP(RM_RPC_FRAGMENTS_MASK, cont_fragments);
+	} while (buf_size_remaining);
+
+out:
+	mutex_unlock(&rm->send_lock);
+	return ret < 0 ? ret : 0;
+}
+
+/**
+ * gh_rm_call: Achieve request-response type communication with RPC
+ * @rm: Pointer to Gunyah resource manager internal data
+ * @message_id: The RM RPC message-id
+ * @req_buff: Request buffer that contains the payload
+ * @req_buf_size: Total size of the payload
+ * @resp_buf: Pointer to a response buffer
+ * @resp_buf_size: Size of the response buffer
+ *
+ * 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_buf_size. The resp_buf should be freed by the caller when 0 is returned
+ * and resp_buf_size != 0.
+ *
+ * req_buff should be not NULL for req_buf_size >0. If req_buf_size == 0,
+ * req_buff *can* be NULL and no additional payload is sent.
+ *
+ * Context: Process context. Will sleep waiting for reply.
+ * Return: 0 on success. <0 if error.
+ */
+int gh_rm_call(struct gh_rm *rm, u32 message_id, void *req_buff, size_t req_buf_size,
+		void **resp_buf, size_t *resp_buf_size)
+{
+	struct gh_rm_connection *connection;
+	u32 seq_id;
+	int ret;
+
+	/* message_id 0 is reserved. req_buf_size implies req_buf is not NULL */
+	if (!message_id || (!req_buff && req_buf_size) || !rm)
+		return -EINVAL;
+
+
+	connection = kzalloc(sizeof(*connection), GFP_KERNEL);
+	if (!connection)
+		return -ENOMEM;
+
+	connection->type = RM_RPC_TYPE_REPLY;
+	connection->msg_id = cpu_to_le32(message_id);
+
+	init_completion(&connection->reply.seq_done);
+
+	/* Allocate a new seq number for this connection */
+	ret = xa_alloc_cyclic(&rm->call_xarray, &seq_id, connection, xa_limit_16b, &rm->next_seq,
+				GFP_KERNEL);
+	if (ret < 0)
+		goto free;
+	connection->reply.seq = lower_16_bits(seq_id);
+
+	/* Send the request to the Resource Manager */
+	ret = gh_rm_send_request(rm, message_id, req_buff, req_buf_size, connection);
+	if (ret < 0)
+		goto out;
+
+	/* Wait for response */
+	ret = wait_for_completion_interruptible(&connection->reply.seq_done);
+	if (ret)
+		goto out;
+
+	/* Check for internal (kernel) error waiting for the response */
+	if (connection->reply.ret) {
+		ret = connection->reply.ret;
+		if (ret != -ENOMEM)
+			kfree(connection->payload);
+		goto out;
+	}
+
+	/* Got a response, did resource manager give us an error? */
+	if (connection->reply.rm_error != GH_RM_ERROR_OK) {
+		dev_warn(rm->dev, "RM rejected message %08x. Error: %d\n", message_id,
+			connection->reply.rm_error);
+		dump_stack();
+		ret = gh_rm_remap_error(connection->reply.rm_error);
+		kfree(connection->payload);
+		goto out;
+	}
+
+	/* Everything looks good, return the payload */
+	if (resp_buf_size)
+		*resp_buf_size = connection->size;
+	if (connection->size && resp_buf)
+		*resp_buf = connection->payload;
+	else {
+		/* kfree in case RM sent us multiple fragments but never any data in
+		 * those fragments. We would've allocated memory for it, but connection->size == 0
+		 */
+		kfree(connection->payload);
+	}
+
+out:
+	xa_erase(&rm->call_xarray, connection->reply.seq);
+free:
+	kfree(connection);
+	return ret;
+}
+
+
+int gh_rm_notifier_register(struct gh_rm *rm, struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&rm->nh, nb);
+}
+EXPORT_SYMBOL_GPL(gh_rm_notifier_register);
+
+int gh_rm_notifier_unregister(struct gh_rm *rm, struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&rm->nh, nb);
+}
+EXPORT_SYMBOL_GPL(gh_rm_notifier_unregister);
+
+struct device *gh_rm_get(struct gh_rm *rm)
+{
+	return get_device(rm->miscdev.this_device);
+}
+EXPORT_SYMBOL_GPL(gh_rm_get);
+
+void gh_rm_put(struct gh_rm *rm)
+{
+	put_device(rm->miscdev.this_device);
+}
+EXPORT_SYMBOL_GPL(gh_rm_put);
+
+static int gh_msgq_platform_probe_direction(struct platform_device *pdev, bool tx,
+					    struct gh_resource *ghrsc)
+{
+	struct device_node *node = pdev->dev.of_node;
+	int ret;
+	int idx = tx ? 0 : 1;
+
+	ghrsc->type = tx ? GH_RESOURCE_TYPE_MSGQ_TX : GH_RESOURCE_TYPE_MSGQ_RX;
+
+	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);
+	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_msgq_tx_data *msg;
+	struct gh_rm *rm;
+	int ret;
+
+	rm = devm_kzalloc(&pdev->dev, sizeof(*rm), GFP_KERNEL);
+	if (!rm)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, rm);
+	rm->dev = &pdev->dev;
+
+	mutex_init(&rm->send_lock);
+	BLOCKING_INIT_NOTIFIER_HEAD(&rm->nh);
+	xa_init_flags(&rm->call_xarray, XA_FLAGS_ALLOC);
+	rm->cache = kmem_cache_create("gh_rm", struct_size(msg, data, GH_MSGQ_MAX_MSG_SIZE), 0,
+		SLAB_HWCACHE_ALIGN, NULL);
+	if (!rm->cache)
+		return -ENOMEM;
+
+	ret = gh_msgq_platform_probe_direction(pdev, true, &rm->tx_ghrsc);
+	if (ret)
+		goto err_cache;
+
+	ret = gh_msgq_platform_probe_direction(pdev, false, &rm->rx_ghrsc);
+	if (ret)
+		goto err_cache;
+
+	rm->msgq_client.dev = &pdev->dev;
+	rm->msgq_client.tx_block = true;
+	rm->msgq_client.rx_callback = gh_rm_msgq_rx_data;
+	rm->msgq_client.tx_done = gh_rm_msgq_tx_done;
+
+	return gh_msgq_init(&pdev->dev, &rm->msgq, &rm->msgq_client, &rm->tx_ghrsc, &rm->rx_ghrsc);
+err_cache:
+	kmem_cache_destroy(rm->cache);
+	return ret;
+}
+
+static int gh_rm_drv_remove(struct platform_device *pdev)
+{
+	struct gh_rm *rm = platform_get_drvdata(pdev);
+
+	mbox_free_channel(gh_msgq_chan(&rm->msgq));
+	gh_msgq_remove(&rm->msgq);
+	kmem_cache_destroy(rm->cache);
+
+	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_rm_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..3665ebc7b020
--- /dev/null
+++ b/drivers/virt/gunyah/rsc_mgr.h
@@ -0,0 +1,16 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+#ifndef __GH_RSC_MGR_PRIV_H
+#define __GH_RSC_MGR_PRIV_H
+
+#include <linux/gunyah.h>
+#include <linux/gunyah_rsc_mgr.h>
+#include <linux/types.h>
+
+struct gh_rm;
+int gh_rm_call(struct gh_rm *rsc_mgr, u32 message_id, void *req_buff, size_t req_buf_size,
+		void **resp_buf, size_t *resp_buf_size);
+
+#endif
diff --git a/include/linux/gunyah_rsc_mgr.h b/include/linux/gunyah_rsc_mgr.h
new file mode 100644
index 000000000000..deca9b3da541
--- /dev/null
+++ b/include/linux/gunyah_rsc_mgr.h
@@ -0,0 +1,21 @@ 
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2022-2023 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
+
+struct gh_rm;
+int gh_rm_notifier_register(struct gh_rm *rm, struct notifier_block *nb);
+int gh_rm_notifier_unregister(struct gh_rm *rm, struct notifier_block *nb);
+struct device *gh_rm_get(struct gh_rm *rm);
+void gh_rm_put(struct gh_rm *rm);
+
+#endif