Re: [RFC PATCH v1 14/38] coco: host: arm64: Device communication support

Aneesh Kumar K.V
2025-08-04T04:17:23Z

Jonathan Cameron <Jonathan.Cameron@huawei.com> writes:

> On Mon, 28 Jul 2025 19:21:51 +0530
> "Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org> wrote:
>
>> Add helpers for device communication from RMM
>>
>> Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
>> ---
>> arch/arm64/include/asm/rmi_cmds.h | 11 ++
>> arch/arm64/include/asm/rmi_smc.h | 49 ++++++
>> drivers/virt/coco/arm-cca-host/arm-cca.c | 45 ++++++
>> drivers/virt/coco/arm-cca-host/rmm-da.c | 198 +++++++++++++++++++++++
>> drivers/virt/coco/arm-cca-host/rmm-da.h | 41 +++++
>> 5 files changed, 344 insertions(+)
>>
>
>> #endif /* __ASM_RMI_CMDS_H */
>> diff --git a/arch/arm64/include/asm/rmi_smc.h b/arch/arm64/include/asm/rmi_smc.h
>> index a84ed61e5001..8bece465b670 100644
>> --- a/arch/arm64/include/asm/rmi_smc.h
>> +++ b/arch/arm64/include/asm/rmi_smc.h
>> @@ -47,6 +47,7 @@
>
>>
>> +#define RMI_DEV_COMM_EXIT_CACHE_REQ BIT(0)
>> +#define RMI_DEV_COMM_EXIT_CACHE_RSP BIT(1)
>> +#define RMI_DEV_COMM_EXIT_SEND BIT(2)
>> +#define RMI_DEV_COMM_EXIT_WAIT BIT(3)
>> +#define RMI_DEV_COMM_EXIT_MULTI BIT(4)
>> +
>> +#define RMI_DEV_COMM_NONE 0
>> +#define RMI_DEV_COMM_RESPONSE 1
>> +#define RMI_DEV_COMM_ERROR 2
>> +
>> +#define RMI_PROTOCOL_SPDM 0
>> +#define RMI_PROTOCOL_SECURE_SPDM 1
>> +
>> +#define RMI_DEV_VCA 0
>> +#define RMI_DEV_CERTIFICATE 1
>> +#define RMI_DEV_MEASUREMENTS 2
>> +#define RMI_DEV_INTERFACE_REPORT 3
>> +
>> +struct rmi_dev_comm_enter {
>> + u64 status;
>> + u64 req_addr;
>> + u64 resp_addr;
>> + u64 resp_len;
>> +};
>> +
>> +struct rmi_dev_comm_exit {
>> + u64 flags;
>> + u64 cache_req_offset;
>> + u64 cache_req_len;
>> + u64 cache_rsp_offset;
>> + u64 cache_rsp_len;
>> + u64 cache_obj_id;
>> + u64 protocol;
>> + u64 req_len;
>> + u64 timeout;
> In latest spec called rsp_timeout.
> Not sure we care that much but if no strong reason otherwise, should
> aim to match the spec text. (Maybe this got renamed?)
>> +};
>
>> diff --git a/drivers/virt/coco/arm-cca-host/arm-cca.c b/drivers/virt/coco/arm-cca-host/arm-cca.c
>> index 84d97dd41191..294a6ef60d5f 100644
>> --- a/drivers/virt/coco/arm-cca-host/arm-cca.c
>> +++ b/drivers/virt/coco/arm-cca-host/arm-cca.c
>> @@ -85,6 +85,45 @@ static void cca_tsm_pci_remove(struct pci_tsm *tsm)
>> vfree(dsc_pf0);
>> }
>>
>> +static int init_dev_communication_buffers(struct cca_host_comm_data *comm_data)
>> +{
>> + int ret = -ENOMEM;
>> +
>> + comm_data->io_params = (struct rmi_dev_comm_data *)get_zeroed_page(GFP_KERNEL);
>
> Hmm. There isn't a DEFINE_FREE() yet for free_page(). Maybe time to add one.
> If we did then we'd use local variables until all allocations succeed then
> assign with no_free_ptr()
>
>
>> + if (!comm_data->io_params)
>> + goto err_out;
>> +
>> + comm_data->resp_buff = (void *)__get_free_page(GFP_KERNEL);
>> + if (!comm_data->resp_buff)
>> + goto err_res_buff;
>> +
>> + comm_data->req_buff = (void *)__get_free_page(GFP_KERNEL);
>> + if (!comm_data->req_buff)
>> + goto err_req_buff;
>> +
>> +
>> + comm_data->io_params->enter.status = RMI_DEV_COMM_NONE;
>> + comm_data->io_params->enter.resp_addr = virt_to_phys(comm_data->resp_buff);
>> + comm_data->io_params->enter.req_addr = virt_to_phys((void *)comm_data->req_buff);
> I think it's already a a void * and even if it were some other pointer type
> no cast would be necessary.
>
>> + comm_data->io_params->enter.resp_len = 0;
>> +
>> + return 0;
>> +
>> +err_req_buff:
>> + free_page((unsigned long)comm_data->resp_buff);
>> +err_res_buff:
>> + free_page((unsigned long)comm_data->io_params);
>> +err_out:
>> + return ret;
>> +}
>> +
>
>> +
>> /* per root port unique with multiple restrictions. For now global */
>> static DECLARE_BITMAP(cca_stream_ids, MAX_STREAM_ID);
>>
>> @@ -124,6 +163,7 @@ static int cca_tsm_connect(struct pci_dev *pdev)
>> rc = tsm_ide_stream_register(pdev, ide);
>> if (rc)
>> goto err_tsm;
>> + init_dev_communication_buffers(&dsc_pf0->comm_data);
>> /*
>> * Take a module reference so that we won't call unregister
>> * without rme_unasign_device
>> @@ -133,6 +173,11 @@ static int cca_tsm_connect(struct pci_dev *pdev)
>> goto err_tsm;
>> }
>> rme_asign_device(pdev);
> rme_assign_device() - I obviously missed this earlier!
>
>> + /*
>> + * Schedule a work to fetch device certificate and setup IDE
> Single line comment probably fine here. Though it perhaps doesn't add
> much over the function name.
>> + */
>> + schedule_rme_ide_setup(pdev);
>> +
>> /*
>> * Once ide is setup enable the stream at endpoint
>> * Root port will be done by RMM
>> diff --git a/drivers/virt/coco/arm-cca-host/rmm-da.c b/drivers/virt/coco/arm-cca-host/rmm-da.c
>> index 426e530ac182..d123940ce82e 100644
>> --- a/drivers/virt/coco/arm-cca-host/rmm-da.c
>> +++ b/drivers/virt/coco/arm-cca-host/rmm-da.c
>> @@ -148,3 +148,201 @@ int rme_asign_device(struct pci_dev *pci_dev)
>> err_out:
>> return ret;
>> }
>> +
>> +static int doe_send_req_resp(struct pci_tsm *tsm)
>> +{
>> + u8 protocol;
>> + int ret, data_obj_type;
>> + struct cca_host_comm_data *comm_data;
>> + struct rmi_dev_comm_exit *io_exit;
>> +
>> + comm_data = to_cca_comm_data(tsm->pdev);
>> +
>> + io_exit = &comm_data->io_params->exit;
>> + protocol = io_exit->protocol;
>
> For all these I'd combine with the declarations.
>
>> +
>> + pr_debug("doe_req size:%lld doe_io_type=%d\n", io_exit->req_len, (int)protocol);
>> +
>> + if (protocol == RMI_PROTOCOL_SPDM)
>> + data_obj_type = PCI_DOE_PROTO_CMA;
>> + else if (protocol == RMI_PROTOCOL_SECURE_SPDM)
>> + data_obj_type = PCI_DOE_PROTO_SSESSION;
>> + else
>> + return -EINVAL;
>> +
>> + ret = pci_tsm_doe_transfer(tsm->dsm_dev, data_obj_type,
>> + comm_data->req_buff, io_exit->req_len,
>> + comm_data->resp_buff, PAGE_SIZE);
>> + pr_debug("doe returned:%d\n", ret);
>> + return ret;
>> +}
>> +
>> +/* Parallel update for cca_dsc contents FIXME!! */
>> +static int __do_dev_communicate(int type, struct pci_tsm *tsm)
>> +{
>> + int ret;
>> + bool is_multi;
>> + u8 *cache_buf;
>> + int *cache_offset;
>> + int nbytes, cache_remaining;
>> + struct cca_host_dsc_pf0 *dsc_pf0;
>> + struct rmi_dev_comm_exit *io_exit;
>> + struct rmi_dev_comm_enter *io_enter;
>> + struct cca_host_comm_data *comm_data;
>> +
>> +
>> + comm_data = to_cca_comm_data(tsm->pdev);
>> + io_enter = &comm_data->io_params->enter;
>> + io_exit = &comm_data->io_params->exit;
>
> Might as well set these local variables as the declaration point
> above. None of them will be very long lines.
>
>> +
>> + dsc_pf0 = to_cca_dsc_pf0(tsm->dsm_dev);
>> +redo_communicate:
>> + is_multi = false;
>> +
>> + if (type == PDEV_COMMUNICATE)
>> + ret = rmi_pdev_communicate(virt_to_phys(dsc_pf0->rmm_pdev),
>> + virt_to_phys(comm_data->io_params));
>> + else
>> + ret = RMI_ERROR_INPUT;
>
> I'd split this case out and return here farther than using the match below
> as it feels like the error message auto to be more specific. Something
> about type not matching.
>

This get updated in the follow up patch as below.

if (type == PDEV_COMMUNICATE)
ret = rmi_pdev_communicate(virt_to_phys(dsc_pf0->rmm_pdev),
virt_to_phys(comm_data->io_params));
else {
struct cca_host_tdi *host_tdi = container_of(tsm->tdi, struct cca_host_tdi, tdi);

ret = rmi_vdev_communicate(virt_to_phys(dsc_pf0->rmm_pdev),
virt_to_phys(host_tdi->rmm_vdev),
virt_to_phys(comm_data->io_params));
}

>
>> + if (ret != RMI_SUCCESS) {
>> + pr_err("pdev communicate error\n");
>> + return ret;
>> + }
>> +
>> + /* caching request from RMM */
>> + if (io_exit->flags & RMI_DEV_COMM_EXIT_CACHE_RSP) {
>> + switch (io_exit->cache_obj_id) {
>> + case RMI_DEV_VCA:
>> + cache_buf = dsc_pf0->vca.buf;
>> + cache_offset = &dsc_pf0->vca.size;
>> + cache_remaining = sizeof(dsc_pf0->vca.buf) - *cache_offset;
>> + break;
>> + case RMI_DEV_CERTIFICATE:
>> + cache_buf = dsc_pf0->cert_chain.cache.buf;
>> + cache_offset = &dsc_pf0->cert_chain.cache.size;
>> + cache_remaining = sizeof(dsc_pf0->cert_chain.cache.buf) - *cache_offset;
>> + break;
>> + default:
>> + /* FIXME!! depending on the DevComms status,
>> + * it might require to ABORT the communcation.
>> + */
>> + return -EINVAL;
>> + }
>> +
>> + if (io_exit->cache_rsp_len > cache_remaining)
>> + return -EINVAL;
>> +
>> + memcpy(cache_buf + *cache_offset,
>> + (comm_data->resp_buff + io_exit->cache_rsp_offset), io_exit->cache_rsp_len);
>> + *cache_offset += io_exit->cache_rsp_len;
>> + }
>> +
>> + /*
>> + * wait for last packet request from RMM.
>> + * We should not find this because our device communication in synchronous
>> + */
>> + if (io_exit->flags & RMI_DEV_COMM_EXIT_WAIT)
>> + return -ENXIO;
>> +
>> + is_multi = !!(io_exit->flags & RMI_DEV_COMM_EXIT_MULTI);
>
> !! doesn't add anything here that I can see over
>
> is_multi = io_exit->flags & RMI_DEV_COMM_EXIT_MULTI;
>
>
>> +
>> + /* next packet to send */
>> + if (io_exit->flags & RMI_DEV_COMM_EXIT_SEND) {
>> + nbytes = doe_send_req_resp(tsm);
>> + if (nbytes < 0) {
>> + /* report error back to RMM */
>> + io_enter->status = RMI_DEV_COMM_ERROR;
>> + } else {
>> + /* send response back to RMM */
>> + io_enter->resp_len = nbytes;
>> + io_enter->status = RMI_DEV_COMM_RESPONSE;
>> + }
>> + } else {
>> + /* no data transmitted => no data received */
>> + io_enter->resp_len = 0;
>> + }
>> +
>> + /* The call need to do multiple request/respnse */
>> + if (is_multi)
>> + goto redo_communicate;
>> +
>> + return 0;
>> +}
>> +
>> +static int do_dev_communicate(int type, struct pci_tsm *tsm, int target_state)
>> +{
>> + int ret;
>> + unsigned long state;
>> + unsigned long error_state;
>> + struct cca_host_dsc_pf0 *dsc_pf0;
>> + struct rmi_dev_comm_enter *io_enter;
>> +
>> + dsc_pf0 = to_cca_dsc_pf0(tsm->dsm_dev);
>> + io_enter = &dsc_pf0->comm_data.io_params->enter;
>> + io_enter->resp_len = 0;
>> + io_enter->status = RMI_DEV_COMM_NONE;
>> +
>> + state = -1;
>> + do {
>> + ret = __do_dev_communicate(type, tsm);
>> + if (ret != 0) {
> if (ret)
>
>> + pr_err("dev communication error\n");
>> + break;
>
> I'd just return in error cases.
>
>> + }
>> +
>> + if (type == PDEV_COMMUNICATE) {
>> + ret = rmi_pdev_get_state(virt_to_phys(dsc_pf0->rmm_pdev),
>> + &state);
>> + error_state = RMI_PDEV_ERROR;
>> + }
>> + if (ret != 0) {
>> + pr_err("Get dev state error\n");
>> + break;
>> + }
>> + } while (state != target_state && state != error_state);
>> +
>> + pr_info("dev_io_complete: status: %d state:%ld\n", ret, state);
>> +
>> + return state;
>> +}

Thanks for the review comments. I'll update the patch with the suggested changes.

-aneesh