Message-ID: <yq5acy9e9eon.fsf@kernel.org>
Date: Sat, 02 Aug 2025 16:24:32 +0530
From: Aneesh Kumar K.V <aneesh.kumar@...nel.org>
To: Jonathan Cameron <Jonathan.Cameron@...wei.com>
Cc: linux-coco@...ts.linux.dev, kvmarm@...ts.linux.dev,
	linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org, aik@....com,
	lukas@...ner.de, Samuel Ortiz <sameo@...osinc.com>,
	Xu Yilun <yilun.xu@...ux.intel.com>,
	Jason Gunthorpe <jgg@...pe.ca>,
	Suzuki K Poulose <Suzuki.Poulose@....com>,
	Steven Price <steven.price@....com>,
	Catalin Marinas <catalin.marinas@....com>,
	Marc Zyngier <maz@...nel.org>, Will Deacon <will@...nel.org>,
	Oliver Upton <oliver.upton@...ux.dev>
Subject: Re: [RFC PATCH v1 13/38] coco: host: arm64: Create a PDEV with rmm

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

> On Mon, 28 Jul 2025 19:21:50 +0530
> "Aneesh Kumar K.V (Arm)" <aneesh.kumar@...nel.org> wrote:
>
>> Create the realm physical device with RMM.
>> 
>> Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@...nel.org>
> Hi Aneesh,
>
> Various small things inline.
>
> Jonathan
>
>> ---
>>  arch/arm64/include/asm/rmi_cmds.h        |  31 +++++
>>  arch/arm64/include/asm/rmi_smc.h         |  72 ++++++++++-
>>  drivers/virt/coco/arm-cca-host/Makefile  |   2 +-
>>  drivers/virt/coco/arm-cca-host/arm-cca.c |  10 +-
>>  drivers/virt/coco/arm-cca-host/rmm-da.c  | 150 +++++++++++++++++++++++
>>  drivers/virt/coco/arm-cca-host/rmm-da.h  |   5 +
>>  6 files changed, 267 insertions(+), 3 deletions(-)
>>  create mode 100644 drivers/virt/coco/arm-cca-host/rmm-da.c
>> 
>> diff --git a/arch/arm64/include/asm/rmi_cmds.h b/arch/arm64/include/asm/rmi_cmds.h
>> index ef53147c1984..f0817bd3bab4 100644
>> --- a/arch/arm64/include/asm/rmi_cmds.h
>> +++ b/arch/arm64/include/asm/rmi_cmds.h
>> @@ -505,4 +505,35 @@ static inline int rmi_rtt_unmap_unprotected(unsigned long rd,
>>  	return res.a0;
>>  }
>>  
>> +static inline unsigned long rmi_pdev_aux_count(unsigned long flags, u64 *aux_count)
>> +{
>> +	struct arm_smccc_res res;
>> +
>> +	arm_smccc_1_1_invoke(SMC_RMI_PDEV_AUX_COUNT, flags, &res);
>> +
>> +	*aux_count = res.a1;
>> +	return res.a0;
>> +}
>> +
>> +static inline unsigned long rmi_pdev_create(unsigned long pdev_phys,
>> +					    unsigned long pdev_params_phys)
>> +{
>> +	struct arm_smccc_res res;
>> +
>> +	arm_smccc_1_1_invoke(SMC_RMI_PDEV_CREATE,
>> +			     pdev_phys, pdev_params_phys, &res);
>> +
>> +	return res.a0;
>> +}
>> +
>> +static inline unsigned long rmi_pdev_get_state(unsigned long pdev_phys, unsigned long *state)
>
> I'd use the enum for the state type and range check in here.
>
>
>> +{
>> +	struct arm_smccc_res res;
>> +
>> +	arm_smccc_1_1_invoke(SMC_RMI_PDEV_GET_STATE, pdev_phys, &res);
>> +
>> +	*state = res.a1;
>> +	return res.a0;
>> +}
>> +
>>  #endif /* __ASM_RMI_CMDS_H */
>> diff --git a/arch/arm64/include/asm/rmi_smc.h b/arch/arm64/include/asm/rmi_smc.h
>> index 42708d500048..a84ed61e5001 100644
>> --- a/arch/arm64/include/asm/rmi_smc.h
>> +++ b/arch/arm64/include/asm/rmi_smc.h
>> @@ -26,7 +26,7 @@
>>  #define SMC_RMI_DATA_CREATE		SMC_RMI_CALL(0x0153)
>>  #define SMC_RMI_DATA_CREATE_UNKNOWN	SMC_RMI_CALL(0x0154)
>>  #define SMC_RMI_DATA_DESTROY		SMC_RMI_CALL(0x0155)
>> -
>
> Probably keep
>
>> +#define SMC_RMI_PDEV_AUX_COUNT		SMC_RMI_CALL(0x0156)
>
> and add one here as different groups.
>
>>  #define SMC_RMI_REALM_ACTIVATE		SMC_RMI_CALL(0x0157)
>>  #define SMC_RMI_REALM_CREATE		SMC_RMI_CALL(0x0158)
>>  #define SMC_RMI_REALM_DESTROY		SMC_RMI_CALL(0x0159)
>> @@ -47,6 +47,9 @@
>>  #define SMC_RMI_RTT_INIT_RIPAS		SMC_RMI_CALL(0x0168)
>>  #define SMC_RMI_RTT_SET_RIPAS		SMC_RMI_CALL(0x0169)
>>  
>> +#define SMC_RMI_PDEV_CREATE             SMC_RMI_CALL(0x0176)
>> +#define SMC_RMI_PDEV_GET_STATE		SMC_RMI_CALL(0x0178)
>> +
>>  #define RMI_ABI_MAJOR_VERSION	1
>>  #define RMI_ABI_MINOR_VERSION	0
>>  
>> @@ -268,4 +271,71 @@ struct rec_run {
>>  	struct rec_exit exit;
>>  };
>>  
>> +enum rmi_pdev_state {
> Type never used, but I think it should be. See above.
>
>> +	RMI_PDEV_NEW,
>> +	RMI_PDEV_NEEDS_KEY,
>> +	RMI_PDEV_HAS_KEY,
>> +	RMI_PDEV_READY,
> Seems someone put another state in here, but I guess you'll update
> when the rest of the stack catches up.
> 	RMI_PDEV_IDE_RESETTING,
>
> Maybe throw a comment here for now.
>
>> +	RMI_PDEV_COMMUNICATING,
>> +	RMI_PDEV_STOPPING,
>> +	RMI_PDEV_STOPPED,
>> +	RMI_PDEV_ERROR,
>> +};
>> +
>> +#define MAX_PDEV_AUX_GRANULES	32
>> +#define MAX_IOCOH_ADDR_RANGE	16
>> +#define MAX_FCOH_ADDR_RANGE	4
>> +
>> +#define RMI_PDEV_SPDM_TRUE	BIT(0)
>> +#define RMI_PDEV_IDE_TRUE	BIT(1)
>> +#define RMI_PDEV_FOCOH		BIT(2)
>> +#define RMI_PDEV_P2P_STREAM	BIT(3)
>
> I'd stick flags in the name (assuming this is
> RmiPDevFlags? I'm not sure as the spec I could
> find has different usages other after BIT(!))
>
>
>> +
>> +#define RMI_HASH_SHA_256	0
>> +#define RMI_HASH_SHA_512	1
>> +
>> +struct rmi_pdev_addr_range {
>> +	unsigned long base;
>> +	unsigned long top;
>
> Whilst we only care about platforms where this is u64, maybe
> just make that explicit so we can trivially see this
> matches the spec?
>
>> +};
>> +
>> +struct rmi_pdev_params {
>
> Reference? Looks like B4.4.25 RmiPdevParams type
> in alp15.  Though as there are some fields missing
> I guess this chagned.
>

This patch series is currently based on the ALP12 specification, available here:
https://developer.arm.com/-/cdn-downloads/permalink/Architectures/Armv9/DEN0137_1.1-alp12.zip

The next revision of the series will be updated to align with the ALP15 specification.

>
>> +	union {
>> +		struct {
>> +			u64 flags;
>> +			u64 pdev_id;
>> +			u64 segment_id;
>> +			u64 ecam_addr;
>> +			u64 root_id;
>> +			u64 cert_id;
>> +			u64 rid_base;
>> +			u64 rid_top;
>> +			u64 hash_algo;
>> +			u64 num_aux;
>> +			u64 ide_sid;
>
> Called ncoh_ide_side in the alpha 15.  Maybe match that unless
> it is changing name in future version.
>
>> +			u64 ncoh_num_addr_range;
>> +			u64 coh_num_addr_range;
>> +		};
>> +		u8 padding1[0x100];
>> +	};
>> +
>> +	union { /* 0x100 */
>> +		u64 aux_granule[MAX_PDEV_AUX_GRANULES];
>> +		u8 padding2[0x100];
>> +	};
>> +
>> +	union { /* 0x200 */
>> +		struct {
>> +			struct rmi_pdev_addr_range ncoh_addr_range[MAX_IOCOH_ADDR_RANGE];
>> +		};
>> +		u8 padding3[0x100];
>> +	};
>> +	union { /* 0x300 */
>> +		struct {
>> +			struct rmi_pdev_addr_range coh_addr_range[MAX_FCOH_ADDR_RANGE];
>> +		};
>> +		u8 padding4[0x100];
>> +	};
>
> Maybe pad out the rest?  Mostly so we can see here that it is 4k.
>

ok

>
>> +};
>> +
>>  #endif /* __ASM_RMI_SMC_H */
>
>> diff --git a/drivers/virt/coco/arm-cca-host/arm-cca.c b/drivers/virt/coco/arm-cca-host/arm-cca.c
>> index c8b0e6db1f47..84d97dd41191 100644
>> --- a/drivers/virt/coco/arm-cca-host/arm-cca.c
>> +++ b/drivers/virt/coco/arm-cca-host/arm-cca.c
>> @@ -124,7 +124,15 @@ static int cca_tsm_connect(struct pci_dev *pdev)
>>  	rc = tsm_ide_stream_register(pdev, ide);
>>  	if (rc)
>>  		goto err_tsm;
>> -
>
> Tidy up.  I'd leave it.
>
>> +	/*
>> +	 * Take a module reference so that we won't call unregister
>> +	 * without rme_unasign_device
>> +	 */
>> +	if (!try_module_get(THIS_MODULE)) {
>> +		rc = -ENXIO;
>> +		goto err_tsm;
>> +	}
>> +	rme_asign_device(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
>> new file mode 100644
>> index 000000000000..426e530ac182
>> --- /dev/null
>> +++ b/drivers/virt/coco/arm-cca-host/rmm-da.c
>> @@ -0,0 +1,150 @@
>
>
>> +
>> +static int init_pdev_params(struct pci_dev *pdev, struct rmi_pdev_params *params)
>> +{
>> +	void *aux;
>
> Probably makes sense to reduce scope of aux to within the loop.
>
>> +	int rid, ret, i;
>> +	phys_addr_t aux_phys;
>> +	struct cca_host_dsc_pf0 *dsc_pf0;
>> +	struct pci_dev *rp = pcie_find_root_port(pdev);
> Only used in one place for now anyway.  Probably better
> to move it down there.
>
>> +	struct pci_config_window *cfg = pdev->bus->sysdata;
>> +
>> +	dsc_pf0 = to_cca_dsc_pf0(pdev);
>
> I'd do that at declaration.  Seems little advantage in doing it
> down here.
>
>> +	/* assign the ep device with RMM */
>> +	rid = pci_dev_id(pdev);
>> +	params->pdev_id = rid;
>> +	/* slot number for certificate chain */
>> +	params->cert_id = 0;
>> +	/* io coherent spdm/ide and non p2p */
>> +	params->flags = RMI_PDEV_SPDM_TRUE | RMI_PDEV_IDE_TRUE;
>> +	params->ide_sid = dsc_pf0->sel_stream->stream_id;
>> +	params->hash_algo = RMI_HASH_SHA_256;
>> +	/* use the rid and MMIO resources of the epdev */
>
> Spell out epdev or associate it with the pdev here more clearly.
>
>> +	params->rid_top = params->rid_base = rid;
>> +	params->ecam_addr = cfg->res.start;
>> +	params->root_id = pci_dev_id(rp);
>
> 	params->root_id = pci_dev_id(pcie_find_root_port(pdev));
> to me acts as better documentation fo what is going on than using
> the local variable rp.
>
>> +
>> +	params->ncoh_num_addr_range = pci_res_to_pdev_addr(params->ncoh_addr_range,
>> +							    ARRAY_SIZE(params->ncoh_addr_range),
>> +							    pdev->resource,
>> +							    DEVICE_COUNT_RESOURCE);
>> +
>> +	rmi_pdev_aux_count(params->flags, &params->num_aux);
>> +	pr_debug("%s using %ld pdev aux granules\n", __func__, (unsigned long)params->num_aux);
>> +	dsc_pf0->num_aux = params->num_aux;
>> +	for (i = 0; i < params->num_aux; i++) {
>
> 		void *aux = (void *)__get_free_page(GFP_KERNEL);
>
>> +		aux = (void *)__get_free_page(GFP_KERNEL);
>> +		if (!aux) {
>> +			ret = -ENOMEM;
>> +			goto err_free_aux;
>> +		}
>> +
>> +		aux_phys = virt_to_phys(aux);
>> +		if (rmi_granule_delegate(aux_phys)) {
>> +			ret = -ENXIO;
>> +			free_page((unsigned long)aux);
>> +			goto err_free_aux;
>> +		}
>> +		params->aux_granule[i] = aux_phys;
>> +		dsc_pf0->aux[i] = aux;
>> +	}
>> +	return 0;
>> +
>> +err_free_aux:
>> +	free_aux_pages(i, dsc_pf0->aux[i]);
>
> I think you want
> 	free_aux_pages(i, dsc_pf0->aux);
> Assuming this is supposed to unwind the loop above.
>
>> +	return -ENOMEM;
>> +}
>> +
> Trivial: Single line probably fine here.
>> +
>> +int rme_asign_device(struct pci_dev *pci_dev)
>> +{
>> +	int ret;
>> +	void *rmm_pdev;
>> +	unsigned long state;
>> +	phys_addr_t rmm_pdev_phys;
>> +	struct rmi_pdev_params *params;
>> +	struct cca_host_dsc_pf0 *dsc_pf0;
>> +
>> +	dsc_pf0 = to_cca_dsc_pf0(pci_dev);
>
> Might as well save a line with
>
> 	struct cca_host_dsc_pf0 *dsc_pf0 = to_cca_dsc_pf0(pci_dev);
>
>> +	rmm_pdev = (void *)get_zeroed_page(GFP_KERNEL);
>> +	if (!rmm_pdev) {
>> +		ret = -ENOMEM;
>
> return -ENOMEM;
>
>> +		goto err_out;
>> +	}
>> +
>> +	rmm_pdev_phys = virt_to_phys(rmm_pdev);
>> +	if (rmi_granule_delegate(rmm_pdev_phys)) {
>> +		ret = -ENXIO;
>> +		goto err_free_pdev;
>> +	}
>> +
>> +	params = (struct rmi_pdev_params *)get_zeroed_page(GFP_KERNEL);
>> +	if (!params) {
>> +		ret = -ENOMEM;
>> +		goto err_granule_undelegate;
>> +	}
>> +
>> +	ret = init_pdev_params(pci_dev, params);
>> +	if (ret)
>> +		goto err_free_params;
>> +
>> +	ret = rmi_pdev_create(rmm_pdev_phys, virt_to_phys(params));
>> +	pr_info("rmi_pdev_create(0x%llx, 0x%llx): %d\n", rmm_pdev_phys, virt_to_phys(params), ret);
>
> RFC, but even so I'd demote to debug and use dynamic debug stuff to enable
> them for your testing.
>
>> +	if (ret)
>> +		goto err_free_aux;
>> +
>> +	rmi_pdev_get_state(rmm_pdev_phys, &state);
>> +	if (state != RMI_PDEV_NEW)
>> +		goto err_free_aux;
>
> Nothing to unwind in rmi_pdev_create()?  We've told the
> RMM about it then we blow away it's resources. Seems unwise!
> Maybe this is cleaned up elsewhere but if so a comment is
> probably good.
>

`pdev_create` is expected to set the device state to `RMI_PDEV_NEW`, so
the subsequent check is redundant if `rmi_pdev_create` returns success.
I will drop that.

>
>> +
>> +	dsc_pf0->rmm_pdev = rmm_pdev;
>> +	free_page((unsigned long)params);
>> +	return 0;
>> +
>> +err_free_aux:
>> +	free_aux_pages(dsc_pf0->num_aux, dsc_pf0->aux);
>> +err_free_params:
>> +	free_page((unsigned long)params);
>> +err_granule_undelegate:
>> +	rmi_granule_undelegate(rmm_pdev_phys);
>> +err_free_pdev:
>> +	free_page((unsigned long)rmm_pdev);
>> +err_out:
>
> One of my favourite nitpicks. Why not just return if nothing to do?
> That tends to save a reviewer a bit of scrolling when checking
> error paths do correct unwinding.
>
>> +	return ret;
>> +}
>> diff --git a/drivers/virt/coco/arm-cca-host/rmm-da.h b/drivers/virt/coco/arm-cca-host/rmm-da.h
>> index 840cb584acdd..179ba68f2430 100644
>> --- a/drivers/virt/coco/arm-cca-host/rmm-da.h
>> +++ b/drivers/virt/coco/arm-cca-host/rmm-da.h
>> @@ -14,6 +14,10 @@
>>  struct cca_host_dsc_pf0 {
>>  	struct pci_tsm_pf0 pci;
>>  	struct pci_ide *sel_stream;
>> +
>> +	void *rmm_pdev;
>> +	int num_aux;
>> +	void *aux[MAX_PDEV_AUX_GRANULES];
>>  };
>>  
>>  static inline struct cca_host_dsc_pf0 *to_cca_dsc_pf0(struct pci_dev *pdev)
>> @@ -26,4 +30,5 @@ static inline struct cca_host_dsc_pf0 *to_cca_dsc_pf0(struct pci_dev *pdev)
>>  	return container_of(tsm, struct cca_host_dsc_pf0, pci.tsm);
>>  }
>>  
>> +int rme_asign_device(struct pci_dev *pdev);
>>  #endif

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

-aneesh

Powered by blists - more mailing lists