Re: [RFC PATCH v4 09/11] coco: guest: arm64: Hook TSM accept to Realm TDISP RUN transition

[Kameron Carr]

On 4/27/2026 1:28 AM, Aneesh Kumar K.V (Arm) wrote:
> Add an accept callback in pci_tsm_ops and implement cca_device_accept() to:
> - verify evidence generation (lock_nonce)
> - allocate and register protected MMIO ranges
> - transition TDI state to RUN
> 
> Reviewed-by: Jonathan Cameron <jonathan.cameron@xxxxxxxxxx>
> Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@xxxxxxxxxx>
> ---
>  drivers/virt/coco/arm-cca-guest/arm-cca.c | 20 +++++++++++
>  drivers/virt/coco/arm-cca-guest/rsi-da.c  | 43 +++++++++++++++++++++++
>  drivers/virt/coco/arm-cca-guest/rsi-da.h  |  1 +
>  3 files changed, 64 insertions(+)
> 
> diff --git a/drivers/virt/coco/arm-cca-guest/arm-cca.c b/drivers/virt/coco/arm-cca-guest/arm-cca.c
> index 320dd5aa7b9a..b29b3948a454 100644
> --- a/drivers/virt/coco/arm-cca-guest/arm-cca.c
> +++ b/drivers/virt/coco/arm-cca-guest/arm-cca.c
> @@ -499,9 +499,29 @@ static void cca_tsm_unlock(struct pci_tsm *tsm)
>  	kfree(cca_dsc);
>  }
>  
> +static int __cca_tsm_accept(struct pci_dev *pdev, unsigned long lock_nonce)
> +{
> +	int ret;
> +
> +	ret = cca_device_accept(pdev, lock_nonce);
> +	if (ret) {
> +		pci_err(pdev, "failed to transition the device to run state (%d)\n", ret);
> +		return ret;
> +	}
> +	return 0;
> +}
> +
> +static int cca_tsm_accept(struct pci_dev *pdev)
> +{
> +	struct cca_guest_dsc *dsc = to_cca_guest_dsc(pdev);
> +
> +	return __cca_tsm_accept(pdev, dsc->dev_info.lock_nonce);
> +}
> +
>  static struct pci_tsm_ops cca_devsec_pci_ops = {
>  	.lock = cca_tsm_lock,
>  	.unlock = cca_tsm_unlock,
> +	.accept	 = cca_tsm_accept,
>  };
>  
>  static void cca_devsec_tsm_remove(void *tsm_dev)
> diff --git a/drivers/virt/coco/arm-cca-guest/rsi-da.c b/drivers/virt/coco/arm-cca-guest/rsi-da.c
> index 039138768f8f..7c2b28fa43a1 100644
> --- a/drivers/virt/coco/arm-cca-guest/rsi-da.c
> +++ b/drivers/virt/coco/arm-cca-guest/rsi-da.c
> @@ -230,3 +230,46 @@ int cca_verify_digests(u64 hash_algo,
>  	}
>  	return 0;
>  }
> +
> +int cca_device_accept(struct pci_dev *pdev, unsigned long lock_nonce)
> +{
> +	int ret;
> +	struct cca_guest_dsc *dsc = to_cca_guest_dsc(pdev);
> +
> +	if (lock_nonce != dsc->dev_info.lock_nonce) {
> +		pci_err(pdev, "Device evidence generation mismatch\n");
> +		return -EIO;
> +	}
> +
> +	/* Allocation private mmio range based on interface report. */
> +	struct pci_tsm_mmio *tsm_mmio __free(kfree) = pci_tsm_mmio_alloc(pdev);
> +	if (!tsm_mmio) {
> +		pci_err(pdev, "Protected mmio range allocation failure\n");
> +		return -ENOMEM;
> +	}
> +
> +	/*
> +	 * Present the private mmio range in the resource hierarchy.
> +	 * We don't use this for ioremap, ioremap check the RIPAS value.
> +	 */
> +	ret = pci_tsm_mmio_setup(pdev, tsm_mmio);
> +	if (ret) {
> +		pci_err(pdev, "Protected mmio setup failure\n");
> +		return ret;
> +	}
> +
> +	ret = cca_map_evidence_report_range(pdev, tsm_mmio);
> +	if (ret) {
> +		pci_err(pdev, "failed to validate the interface report\n");
> +		return ret;
> +	}
> +
> +	ret = rhi_vdev_set_tdi_state(pdev, RHI_DA_TDI_CONFIG_RUN);
> +	if (ret) {
> +		pci_err(pdev, "failed to switch the device (%u) to RUN state\n", ret);
> +		return ret;
> +	}

After calling pci_tsm_mmio_setup() we have mappings from insert_resource()
then failures from later return codes never call mmio_teardown() so
remove_resource() is never called, only kfree on the tsm_mmio.

Likewise after cca_map_evidence_report_range() the mmio entry memory ranges
have state RIPAS_DEV. Later failures never restore RIPAS_EMPTY.

Could clean up be handled better? Is there a reason these failures don't
have a rollback path?

Regards,
Kameron

> +
> +	dsc->pci.mmio = no_free_ptr(tsm_mmio);
> +	return 0;
> +}
> diff --git a/drivers/virt/coco/arm-cca-guest/rsi-da.h b/drivers/virt/coco/arm-cca-guest/rsi-da.h
> index 07a044d3e335..eeb049d374c5 100644
> --- a/drivers/virt/coco/arm-cca-guest/rsi-da.h
> +++ b/drivers/virt/coco/arm-cca-guest/rsi-da.h
> @@ -61,5 +61,6 @@ int cca_verify_digests(u64 hash_algo,
>  		uint8_t *interface_report, size_t interface_report_size,
>  		uint8_t *measurements, size_t measurements_size,
>  		struct rsi_vdevice_info *dev_info);
> +int cca_device_accept(struct pci_dev *pdev, unsigned long lock_nonce);
>  
>  #endif