linux-kernel - Re: [RFC PATCH v1 34/38] coco: guest: arm64: Validate mmio range found in the interface report

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Message-ID: <20250730160626.00003fee@huawei.com>
Date: Wed, 30 Jul 2025 16:06:26 +0100
From: Jonathan Cameron <Jonathan.Cameron@...wei.com>
To: "Aneesh Kumar K.V (Arm)" <aneesh.kumar@...nel.org>
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 34/38] coco: guest: arm64: Validate mmio range
 found in the interface report

On Mon, 28 Jul 2025 19:22:11 +0530
"Aneesh Kumar K.V (Arm)" <aneesh.kumar@...nel.org> wrote:

> This starts the sequence to transition the realm device to the TDISP RUN
> state by writing 1 to 'tsm/accept'.
> 
> Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@...nel.org>
Just some trivial stuff.


> diff --git a/drivers/virt/coco/arm-cca-guest/rsi-da.c b/drivers/virt/coco/arm-cca-guest/rsi-da.c
> index 47b379318e7c..936f844880de 100644
> --- a/drivers/virt/coco/arm-cca-guest/rsi-da.c
> +++ b/drivers/virt/coco/arm-cca-guest/rsi-da.c
> @@ -215,3 +215,135 @@ int rsi_device_lock(struct pci_dev *pdev)
>  
>  	return ret;
>  }

> +
> +int rsi_update_interface_report(struct pci_dev *pdev, bool validate)
> +{
> +	int ret;
> +	struct resource *r;
> +	int msix_tbl_bar, msix_pba_bar;
> +	unsigned int range_id;
> +	unsigned long mmio_start_phys;
> +	unsigned long mmio_flags = 0; /* non coherent, not limited order */
> +	struct pci_tdisp_mmio_range *mmio_range;
> +	struct pci_tdisp_device_interface_report *interface_report;
> +	struct cca_guest_dsc *dsm = to_cca_guest_dsc(pdev);
> +	int vdev_id = (pci_domain_nr(pdev->bus) << 16) |
> +		PCI_DEVID(pdev->bus->number, pdev->devfn);
> +
> +
Single line.
> +	interface_report = (struct pci_tdisp_device_interface_report *)dsm->interface_report;
> +	mmio_range = (struct pci_tdisp_mmio_range *)(interface_report + 1);
> +
> +
Single line

> +	msix_tbl_bar = get_msix_bar(pdev, PCI_MSIX_TABLE);
> +	msix_pba_bar = get_msix_bar(pdev, PCI_MSIX_PBA);
> +
> +	for (int i = 0; i < interface_report->mmio_range_count; i++, mmio_range++) {
> +
> +		/*FIXME!! units in 4K size*/
> +		range_id = FIELD_GET(TSM_INTF_REPORT_MMIO_RANGE_ID, mmio_range->range_attributes);
> +
> +		/* no secure interrupts */
> +		if (msix_tbl_bar != -1 && range_id == msix_tbl_bar) {

That first condition can get hiked out of the loop.

> +			pr_info("Skipping misx table\n");
> +			continue;
> +		}
> +
> +		if (msix_pba_bar != -1 && range_id == msix_pba_bar) {

Likewise.

> +			pr_info("Skipping misx pba\n");
> +			continue;
> +		}
> +
> +		r = pci_resource_n(pdev, range_id);
> +
> +		if (r->end == r->start ||
> +		    ((r->end - r->start + 1) & ~PAGE_MASK) || !mmio_range->num_pages) {
resource_size() 
> +			pci_warn(pdev, "Skipping broken range [%d] #%d %d pages, %llx..%llx\n",
> +				i, range_id, mmio_range->num_pages, r->start, r->end);
> +			continue;
> +		}
> +
> +		if (FIELD_GET(TSM_INTF_REPORT_MMIO_IS_NON_TEE, mmio_range->range_attributes)) {
> +			pci_info(pdev, "Skipping non-TEE range [%d] #%d %d pages, %llx..%llx\n",
> +				 i, range_id, mmio_range->num_pages, r->start, r->end);
> +			continue;
> +		}
> +
> +		/* No secure interrupts, we should not find this set, ignore for now. */
> +		if (FIELD_GET(TSM_INTF_REPORT_MMIO_MSIX_TABLE, mmio_range->range_attributes) ||
> +		    FIELD_GET(TSM_INTF_REPORT_MMIO_PBA, mmio_range->range_attributes)) {
> +			pci_info(pdev, "Skipping MSIX (%ld/%ld) range [%d] #%d %d pages, %llx..%llx\n",
> +				 FIELD_GET(TSM_INTF_REPORT_MMIO_MSIX_TABLE, mmio_range->range_attributes),
> +				 FIELD_GET(TSM_INTF_REPORT_MMIO_PBA, mmio_range->range_attributes),
> +				 i, range_id, mmio_range->num_pages, r->start, r->end);
> +			continue;
> +		}
> +
> +		mmio_start_phys = mmio_range->first_page;
> +		if (validate)
> +			ret = rsi_validate_dev_mapping(vdev_id, dsm->instance_id,
> +						       r->start, r->end + 1,
> +						       mmio_start_phys << 12, mmio_flags);
> +		else
> +			ret = rsi_invalidate_dev_mapping(r->start, r->end + 1);
> +		if (ret) {
> +			pci_err(pdev, "failed to set protection attributes for the address range\n");
> +			return -EIO;
> +		}
> +	}
> +	return 0;
> +}