Re: [PATCH 4/4] platform/x86/intel/vsec: Plumb ACPI PMT discovery tables through vsec

Ilpo Järvinen
2026-01-15T13:15:10Z

On Tue, 6 Jan 2026, David E. Box wrote:

> Newer platform will optionally expose PMT discovery via ACPI instead of PCI
> BARs. Add a generic discovery source flag and carry ACPI discovery entries
> alongside the existing PCI resource path so PMT clients can consume either.
>
> Changes:
> - Add enum intel_vsec_disc_source { _PCI, _ACPI }.
> - Extend intel_vsec_platform_info and intel_vsec_device with source enum
> and ACPI discovery table pointer/
> - When src==ACPI, skip BAR resource setup and copy the ACPI discovery
> entries into the aux device.
>
> No user-visible behavior change yet; this only wires ACPI data through vsec
> in preparation for ACPI-enumerated PMT clients.
>
> Signed-off-by: David E. Box <david.e.box@linux.intel.com>
> ---
> drivers/platform/x86/intel/vsec.c | 16 ++++++++++++++++
> include/linux/intel_vsec.h | 20 +++++++++++++++++++-
> 2 files changed, 35 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/platform/x86/intel/vsec.c b/drivers/platform/x86/intel/vsec.c
> index 42471fd609b1..705672dcdd11 100644
> --- a/drivers/platform/x86/intel/vsec.c
> +++ b/drivers/platform/x86/intel/vsec.c
> @@ -109,6 +109,7 @@ static void intel_vsec_dev_release(struct device *dev)
>
> ida_free(intel_vsec_dev->ida, intel_vsec_dev->auxdev.id);
>
> + kfree(intel_vsec_dev->acpi_disc);
> kfree(intel_vsec_dev->resource);
> kfree(intel_vsec_dev);
> }
> @@ -321,6 +322,10 @@ static int intel_vsec_add_dev(struct device *dev, struct intel_vsec_header *head
> * auxiliary device driver.
> */
> for (i = 0, tmp = res; i < header->num_entries; i++, tmp++) {
> + /* This check doesn't apply to ACPI based discovery */

"This check" is somewhat vague, if it doesn't require a novel, it would be
better to write out what check.

> + if (info->src == INTEL_VSEC_DISC_ACPI)
> + break;
> +
> tmp->start = base_addr + header->offset + i * (header->entry_size * sizeof(u32));
> tmp->end = tmp->start + (header->entry_size * sizeof(u32)) - 1;
> tmp->flags = IORESOURCE_MEM;
> @@ -339,6 +344,17 @@ static int intel_vsec_add_dev(struct device *dev, struct intel_vsec_header *head
> intel_vsec_dev->base_addr = info->base_addr;
> intel_vsec_dev->priv_data = info->priv_data;
> intel_vsec_dev->cap_id = cap_id;
> + intel_vsec_dev->src = info->src;
> +
> + if (info->src == INTEL_VSEC_DISC_ACPI) {
> + size_t bytes;
> +
> + bytes = intel_vsec_dev->num_resources * sizeof(info->acpi_disc[0]);

Should this use some overflow.h helper?

> +
> + intel_vsec_dev->acpi_disc = kmemdup(info->acpi_disc, bytes, GFP_KERNEL);

include for kmemdup() seems missing.

> + if (!intel_vsec_dev->acpi_disc)
> + return -ENOMEM;
> + }
>
> if (header->id == VSEC_ID_SDSI)
> intel_vsec_dev->ida = &intel_vsec_sdsi_ida;
> diff --git a/include/linux/intel_vsec.h b/include/linux/intel_vsec.h
> index 931ff42361a9..9d7795480c49 100644
> --- a/include/linux/intel_vsec.h
> +++ b/include/linux/intel_vsec.h
> @@ -32,6 +32,11 @@
> struct resource;
> struct pci_dev;
>
> +enum intel_vsec_disc_source {
> + INTEL_VSEC_DISC_PCI, /* PCI, default */
> + INTEL_VSEC_DISC_ACPI, /* ACPI */
> +};
> +
> enum intel_vsec_id {
> VSEC_ID_TELEMETRY = 2,
> VSEC_ID_WATCHER = 3,
> @@ -102,6 +107,10 @@ struct vsec_feature_dependency {
> * @parent: parent device in the auxbus chain
> * @headers: list of headers to define the PMT client devices to create
> * @deps: array of feature dependencies
> + * @acpi_disc: ACPI discovery tables, each entry is two QWORDs
> + * in little-endian format as defined by the PMT ACPI spec.
> + * Valid only when @provider == INTEL_VSEC_PROV_ACPI.
> + * @src: source of discovery table data
> * @priv_data: private data, usable by parent devices, currently a callback
> * @caps: bitmask of PMT capabilities for the given headers
> * @quirks: bitmask of VSEC device quirks
> @@ -112,6 +121,8 @@ struct intel_vsec_platform_info {
> struct device *parent;
> struct intel_vsec_header **headers;
> const struct vsec_feature_dependency *deps;
> + u32 (*acpi_disc)[4];
> + enum intel_vsec_disc_source src;
> void *priv_data;
> unsigned long caps;
> unsigned long quirks;
> @@ -123,7 +134,12 @@ struct intel_vsec_platform_info {
> * struct intel_sec_device - Auxbus specific device information
> * @auxdev: auxbus device struct for auxbus access
> * @dev: struct device associated with the device
> - * @resource: any resources shared by the parent
> + * @resource: PCI discovery resources (BAR windows), one per discovery
> + * instance. Valid only when @src == INTEL_VSEC_PROV_PCI
> + * @acpi_disc: ACPI discovery tables, each entry is two QWORDs
> + * in little-endian format as defined by the PMT ACPI spec.
> + * Valid only when @src == INTEL_VSEC_PROV_ACPI.
> + * @src: source of discovery table data
> * @ida: id reference
> * @num_resources: number of resources
> * @id: xarray id
> @@ -136,6 +152,8 @@ struct intel_vsec_device {
> struct auxiliary_device auxdev;
> struct device *dev;
> struct resource *resource;
> + u32 (*acpi_disc)[4];
> + enum intel_vsec_disc_source src;
> struct ida *ida;
> int num_resources;
> int id; /* xa */
>

--
i.