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Commit d35165a9 authored by Jiang Liu's avatar Jiang Liu Committed by Joerg Roedel
Browse files

iommu/vt-d: Search for ACPI _DSM method for DMAR hotplug 



According to Intel VT-d specification, _DSM method to support DMAR
hotplug should exist directly under corresponding ACPI object
representing PCI host bridge. But some BIOSes doesn't conform to
this, so search for _DSM method in the subtree starting from the
ACPI object representing the PCI host bridge.

Signed-off-by: default avatarJiang Liu <jiang.liu@linux.intel.com>
Reviewed-by: default avatarYijing Wang <wangyijing@huawei.com>
Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent 6b197249

drivers/iommu/dmar.c

+30 −3
Original line number Diff line number Diff line
@@ -1942,21 +1942,48 @@ static int dmar_hotplug_remove(acpi_handle handle) 
	return ret;

}



static acpi_status dmar_get_dsm_handle(acpi_handle handle, u32 lvl,

				       void *context, void **retval)

{

	acpi_handle *phdl = retval;



	if (dmar_detect_dsm(handle, DMAR_DSM_FUNC_DRHD)) {

		*phdl = handle;

		return AE_CTRL_TERMINATE;

	}



	return AE_OK;

}



static int dmar_device_hotplug(acpi_handle handle, bool insert)

{

	int ret;

	acpi_handle tmp = NULL;

	acpi_status status;



	if (!dmar_in_use())

		return 0;



	if (!dmar_detect_dsm(handle, DMAR_DSM_FUNC_DRHD))

	if (dmar_detect_dsm(handle, DMAR_DSM_FUNC_DRHD)) {

		tmp = handle;

	} else {

		status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle,

					     ACPI_UINT32_MAX,

					     dmar_get_dsm_handle,

					     NULL, NULL, &tmp);

		if (ACPI_FAILURE(status)) {

			pr_warn("Failed to locate _DSM method.\n");

			return -ENXIO;

		}

	}

	if (tmp == NULL)

		return 0;



	down_write(&dmar_global_lock);

	if (insert)

		ret = dmar_hotplug_insert(handle);

		ret = dmar_hotplug_insert(tmp);

	else

		ret = dmar_hotplug_remove(handle);

		ret = dmar_hotplug_remove(tmp);

	up_write(&dmar_global_lock);



	return ret;