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Message-ID: <cec62a4649113a09165294052aa4c250572846fd.1682234302.git.nicolinc@nvidia.com>
Date: Sun, 23 Apr 2023 00:40:31 -0700
From: Nicolin Chen <nicolinc@...dia.com>
To: <jgg@...dia.com>, <kevin.tian@...el.com>
CC: <robin.murphy@....com>, <eric.auger@...hat.com>,
<yi.l.liu@...el.com>, <baolu.lu@...ux.intel.com>,
<will@...nel.org>, <joro@...tes.org>,
<shameerali.kolothum.thodi@...wei.com>, <jean-philippe@...aro.org>,
<linux-arm-kernel@...ts.infradead.org>, <iommu@...ts.linux.dev>,
<linux-kernel@...r.kernel.org>
Subject: [PATCH RFC v3 1/4] iommu: Add set/unset_dev_user_data ops
The device behind an IOMMU might be used in the user space by a VM. So, it
might have some user space data. For example, a device behind an SMMU has
a static stream ID. In a virtualization use case, both a host environment
and a guest environment have their own Stream IDs. A link (a lookup table)
between the physical Stream ID and the virtual (user) Stream ID is needed
when the host handles the user cache invalidation commands.
Add a pair of new ops to allow user space to forward user_data of a device
via iommufd, and a new dev_user_data_len for data structure sanity done by
the iommufd core.
Signed-off-by: Nicolin Chen <nicolinc@...dia.com>
---
include/linux/iommu.h | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 5c99aeaccd1d..33b11d87b374 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -257,6 +257,15 @@ struct iommu_iotlb_gather {
* @remove_dev_pasid: Remove any translation configurations of a specific
* pasid, so that any DMA transactions with this pasid
* will be blocked by the hardware.
+ * @set/unset_dev_user_data: set/unset an iommu specific device data from user
+ * space. The user device data info will be used by
+ * the driver to take care of user space requests.
+ * The device data structure must be defined in
+ * include/uapi/linux/iommufd.h.
+ * @dev_user_data_len: Length of the device data from user space (in bytes),
+ * simply the "sizeof" the data structure defined in the
+ * include/uapi/linux/iommufd.h. This is used by iommufd
+ * core to run a data length validation.
* @hw_info_type: One of enum iommu_hw_info_type defined in
* include/uapi/linux/iommufd.h. It is used to tag the type
* of data returned by .hw_info callback. The drivers that
@@ -303,6 +312,10 @@ struct iommu_ops {
int (*def_domain_type)(struct device *dev);
void (*remove_dev_pasid)(struct device *dev, ioasid_t pasid);
+ int (*set_dev_user_data)(struct device *dev, const void *user_data);
+ void (*unset_dev_user_data)(struct device *dev);
+ size_t dev_user_data_len;
+
const struct iommu_domain_ops *default_domain_ops;
enum iommu_hw_info_type hw_info_type;
unsigned long long hwpt_type_bitmap;
--
2.40.0
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