lkml.org 
[lkml]   [2022]   [Mar]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH RFC v2 04/11] iommu: Add attach/detach_dev_pasid domain ops
Date
Attaching an IOMMU domain to a PASID of a device is a generic operation
for modern IOMMU drivers which support PASID-granular DMA address
translation. Currently visible usage scenarios include (but not limited):

- SVA (Shared Virtual Address)
- kernel DMA with PASID
- hardware-assist mediated device

This adds a pair of common domain ops for this purpose and adds some
common helpers to attach/detach a domain to/from a {device, PASID} and
get/put the domain attached to {device, PASID}.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
include/linux/iommu.h | 36 ++++++++++++++++++
drivers/iommu/iommu.c | 88 +++++++++++++++++++++++++++++++++++++++++++
2 files changed, 124 insertions(+)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 29c4c2edd706..a46285488a57 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -269,6 +269,8 @@ struct iommu_ops {
* struct iommu_domain_ops - domain specific operations
* @attach_dev: attach an iommu domain to a device
* @detach_dev: detach an iommu domain from a device
+ * @attach_dev_pasid: attach an iommu domain to a pasid of device
+ * @detach_dev_pasid: detach an iommu domain from a pasid of device
* @map: map a physically contiguous memory region to an iommu domain
* @map_pages: map a physically contiguous set of pages of the same size to
* an iommu domain.
@@ -286,6 +288,10 @@ struct iommu_ops {
struct iommu_domain_ops {
int (*attach_dev)(struct iommu_domain *domain, struct device *dev);
void (*detach_dev)(struct iommu_domain *domain, struct device *dev);
+ int (*attach_dev_pasid)(struct iommu_domain *domain,
+ struct device *dev, ioasid_t id);
+ void (*detach_dev_pasid)(struct iommu_domain *domain,
+ struct device *dev, ioasid_t id);

int (*map)(struct iommu_domain *domain, unsigned long iova,
phys_addr_t paddr, size_t size, int prot, gfp_t gfp);
@@ -679,6 +685,14 @@ int iommu_group_claim_dma_owner(struct iommu_group *group, void *owner);
void iommu_group_release_dma_owner(struct iommu_group *group);
bool iommu_group_dma_owner_claimed(struct iommu_group *group);

+int iommu_attach_device_pasid(struct iommu_domain *domain,
+ struct device *dev, ioasid_t pasid);
+void iommu_detach_device_pasid(struct iommu_domain *domain,
+ struct device *dev, ioasid_t pasid);
+struct iommu_domain *
+iommu_get_domain_for_dev_pasid(struct device *dev, ioasid_t pasid);
+void iommu_put_domain_for_dev_pasid(struct iommu_domain *domain);
+
#else /* CONFIG_IOMMU_API */

struct iommu_ops {};
@@ -1047,6 +1061,28 @@ static inline bool iommu_group_dma_owner_claimed(struct iommu_group *group)
{
return false;
}
+
+static inline int iommu_attach_device_pasid(struct iommu_domain *domain,
+ struct device *dev, ioasid_t pasid)
+{
+ return -ENODEV;
+}
+
+static inline void iommu_detach_device_pasid(struct iommu_domain *domain,
+ struct device *dev, ioasid_t pasid)
+{
+}
+
+static inline struct iommu_domain *
+iommu_get_domain_for_dev_pasid(struct device *dev, ioasid_t pasid)
+{
+ return NULL;
+}
+
+static inline void
+iommu_put_domain_for_dev_pasid(struct iommu_domain *domain)
+{
+}
#endif /* CONFIG_IOMMU_API */

/**
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 9fb8a5b4491e..8163ad7f6902 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -27,6 +27,8 @@
#include <linux/cc_platform.h>
#include <trace/events/iommu.h>

+#include "iommu-sva-lib.h"
+
static struct kset *iommu_group_kset;
static DEFINE_IDA(iommu_group_ida);

@@ -38,6 +40,7 @@ struct iommu_group {
struct kobject kobj;
struct kobject *devices_kobj;
struct list_head devices;
+ struct xarray pasid_array;
struct mutex mutex;
void *iommu_data;
void (*iommu_data_release)(void *iommu_data);
@@ -631,6 +634,7 @@ struct iommu_group *iommu_group_alloc(void)
mutex_init(&group->mutex);
INIT_LIST_HEAD(&group->devices);
INIT_LIST_HEAD(&group->entry);
+ xa_init(&group->pasid_array);

ret = ida_simple_get(&iommu_group_ida, 0, 0, GFP_KERNEL);
if (ret < 0) {
@@ -3173,3 +3177,87 @@ bool iommu_group_dma_owner_claimed(struct iommu_group *group)
return user;
}
EXPORT_SYMBOL_GPL(iommu_group_dma_owner_claimed);
+
+int iommu_attach_device_pasid(struct iommu_domain *domain,
+ struct device *dev, ioasid_t pasid)
+{
+ struct iommu_group *group;
+ int ret = -EINVAL;
+ void *curr;
+
+ if (!domain->ops->attach_dev_pasid)
+ return -EINVAL;
+
+ group = iommu_group_get(dev);
+ if (!group)
+ return -ENODEV;
+
+ mutex_lock(&group->mutex);
+ /*
+ * To keep things simple, we currently don't support IOMMU groups
+ * with more than one device. Existing SVA-capable systems are not
+ * affected by the problems that required IOMMU groups (lack of ACS
+ * isolation, device ID aliasing and other hardware issues).
+ */
+ if (!iommu_group_singleton_lockdown(group))
+ goto out_unlock;
+
+ xa_lock(&group->pasid_array);
+ curr = __xa_cmpxchg(&group->pasid_array, pasid, NULL,
+ domain, GFP_KERNEL);
+ xa_unlock(&group->pasid_array);
+ if (curr)
+ goto out_unlock;
+
+ ret = domain->ops->attach_dev_pasid(domain, dev, pasid);
+ if (ret)
+ xa_erase(&group->pasid_array, pasid);
+
+out_unlock:
+ mutex_unlock(&group->mutex);
+ iommu_group_put(group);
+
+ return ret;
+}
+
+void iommu_detach_device_pasid(struct iommu_domain *domain,
+ struct device *dev, ioasid_t pasid)
+{
+ struct iommu_group *group;
+
+ group = iommu_group_get(dev);
+ if (WARN_ON(!group))
+ return;
+
+ mutex_lock(&group->mutex);
+ domain->ops->detach_dev_pasid(domain, dev, pasid);
+ xa_erase(&group->pasid_array, pasid);
+ mutex_unlock(&group->mutex);
+ iommu_group_put(group);
+}
+
+struct iommu_domain *
+iommu_get_domain_for_dev_pasid(struct device *dev, ioasid_t pasid)
+{
+ struct iommu_domain *domain;
+ struct iommu_group *group;
+
+ group = iommu_group_get(dev);
+ if (!group)
+ return NULL;
+
+ mutex_lock(&group->mutex);
+ domain = xa_load(&group->pasid_array, pasid);
+ if (domain && domain->type == IOMMU_DOMAIN_SVA)
+ iommu_sva_domain_get_user(domain);
+ mutex_unlock(&group->mutex);
+ iommu_group_put(group);
+
+ return domain;
+}
+
+void iommu_put_domain_for_dev_pasid(struct iommu_domain *domain)
+{
+ if (domain->type == IOMMU_DOMAIN_SVA)
+ iommu_sva_domain_put_user(domain);
+}
--
2.25.1
\
 
 \ /
  Last update: 2022-03-29 07:41    [W:0.294 / U:1.936 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site