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Date: Wed, 2 Aug 2023 14:24:21 -0700
From: Jacob Pan <jacob.jun.pan@...ux.intel.com>
To: LKML <linux-kernel@...r.kernel.org>, iommu@...ts.linux.dev,
"Lu Baolu" <baolu.lu@...ux.intel.com>,
Joerg Roedel <joro@...tes.org>,
Jean-Philippe Brucker <jean-philippe@...aro.com>,
"Robin Murphy" <robin.murphy@....com>
Cc: Jason Gunthorpe <jgg@...dia.com>, "Will Deacon" <will@...nel.org>,
"Tian, Kevin" <kevin.tian@...el.com>, Yi Liu <yi.l.liu@...el.com>,
"Yu, Fenghua" <fenghua.yu@...el.com>,
Tony Luck <tony.luck@...el.com>,
Jacob Pan <jacob.jun.pan@...ux.intel.com>
Subject: [PATCH v12 2/8] iommu: Move global PASID allocation from SVA to core
Intel ENQCMD requires a single PASID to be shared between multiple
devices, as the PASID is stored in a single MSR register per-process
and userspace can use only that one PASID.
This means that the PASID allocation for any ENQCMD using device driver
must always come from a shared global pool, regardless of what kind of
domain the PASID will be used with.
Split the code for the global PASID allocator into
iommu_alloc/free_global_pasid() so that drivers can attach non-SVA
domains to PASIDs as well.
This patch moves global PASID allocation APIs from SVA to IOMMU APIs.
Reserved PASIDs, currently only RID_PASID, are excluded from the global
PASID allocation.
It is expected that device drivers will use the allocated PASIDs to
attach to appropriate IOMMU domains for use.
Reviewed-by: Lu Baolu <baolu.lu@...ux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@...el.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@...ux.intel.com>
---
v8: fix off-by-one in max_pasid check
v7: simplify range check (Baolu)
v6: explicitly exclude reserved a range from SVA PASID allocation
check mm PASID compatibility with device
v5: move PASID range check inside API so that device drivers only pass
in struct device* (Kevin)
v4: move dummy functions outside ifdef CONFIG_IOMMU_SVA (Baolu)
---
drivers/iommu/iommu-sva.c | 29 ++++++++++-------------------
drivers/iommu/iommu.c | 28 ++++++++++++++++++++++++++++
include/linux/iommu.h | 10 ++++++++++
3 files changed, 48 insertions(+), 19 deletions(-)
diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c
index 05c0fb2acbc4..b78671a8a914 100644
--- a/drivers/iommu/iommu-sva.c
+++ b/drivers/iommu/iommu-sva.c
@@ -10,34 +10,30 @@
#include "iommu-sva.h"
static DEFINE_MUTEX(iommu_sva_lock);
-static DEFINE_IDA(iommu_global_pasid_ida);
/* Allocate a PASID for the mm within range (inclusive) */
-static int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max)
+static int iommu_sva_alloc_pasid(struct mm_struct *mm, struct device *dev)
{
+ ioasid_t pasid;
int ret = 0;
- if (min == IOMMU_PASID_INVALID ||
- max == IOMMU_PASID_INVALID ||
- min == 0 || max < min)
- return -EINVAL;
-
if (!arch_pgtable_dma_compat(mm))
return -EBUSY;
mutex_lock(&iommu_sva_lock);
/* Is a PASID already associated with this mm? */
if (mm_valid_pasid(mm)) {
- if (mm->pasid < min || mm->pasid > max)
+ if (mm->pasid >= dev->iommu->max_pasids)
ret = -EOVERFLOW;
goto out;
}
- ret = ida_alloc_range(&iommu_global_pasid_ida, min, max, GFP_KERNEL);
- if (ret < 0)
+ pasid = iommu_alloc_global_pasid(dev);
+ if (pasid == IOMMU_PASID_INVALID) {
+ ret = -ENOSPC;
goto out;
-
- mm->pasid = ret;
+ }
+ mm->pasid = pasid;
ret = 0;
out:
mutex_unlock(&iommu_sva_lock);
@@ -64,15 +60,10 @@ struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm
{
struct iommu_domain *domain;
struct iommu_sva *handle;
- ioasid_t max_pasids;
int ret;
- max_pasids = dev->iommu->max_pasids;
- if (!max_pasids)
- return ERR_PTR(-EOPNOTSUPP);
-
/* Allocate mm->pasid if necessary. */
- ret = iommu_sva_alloc_pasid(mm, 1, max_pasids - 1);
+ ret = iommu_sva_alloc_pasid(mm, dev);
if (ret)
return ERR_PTR(ret);
@@ -217,5 +208,5 @@ void mm_pasid_drop(struct mm_struct *mm)
if (likely(!mm_valid_pasid(mm)))
return;
- ida_free(&iommu_global_pasid_ida, mm->pasid);
+ iommu_free_global_pasid(mm->pasid);
}
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 4352a149a935..1461c845d76a 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -39,6 +39,7 @@
static struct kset *iommu_group_kset;
static DEFINE_IDA(iommu_group_ida);
+static DEFINE_IDA(iommu_global_pasid_ida);
static unsigned int iommu_def_domain_type __read_mostly;
static bool iommu_dma_strict __read_mostly = IS_ENABLED(CONFIG_IOMMU_DEFAULT_DMA_STRICT);
@@ -3414,3 +3415,30 @@ struct iommu_domain *iommu_sva_domain_alloc(struct device *dev,
return domain;
}
+
+ioasid_t iommu_alloc_global_pasid(struct device *dev)
+{
+ int ret;
+
+ /* max_pasids == 0 means that the device does not support PASID */
+ if (!dev->iommu->max_pasids)
+ return IOMMU_PASID_INVALID;
+
+ /*
+ * max_pasids is set up by vendor driver based on number of PASID bits
+ * supported but the IDA allocation is inclusive.
+ */
+ ret = ida_alloc_range(&iommu_global_pasid_ida, IOMMU_FIRST_GLOBAL_PASID,
+ dev->iommu->max_pasids - 1, GFP_KERNEL);
+ return ret < 0 ? IOMMU_PASID_INVALID : ret;
+}
+EXPORT_SYMBOL_GPL(iommu_alloc_global_pasid);
+
+void iommu_free_global_pasid(ioasid_t pasid)
+{
+ if (WARN_ON(pasid == IOMMU_PASID_INVALID))
+ return;
+
+ ida_free(&iommu_global_pasid_ida, pasid);
+}
+EXPORT_SYMBOL_GPL(iommu_free_global_pasid);
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 485e4bb0347e..a745798b3f1d 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -197,6 +197,7 @@ enum iommu_dev_features {
};
#define IOMMU_NO_PASID (0U) /* Reserved for DMA w/o PASID */
+#define IOMMU_FIRST_GLOBAL_PASID (1U) /*starting range for allocation */
#define IOMMU_PASID_INVALID (-1U)
typedef unsigned int ioasid_t;
@@ -730,6 +731,8 @@ void iommu_detach_device_pasid(struct iommu_domain *domain,
struct iommu_domain *
iommu_get_domain_for_dev_pasid(struct device *dev, ioasid_t pasid,
unsigned int type);
+ioasid_t iommu_alloc_global_pasid(struct device *dev);
+void iommu_free_global_pasid(ioasid_t pasid);
#else /* CONFIG_IOMMU_API */
struct iommu_ops {};
@@ -1091,6 +1094,13 @@ iommu_get_domain_for_dev_pasid(struct device *dev, ioasid_t pasid,
{
return NULL;
}
+
+static inline ioasid_t iommu_alloc_global_pasid(struct device *dev)
+{
+ return IOMMU_PASID_INVALID;
+}
+
+static inline void iommu_free_global_pasid(ioasid_t pasid) {}
#endif /* CONFIG_IOMMU_API */
/**
--
2.25.1
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