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authorWill Deacon <will@kernel.org>2020-12-08 15:07:49 +0000
committerWill Deacon <will@kernel.org>2020-12-08 15:07:49 +0000
commita5f12de3ece88cddac27edf6618450f6c22906f1 (patch)
tree2778d7d5619377cbb8fe9e96ddcfc7ac51c3930f /drivers/iommu
parent854623fdea9dc3ae8543a4d5d8448ebbaee61acc (diff)
parent2f7e8c553e98d6fcddeaf18aa90ea908e3f1418e (diff)
downloadlinux-a5f12de3ece88cddac27edf6618450f6c22906f1.tar.bz2
Merge branch 'for-next/iommu/svm' into for-next/iommu/core
More steps along the way to Shared Virtual {Addressing, Memory} support for Arm's SMMUv3, including the addition of a helper library that can be shared amongst other IOMMU implementations wishing to support this feature. * for-next/iommu/svm: iommu/arm-smmu-v3: Hook up ATC invalidation to mm ops iommu/arm-smmu-v3: Implement iommu_sva_bind/unbind() iommu/sva: Add PASID helpers iommu/ioasid: Add ioasid references
Diffstat (limited to 'drivers/iommu')
-rw-r--r--drivers/iommu/Kconfig7
-rw-r--r--drivers/iommu/Makefile1
-rw-r--r--drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c244
-rw-r--r--drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c50
-rw-r--r--drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h30
-rw-r--r--drivers/iommu/intel/iommu.c4
-rw-r--r--drivers/iommu/intel/svm.c6
-rw-r--r--drivers/iommu/ioasid.c38
-rw-r--r--drivers/iommu/iommu-sva-lib.c86
-rw-r--r--drivers/iommu/iommu-sva-lib.h15
10 files changed, 460 insertions, 21 deletions
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index 04878caf6da4..192ef8f61310 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -103,6 +103,11 @@ config IOMMU_DMA
select IRQ_MSI_IOMMU
select NEED_SG_DMA_LENGTH
+# Shared Virtual Addressing library
+config IOMMU_SVA_LIB
+ bool
+ select IOASID
+
config FSL_PAMU
bool "Freescale IOMMU support"
depends on PCI
@@ -311,6 +316,8 @@ config ARM_SMMU_V3
config ARM_SMMU_V3_SVA
bool "Shared Virtual Addressing support for the ARM SMMUv3"
depends on ARM_SMMU_V3
+ select IOMMU_SVA_LIB
+ select MMU_NOTIFIER
help
Support for sharing process address spaces with devices using the
SMMUv3.
diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
index 11f1771104f3..61bd30cd8369 100644
--- a/drivers/iommu/Makefile
+++ b/drivers/iommu/Makefile
@@ -27,3 +27,4 @@ obj-$(CONFIG_FSL_PAMU) += fsl_pamu.o fsl_pamu_domain.o
obj-$(CONFIG_S390_IOMMU) += s390-iommu.o
obj-$(CONFIG_HYPERV_IOMMU) += hyperv-iommu.o
obj-$(CONFIG_VIRTIO_IOMMU) += virtio-iommu.o
+obj-$(CONFIG_IOMMU_SVA_LIB) += iommu-sva-lib.o
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
index 9255c9600fb8..e13b092e6004 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
@@ -5,11 +5,35 @@
#include <linux/mm.h>
#include <linux/mmu_context.h>
+#include <linux/mmu_notifier.h>
#include <linux/slab.h>
#include "arm-smmu-v3.h"
+#include "../../iommu-sva-lib.h"
#include "../../io-pgtable-arm.h"
+struct arm_smmu_mmu_notifier {
+ struct mmu_notifier mn;
+ struct arm_smmu_ctx_desc *cd;
+ bool cleared;
+ refcount_t refs;
+ struct list_head list;
+ struct arm_smmu_domain *domain;
+};
+
+#define mn_to_smmu(mn) container_of(mn, struct arm_smmu_mmu_notifier, mn)
+
+struct arm_smmu_bond {
+ struct iommu_sva sva;
+ struct mm_struct *mm;
+ struct arm_smmu_mmu_notifier *smmu_mn;
+ struct list_head list;
+ refcount_t refs;
+};
+
+#define sva_to_bond(handle) \
+ container_of(handle, struct arm_smmu_bond, sva)
+
static DEFINE_MUTEX(sva_lock);
/*
@@ -64,7 +88,6 @@ arm_smmu_share_asid(struct mm_struct *mm, u16 asid)
return NULL;
}
-__maybe_unused
static struct arm_smmu_ctx_desc *arm_smmu_alloc_shared_cd(struct mm_struct *mm)
{
u16 asid;
@@ -145,7 +168,6 @@ out_put_context:
return err < 0 ? ERR_PTR(err) : ret;
}
-__maybe_unused
static void arm_smmu_free_shared_cd(struct arm_smmu_ctx_desc *cd)
{
if (arm_smmu_free_asid(cd)) {
@@ -155,6 +177,215 @@ static void arm_smmu_free_shared_cd(struct arm_smmu_ctx_desc *cd)
}
}
+static void arm_smmu_mm_invalidate_range(struct mmu_notifier *mn,
+ struct mm_struct *mm,
+ unsigned long start, unsigned long end)
+{
+ struct arm_smmu_mmu_notifier *smmu_mn = mn_to_smmu(mn);
+
+ arm_smmu_atc_inv_domain(smmu_mn->domain, mm->pasid, start,
+ end - start + 1);
+}
+
+static void arm_smmu_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
+{
+ struct arm_smmu_mmu_notifier *smmu_mn = mn_to_smmu(mn);
+ struct arm_smmu_domain *smmu_domain = smmu_mn->domain;
+
+ mutex_lock(&sva_lock);
+ if (smmu_mn->cleared) {
+ mutex_unlock(&sva_lock);
+ return;
+ }
+
+ /*
+ * DMA may still be running. Keep the cd valid to avoid C_BAD_CD events,
+ * but disable translation.
+ */
+ arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, &quiet_cd);
+
+ arm_smmu_tlb_inv_asid(smmu_domain->smmu, smmu_mn->cd->asid);
+ arm_smmu_atc_inv_domain(smmu_domain, mm->pasid, 0, 0);
+
+ smmu_mn->cleared = true;
+ mutex_unlock(&sva_lock);
+}
+
+static void arm_smmu_mmu_notifier_free(struct mmu_notifier *mn)
+{
+ kfree(mn_to_smmu(mn));
+}
+
+static struct mmu_notifier_ops arm_smmu_mmu_notifier_ops = {
+ .invalidate_range = arm_smmu_mm_invalidate_range,
+ .release = arm_smmu_mm_release,
+ .free_notifier = arm_smmu_mmu_notifier_free,
+};
+
+/* Allocate or get existing MMU notifier for this {domain, mm} pair */
+static struct arm_smmu_mmu_notifier *
+arm_smmu_mmu_notifier_get(struct arm_smmu_domain *smmu_domain,
+ struct mm_struct *mm)
+{
+ int ret;
+ struct arm_smmu_ctx_desc *cd;
+ struct arm_smmu_mmu_notifier *smmu_mn;
+
+ list_for_each_entry(smmu_mn, &smmu_domain->mmu_notifiers, list) {
+ if (smmu_mn->mn.mm == mm) {
+ refcount_inc(&smmu_mn->refs);
+ return smmu_mn;
+ }
+ }
+
+ cd = arm_smmu_alloc_shared_cd(mm);
+ if (IS_ERR(cd))
+ return ERR_CAST(cd);
+
+ smmu_mn = kzalloc(sizeof(*smmu_mn), GFP_KERNEL);
+ if (!smmu_mn) {
+ ret = -ENOMEM;
+ goto err_free_cd;
+ }
+
+ refcount_set(&smmu_mn->refs, 1);
+ smmu_mn->cd = cd;
+ smmu_mn->domain = smmu_domain;
+ smmu_mn->mn.ops = &arm_smmu_mmu_notifier_ops;
+
+ ret = mmu_notifier_register(&smmu_mn->mn, mm);
+ if (ret) {
+ kfree(smmu_mn);
+ goto err_free_cd;
+ }
+
+ ret = arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, cd);
+ if (ret)
+ goto err_put_notifier;
+
+ list_add(&smmu_mn->list, &smmu_domain->mmu_notifiers);
+ return smmu_mn;
+
+err_put_notifier:
+ /* Frees smmu_mn */
+ mmu_notifier_put(&smmu_mn->mn);
+err_free_cd:
+ arm_smmu_free_shared_cd(cd);
+ return ERR_PTR(ret);
+}
+
+static void arm_smmu_mmu_notifier_put(struct arm_smmu_mmu_notifier *smmu_mn)
+{
+ struct mm_struct *mm = smmu_mn->mn.mm;
+ struct arm_smmu_ctx_desc *cd = smmu_mn->cd;
+ struct arm_smmu_domain *smmu_domain = smmu_mn->domain;
+
+ if (!refcount_dec_and_test(&smmu_mn->refs))
+ return;
+
+ list_del(&smmu_mn->list);
+ arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, NULL);
+
+ /*
+ * If we went through clear(), we've already invalidated, and no
+ * new TLB entry can have been formed.
+ */
+ if (!smmu_mn->cleared) {
+ arm_smmu_tlb_inv_asid(smmu_domain->smmu, cd->asid);
+ arm_smmu_atc_inv_domain(smmu_domain, mm->pasid, 0, 0);
+ }
+
+ /* Frees smmu_mn */
+ mmu_notifier_put(&smmu_mn->mn);
+ arm_smmu_free_shared_cd(cd);
+}
+
+static struct iommu_sva *
+__arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm)
+{
+ int ret;
+ struct arm_smmu_bond *bond;
+ struct arm_smmu_master *master = dev_iommu_priv_get(dev);
+ struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
+ struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+
+ if (!master || !master->sva_enabled)
+ return ERR_PTR(-ENODEV);
+
+ /* If bind() was already called for this {dev, mm} pair, reuse it. */
+ list_for_each_entry(bond, &master->bonds, list) {
+ if (bond->mm == mm) {
+ refcount_inc(&bond->refs);
+ return &bond->sva;
+ }
+ }
+
+ bond = kzalloc(sizeof(*bond), GFP_KERNEL);
+ if (!bond)
+ return ERR_PTR(-ENOMEM);
+
+ /* Allocate a PASID for this mm if necessary */
+ ret = iommu_sva_alloc_pasid(mm, 1, (1U << master->ssid_bits) - 1);
+ if (ret)
+ goto err_free_bond;
+
+ bond->mm = mm;
+ bond->sva.dev = dev;
+ refcount_set(&bond->refs, 1);
+
+ bond->smmu_mn = arm_smmu_mmu_notifier_get(smmu_domain, mm);
+ if (IS_ERR(bond->smmu_mn)) {
+ ret = PTR_ERR(bond->smmu_mn);
+ goto err_free_pasid;
+ }
+
+ list_add(&bond->list, &master->bonds);
+ return &bond->sva;
+
+err_free_pasid:
+ iommu_sva_free_pasid(mm);
+err_free_bond:
+ kfree(bond);
+ return ERR_PTR(ret);
+}
+
+struct iommu_sva *
+arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm, void *drvdata)
+{
+ struct iommu_sva *handle;
+ struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
+ struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+
+ if (smmu_domain->stage != ARM_SMMU_DOMAIN_S1)
+ return ERR_PTR(-EINVAL);
+
+ mutex_lock(&sva_lock);
+ handle = __arm_smmu_sva_bind(dev, mm);
+ mutex_unlock(&sva_lock);
+ return handle;
+}
+
+void arm_smmu_sva_unbind(struct iommu_sva *handle)
+{
+ struct arm_smmu_bond *bond = sva_to_bond(handle);
+
+ mutex_lock(&sva_lock);
+ if (refcount_dec_and_test(&bond->refs)) {
+ list_del(&bond->list);
+ arm_smmu_mmu_notifier_put(bond->smmu_mn);
+ iommu_sva_free_pasid(bond->mm);
+ kfree(bond);
+ }
+ mutex_unlock(&sva_lock);
+}
+
+u32 arm_smmu_sva_get_pasid(struct iommu_sva *handle)
+{
+ struct arm_smmu_bond *bond = sva_to_bond(handle);
+
+ return bond->mm->pasid;
+}
+
bool arm_smmu_sva_supported(struct arm_smmu_device *smmu)
{
unsigned long reg, fld;
@@ -246,3 +477,12 @@ int arm_smmu_master_disable_sva(struct arm_smmu_master *master)
return 0;
}
+
+void arm_smmu_sva_notifier_synchronize(void)
+{
+ /*
+ * Some MMU notifiers may still be waiting to be freed, using
+ * arm_smmu_mmu_notifier_free(). Wait for them.
+ */
+ mmu_notifier_synchronize();
+}
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index c9cafce51835..2ddf5ecc75f8 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -76,6 +76,12 @@ struct arm_smmu_option_prop {
DEFINE_XARRAY_ALLOC1(arm_smmu_asid_xa);
DEFINE_MUTEX(arm_smmu_asid_lock);
+/*
+ * Special value used by SVA when a process dies, to quiesce a CD without
+ * disabling it.
+ */
+struct arm_smmu_ctx_desc quiet_cd = { 0 };
+
static struct arm_smmu_option_prop arm_smmu_options[] = {
{ ARM_SMMU_OPT_SKIP_PREFETCH, "hisilicon,broken-prefetch-cmd" },
{ ARM_SMMU_OPT_PAGE0_REGS_ONLY, "cavium,cn9900-broken-page1-regspace"},
@@ -91,11 +97,6 @@ static inline void __iomem *arm_smmu_page1_fixup(unsigned long offset,
return smmu->base + offset;
}
-static struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)
-{
- return container_of(dom, struct arm_smmu_domain, domain);
-}
-
static void parse_driver_options(struct arm_smmu_device *smmu)
{
int i = 0;
@@ -983,7 +984,9 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
* (2) Install a secondary CD, for SID+SSID traffic.
* (3) Update ASID of a CD. Atomically write the first 64 bits of the
* CD, then invalidate the old entry and mappings.
- * (4) Remove a secondary CD.
+ * (4) Quiesce the context without clearing the valid bit. Disable
+ * translation, and ignore any translation fault.
+ * (5) Remove a secondary CD.
*/
u64 val;
bool cd_live;
@@ -1000,8 +1003,10 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
val = le64_to_cpu(cdptr[0]);
cd_live = !!(val & CTXDESC_CD_0_V);
- if (!cd) { /* (4) */
+ if (!cd) { /* (5) */
val = 0;
+ } else if (cd == &quiet_cd) { /* (4) */
+ val |= CTXDESC_CD_0_TCR_EPD0;
} else if (cd_live) { /* (3) */
val &= ~CTXDESC_CD_0_ASID;
val |= FIELD_PREP(CTXDESC_CD_0_ASID, cd->asid);
@@ -1519,6 +1524,20 @@ arm_smmu_atc_inv_to_cmd(int ssid, unsigned long iova, size_t size,
size_t inval_grain_shift = 12;
unsigned long page_start, page_end;
+ /*
+ * ATS and PASID:
+ *
+ * If substream_valid is clear, the PCIe TLP is sent without a PASID
+ * prefix. In that case all ATC entries within the address range are
+ * invalidated, including those that were requested with a PASID! There
+ * is no way to invalidate only entries without PASID.
+ *
+ * When using STRTAB_STE_1_S1DSS_SSID0 (reserving CD 0 for non-PASID
+ * traffic), translation requests without PASID create ATC entries
+ * without PASID, which must be invalidated with substream_valid clear.
+ * This has the unpleasant side-effect of invalidating all PASID-tagged
+ * ATC entries within the address range.
+ */
*cmd = (struct arm_smmu_cmdq_ent) {
.opcode = CMDQ_OP_ATC_INV,
.substream_valid = !!ssid,
@@ -1577,8 +1596,8 @@ static int arm_smmu_atc_inv_master(struct arm_smmu_master *master)
return arm_smmu_cmdq_issue_sync(master->smmu);
}
-static int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain,
- int ssid, unsigned long iova, size_t size)
+int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain, int ssid,
+ unsigned long iova, size_t size)
{
int i;
unsigned long flags;
@@ -1794,6 +1813,7 @@ static struct iommu_domain *arm_smmu_domain_alloc(unsigned type)
mutex_init(&smmu_domain->init_mutex);
INIT_LIST_HEAD(&smmu_domain->devices);
spin_lock_init(&smmu_domain->devices_lock);
+ INIT_LIST_HEAD(&smmu_domain->mmu_notifiers);
return &smmu_domain->domain;
}
@@ -2589,6 +2609,9 @@ static struct iommu_ops arm_smmu_ops = {
.dev_feat_enabled = arm_smmu_dev_feature_enabled,
.dev_enable_feat = arm_smmu_dev_enable_feature,
.dev_disable_feat = arm_smmu_dev_disable_feature,
+ .sva_bind = arm_smmu_sva_bind,
+ .sva_unbind = arm_smmu_sva_unbind,
+ .sva_get_pasid = arm_smmu_sva_get_pasid,
.pgsize_bitmap = -1UL, /* Restricted during device attach */
};
@@ -3611,6 +3634,12 @@ static const struct of_device_id arm_smmu_of_match[] = {
};
MODULE_DEVICE_TABLE(of, arm_smmu_of_match);
+static void arm_smmu_driver_unregister(struct platform_driver *drv)
+{
+ arm_smmu_sva_notifier_synchronize();
+ platform_driver_unregister(drv);
+}
+
static struct platform_driver arm_smmu_driver = {
.driver = {
.name = "arm-smmu-v3",
@@ -3621,7 +3650,8 @@ static struct platform_driver arm_smmu_driver = {
.remove = arm_smmu_device_remove,
.shutdown = arm_smmu_device_shutdown,
};
-module_platform_driver(arm_smmu_driver);
+module_driver(arm_smmu_driver, platform_driver_register,
+ arm_smmu_driver_unregister);
MODULE_DESCRIPTION("IOMMU API for ARM architected SMMUv3 implementations");
MODULE_AUTHOR("Will Deacon <will@kernel.org>");
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index d4b7f40ccb02..96c2e9565e00 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -678,15 +678,25 @@ struct arm_smmu_domain {
struct list_head devices;
spinlock_t devices_lock;
+
+ struct list_head mmu_notifiers;
};
+static inline struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)
+{
+ return container_of(dom, struct arm_smmu_domain, domain);
+}
+
extern struct xarray arm_smmu_asid_xa;
extern struct mutex arm_smmu_asid_lock;
+extern struct arm_smmu_ctx_desc quiet_cd;
int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
struct arm_smmu_ctx_desc *cd);
void arm_smmu_tlb_inv_asid(struct arm_smmu_device *smmu, u16 asid);
bool arm_smmu_free_asid(struct arm_smmu_ctx_desc *cd);
+int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain, int ssid,
+ unsigned long iova, size_t size);
#ifdef CONFIG_ARM_SMMU_V3_SVA
bool arm_smmu_sva_supported(struct arm_smmu_device *smmu);
@@ -694,6 +704,11 @@ bool arm_smmu_master_sva_supported(struct arm_smmu_master *master);
bool arm_smmu_master_sva_enabled(struct arm_smmu_master *master);
int arm_smmu_master_enable_sva(struct arm_smmu_master *master);
int arm_smmu_master_disable_sva(struct arm_smmu_master *master);
+struct iommu_sva *arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm,
+ void *drvdata);
+void arm_smmu_sva_unbind(struct iommu_sva *handle);
+u32 arm_smmu_sva_get_pasid(struct iommu_sva *handle);
+void arm_smmu_sva_notifier_synchronize(void);
#else /* CONFIG_ARM_SMMU_V3_SVA */
static inline bool arm_smmu_sva_supported(struct arm_smmu_device *smmu)
{
@@ -719,5 +734,20 @@ static inline int arm_smmu_master_disable_sva(struct arm_smmu_master *master)
{
return -ENODEV;
}
+
+static inline struct iommu_sva *
+arm_smmu_sva_bind(struct device *dev, struct mm_struct *mm, void *drvdata)
+{
+ return ERR_PTR(-ENODEV);
+}
+
+static inline void arm_smmu_sva_unbind(struct iommu_sva *handle) {}
+
+static inline u32 arm_smmu_sva_get_pasid(struct iommu_sva *handle)
+{
+ return IOMMU_PASID_INVALID;
+}
+
+static inline void arm_smmu_sva_notifier_synchronize(void) {}
#endif /* CONFIG_ARM_SMMU_V3_SVA */
#endif /* _ARM_SMMU_V3_H */
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 83674e32e58b..1ceebe2cfa35 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -5191,7 +5191,7 @@ static void auxiliary_unlink_device(struct dmar_domain *domain,
domain->auxd_refcnt--;
if (!domain->auxd_refcnt && domain->default_pasid > 0)
- ioasid_free(domain->default_pasid);
+ ioasid_put(domain->default_pasid);
}
static int aux_domain_add_dev(struct dmar_domain *domain,
@@ -5252,7 +5252,7 @@ attach_failed:
spin_unlock(&iommu->lock);
spin_unlock_irqrestore(&device_domain_lock, flags);
if (!domain->auxd_refcnt && domain->default_pasid > 0)
- ioasid_free(domain->default_pasid);
+ ioasid_put(domain->default_pasid);
return ret;
}
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index 3242ebd0bca3..4fa248b98031 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -598,7 +598,7 @@ intel_svm_bind_mm(struct device *dev, unsigned int flags,
if (mm) {
ret = mmu_notifier_register(&svm->notifier, mm);
if (ret) {
- ioasid_free(svm->pasid);
+ ioasid_put(svm->pasid);
kfree(svm);
kfree(sdev);
goto out;
@@ -616,7 +616,7 @@ intel_svm_bind_mm(struct device *dev, unsigned int flags,
if (ret) {
if (mm)
mmu_notifier_unregister(&svm->notifier, mm);
- ioasid_free(svm->pasid);
+ ioasid_put(svm->pasid);
kfree(svm);
kfree(sdev);
goto out;
@@ -689,7 +689,7 @@ static int intel_svm_unbind_mm(struct device *dev, u32 pasid)
kfree_rcu(sdev, rcu);
if (list_empty(&svm->devs)) {
- ioasid_free(svm->pasid);
+ ioasid_put(svm->pasid);
if (svm->mm) {
mmu_notifier_unregister(&svm->notifier, svm->mm);
/* Clear mm's pasid. */
diff --git a/drivers/iommu/ioasid.c b/drivers/iommu/ioasid.c
index 0f8dd377aada..50ee27bbd04e 100644
--- a/drivers/iommu/ioasid.c
+++ b/drivers/iommu/ioasid.c
@@ -2,7 +2,7 @@
/*
* I/O Address Space ID allocator. There is one global IOASID space, split into
* subsets. Users create a subset with DECLARE_IOASID_SET, then allocate and
- * free IOASIDs with ioasid_alloc and ioasid_free.
+ * free IOASIDs with ioasid_alloc and ioasid_put.
*/
#include <linux/ioasid.h>
#include <linux/module.h>
@@ -15,6 +15,7 @@ struct ioasid_data {
struct ioasid_set *set;
void *private;
struct rcu_head rcu;
+ refcount_t refs;
};
/*
@@ -314,6 +315,7 @@ ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max,
data->set = set;
data->private = private;
+ refcount_set(&data->refs, 1);
/*
* Custom allocator needs allocator data to perform platform specific
@@ -346,11 +348,34 @@ exit_free:
EXPORT_SYMBOL_GPL(ioasid_alloc);
/**
- * ioasid_free - Free an IOASID
+ * ioasid_get - obtain a reference to the IOASID
+ */
+void ioasid_get(ioasid_t ioasid)
+{
+ struct ioasid_data *ioasid_data;
+
+ spin_lock(&ioasid_allocator_lock);
+ ioasid_data = xa_load(&active_allocator->xa, ioasid);
+ if (ioasid_data)
+ refcount_inc(&ioasid_data->refs);
+ else
+ WARN_ON(1);
+ spin_unlock(&ioasid_allocator_lock);
+}
+EXPORT_SYMBOL_GPL(ioasid_get);
+
+/**
+ * ioasid_put - Release a reference to an ioasid
* @ioasid: the ID to remove
+ *
+ * Put a reference to the IOASID, free it when the number of references drops to
+ * zero.
+ *
+ * Return: %true if the IOASID was freed, %false otherwise.
*/
-void ioasid_free(ioasid_t ioasid)
+bool ioasid_put(ioasid_t ioasid)
{
+ bool free = false;
struct ioasid_data *ioasid_data;
spin_lock(&ioasid_allocator_lock);
@@ -360,6 +385,10 @@ void ioasid_free(ioasid_t ioasid)
goto exit_unlock;
}
+ free = refcount_dec_and_test(&ioasid_data->refs);
+ if (!free)
+ goto exit_unlock;
+
active_allocator->ops->free(ioasid, active_allocator->ops->pdata);
/* Custom allocator needs additional steps to free the xa element */
if (active_allocator->flags & IOASID_ALLOCATOR_CUSTOM) {
@@ -369,8 +398,9 @@ void ioasid_free(ioasid_t ioasid)
exit_unlock:
spin_unlock(&ioasid_allocator_lock);
+ return free;
}
-EXPORT_SYMBOL_GPL(ioasid_free);
+EXPORT_SYMBOL_GPL(ioasid_put);
/**
* ioasid_find - Find IOASID data
diff --git a/drivers/iommu/iommu-sva-lib.c b/drivers/iommu/iommu-sva-lib.c
new file mode 100644
index 000000000000..bd41405d34e9
--- /dev/null
+++ b/drivers/iommu/iommu-sva-lib.c
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Helpers for IOMMU drivers implementing SVA
+ */
+#include <linux/mutex.h>
+#include <linux/sched/mm.h>
+
+#include "iommu-sva-lib.h"
+
+static DEFINE_MUTEX(iommu_sva_lock);
+static DECLARE_IOASID_SET(iommu_sva_pasid);
+
+/**
+ * iommu_sva_alloc_pasid - Allocate a PASID for the mm
+ * @mm: the mm
+ * @min: minimum PASID value (inclusive)
+ * @max: maximum PASID value (inclusive)
+ *
+ * Try to allocate a PASID for this mm, or take a reference to the existing one
+ * provided it fits within the [@min, @max] range. On success the PASID is
+ * available in mm->pasid, and must be released with iommu_sva_free_pasid().
+ * @min must be greater than 0, because 0 indicates an unused mm->pasid.
+ *
+ * Returns 0 on success and < 0 on error.
+ */
+int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max)
+{
+ int ret = 0;
+ ioasid_t pasid;
+
+ if (min == INVALID_IOASID || max == INVALID_IOASID ||
+ min == 0 || max < min)
+ return -EINVAL;
+
+ mutex_lock(&iommu_sva_lock);
+ if (mm->pasid) {
+ if (mm->pasid >= min && mm->pasid <= max)
+ ioasid_get(mm->pasid);
+ else
+ ret = -EOVERFLOW;
+ } else {
+ pasid = ioasid_alloc(&iommu_sva_pasid, min, max, mm);
+ if (pasid == INVALID_IOASID)
+ ret = -ENOMEM;
+ else
+ mm->pasid = pasid;
+ }
+ mutex_unlock(&iommu_sva_lock);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(iommu_sva_alloc_pasid);
+
+/**
+ * iommu_sva_free_pasid - Release the mm's PASID
+ * @mm: the mm
+ *
+ * Drop one reference to a PASID allocated with iommu_sva_alloc_pasid()
+ */
+void iommu_sva_free_pasid(struct mm_struct *mm)
+{
+ mutex_lock(&iommu_sva_lock);
+ if (ioasid_put(mm->pasid))
+ mm->pasid = 0;
+ mutex_unlock(&iommu_sva_lock);
+}
+EXPORT_SYMBOL_GPL(iommu_sva_free_pasid);
+
+/* ioasid_find getter() requires a void * argument */
+static bool __mmget_not_zero(void *mm)
+{
+ return mmget_not_zero(mm);
+}
+
+/**
+ * iommu_sva_find() - Find mm associated to the given PASID
+ * @pasid: Process Address Space ID assigned to the mm
+ *
+ * On success a reference to the mm is taken, and must be released with mmput().
+ *
+ * Returns the mm corresponding to this PASID, or an error if not found.
+ */
+struct mm_struct *iommu_sva_find(ioasid_t pasid)
+{
+ return ioasid_find(&iommu_sva_pasid, pasid, __mmget_not_zero);
+}
+EXPORT_SYMBOL_GPL(iommu_sva_find);
diff --git a/drivers/iommu/iommu-sva-lib.h b/drivers/iommu/iommu-sva-lib.h
new file mode 100644
index 000000000000..b40990aef3fd
--- /dev/null
+++ b/drivers/iommu/iommu-sva-lib.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * SVA library for IOMMU drivers
+ */
+#ifndef _IOMMU_SVA_LIB_H
+#define _IOMMU_SVA_LIB_H
+
+#include <linux/ioasid.h>
+#include <linux/mm_types.h>
+
+int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t max);
+void iommu_sva_free_pasid(struct mm_struct *mm);
+struct mm_struct *iommu_sva_find(ioasid_t pasid);
+
+#endif /* _IOMMU_SVA_LIB_H */