Hook process operations to support PASID and page table sharing with the
SMMUv3:
* process_allocate pins down its ASID and initializes the context
descriptor fields.
* process_free releases the ASID.
* process_attach checks device capabilities and writes the context
descriptor. More work is required to ensure that the process' ASID isn't
being used for io-pgtables.
* process_detach clears the context descriptor and sends required
invalidations.
* process_invalidate sends required invalidations.
* process_exit stops us of the PASID, clears the context descriptor and
performs required invalidations.
Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@xxxxxxx>
---
drivers/iommu/arm-smmu-v3.c | 207 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 207 insertions(+)
diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 71fc3a2c8a95..c86a1182c137 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -29,6 +29,7 @@
#include <linux/interrupt.h>
#include <linux/iommu.h>
#include <linux/iopoll.h>
+#include <linux/mmu_context.h>
#include <linux/module.h>
#include <linux/msi.h>
#include <linux/of.h>
@@ -37,6 +38,7 @@
#include <linux/of_platform.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
+#include <linux/sched/mm.h>
#include <linux/amba/bus.h>
@@ -642,6 +644,7 @@ struct arm_smmu_strtab_cfg {
struct arm_smmu_asid_state {
struct arm_smmu_domain *domain;
+ unsigned long refs;
};
/* An SMMUv3 instance */
@@ -712,6 +715,9 @@ struct arm_smmu_master_data {
struct device *dev;
size_t num_ssids;
+ bool can_fault;
+ /* Number of processes attached */
+ int processes;
};
/* SMMU private data for an IOMMU domain */
@@ -740,6 +746,11 @@ struct arm_smmu_domain {
spinlock_t devices_lock;
};
+struct arm_smmu_process {
+ struct iommu_process process;
+ struct arm_smmu_ctx_desc ctx_desc;
+};
+
struct arm_smmu_option_prop {
u32 opt;
const char *prop;
@@ -766,6 +777,11 @@ static struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)
return container_of(dom, struct arm_smmu_domain, domain);
}
+static struct arm_smmu_process *to_smmu_process(struct iommu_process *process)
+{
+ return container_of(process, struct arm_smmu_process, process);
+}
+
static void parse_driver_options(struct arm_smmu_device *smmu)
{
int i = 0;
@@ -2032,6 +2048,13 @@ static void arm_smmu_detach_dev(struct device *dev)
struct arm_smmu_master_data *master = dev->iommu_fwspec->iommu_priv;
struct arm_smmu_domain *smmu_domain = master->domain;
+ /*
+ * Core is preventing concurrent calls between attach and bind, so this
+ * read only races with process_exit (FIXME).
+ */
+ if (master->processes)
+ __iommu_process_unbind_dev_all(&smmu_domain->domain, dev);
+
if (smmu_domain) {
spin_lock_irqsave(&smmu_domain->devices_lock, flags);
list_del(&master->list);
@@ -2143,6 +2166,184 @@ arm_smmu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova)
return ops->iova_to_phys(ops, iova);
}
+static int arm_smmu_process_init_pgtable(struct arm_smmu_process *smmu_process,
+ struct mm_struct *mm)
+{
+ int asid;
+
+ asid = mm_context_get(mm);
+ if (!asid)
+ return -ENOSPC;
+
+ smmu_process->ctx_desc.asid = asid;
+ /* TODO: init the rest */
+
+ return 0;
+}
+
+static struct iommu_process *arm_smmu_process_alloc(struct task_struct *task)
+{
+ int ret;
+ struct mm_struct *mm;
+ struct arm_smmu_process *smmu_process;
+
+ smmu_process = kzalloc(sizeof(*smmu_process), GFP_KERNEL);
+
+ mm = get_task_mm(task);
+ if (!mm) {
+ kfree(smmu_process);
+ return NULL;
+ }
+
+ ret = arm_smmu_process_init_pgtable(smmu_process, mm);
+ mmput(mm);
+ if (ret) {
+ kfree(smmu_process);
+ return NULL;
+ }
+
+ return &smmu_process->process;
+}
+
+static void arm_smmu_process_free(struct iommu_process *process)
+{
+ struct arm_smmu_process *smmu_process = to_smmu_process(process);
+
+ /* Unpin ASID */
+ mm_context_put(process->mm);
+
+ kfree(smmu_process);
+}
+
+static int arm_smmu_process_share(struct arm_smmu_domain *smmu_domain,
+ struct arm_smmu_process *smmu_process)
+{
+ int asid, ret;
+ struct arm_smmu_asid_state *asid_state;
+ struct arm_smmu_device *smmu = smmu_domain->smmu;
+
+ asid = smmu_process->ctx_desc.asid;
+
+ asid_state = idr_find(&smmu->asid_idr, asid);
+ if (asid_state && asid_state->domain) {
+ return -EEXIST;
+ } else if (asid_state) {
+ asid_state->refs++;
+ return 0;
+ }
+
+ asid_state = kzalloc(sizeof(*asid_state), GFP_ATOMIC);
+ asid_state->refs = 1;
+
+ if (!asid_state)
+ return -ENOMEM;
+
+ ret = idr_alloc(&smmu->asid_idr, asid_state, asid, asid + 1, GFP_ATOMIC);
+ return ret < 0 ? ret : 0;
+}
+
+static int arm_smmu_process_attach(struct iommu_domain *domain,
+ struct device *dev,
+ struct iommu_process *process, bool first)
+{
+ int ret;
+ struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+ struct arm_smmu_process *smmu_process = to_smmu_process(process);
+ struct arm_smmu_device *smmu = smmu_domain->smmu;
+ struct arm_smmu_master_data *master = dev->iommu_fwspec->iommu_priv;
+
+ if (!(smmu->features & ARM_SMMU_FEAT_SVM))
+ return -ENODEV;
+
+ /* TODO: process->no_pasid */
+ if (process->pasid >= master->num_ssids)
+ return -ENODEV;
+
+ /* TODO: process->no_need_for_pri_ill_pin_everything */
+ if (!master->can_fault)
+ return -ENODEV;
+
+ master->processes++;
+
+ if (!first)
+ return 0;
+
+ spin_lock(&smmu->asid_lock);
+ ret = arm_smmu_process_share(smmu_domain, smmu_process);
+ spin_unlock(&smmu->asid_lock);
+ if (ret)
+ return ret;
+
+ arm_smmu_write_ctx_desc(smmu_domain, process->pasid, &smmu_process->ctx_desc);
+
+ return 0;
+}
+
+static void arm_smmu_process_detach(struct iommu_domain *domain,
+ struct device *dev,
+ struct iommu_process *process, bool last)
+{
+ struct arm_smmu_asid_state *asid_state;
+ struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+ struct arm_smmu_process *smmu_process = to_smmu_process(process);
+ struct arm_smmu_master_data *master = dev->iommu_fwspec->iommu_priv;
+ struct arm_smmu_device *smmu = smmu_domain->smmu;
+
+ master->processes--;
+
+ if (last) {
+ spin_lock(&smmu->asid_lock);
+ asid_state = idr_find(&smmu->asid_idr, smmu_process->ctx_desc.asid);
+ if (--asid_state->refs == 0) {
+ idr_remove(&smmu->asid_idr, smmu_process->ctx_desc.asid);
+ kfree(asid_state);
+ }
+ spin_unlock(&smmu->asid_lock);
+
+ arm_smmu_write_ctx_desc(smmu_domain, process->pasid, NULL);
+ }
+
+ /* TODO: Invalidate ATC. */
+ /* TODO: Invalidate all mappings if last and not DVM. */
+}
+
+static void arm_smmu_process_invalidate(struct iommu_domain *domain,
+ struct iommu_process *process,
+ unsigned long iova, size_t size)
+{
+ /*
+ * TODO: Invalidate ATC.
+ * TODO: Invalidate mapping if not DVM
+ */
+}
+
+static void arm_smmu_process_exit(struct iommu_domain *domain,
+ struct iommu_process *process)
+{
+ struct arm_smmu_master_data *master;
+ struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+
+ if (!domain->process_exit)
+ return;
+
+ spin_lock(&smmu_domain->devices_lock);
+ list_for_each_entry(master, &smmu_domain->devices, list) {
+ if (!master->processes)
+ continue;
+
+ master->processes--;
+ domain->process_exit(domain, master->dev, process->pasid,
+ domain->process_exit_token);
+
+ /* TODO: inval ATC */
+ }
+ spin_unlock(&smmu_domain->devices_lock);
+
+ arm_smmu_write_ctx_desc(smmu_domain, process->pasid, NULL);
+
+ /* TODO: Invalidate all mappings if not DVM */
+}
+
static struct platform_driver arm_smmu_driver;
static int arm_smmu_match_node(struct device *dev, void *data)
@@ -2351,6 +2552,12 @@ static struct iommu_ops arm_smmu_ops = {
.domain_alloc = arm_smmu_domain_alloc,
.domain_free = arm_smmu_domain_free,
.attach_dev = arm_smmu_attach_dev,
+ .process_alloc = arm_smmu_process_alloc,
+ .process_free = arm_smmu_process_free,
+ .process_attach = arm_smmu_process_attach,
+ .process_detach = arm_smmu_process_detach,
+ .process_invalidate = arm_smmu_process_invalidate,
+ .process_exit = arm_smmu_process_exit,
.map = arm_smmu_map,
.unmap = arm_smmu_unmap,
.map_sg = default_iommu_map_sg,
--
2.13.3
--
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