The SMMU provides a Stall model for handling page faults in platform
devices. It is similar to PCIe PRI, but doesn't require devices to have
their own translation cache. Instead, faulting transactions are parked
and the OS is given a chance to fix the page tables and retry the
transaction.
Enable stall for devices that support it (opt-in by firmware). When an
event corresponds to a translation error, call the IOMMU fault handler.
If the fault is recoverable, it will call us back to terminate or
continue the stall.
Signed-off-by: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>
---
v8:
* Extract firwmare setting into separate patch
* Don't drain event queue on unbind()
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 36 ++++
.../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 26 ++-
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 173 +++++++++++++++++-
3 files changed, 224 insertions(+), 11 deletions(-)
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 7bd98fdce5c3..124f604ed677 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -361,6 +361,13 @@
#define CMDQ_PRI_1_GRPID GENMASK_ULL(8, 0)
#define CMDQ_PRI_1_RESP GENMASK_ULL(13, 12)
+#define CMDQ_RESUME_0_SID GENMASK_ULL(63, 32)
+#define CMDQ_RESUME_0_RESP_TERM 0UL
+#define CMDQ_RESUME_0_RESP_RETRY 1UL
+#define CMDQ_RESUME_0_RESP_ABORT 2UL
+#define CMDQ_RESUME_0_RESP GENMASK_ULL(13, 12)
+#define CMDQ_RESUME_1_STAG GENMASK_ULL(15, 0)
+
#define CMDQ_SYNC_0_CS GENMASK_ULL(13, 12)
#define CMDQ_SYNC_0_CS_NONE 0
#define CMDQ_SYNC_0_CS_IRQ 1
@@ -377,6 +384,25 @@
#define EVTQ_0_ID GENMASK_ULL(7, 0)
+#define EVT_ID_TRANSLATION_FAULT 0x10
+#define EVT_ID_ADDR_SIZE_FAULT 0x11
+#define EVT_ID_ACCESS_FAULT 0x12
+#define EVT_ID_PERMISSION_FAULT 0x13
+
+#define EVTQ_0_SSV (1UL << 11)
+#define EVTQ_0_SSID GENMASK_ULL(31, 12)
+#define EVTQ_0_SID GENMASK_ULL(63, 32)
+#define EVTQ_1_STAG GENMASK_ULL(15, 0)
+#define EVTQ_1_STALL (1UL << 31)
+#define EVTQ_1_PRIV (1UL << 33)
+#define EVTQ_1_EXEC (1UL << 34)
+#define EVTQ_1_READ (1UL << 35)
+#define EVTQ_1_S2 (1UL << 39)
+#define EVTQ_1_CLASS GENMASK_ULL(41, 40)
+#define EVTQ_1_TT_READ (1UL << 44)
+#define EVTQ_2_ADDR GENMASK_ULL(63, 0)
+#define EVTQ_3_IPA GENMASK_ULL(51, 12)
+
/* PRI queue */
#define PRIQ_ENT_SZ_SHIFT 4
#define PRIQ_ENT_DWORDS ((1 << PRIQ_ENT_SZ_SHIFT) >> 3)
@@ -471,6 +497,13 @@ struct arm_smmu_cmdq_ent {
enum pri_resp resp;
} pri;
+ #define CMDQ_OP_RESUME 0x44
+ struct {
+ u32 sid;
+ u16 stag;
+ u8 resp;
+ } resume;
+
#define CMDQ_OP_CMD_SYNC 0x46
struct {
u64 msiaddr;
@@ -529,6 +562,7 @@ struct arm_smmu_cmdq_batch {
struct arm_smmu_evtq {
struct arm_smmu_queue q;
+ struct iopf_queue *iopf;
u32 max_stalls;
};
@@ -668,6 +702,7 @@ struct arm_smmu_master {
struct arm_smmu_stream *streams;
unsigned int num_streams;
bool ats_enabled;
+ bool stall_enabled;
bool sva_enabled;
struct list_head bonds;
unsigned int ssid_bits;
@@ -687,6 +722,7 @@ struct arm_smmu_domain {
struct io_pgtable_ops *pgtbl_ops;
bool non_strict;
+ bool stall_enabled;
atomic_t nr_ats_masters;
enum arm_smmu_domain_stage stage;
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 f734797ea07a..64e2082ef9ed 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
@@ -435,7 +435,7 @@ bool arm_smmu_sva_supported(struct arm_smmu_device *smmu)
static bool arm_smmu_iopf_supported(struct arm_smmu_master *master)
{
- return false;
+ return master->stall_enabled;
}
bool arm_smmu_master_sva_supported(struct arm_smmu_master *master)
@@ -459,24 +459,46 @@ bool arm_smmu_master_sva_enabled(struct arm_smmu_master *master)
int arm_smmu_master_enable_sva(struct arm_smmu_master *master)
{
+ int ret;
+ struct device *dev = master->dev;
+
+ if (master->stall_enabled) {
+ ret = iopf_queue_add_device(master->smmu->evtq.iopf, dev);
+ if (ret)
+ return ret;
+ }
+
+ ret = iommu_register_device_fault_handler(dev, iommu_queue_iopf, dev);
+ if (ret)
+ goto err_disable_iopf;
+
mutex_lock(&sva_lock);
master->sva_enabled = true;
mutex_unlock(&sva_lock);
return 0;
+
+err_disable_iopf:
+ iopf_queue_remove_device(master->smmu->evtq.iopf, dev);
+ return ret;
}
int arm_smmu_master_disable_sva(struct arm_smmu_master *master)
{
+ struct device *dev = master->dev;
+
mutex_lock(&sva_lock);
if (!list_empty(&master->bonds)) {
- dev_err(master->dev, "cannot disable SVA, device is bound\n");
+ dev_err(dev, "cannot disable SVA, device is bound\n");
mutex_unlock(&sva_lock);
return -EBUSY;
}
master->sva_enabled = false;
mutex_unlock(&sva_lock);
+ iommu_unregister_device_fault_handler(dev);
+ iopf_queue_remove_device(master->smmu->evtq.iopf, dev);
+
return 0;
}
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 d87c87136d63..d412d063d3b6 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -32,6 +32,7 @@
#include <linux/amba/bus.h>
#include "arm-smmu-v3.h"
+#include "../../iommu-sva-lib.h"
static bool disable_bypass = 1;
module_param(disable_bypass, bool, 0444);
@@ -324,6 +325,11 @@ static int arm_smmu_cmdq_build_cmd(u64 *cmd, struct arm_smmu_cmdq_ent *ent)
}
cmd[1] |= FIELD_PREP(CMDQ_PRI_1_RESP, ent->pri.resp);
break;
+ case CMDQ_OP_RESUME:
+ cmd[0] |= FIELD_PREP(CMDQ_RESUME_0_SID, ent->resume.sid);
+ cmd[0] |= FIELD_PREP(CMDQ_RESUME_0_RESP, ent->resume.resp);
+ cmd[1] |= FIELD_PREP(CMDQ_RESUME_1_STAG, ent->resume.stag);
+ break;
case CMDQ_OP_CMD_SYNC:
if (ent->sync.msiaddr) {
cmd[0] |= FIELD_PREP(CMDQ_SYNC_0_CS, CMDQ_SYNC_0_CS_IRQ);
@@ -887,6 +893,44 @@ static int arm_smmu_cmdq_batch_submit(struct arm_smmu_device *smmu,
return arm_smmu_cmdq_issue_cmdlist(smmu, cmds->cmds, cmds->num, true);
}
+static int arm_smmu_page_response(struct device *dev,
+ struct iommu_fault_event *unused,
+ struct iommu_page_response *resp)
+{
+ struct arm_smmu_cmdq_ent cmd = {0};
+ struct arm_smmu_master *master = dev_iommu_priv_get(dev);
+ int sid = master->streams[0].id;
+
+ if (master->stall_enabled) {
+ cmd.opcode = CMDQ_OP_RESUME;
+ cmd.resume.sid = sid;
+ cmd.resume.stag = resp->grpid;
+ switch (resp->code) {
+ case IOMMU_PAGE_RESP_INVALID:
+ case IOMMU_PAGE_RESP_FAILURE:
+ cmd.resume.resp = CMDQ_RESUME_0_RESP_ABORT;
+ break;
+ case IOMMU_PAGE_RESP_SUCCESS:
+ cmd.resume.resp = CMDQ_RESUME_0_RESP_RETRY;
+ break;
+ default:
+ return -EINVAL;
+ }
+ } else {
+ return -ENODEV;
+ }
+
+ arm_smmu_cmdq_issue_cmd(master->smmu, &cmd);
+ /*
+ * Don't send a SYNC, it doesn't do anything for RESUME or PRI_RESP.
+ * RESUME consumption guarantees that the stalled transaction will be
+ * terminated... at some point in the future. PRI_RESP is fire and
+ * forget.
+ */
+
+ return 0;
+}
+
/* Context descriptor manipulation functions */
void arm_smmu_tlb_inv_asid(struct arm_smmu_device *smmu, u16 asid)
{
@@ -1049,8 +1093,7 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
FIELD_PREP(CTXDESC_CD_0_ASID, cd->asid) |
CTXDESC_CD_0_V;
- /* STALL_MODEL==0b10 && CD.S==0 is ILLEGAL */
- if (smmu->features & ARM_SMMU_FEAT_STALL_FORCE)
+ if (smmu_domain->stall_enabled)
val |= CTXDESC_CD_0_S;
}
@@ -1294,7 +1337,7 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
FIELD_PREP(STRTAB_STE_1_STRW, strw));
if (smmu->features & ARM_SMMU_FEAT_STALLS &&
- !(smmu->features & ARM_SMMU_FEAT_STALL_FORCE))
+ !master->stall_enabled)
dst[1] |= cpu_to_le64(STRTAB_STE_1_S1STALLD);
val |= (s1_cfg->cdcfg.cdtab_dma & STRTAB_STE_0_S1CTXPTR_MASK) |
@@ -1371,7 +1414,6 @@ static int arm_smmu_init_l2_strtab(struct arm_smmu_device *smmu, u32 sid)
return 0;
}
-__maybe_unused
static struct arm_smmu_master *
arm_smmu_find_master(struct arm_smmu_device *smmu, u32 sid)
{
@@ -1398,9 +1440,96 @@ arm_smmu_find_master(struct arm_smmu_device *smmu, u32 sid)
}
/* IRQ and event handlers */
+static int arm_smmu_handle_evt(struct arm_smmu_device *smmu, u64 *evt)
+{
+ int ret;
+ u32 perm = 0;
+ struct arm_smmu_master *master;
+ bool ssid_valid = evt[0] & EVTQ_0_SSV;
+ u8 type = FIELD_GET(EVTQ_0_ID, evt[0]);
+ u32 sid = FIELD_GET(EVTQ_0_SID, evt[0]);
+ struct iommu_fault_event fault_evt = { };
+ struct iommu_fault *flt = &fault_evt.fault;
+
+ /* Stage-2 is always pinned at the moment */
+ if (evt[1] & EVTQ_1_S2)
+ return -EFAULT;
+
+ master = arm_smmu_find_master(smmu, sid);
+ if (!master)
+ return -EINVAL;
+
+ if (evt[1] & EVTQ_1_READ)
+ perm |= IOMMU_FAULT_PERM_READ;
+ else
+ perm |= IOMMU_FAULT_PERM_WRITE;
+
+ if (evt[1] & EVTQ_1_EXEC)
+ perm |= IOMMU_FAULT_PERM_EXEC;
+
+ if (evt[1] & EVTQ_1_PRIV)
+ perm |= IOMMU_FAULT_PERM_PRIV;
+
+ if (evt[1] & EVTQ_1_STALL) {
+ flt->type = IOMMU_FAULT_PAGE_REQ;
+ flt->prm = (struct iommu_fault_page_request) {
+ .flags = IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE,
+ .grpid = FIELD_GET(EVTQ_1_STAG, evt[1]),
+ .perm = perm,
+ .addr = FIELD_GET(EVTQ_2_ADDR, evt[2]),
+ };
+
+ if (ssid_valid) {
+ flt->prm.flags |= IOMMU_FAULT_PAGE_REQUEST_PASID_VALID;
+ flt->prm.pasid = FIELD_GET(EVTQ_0_SSID, evt[0]);
+ }
+ } else {
+ flt->type = IOMMU_FAULT_DMA_UNRECOV;
+ flt->event = (struct iommu_fault_unrecoverable) {
+ .flags = IOMMU_FAULT_UNRECOV_ADDR_VALID |
+ IOMMU_FAULT_UNRECOV_FETCH_ADDR_VALID,
+ .perm = perm,
+ .addr = FIELD_GET(EVTQ_2_ADDR, evt[2]),
+ .fetch_addr = FIELD_GET(EVTQ_3_IPA, evt[3]),
+ };
+
+ if (ssid_valid) {
+ flt->event.flags |= IOMMU_FAULT_UNRECOV_PASID_VALID;
+ flt->event.pasid = FIELD_GET(EVTQ_0_SSID, evt[0]);
+ }
+
+ switch (type) {
+ case EVT_ID_TRANSLATION_FAULT:
+ case EVT_ID_ADDR_SIZE_FAULT:
+ case EVT_ID_ACCESS_FAULT:
+ flt->event.reason = IOMMU_FAULT_REASON_PTE_FETCH;
+ break;
+ case EVT_ID_PERMISSION_FAULT:
+ flt->event.reason = IOMMU_FAULT_REASON_PERMISSION;
+ break;
+ default:
+ /* TODO: report other unrecoverable faults. */
+ return -EFAULT;
+ }
+ }
+
+ ret = iommu_report_device_fault(master->dev, &fault_evt);
+ if (ret && flt->type == IOMMU_FAULT_PAGE_REQ) {
+ /* Nobody cared, abort the access */
+ struct iommu_page_response resp = {
+ .pasid = flt->prm.pasid,
+ .grpid = flt->prm.grpid,
+ .code = IOMMU_PAGE_RESP_FAILURE,
+ };
+ arm_smmu_page_response(master->dev, NULL, &resp);
+ }
+
+ return ret;
+}
+
static irqreturn_t arm_smmu_evtq_thread(int irq, void *dev)
{
- int i;
+ int i, ret;
struct arm_smmu_device *smmu = dev;
struct arm_smmu_queue *q = &smmu->evtq.q;
struct arm_smmu_ll_queue *llq = &q->llq;
@@ -1410,11 +1539,15 @@ static irqreturn_t arm_smmu_evtq_thread(int irq, void *dev)
while (!queue_remove_raw(q, evt)) {
u8 id = FIELD_GET(EVTQ_0_ID, evt[0]);
- dev_info(smmu->dev, "event 0x%02x received:\n", id);
- for (i = 0; i < ARRAY_SIZE(evt); ++i)
- dev_info(smmu->dev, "\t0x%016llx\n",
- (unsigned long long)evt[i]);
+ ret = arm_smmu_handle_evt(smmu, evt);
+ if (ret) {
+ dev_info(smmu->dev, "event 0x%02x received:\n",
+ id);
+ for (i = 0; i < ARRAY_SIZE(evt); ++i)
+ dev_info(smmu->dev, "\t0x%016llx\n",
+ (unsigned long long)evt[i]);
+ }
}
/*
@@ -1927,6 +2060,8 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
cfg->s1cdmax = master->ssid_bits;
+ smmu_domain->stall_enabled = master->stall_enabled;
+
ret = arm_smmu_alloc_cd_tables(smmu_domain);
if (ret)
goto out_free_asid;
@@ -2270,6 +2405,12 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
smmu_domain->s1_cfg.s1cdmax, master->ssid_bits);
ret = -EINVAL;
goto out_unlock;
+ } else if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1 &&
+ smmu_domain->stall_enabled != master->stall_enabled) {
+ dev_err(dev, "cannot attach to stall-%s domain\n",
+ smmu_domain->stall_enabled ? "enabled" : "disabled");
+ ret = -EINVAL;
+ goto out_unlock;
}
master->domain = smmu_domain;
@@ -2503,6 +2644,10 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev)
master->ssid_bits = min_t(u8, master->ssid_bits,
CTXDESC_LINEAR_CDMAX);
+ if ((smmu->features & ARM_SMMU_FEAT_STALLS && fwspec->can_stall) ||
+ smmu->features & ARM_SMMU_FEAT_STALL_FORCE)
+ master->stall_enabled = true;
+
return &smmu->iommu;
err_free_master:
@@ -2521,6 +2666,7 @@ static void arm_smmu_release_device(struct device *dev)
master = dev_iommu_priv_get(dev);
WARN_ON(arm_smmu_master_sva_enabled(master));
+ iopf_queue_remove_device(master->smmu->evtq.iopf, dev);
arm_smmu_detach_dev(master);
arm_smmu_disable_pasid(master);
arm_smmu_remove_master(master);
@@ -2727,6 +2873,7 @@ static struct iommu_ops arm_smmu_ops = {
.sva_bind = arm_smmu_sva_bind,
.sva_unbind = arm_smmu_sva_unbind,
.sva_get_pasid = arm_smmu_sva_get_pasid,
+ .page_response = arm_smmu_page_response,
.pgsize_bitmap = -1UL, /* Restricted during device attach */
};
@@ -2804,6 +2951,7 @@ static int arm_smmu_cmdq_init(struct arm_smmu_device *smmu)
static int arm_smmu_init_queues(struct arm_smmu_device *smmu)
{
int ret;
+ bool sva = arm_smmu_sva_supported(smmu);
/* cmdq */
ret = arm_smmu_init_one_queue(smmu, &smmu->cmdq.q, ARM_SMMU_CMDQ_PROD,
@@ -2823,6 +2971,12 @@ static int arm_smmu_init_queues(struct arm_smmu_device *smmu)
if (ret)
return ret;
+ if (sva && smmu->features & ARM_SMMU_FEAT_STALLS) {
+ smmu->evtq.iopf = iopf_queue_alloc(dev_name(smmu->dev));
+ if (!smmu->evtq.iopf)
+ return -ENOMEM;
+ }
+
/* priq */
if (!(smmu->features & ARM_SMMU_FEAT_PRI))
return 0;
@@ -3789,6 +3943,7 @@ static int arm_smmu_device_remove(struct platform_device *pdev)
iommu_device_unregister(&smmu->iommu);
iommu_device_sysfs_remove(&smmu->iommu);
arm_smmu_device_disable(smmu);
+ iopf_queue_free(smmu->evtq.iopf);
return 0;
}
--
2.29.1
