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The idea is to invoke runtime_pm helpers at common points which are used by exposed ops or interrupt handlers. TLB and CFG invalidations are elided if the SMMU is suspended by observing the CMDQ_PROD_STOP_FLAG. Signed-off-by: Pranjal Shrivastava --- .../arm/arm-smmu-v3/arm-smmu-v3-iommufd.c | 10 +- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 101 ++++++++++++++++-- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 5 +- 3 files changed, 108 insertions(+), 8 deletions(-) diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c index 1e9f7d2de344..2d729034e3bb 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c @@ -15,6 +15,11 @@ void *arm_smmu_hw_info(struct device *dev, u32 *length, struct iommu_hw_info_arm_smmuv3 *info; u32 __iomem *base_idr; unsigned int i; + int ret; + + ret = arm_smmu_rpm_get(master->smmu); + if (ret < 0) + return ERR_PTR(-EIO); if (*type != IOMMU_HW_INFO_TYPE_DEFAULT && *type != IOMMU_HW_INFO_TYPE_ARM_SMMUV3) { @@ -24,8 +29,10 @@ void *arm_smmu_hw_info(struct device *dev, u32 *length, } info = kzalloc_obj(*info); - if (!info) + if (!info) { + arm_smmu_rpm_put(master->smmu); return ERR_PTR(-ENOMEM); + } base_idr = master->smmu->base + ARM_SMMU_IDR0; for (i = 0; i <= 5; i++) @@ -36,6 +43,7 @@ void *arm_smmu_hw_info(struct device *dev, u32 *length, *length = sizeof(*info); *type = IOMMU_HW_INFO_TYPE_ARM_SMMUV3; + arm_smmu_rpm_put(master->smmu); return info; } 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 24a1bcc8974f..2e260f85b8fd 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c @@ -112,7 +112,7 @@ static int arm_smmu_alloc_cd_tables(struct arm_smmu_master *master); static bool arm_smmu_ats_supported(struct arm_smmu_master *master); /* Runtime PM helpers */ -__maybe_unused static int arm_smmu_rpm_get(struct arm_smmu_device *smmu) +int arm_smmu_rpm_get(struct arm_smmu_device *smmu) { int ret; @@ -128,7 +128,7 @@ __maybe_unused static int arm_smmu_rpm_get(struct arm_smmu_device *smmu) return 0; } -__maybe_unused static void arm_smmu_rpm_put(struct arm_smmu_device *smmu) +void arm_smmu_rpm_put(struct arm_smmu_device *smmu) { int ret; @@ -983,7 +983,9 @@ static void arm_smmu_page_response(struct device *dev, struct iopf_fault *unused struct iommu_page_response *resp) { struct arm_smmu_master *master = dev_iommu_priv_get(dev); + struct arm_smmu_device *smmu = master->smmu; u8 resume_resp; + int ret; if (WARN_ON(!master->stall_enabled)) return; @@ -1001,6 +1003,25 @@ static void arm_smmu_page_response(struct device *dev, struct iopf_fault *unused break; } + /* + * The SMMU is guaranteed to be active via device_link if any master is + * active. Furthermore, on suspend we set GBPA to abort, flushing any + * pending stalled transactions. + * + * Receiving a page fault while suspended implies a bug in the power + * dependency chain or a stale event. Since the SMMU is powered down + * and the command queue is inaccessible, we cannot issue the + * RESUME command and must drop it. + */ + if (arm_smmu_cmdq_can_elide(smmu)) { + dev_err(smmu->dev, "Ignoring page fault while suspended\n"); + return; + } + + ret = arm_smmu_rpm_get(smmu); + if (ret < 0) + return; + arm_smmu_cmdq_issue_cmd(master->smmu, arm_smmu_make_cmd_resume(master->streams[0].id, resp->grpid, @@ -1011,6 +1032,7 @@ static void arm_smmu_page_response(struct device *dev, struct iopf_fault *unused * terminated... at some point in the future. PRI_RESP is fire and * forget. */ + arm_smmu_rpm_put(smmu); } /* Invalidation array manipulation functions */ @@ -1536,7 +1558,6 @@ static void arm_smmu_sync_cd(struct arm_smmu_master *master, smmu, &cmds, arm_smmu_make_cmd_cfgi_cd(master->streams[i].id, ssid, leaf)); - arm_smmu_cmdq_batch_submit(smmu, &cmds); } @@ -1828,9 +1849,9 @@ static void arm_smmu_ste_writer_sync_entry(struct arm_smmu_entry_writer *writer) { struct arm_smmu_ste_writer *ste_writer = container_of(writer, struct arm_smmu_ste_writer, writer); + struct arm_smmu_device *smmu = writer->master->smmu; - arm_smmu_cmdq_issue_cmd_with_sync( - writer->master->smmu, + arm_smmu_cmdq_issue_cmd_with_sync(smmu, arm_smmu_make_cmd_cfgi_ste(ste_writer->sid, true)); } @@ -2230,6 +2251,7 @@ static void arm_smmu_dump_event(struct arm_smmu_device *smmu, u64 *raw, static irqreturn_t arm_smmu_evtq_thread(int irq, void *dev) { + int ret; u64 evt[EVTQ_ENT_DWORDS]; struct arm_smmu_event event = {0}; struct arm_smmu_device *smmu = dev; @@ -2238,6 +2260,10 @@ static irqreturn_t arm_smmu_evtq_thread(int irq, void *dev) static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL, DEFAULT_RATELIMIT_BURST); + ret = arm_smmu_rpm_get(smmu); + if (ret < 0) + return IRQ_NONE; + do { while (!queue_remove_raw(q, evt)) { arm_smmu_decode_event(smmu, evt, &event); @@ -2258,6 +2284,7 @@ static irqreturn_t arm_smmu_evtq_thread(int irq, void *dev) /* Sync our overflow flag, as we believe we're up to speed */ queue_sync_cons_ovf(q); + arm_smmu_rpm_put(smmu); return IRQ_HANDLED; } @@ -2295,6 +2322,11 @@ static irqreturn_t arm_smmu_priq_thread(int irq, void *dev) struct arm_smmu_queue *q = &smmu->priq.q; struct arm_smmu_ll_queue *llq = &q->llq; u64 evt[PRIQ_ENT_DWORDS]; + int ret; + + ret = arm_smmu_rpm_get(smmu); + if (ret < 0) + return IRQ_NONE; do { while (!queue_remove_raw(q, evt)) @@ -2306,6 +2338,7 @@ static irqreturn_t arm_smmu_priq_thread(int irq, void *dev) /* Sync our overflow flag, as we believe we're up to speed */ queue_sync_cons_ovf(q); + arm_smmu_rpm_put(smmu); return IRQ_HANDLED; } @@ -2361,8 +2394,33 @@ static irqreturn_t arm_smmu_handle_gerror(struct arm_smmu_device *smmu) static irqreturn_t arm_smmu_gerror_handler(int irq, void *dev) { struct arm_smmu_device *smmu = dev; + irqreturn_t ret; + + /* + * Global Errors are only processed if the SMMU is active. + * + * If the STOP_FLAG is set (can_elide == true), the hardware is + * either already disabled or in the process of being disabled. + * Any errors captured during the quiesce/drain phase will be + * handled by the explicit arm_smmu_handle_gerror() call at the + * end of arm_smmu_runtime_suspend() callback. On resume, the + * STOP_FLAG is cleared before interrupts are re-enabled, ensuring + * no valid errors are missed. + * + * A lockless check is favoured here over a dynamic PM core check + * since the runtime_pm_get_if_active would return false during + * transient states like RPM_RESUMING & ignore level-triggered + * interrupts. + */ + if (arm_smmu_cmdq_can_elide(smmu)) { + dev_err(smmu->dev, + "Ignoring gerror interrupt because the SMMU is suspended\n"); + return IRQ_NONE; + } + + ret = arm_smmu_handle_gerror(smmu); - return arm_smmu_handle_gerror(smmu); + return ret; } static irqreturn_t arm_smmu_combined_irq_thread(int irq, void *dev) @@ -2445,6 +2503,10 @@ static int arm_smmu_atc_inv_master(struct arm_smmu_master *master, struct arm_smmu_cmd cmd; struct arm_smmu_cmdq_batch cmds; + /* Shouldn't hit the WARN if there's no devlink inconsistency */ + if (WARN_ON_ONCE(arm_smmu_cmdq_can_elide(master->smmu))) + return 0; + cmd = arm_smmu_make_cmd_atc_inv_all(0, IOMMU_NO_PASID); arm_smmu_cmdq_batch_init_cmd(master->smmu, &cmds, &cmd); for (i = 0; i < master->num_streams; i++) @@ -2690,7 +2752,16 @@ static void __arm_smmu_domain_inv_range(struct arm_smmu_invs *invs, if (cmds.num && (next == end || arm_smmu_invs_end_batch(cur, next))) { + + /* + * Concurrent suspend races are benign: the cmdq allocation cmpxchg + * loop acts as the serialization point to safely drop the batch + * without MMIO accesses. Concurrent resume is caught by the HW + * reset cache invalidation, ensuring state consistency. + */ arm_smmu_cmdq_batch_submit(smmu, &cmds); + + /* Drop this batch to ensure the next one's fresh */ cmds.num = 0; } cur = next; @@ -2703,6 +2774,9 @@ void arm_smmu_domain_inv_range(struct arm_smmu_domain *smmu_domain, { struct arm_smmu_invs *invs; + if (arm_smmu_cmdq_can_elide(smmu_domain->smmu)) + return; + /* * An invalidation request must follow some IOPTE change and then load * an invalidation array. In the meantime, a domain attachment mutates @@ -5631,10 +5705,19 @@ static int arm_smmu_device_probe(struct platform_device *pdev) static void arm_smmu_device_remove(struct platform_device *pdev) { struct arm_smmu_device *smmu = platform_get_drvdata(pdev); + int ret; iommu_device_unregister(&smmu->iommu); iommu_device_sysfs_remove(&smmu->iommu); + + ret = arm_smmu_rpm_get(smmu); + if (ret < 0) + goto free_iopf; + arm_smmu_device_disable(smmu); + arm_smmu_rpm_put(smmu); + +free_iopf: iopf_queue_free(smmu->evtq.iopf); ida_destroy(&smmu->vmid_map); } @@ -5642,8 +5725,14 @@ static void arm_smmu_device_remove(struct platform_device *pdev) static void arm_smmu_device_shutdown(struct platform_device *pdev) { struct arm_smmu_device *smmu = platform_get_drvdata(pdev); + int ret; + + ret = arm_smmu_rpm_get(smmu); + if (ret < 0) + return; arm_smmu_device_disable(smmu); + arm_smmu_rpm_put(smmu); } static int __maybe_unused arm_smmu_runtime_suspend(struct device *dev) 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 51a3281a1e46..0bd5ad2670e0 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h @@ -1230,11 +1230,14 @@ int arm_smmu_cmdq_issue_cmdlist(struct arm_smmu_device *smmu, * If we lose the race, that loop observes Q_STOP == 1 and safely * drops the command. If we win, the suspend thread waits for us. */ -static inline bool arm_smmu_can_elide(struct arm_smmu_device *smmu) +static inline bool arm_smmu_cmdq_can_elide(struct arm_smmu_device *smmu) { return !!Q_STOP(READ_ONCE(smmu->cmdq.q.llq.prod)); } +int arm_smmu_rpm_get(struct arm_smmu_device *smmu); +void arm_smmu_rpm_put(struct arm_smmu_device *smmu); + #ifdef CONFIG_ARM_SMMU_V3_SVA bool arm_smmu_sva_supported(struct arm_smmu_device *smmu); void arm_smmu_sva_notifier_synchronize(void); -- 2.54.0.1013.g208068f2d8-goog