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Message-ID: <20200623083643.GB4098287@ulmo>
Date: Tue, 23 Jun 2020 10:36:43 +0200
From: Thierry Reding <thierry.reding@...il.com>
To: Krishna Reddy <vdumpa@...dia.com>
Cc: snikam@...dia.com, mperttunen@...dia.com, bhuntsman@...dia.com,
will@...nel.org, joro@...tes.org, linux-kernel@...r.kernel.org,
praithatha@...dia.com, talho@...dia.com,
iommu@...ts.linux-foundation.org, nicolinc@...dia.com,
linux-tegra@...r.kernel.org, yhsu@...dia.com, treding@...dia.com,
robin.murphy@....com, linux-arm-kernel@...ts.infradead.org,
bbiswas@...dia.com
Subject: Re: [PATCH v6 3/4] iommu/arm-smmu: Add global/context fault
implementation hooks
On Thu, Jun 04, 2020 at 04:44:13PM -0700, Krishna Reddy wrote:
> Add global/context fault hooks to allow NVIDIA SMMU implementation
> handle faults across multiple SMMUs.
>
> Signed-off-by: Krishna Reddy <vdumpa@...dia.com>
> ---
> drivers/iommu/arm-smmu-nvidia.c | 100 ++++++++++++++++++++++++++++++++
> drivers/iommu/arm-smmu.c | 11 +++-
> drivers/iommu/arm-smmu.h | 3 +
> 3 files changed, 112 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iommu/arm-smmu-nvidia.c b/drivers/iommu/arm-smmu-nvidia.c
> index dafc293a45217..5999b6a770992 100644
> --- a/drivers/iommu/arm-smmu-nvidia.c
> +++ b/drivers/iommu/arm-smmu-nvidia.c
> @@ -117,6 +117,104 @@ static int nsmmu_reset(struct arm_smmu_device *smmu)
> return 0;
> }
>
> +static struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)
> +{
> + return container_of(dom, struct arm_smmu_domain, domain);
> +}
> +
> +static irqreturn_t nsmmu_global_fault_inst(int irq,
> + struct arm_smmu_device *smmu,
> + int inst)
> +{
> + u32 gfsr, gfsynr0, gfsynr1, gfsynr2;
> +
> + gfsr = readl_relaxed(nsmmu_page(smmu, inst, 0) + ARM_SMMU_GR0_sGFSR);
> + gfsynr0 = readl_relaxed(nsmmu_page(smmu, inst, 0) +
> + ARM_SMMU_GR0_sGFSYNR0);
> + gfsynr1 = readl_relaxed(nsmmu_page(smmu, inst, 0) +
> + ARM_SMMU_GR0_sGFSYNR1);
> + gfsynr2 = readl_relaxed(nsmmu_page(smmu, inst, 0) +
> + ARM_SMMU_GR0_sGFSYNR2);
> +
> + if (!gfsr)
> + return IRQ_NONE;
> +
> + dev_err_ratelimited(smmu->dev,
> + "Unexpected global fault, this could be serious\n");
> + dev_err_ratelimited(smmu->dev,
> + "\tGFSR 0x%08x, GFSYNR0 0x%08x, GFSYNR1 0x%08x, GFSYNR2 0x%08x\n",
> + gfsr, gfsynr0, gfsynr1, gfsynr2);
> +
> + writel_relaxed(gfsr, nsmmu_page(smmu, inst, 0) + ARM_SMMU_GR0_sGFSR);
> + return IRQ_HANDLED;
> +}
> +
> +static irqreturn_t nsmmu_global_fault(int irq, void *dev)
> +{
> + int inst;
> + irqreturn_t irq_ret = IRQ_NONE;
> + struct arm_smmu_device *smmu = dev;
> +
> + for (inst = 0; inst < to_nvidia_smmu(smmu)->num_inst; inst++) {
> + irq_ret = nsmmu_global_fault_inst(irq, smmu, inst);
> + if (irq_ret == IRQ_HANDLED)
> + return irq_ret;
> + }
> +
> + return irq_ret;
> +}
> +
> +static irqreturn_t nsmmu_context_fault_bank(int irq,
> + struct arm_smmu_device *smmu,
> + int idx, int inst)
> +{
> + u32 fsr, fsynr, cbfrsynra;
> + unsigned long iova;
> +
> + fsr = arm_smmu_cb_read(smmu, idx, ARM_SMMU_CB_FSR);
> + if (!(fsr & ARM_SMMU_FSR_FAULT))
> + return IRQ_NONE;
> +
> + fsynr = readl_relaxed(nsmmu_page(smmu, inst, smmu->numpage + idx) +
> + ARM_SMMU_CB_FSYNR0);
> + iova = readq_relaxed(nsmmu_page(smmu, inst, smmu->numpage + idx) +
> + ARM_SMMU_CB_FAR);
> + cbfrsynra = readl_relaxed(nsmmu_page(smmu, inst, 1) +
> + ARM_SMMU_GR1_CBFRSYNRA(idx));
> +
> + dev_err_ratelimited(smmu->dev,
> + "Unhandled context fault: fsr=0x%x, iova=0x%08lx, fsynr=0x%x, cbfrsynra=0x%x, cb=%d\n",
> + fsr, iova, fsynr, cbfrsynra, idx);
> +
> + writel_relaxed(fsr, nsmmu_page(smmu, inst, smmu->numpage + idx) +
> + ARM_SMMU_CB_FSR);
> + return IRQ_HANDLED;
> +}
> +
> +static irqreturn_t nsmmu_context_fault(int irq, void *dev)
> +{
> + int inst, idx;
> + irqreturn_t irq_ret = IRQ_NONE;
> + struct iommu_domain *domain = dev;
> + struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
> + struct arm_smmu_device *smmu = smmu_domain->smmu;
> +
> + for (inst = 0; inst < to_nvidia_smmu(smmu)->num_inst; inst++) {
> + /* Interrupt line shared between all context faults.
> + * Check for faults across all contexts.
> + */
> + for (idx = 0; idx < smmu->num_context_banks; idx++) {
> + irq_ret = nsmmu_context_fault_bank(irq, smmu,
> + idx, inst);
> +
> + if (irq_ret == IRQ_HANDLED)
> + return irq_ret;
> + }
> + }
> +
> + return irq_ret;
> +}
> +
> static const struct arm_smmu_impl nvidia_smmu_impl = {
> .read_reg = nsmmu_read_reg,
> .write_reg = nsmmu_write_reg,
> @@ -124,6 +222,8 @@ static const struct arm_smmu_impl nvidia_smmu_impl = {
> .write_reg64 = nsmmu_write_reg64,
> .reset = nsmmu_reset,
> .tlb_sync = nsmmu_tlb_sync,
> + .global_fault = nsmmu_global_fault,
> + .context_fault = nsmmu_context_fault,
> };
>
> struct arm_smmu_device *nvidia_smmu_impl_init(struct arm_smmu_device *smmu)
> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index 243bc4cb2705b..d720e1e191176 100644
> --- a/drivers/iommu/arm-smmu.c
> +++ b/drivers/iommu/arm-smmu.c
> @@ -673,6 +673,7 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain,
> enum io_pgtable_fmt fmt;
> struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
> struct arm_smmu_cfg *cfg = &smmu_domain->cfg;
> + irqreturn_t (*context_fault)(int irq, void *dev);
>
> mutex_lock(&smmu_domain->init_mutex);
> if (smmu_domain->smmu)
> @@ -835,7 +836,9 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain,
> * handler seeing a half-initialised domain state.
> */
> irq = smmu->irqs[smmu->num_global_irqs + cfg->irptndx];
> - ret = devm_request_irq(smmu->dev, irq, arm_smmu_context_fault,
> + context_fault = (smmu->impl && smmu->impl->context_fault) ?
> + smmu->impl->context_fault : arm_smmu_context_fault;
A simpler way might have been to assign arm_smmu_context_fault to all
implementations. That way we wouldn't have to perform this check here
and instead just always using smmu->impl->context_fault.
> + ret = devm_request_irq(smmu->dev, irq, context_fault,
> IRQF_SHARED, "arm-smmu-context-fault", domain);
> if (ret < 0) {
> dev_err(smmu->dev, "failed to request context IRQ %d (%u)\n",
> @@ -2107,6 +2110,7 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
> struct arm_smmu_device *smmu;
> struct device *dev = &pdev->dev;
> int num_irqs, i, err;
> + irqreturn_t (*global_fault)(int irq, void *dev);
>
> smmu = devm_kzalloc(dev, sizeof(*smmu), GFP_KERNEL);
> if (!smmu) {
> @@ -2193,9 +2197,12 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
> smmu->num_context_irqs = smmu->num_context_banks;
> }
>
> + global_fault = (smmu->impl && smmu->impl->global_fault) ?
> + smmu->impl->global_fault : arm_smmu_global_fault;
> +
Same as above.
Thierry
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