Re: [PATCH 4/7] iommu/arm-smmu: Add global/context fault implementation hooks

Thierry Reding
2019-08-30T11:18:42Z

[-- Attachment #1.1: Type: text/plain, Size: 6366 bytes --]

On Thu, Aug 29, 2019 at 03:47:04PM -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@nvidia.com>
> ---
> drivers/iommu/arm-smmu-nvidia.c | 127 ++++++++++++++++++++++++++++++++++++++++
> drivers/iommu/arm-smmu.c | 6 ++
> drivers/iommu/arm-smmu.h | 4 ++
> 3 files changed, 137 insertions(+)
>
> diff --git a/drivers/iommu/arm-smmu-nvidia.c b/drivers/iommu/arm-smmu-nvidia.c
> index a429b2c..b2a3c49 100644
> --- a/drivers/iommu/arm-smmu-nvidia.c
> +++ b/drivers/iommu/arm-smmu-nvidia.c
> @@ -14,6 +14,10 @@
>
> #define NUM_SMMU_INSTANCES 3
>
> +static irqreturn_t nsmmu_context_fault_inst(int irq,
> + struct arm_smmu_device *smmu,
> + int idx, int inst);

More of these signed integers that could be unsigned. Also why the need
to predeclare this? Can you not just put the definition of the function
up here?

> +
> struct nvidia_smmu {
> struct arm_smmu_device smmu;
> int num_inst;
> @@ -87,12 +91,135 @@ static void nsmmu_tlb_sync(struct arm_smmu_device *smmu, int page,
> nsmmu_tlb_sync_wait(smmu, page, sync, status, i);
> }
>
> +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, struct arm_smmu_device *smmu)
> +{
> + int i;
> + irqreturn_t irq_ret = IRQ_NONE;
> +
> + /* Interrupt line is shared between global and context faults.
> + * Check for both type of interrupts on either fault handlers.
> + */
> + for (i = 0; i < to_nsmmu(smmu)->num_inst; i++) {
> + irq_ret = nsmmu_context_fault_inst(irq, smmu, 0, i);
> + if (irq_ret == IRQ_HANDLED)
> + return irq_ret;
> + }
> +
> + for (i = 0; i < to_nsmmu(smmu)->num_inst; i++) {
> + irq_ret = nsmmu_global_fault_inst(irq, smmu, i);
> + 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 & 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_inst(int irq,
> + struct arm_smmu_device *smmu,
> + int idx, int inst)
> +{
> + irqreturn_t irq_ret = IRQ_NONE;
> +
> + /* Interrupt line shared between global and 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)
> + break;
> + }
> +
> + return irq_ret;
> +}
> +
> +static irqreturn_t nsmmu_context_fault(int irq,
> + struct arm_smmu_device *smmu,
> + int cbndx)
> +{
> + int i;
> + irqreturn_t irq_ret = IRQ_NONE;
> +
> + /* Interrupt line is shared between global and context faults.
> + * Check for both type of interrupts on either fault handlers.
> + */
> + for (i = 0; i < to_nsmmu(smmu)->num_inst; i++) {
> + irq_ret = nsmmu_global_fault_inst(irq, smmu, i);
> + if (irq_ret == IRQ_HANDLED)
> + return irq_ret;
> + }
> +
> + for (i = 0; i < to_nsmmu(smmu)->num_inst; i++) {
> + irq_ret = nsmmu_context_fault_inst(irq, smmu, cbndx, i);
> + if (irq_ret == IRQ_HANDLED)
> + return irq_ret;
> + }
> +
> + return irq_ret;
> +}
> +
> static const struct arm_smmu_impl nsmmu_impl = {
> .read_reg = nsmmu_read_reg,
> .write_reg = nsmmu_write_reg,
> .read_reg64 = nsmmu_read_reg64,
> .write_reg64 = nsmmu_write_reg64,
> .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 f5454e71..9cc532d 100644
> --- a/drivers/iommu/arm-smmu.c
> +++ b/drivers/iommu/arm-smmu.c
> @@ -454,6 +454,9 @@ static irqreturn_t arm_smmu_context_fault(int irq, void *dev)
> struct arm_smmu_device *smmu = smmu_domain->smmu;
> int idx = smmu_domain->cfg.cbndx;
>
> + if (smmu->impl->context_fault)
> + return smmu->impl->context_fault(irq, smmu, idx);
> +

Same comment here...

> fsr = arm_smmu_cb_read(smmu, idx, ARM_SMMU_CB_FSR);
> if (!(fsr & FSR_FAULT))
> return IRQ_NONE;
> @@ -475,6 +478,9 @@ static irqreturn_t arm_smmu_global_fault(int irq, void *dev)
> u32 gfsr, gfsynr0, gfsynr1, gfsynr2;
> struct arm_smmu_device *smmu = dev;
>
> + if (smmu->impl->global_fault)
> + return smmu->impl->global_fault(irq, smmu);

... and here about the extra level of indirection.

Thierry

[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

[-- Attachment #2: Type: text/plain, Size: 156 bytes --]