drm/msm: Support IO_PGTABLE_QUIRK_NO_WARN_ON

With user managed VMs and multiple queues, it is in theory possible to
trigger map/unmap errors.  These will (in a later patch) mark the VM as
unusable.  But we want to tell the io-pgtable helpers not to spam the
log.  In addition, in the unmap path, we don't want to bail early from
the unmap, to ensure we don't leave some dangling pages mapped.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>
Tested-by: Antonino Maniscalco <antomani103@gmail.com>
Reviewed-by: Antonino Maniscalco <antomani103@gmail.com>
Patchwork: https://patchwork.freedesktop.org/patch/661520/

Author: robclark

drivers/gpu/drm/msm/adreno/a6xx_gpu.c

@@ -2280,7 +2280,7 @@ a6xx_create_private_vm(struct msm_gpu *gpu, bool kernel_managed)
 {
 	struct msm_mmu *mmu;
 
-	mmu = msm_iommu_pagetable_create(to_msm_vm(gpu->vm)->mmu);
+	mmu = msm_iommu_pagetable_create(to_msm_vm(gpu->vm)->mmu, kernel_managed);
 
 	if (IS_ERR(mmu))
 		return ERR_CAST(mmu);

drivers/gpu/drm/msm/msm_iommu.c

@@ -94,23 +94,32 @@ static int msm_iommu_pagetable_unmap(struct msm_mmu *mmu, u64 iova,
 {
 	struct msm_iommu_pagetable *pagetable = to_pagetable(mmu);
 	struct io_pgtable_ops *ops = pagetable->pgtbl_ops;
+	int ret = 0;
 
 	while (size) {
-		size_t unmapped, pgsize, count;
+		size_t pgsize, count;
+		ssize_t unmapped;
 
 		pgsize = calc_pgsize(pagetable, iova, iova, size, &count);
 
 		unmapped = ops->unmap_pages(ops, iova, pgsize, count, NULL);
-		if (!unmapped)
-			break;
+		if (unmapped <= 0) {
+			ret = -EINVAL;
+			/*
+			 * Continue attempting to unamp the remained of the
+			 * range, so we don't end up with some dangling
+			 * mapped pages
+			 */
+			unmapped = PAGE_SIZE;
+		}
 
 		iova += unmapped;
 		size -= unmapped;
 	}
 
 	iommu_flush_iotlb_all(to_msm_iommu(pagetable->parent)->domain);
 
-	return (size == 0) ? 0 : -EINVAL;
+	return ret;
 }
 
 static int msm_iommu_pagetable_map_prr(struct msm_mmu *mmu, u64 iova, size_t len, int prot)
@@ -324,7 +333,7 @@ static const struct iommu_flush_ops tlb_ops = {
 static int msm_gpu_fault_handler(struct iommu_domain *domain, struct device *dev,
 		unsigned long iova, int flags, void *arg);
 
-struct msm_mmu *msm_iommu_pagetable_create(struct msm_mmu *parent)
+struct msm_mmu *msm_iommu_pagetable_create(struct msm_mmu *parent, bool kernel_managed)
 {
 	struct adreno_smmu_priv *adreno_smmu = dev_get_drvdata(parent->dev);
 	struct msm_iommu *iommu = to_msm_iommu(parent);
@@ -358,6 +367,10 @@ struct msm_mmu *msm_iommu_pagetable_create(struct msm_mmu *parent)
 	ttbr0_cfg.quirks &= ~IO_PGTABLE_QUIRK_ARM_TTBR1;
 	ttbr0_cfg.tlb = &tlb_ops;
 
+	if (!kernel_managed) {
+		ttbr0_cfg.quirks |= IO_PGTABLE_QUIRK_NO_WARN;
+	}
+
 	pagetable->pgtbl_ops = alloc_io_pgtable_ops(ARM_64_LPAE_S1,
 		&ttbr0_cfg, pagetable);
 

drivers/gpu/drm/msm/msm_mmu.h

@@ -51,7 +51,7 @@ static inline void msm_mmu_set_fault_handler(struct msm_mmu *mmu, void *arg,
 	mmu->handler = handler;
 }
 
-struct msm_mmu *msm_iommu_pagetable_create(struct msm_mmu *parent);
+struct msm_mmu *msm_iommu_pagetable_create(struct msm_mmu *parent, bool kernel_managed);
 
 int msm_iommu_pagetable_params(struct msm_mmu *mmu, phys_addr_t *ttbr,
 			       int *asid);