nouveau/svm: use the new migration invalidation

Use the new MMU_NOTIFY_MIGRATE event to skip GPU MMU invalidations of
device private memory and handle the invalidation in the driver as part of
migrating device private memory.

Link: https://lore.kernel.org/r/20200723223004.9586-5-rcampbell@nvidia.com
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

Author: Ralph Campbell

drivers/gpu/drm/nouveau/nouveau_dmem.c

@@ -140,6 +140,7 @@ static vm_fault_t nouveau_dmem_fault_copy_one(struct nouveau_drm *drm,
 {
 	struct device *dev = drm->dev->dev;
 	struct page *dpage, *spage;
+	struct nouveau_svmm *svmm;
 
 	spage = migrate_pfn_to_page(args->src[0]);
 	if (!spage || !(args->src[0] & MIGRATE_PFN_MIGRATE))
@@ -154,14 +155,19 @@ static vm_fault_t nouveau_dmem_fault_copy_one(struct nouveau_drm *drm,
 	if (dma_mapping_error(dev, *dma_addr))
 		goto error_free_page;
 
+	svmm = spage->zone_device_data;
+	mutex_lock(&svmm->mutex);
+	nouveau_svmm_invalidate(svmm, args->start, args->end);
 	if (drm->dmem->migrate.copy_func(drm, 1, NOUVEAU_APER_HOST, *dma_addr,
 			NOUVEAU_APER_VRAM, nouveau_dmem_page_addr(spage)))
 		goto error_dma_unmap;
+	mutex_unlock(&svmm->mutex);
 
 	args->dst[0] = migrate_pfn(page_to_pfn(dpage)) | MIGRATE_PFN_LOCKED;
 	return 0;
 
 error_dma_unmap:
+	mutex_unlock(&svmm->mutex);
 	dma_unmap_page(dev, *dma_addr, PAGE_SIZE, DMA_BIDIRECTIONAL);
 error_free_page:
 	__free_page(dpage);
@@ -531,7 +537,8 @@ nouveau_dmem_init(struct nouveau_drm *drm)
 }
 
 static unsigned long nouveau_dmem_migrate_copy_one(struct nouveau_drm *drm,
-		unsigned long src, dma_addr_t *dma_addr, u64 *pfn)
+		struct nouveau_svmm *svmm, unsigned long src,
+		dma_addr_t *dma_addr, u64 *pfn)
 {
 	struct device *dev = drm->dev->dev;
 	struct page *dpage, *spage;
@@ -561,6 +568,7 @@ static unsigned long nouveau_dmem_migrate_copy_one(struct nouveau_drm *drm,
 			goto out_free_page;
 	}
 
+	dpage->zone_device_data = svmm;
 	*pfn = NVIF_VMM_PFNMAP_V0_V | NVIF_VMM_PFNMAP_V0_VRAM |
 		((paddr >> PAGE_SHIFT) << NVIF_VMM_PFNMAP_V0_ADDR_SHIFT);
 	if (src & MIGRATE_PFN_WRITE)
@@ -584,8 +592,8 @@ static void nouveau_dmem_migrate_chunk(struct nouveau_drm *drm,
 	unsigned long addr = args->start, nr_dma = 0, i;
 
 	for (i = 0; addr < args->end; i++) {
-		args->dst[i] = nouveau_dmem_migrate_copy_one(drm, args->src[i],
-				dma_addrs + nr_dma, pfns + i);
+		args->dst[i] = nouveau_dmem_migrate_copy_one(drm, svmm,
+				args->src[i], dma_addrs + nr_dma, pfns + i);
 		if (!dma_mapping_error(drm->dev->dev, dma_addrs[nr_dma]))
 			nr_dma++;
 		addr += PAGE_SIZE;
@@ -616,6 +624,7 @@ nouveau_dmem_migrate_vma(struct nouveau_drm *drm,
 	struct migrate_vma args = {
 		.vma		= vma,
 		.start		= start,
+		.pgmap_owner	= drm->dev,
 		.flags		= MIGRATE_VMA_SELECT_SYSTEM,
 	};
 	unsigned long i;

drivers/gpu/drm/nouveau/nouveau_svm.c

@@ -93,17 +93,6 @@ nouveau_ivmm_find(struct nouveau_svm *svm, u64 inst)
 	return NULL;
 }
 
-struct nouveau_svmm {
-	struct mmu_notifier notifier;
-	struct nouveau_vmm *vmm;
-	struct {
-		unsigned long start;
-		unsigned long limit;
-	} unmanaged;
-
-	struct mutex mutex;
-};
-
 #define SVMM_DBG(s,f,a...)                                                     \
 	NV_DEBUG((s)->vmm->cli->drm, "svm-%p: "f"\n", (s), ##a)
 #define SVMM_ERR(s,f,a...)                                                     \
@@ -246,7 +235,7 @@ nouveau_svmm_join(struct nouveau_svmm *svmm, u64 inst)
 }
 
 /* Invalidate SVMM address-range on GPU. */
-static void
+void
 nouveau_svmm_invalidate(struct nouveau_svmm *svmm, u64 start, u64 limit)
 {
 	if (limit > start) {
@@ -279,6 +268,14 @@ nouveau_svmm_invalidate_range_start(struct mmu_notifier *mn,
 	if (unlikely(!svmm->vmm))
 		goto out;
 
+	/*
+	 * Ignore invalidation callbacks for device private pages since
+	 * the invalidation is handled as part of the migration process.
+	 */
+	if (update->event == MMU_NOTIFY_MIGRATE &&
+	    update->migrate_pgmap_owner == svmm->vmm->cli->drm->dev)
+		goto out;
+
 	if (limit > svmm->unmanaged.start && start < svmm->unmanaged.limit) {
 		if (start < svmm->unmanaged.start) {
 			nouveau_svmm_invalidate(svmm, start,

drivers/gpu/drm/nouveau/nouveau_svm.h

@@ -1,11 +1,21 @@
 #ifndef __NOUVEAU_SVM_H__
 #define __NOUVEAU_SVM_H__
 #include <nvif/os.h>
+#include <linux/mmu_notifier.h>
 struct drm_device;
 struct drm_file;
 struct nouveau_drm;
 
-struct nouveau_svmm;
+struct nouveau_svmm {
+	struct mmu_notifier notifier;
+	struct nouveau_vmm *vmm;
+	struct {
+		unsigned long start;
+		unsigned long limit;
+	} unmanaged;
+
+	struct mutex mutex;
+};
 
 #if IS_ENABLED(CONFIG_DRM_NOUVEAU_SVM)
 void nouveau_svm_init(struct nouveau_drm *);
@@ -19,6 +29,7 @@ int nouveau_svmm_join(struct nouveau_svmm *, u64 inst);
 void nouveau_svmm_part(struct nouveau_svmm *, u64 inst);
 int nouveau_svmm_bind(struct drm_device *, void *, struct drm_file *);
 
+void nouveau_svmm_invalidate(struct nouveau_svmm *svmm, u64 start, u64 limit);
 u64 *nouveau_pfns_alloc(unsigned long npages);
 void nouveau_pfns_free(u64 *pfns);
 void nouveau_pfns_map(struct nouveau_svmm *svmm, struct mm_struct *mm,