linux-kernel - [PATCH] vhost_vdpa: fix the crash in unmap a large memory

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Date:   Thu, 24 Nov 2022 14:23:09 +0800
From:   Cindy Lu <lulu@...hat.com>
To:     mst@...hat.com, jasowang@...hat.com, lulu@...hat.com,
        virtualization@...ts.linux-foundation.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] vhost_vdpa: fix the crash in unmap a large memory

While testing in vIOMMU, sometimes guest will unmap very large memory,
which will cause the crash. To fix this,Move the iommu_unmap to
vhost_vdpa_pa_unmap/vhost_vdpa_va_unmap and only unmap the memory
that saved in iotlb.

Signed-off-by: Cindy Lu <lulu@...hat.com>
---
 drivers/vhost/vdpa.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 166044642fd5..c392979702cf 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -692,6 +692,8 @@ static void vhost_vdpa_pa_unmap(struct vhost_vdpa *v,
 	struct vhost_iotlb_map *map;
 	struct page *page;
 	unsigned long pfn, pinned;
+	struct vdpa_device *vdpa = v->vdpa;
+	const struct vdpa_config_ops *ops = vdpa->config;
 
 	while ((map = vhost_iotlb_itree_first(iotlb, start, last)) != NULL) {
 		pinned = PFN_DOWN(map->size);
@@ -703,6 +705,8 @@ static void vhost_vdpa_pa_unmap(struct vhost_vdpa *v,
 			unpin_user_page(page);
 		}
 		atomic64_sub(PFN_DOWN(map->size), &dev->mm->pinned_vm);
+		if ((ops->dma_map == NULL) && (ops->set_map == NULL))
+			iommu_unmap(v->domain, map->start, map->size);
 		vhost_iotlb_map_free(iotlb, map);
 	}
 }
@@ -713,11 +717,15 @@ static void vhost_vdpa_va_unmap(struct vhost_vdpa *v,
 {
 	struct vhost_iotlb_map *map;
 	struct vdpa_map_file *map_file;
+	struct vdpa_device *vdpa = v->vdpa;
+	const struct vdpa_config_ops *ops = vdpa->config;
 
 	while ((map = vhost_iotlb_itree_first(iotlb, start, last)) != NULL) {
 		map_file = (struct vdpa_map_file *)map->opaque;
 		fput(map_file->file);
 		kfree(map_file);
+		if ((ops->dma_map == NULL) && (ops->set_map == NULL))
+			iommu_unmap(v->domain, map->start, map->size);
 		vhost_iotlb_map_free(iotlb, map);
 	}
 }
@@ -805,8 +813,6 @@ static void vhost_vdpa_unmap(struct vhost_vdpa *v,
 	} else if (ops->set_map) {
 		if (!v->in_batch)
 			ops->set_map(vdpa, asid, iotlb);
-	} else {
-		iommu_unmap(v->domain, iova, size);
 	}
 
 	/* If we are in the middle of batch processing, delay the free
-- 
2.34.3