Re: [RESEND PATCH 2/3] nouveau: fix mixed normal and device private page migration

From: John Hubbard
Date: Mon Jun 22 2020 - 20:31:10 EST


On 2020-06-22 16:38, Ralph Campbell wrote:
The OpenCL function clEnqueueSVMMigrateMem(), without any flags, will
migrate memory in the given address range to device private memory. The
source pages might already have been migrated to device private memory.
In that case, the source struct page is not checked to see if it is
a device private page and incorrectly computes the GPU's physical
address of local memory leading to data corruption.
Fix this by checking the source struct page and computing the correct
physical address.

Signed-off-by: Ralph Campbell <rcampbell@xxxxxxxxxx>
---
drivers/gpu/drm/nouveau/nouveau_dmem.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/nouveau/nouveau_dmem.c b/drivers/gpu/drm/nouveau/nouveau_dmem.c
index cc9993837508..f6a806ba3caa 100644
--- a/drivers/gpu/drm/nouveau/nouveau_dmem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_dmem.c
@@ -540,6 +540,12 @@ static unsigned long nouveau_dmem_migrate_copy_one(struct nouveau_drm *drm,
if (!(src & MIGRATE_PFN_MIGRATE))
goto out;
+ if (spage && is_device_private_page(spage)) {
+ paddr = nouveau_dmem_page_addr(spage);
+ *dma_addr = DMA_MAPPING_ERROR;
+ goto done;
+ }
+
dpage = nouveau_dmem_page_alloc_locked(drm);
if (!dpage)
goto out;
@@ -560,6 +566,7 @@ static unsigned long nouveau_dmem_migrate_copy_one(struct nouveau_drm *drm,
goto out_free_page;
}
+done:
*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)
@@ -615,6 +622,7 @@ nouveau_dmem_migrate_vma(struct nouveau_drm *drm,
struct migrate_vma args = {
.vma = vma,
.start = start,
+ .src_owner = drm->dev,

Hi Ralph,

This .src_owner setting does look like a required fix, but it seems like
a completely separate fix from what is listed in this patch's commit
description, right? (It feels like a casualty of rearranging the patches.)


thanks,
--
John Hubbard
NVIDIA