drm/i915/gvt: Pin vgpu dma address before using

Dma-buf display uses the vgpu dma address saved in the guest part GGTT
table which is updated by vCPU thread. In host side, when the dma
address is used by qemu ui thread, gvt-g must make sure the dma address
is validated before letting it go to the HW. Invalid guest dma address
will easily cause DMA fault and make GPU hang.

v2: Rebase

Fixes: e546e281d33d ("drm/i915/gvt: Dmabuf support for GVT-g")
Acked-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Tina Zhang <tina.zhang@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20191212141342.3417-1-tina.zhang@intel.com

1 files changed, 59 insertions, 4 deletions

diff --git a/drivers/gpu/drm/i915/gvt/dmabuf.c b/drivers/gpu/drm/i915/gvt/dmabuf.c
index ee0f3094e6d0..2477a1e5a166 100644
--- a/drivers/gpu/drm/i915/gvt/dmabuf.c
+++ b/drivers/gpu/drm/i915/gvt/dmabuf.c
@@ -36,13 +36,32 @@
 
 #define GEN8_DECODE_PTE(pte) (pte & GENMASK_ULL(63, 12))
 
+static int vgpu_pin_dma_address(struct intel_vgpu *vgpu,
+				unsigned long size,
+				dma_addr_t dma_addr)
+{
+	int ret = 0;
+
+	if (intel_gvt_hypervisor_dma_pin_guest_page(vgpu, dma_addr))
+		ret = -EINVAL;
+
+	return ret;
+}
+
+static void vgpu_unpin_dma_address(struct intel_vgpu *vgpu,
+				   dma_addr_t dma_addr)
+{
+	intel_gvt_hypervisor_dma_unmap_guest_page(vgpu, dma_addr);
+}
+
 static int vgpu_gem_get_pages(
 		struct drm_i915_gem_object *obj)
 {
 	struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
+	struct intel_vgpu *vgpu;
 	struct sg_table *st;
 	struct scatterlist *sg;
-	int i, ret;
+	int i, j, ret;
 	gen8_pte_t __iomem *gtt_entries;
 	struct intel_vgpu_fb_info *fb_info;
 	u32 page_num;
@@ -51,6 +70,10 @@ static int vgpu_gem_get_pages(
 	if (WARN_ON(!fb_info))
 		return -ENODEV;
 
+	vgpu = fb_info->obj->vgpu;
+	if (WARN_ON(!vgpu))
+		return -ENODEV;
+
 	st = kmalloc(sizeof(*st), GFP_KERNEL);
 	if (unlikely(!st))
 		return -ENOMEM;
@@ -64,21 +87,53 @@ static int vgpu_gem_get_pages(
 	gtt_entries = (gen8_pte_t __iomem *)dev_priv->ggtt.gsm +
 		(fb_info->start >> PAGE_SHIFT);
 	for_each_sg(st->sgl, sg, page_num, i) {
+		dma_addr_t dma_addr =
+			GEN8_DECODE_PTE(readq(&gtt_entries[i]));
+		if (vgpu_pin_dma_address(vgpu, PAGE_SIZE, dma_addr)) {
+			ret = -EINVAL;
+			goto out;
+		}
+
 		sg->offset = 0;
 		sg->length = PAGE_SIZE;
-		sg_dma_address(sg) =
-			GEN8_DECODE_PTE(readq(&gtt_entries[i]));
 		sg_dma_len(sg) = PAGE_SIZE;
+		sg_dma_address(sg) = dma_addr;
 	}
 
 	__i915_gem_object_set_pages(obj, st, PAGE_SIZE);
+out:
+	if (ret) {
+		dma_addr_t dma_addr;
+
+		for_each_sg(st->sgl, sg, i, j) {
+			dma_addr = sg_dma_address(sg);
+			if (dma_addr)
+				vgpu_unpin_dma_address(vgpu, dma_addr);
+		}
+		sg_free_table(st);
+		kfree(st);
+	}
+
+	return ret;
 
-	return 0;
 }
 
 static void vgpu_gem_put_pages(struct drm_i915_gem_object *obj,
 		struct sg_table *pages)
 {
+	struct scatterlist *sg;
+
+	if (obj->base.dma_buf) {
+		struct intel_vgpu_fb_info *fb_info = obj->gvt_info;
+		struct intel_vgpu_dmabuf_obj *obj = fb_info->obj;
+		struct intel_vgpu *vgpu = obj->vgpu;
+		int i;
+
+		for_each_sg(pages->sgl, sg, fb_info->size, i)
+			vgpu_unpin_dma_address(vgpu,
+					       sg_dma_address(sg));
+	}
+
 	sg_free_table(pages);
 	kfree(pages);
 }