2 files changed, 19 insertions, 5 deletions
diff --git a/drivers/virt/vboxguest/vboxguest_linux.c b/drivers/virt/vboxguest/vboxguest_linux.c
index 82e280d..398d226 100644
--- a/drivers/virt/vboxguest/vboxguest_linux.c
+++ b/drivers/virt/vboxguest/vboxguest_linux.c
@@ -87,6 +87,7 @@ static long vbg_misc_device_ioctl(struct file *filp, unsigned int req,
 	struct vbg_session *session = filp->private_data;
 	size_t returned_size, size;
 	struct vbg_ioctl_hdr hdr;
+	bool is_vmmdev_req;
 	int ret = 0;
 	void *buf;
 
@@ -106,8 +107,17 @@ static long vbg_misc_device_ioctl(struct file *filp, unsigned int req,
 	if (size > SZ_16M)
 		return -E2BIG;
 
-	/* __GFP_DMA32 because IOCTL_VMMDEV_REQUEST passes this to the host */
-	buf = kmalloc(size, GFP_KERNEL | __GFP_DMA32);
+	/*
+	 * IOCTL_VMMDEV_REQUEST needs the buffer to be below 4G to avoid
+	 * the need for a bounce-buffer and another copy later on.
+	 */
+	is_vmmdev_req = (req & ~IOCSIZE_MASK) == VBG_IOCTL_VMMDEV_REQUEST(0) ||
+			 req == VBG_IOCTL_VMMDEV_REQUEST_BIG;
+
+	if (is_vmmdev_req)
+		buf = vbg_req_alloc(size, VBG_IOCTL_HDR_TYPE_DEFAULT);
+	else
+		buf = kmalloc(size, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
 
@@ -132,7 +142,10 @@ static long vbg_misc_device_ioctl(struct file *filp, unsigned int req,
 		ret = -EFAULT;
 
 out:
-	kfree(buf);
+	if (is_vmmdev_req)
+		vbg_req_free(buf, size);
+	else
+		kfree(buf);
 
 	return ret;
 }
diff --git a/drivers/virt/vboxguest/vboxguest_utils.c b/drivers/virt/vboxguest/vboxguest_utils.c
index bad9154..bf447421 100644
--- a/drivers/virt/vboxguest/vboxguest_utils.c
+++ b/drivers/virt/vboxguest/vboxguest_utils.c
@@ -65,8 +65,9 @@ VBG_LOG(vbg_debug, pr_debug);
 void *vbg_req_alloc(size_t len, enum vmmdev_request_type req_type)
 {
 	struct vmmdev_request_header *req;
+	int order = get_order(PAGE_ALIGN(len));
 
-	req = kmalloc(len, GFP_KERNEL | __GFP_DMA32);
+	req = (void *)__get_free_pages(GFP_KERNEL | GFP_DMA32, order);
 	if (!req)
 		return NULL;
 
@@ -87,7 +88,7 @@ void vbg_req_free(void *req, size_t len)
 	if (!req)
 		return;
 
-	kfree(req);
+	free_pages((unsigned long)req, get_order(PAGE_ALIGN(len)));
 }
 
 /* Note this function returns a VBox status code, not a negative errno!! */