[PATCH RFC 2/7] virtio-gpu-virgl: check page alignment of blob mapping

[Joelle van Dyne <j@getutm.app>]

Currently if a mapping is not page aligned, it will sliently fail and the
guest, assuming it is mapped, will attempt to access the memory and fail.
This is particularly an issue on macOS when the host page size is 16KiB and
the guest page size is 4KiB.

Signed-off-by: Joelle van Dyne <j@getutm.app>
---
 hw/display/virtio-gpu-virgl.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/hw/display/virtio-gpu-virgl.c b/hw/display/virtio-gpu-virgl.c
index 20c856c04e..adf02ac22b 100644
--- a/hw/display/virtio-gpu-virgl.c
+++ b/hw/display/virtio-gpu-virgl.c
@@ -116,6 +116,20 @@ virtio_gpu_virgl_map_resource_blob(VirtIOGPU *g,
         return ret;
     }
 
+    if (!QEMU_IS_ALIGNED((uintptr_t)data, qemu_real_host_page_size())) {
+        virgl_renderer_resource_unmap(res->base.resource_id);
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: address %p is not aligned to page size\n",
+                      __func__, data);
+        return -ENOMEM;
+    }
+
+    if (!QEMU_IS_ALIGNED(size, qemu_real_host_page_size())) {
+        virgl_renderer_resource_unmap(res->base.resource_id);
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: size 0x%llx is not aligned to page size\n",
+                      __func__, size);
+        return -ENOMEM;
+    }
+
     vmr = g_new0(struct virtio_gpu_virgl_hostmem_region, 1);
     vmr->g = g;
 
-- 
2.41.0