diff --git a/src/microsoft/vulkan/dzn_util.c b/src/microsoft/vulkan/dzn_util.c
index 7f9dac363ce..5c7750d9ac9 100644
--- a/src/microsoft/vulkan/dzn_util.c
+++ b/src/microsoft/vulkan/dzn_util.c
@@ -281,7 +281,7 @@ dzn_translate_viewport(D3D12_VIEWPORT *out,
    out->TopLeftX = in->x;
    out->TopLeftY = in->height < 0 ? in->height + in->y : in->y;
    out->Width = in->width;
-   out->Height = abs(in->height);
+   out->Height = fabs(in->height);
    out->MinDepth = MIN2(in->minDepth, in->maxDepth);
    out->MaxDepth = MAX2(in->maxDepth, in->minDepth);
 }