When Linux runs as the root partition, it will need to make hypercalls which return data from the hypervisor. Allocate pages for storing results when Linux runs as the root partition. Signed-off-by: Lillian Grassin-Drake <ligrassi@microsoft.com> Co-Developed-by: Lillian Grassin-Drake <ligrassi@microsoft.com> Signed-off-by: Wei Liu <wei.liu@kernel.org> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/20210203150435.27941-6-wei.liu@kernel.org