On Mon, 21 Jun 2021 11:24:40 -0700, Nathan Chancellor wrote:

LLVM does not emit optimal byteswap assembly, which results in high
stack usage in kvmhv_enter_nested_guest() due to the inlining of
byteswap_pt_regs(). With LLVM 12.0.0:

arch/powerpc/kvm/book3s_hv_nested.c:289:6: error: stack frame size of
2512 bytes in function 'kvmhv_enter_nested_guest' [-Werror,-Wframe-larger-than=]
long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu)
     ^
1 error generated.

[...]

Applied to powerpc/topic/ppc-kvm.

[1/1] KVM: PPC: Book3S HV: Workaround high stack usage with clang
      https://git.kernel.org/powerpc/c/51696f39cbee5bb684e7959c0c98b5f54548aa34

cheers