Re: [PATCH 03/22] x86/kvm: Fix frame pointer usage in vmx_vmenter()

[Paolo Bonzini]

On 15/07/19 02:36, Josh Poimboeuf wrote:
> With CONFIG_FRAME_POINTER, vmx_vmenter() needs to do frame pointer setup
> before calling kvm_spurious_fault().
> 
> Fixes the following warning:
> 
>   arch/x86/kvm/vmx/vmenter.o: warning: objtool: vmx_vmenter()+0x14: call without frame pointer save/setup
> 
> Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>

This is not enough, because the RSP value must match what is computed at
this place:

        /* Adjust RSP to account for the CALL to vmx_vmenter(). */
        lea -WORD_SIZE(%_ASM_SP), %_ASM_ARG2
        call vmx_update_host_rsp

Is this important since kvm_spurious_fault is just BUG()?  There is no
macro currently to support CONFIG_DEBUG_BUGVERBOSE in assembly code, but
it's also fine if you just change the call to ud2.

Paolo