Re: [Xen-devel] [PATCH 1/4] VMX: streamline entry.S code

[Tim Deegan <tim@xxxxxxx>]

At 15:01 +0100 on 23 Aug (1377270100), Jan Beulich wrote:
> +ENTRY(vmx_asm_vmexit_handler)
>          push %rdi
>          push %rsi
>          push %rdx
>          push %rcx
>          push %rax
> +        mov  %cr2,%rax
>          push %r8
>          push %r9
>          push %r10
>          push %r11
>          push %rbx
> +        GET_CURRENT(%rbx)

I see this avoids a potential stall below, but OTOH it introduces an
explicit %rsp access into a string of push ops, which is frowned on
(IIRC there's special fast-forwarding of %rsp in chains of pushes).
I'd be inclined to leave it alone unless there's a measurable
improvement, since the code's more readable as-is.

Either way,

Reviewed-by: Tim Deegan <tim@xxxxxxx>

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