Re: [PATCH v3 7/7] x86/kvm: use Enlightened VMCS when running on Hyper-V

[Radim KrÄmÃÅ]

2018-03-15 18:02+0100, Radim KrÄmÃÅ:
> We actually already have mov in the assembly:
> 
>   "cmp %%" _ASM_SP ", %c[host_rsp](%0) \n\t"

Oh hell, I didn't pay attention to this line before.

>   "je 1f \n\t"
>   "mov %%" _ASM_SP ", %c[host_rsp](%0) \n\t" // here
>   __ex(ASM_VMX_VMWRITE_RSP_RDX) "\n\t"

I bet this path is executed only once in VM's lifetime and what we're
doing is wasting more resources than we're ever going to save ...

>   "1: \n\t"