Re: [PATCH v2 7/9] KVM: x86/mmu: Add try_get_mt_mask to x86_ops

[Sean Christopherson]

On Mon, Apr 11, 2022, Sean Christopherson wrote:
> It's obviously not a hard dependency, but using a u64 for the mask here and then
> undoing the whole thing is rather silly.  Compile tested only at this point, I'll
> test on an actual system ASAP and let you know if I did something stupid.
> 
> From: Sean Christopherson <seanjc@xxxxxxxxxx>
> Date: Mon, 11 Apr 2022 15:12:16 -0700
> Subject: [PATCH] KVM: x86: Restrict get_mt_mask() to a u8, use
>  KVM_X86_OP_OPTIONAL_RET0

Verified this works as expected when patching in RET0 on a 32-bit kernel (returning
a u64 results in reserved bits in the upper half being set due to EDX not being cleared).